Hugo de VRIES
These pages are provided "as is", in the form they had when they were created, except for typographic corrections when found. Links are periodically checked for validity. Unfortunately, the memory of the WWW is very short, and links become obsolete fast. In this case they are deleted. This implies that original information is progressively lost, exactly as in human memory...
30 august
2006. The journal Cell reports a study where
researchers could alleviate
some of the memory defect in a mouse model of Alzheimer disease.
The research suggests that boosting the function of an enzyme known as
"ubiquitin C-terminal hydrolase L1", may provide a promising strategy
for counteracting Alzheimer's disease, and perhaps reversing its
effects. We are far from applications to human, but this is a
considerable step forward in the understanding of the disease. A
outbreak of cholera (frequent in summer time) is not contained in
Abidjan, Ivory Coast.
29 august
2006. The chikungunya outbreak is spreading in Southern
India, now clearly present in the district of Coimbatore in Tamil
Nadu.
26 august
2006. The Associated Press reports that Vietnam, which had
been free from bird flu for several months, has detected the disease
in ducks for the second time this month. The FAO points uncontrolled
poultry trade in the region as a major cause of the spread of the
disease. Plague continues to spread in a
very worrying way in the region of Ituri in Congo.
24 august
2006. A completely new strategy might help fighting the AIDS
virus. Nature Medicine (DOI: 10.1038/nm1482) reports that a
team of investigators from the Université de Montréal and the Centre
hospitalier de l'Université de Montréal observed that the
immunocompetent cells fighting HIV (killer T cells) make more of a
protein called PD-1 when then begin to lose their killing capacity and
that this protein acts as a control of the cells behaviour. One could
design drugs counteracting the effect or the synthesis of this protein
to boost the immune response. There is still a long way until a drug
is applicable however, as the protein exists in many tissue,
suggesting that impairing its function might have deleterious effects.
23 august
2006.Ticks are vectors of many diseases in addition to
Crimean-Congo fever. In particular they carry bacteria of the Borrelia
genus, causing borreliosis, Lyme's disease being the most well-known
such disease in developed countries. Recent investigations in Senegal
have shown a very high incidence of borreliosis (more than 10% on a
yearly basis), often mistaken for malaria, as it results in a cyclic
pattern of fever. This rises the question of the overall incidence of
the disease in Africa as a whole, as
reported by allAfrica.com and this shows that the role played by
ticks is probably underevaluated there.
22 august
2006. Turkey is witnessing a fairly large outbreak of
Crimean-Congo fever, with 24 deaths since the beginning of the year.
20 august
2006. The Kathmandu Post reports that an unknown disease
causing fever and bleeding has killed at least 14 people in the
district of Nuwakot in Nepal. The disease appeared to have first
appeared in dogs and chicken. This is reminiscent of symptoms of
Crimean-Congo fever.
18 august
2006. Several reports suggest that many people in the Garut
District of West Java Province have shown flu like symptoms. Two died
recently and are being investigated. There is no evidence so far of
human to human contamination, but, if confirmed this cluster is
worrying.
14 august
2006. West Siberia is still witnessing outbreaks of avian
flu, now in the Tomsk district, with domestic
pigeons infected. Bangalore does not see chikungunya receding as Aedes
mosquitoes continue to breed in the region and transmit the disease.
It is likely that one million people have been infected in Southern
India since the beginning of the year.
12 august
2006. The Scientist reports a remarkable discovery in
cancerology. At least in dogs, tumor cells can be efficiently sexually
transmitted, and propagate tumors through generations. The canine
transmissible venereal tumor (CTVT) is present in dogs world-wide, and
it correponds to cells that do not belong to their host, but were
probably present as early as the time when dogs were domesticated.
Dogs also make the headlines in China, where an epidemic of rabies has
triggered culling (usually by hanging) of many dogs in the Yunnan
province.
27 july
2006.It may be that as many as eleven more bird flu cases are
recorded in Thailand's lower northern province of Phichit. 44 persons
are under surveillance for H5N1 flu in Thailand. Poultry is dying in
Laos, and bird flu is suspected. If these cases are confirmed this
will be reported by the major media and we shall not further document
that here.
25 july
2006. According to the Xinhua news agency four provinces in
Thailand have been declared "red zones" for dengue fever. This
situation is of great concern as, simultaneously there appears to be
several cases of human H5N1 flu in Phichit one of the red zone
provinces, while symptoms are superficially similar to those caused by
flu. A puzzling case of Lassa hemorrhagic fever has been diagnosed in
a previously sick patient who travelled from Sierra Leone to Belgium
and Germany. All persons who may have had contact with the patient
have been contacted.
22 july
2006. The number of arthropods-borne haemorrhagic Crimean-Congo
fever cases is increasing in Turkey. Travellers are advised to
beware of tick bites.
21 july
2006. According to Reuters news agency Bulgaria has detected
bird flu in three farms. The identification of the virus is underway.
19 july
2006. First reported in December 2005 in Andhra Pradesh,
chikungunya which began as an urban phenomenon, caused by mosquitoes
of the Aedes genus ("tiger" mosquito) has spread rapidly to
1,408 villages in Southern India. The actual number of cases is not
known but is probably very high.
14 july
2006.In Thailand, hundreds of birds, including poultry, have
died from unknown causes in the eastern province of Chachoengsao over
the past week, triggering an investigation over avian flu.
13 july
2006. Partial sequences of the
H5N1 virus hemagglutinin gene from Nigeria is now available at the
INSDC. Mutations in the gene will help tracing the origin of the
virus, as there is still ongoing discussion whether it was brought in
Africa by migratory birds or by imported chicken from Asia. At least
two independent origins were found as published
last week. The magazine Nature, basing a news report on
confidential genetic sequence data — something quite unusual and
departing from appropriate scientific information — shows that the
H5N1 virus mutated multiple times as it spread through an Indonesia
family last May. This is in line with what has been observed
previously with the
evolution of the SARS coronavirus, but the functional meaning of
that particular evolution is unclear: it is not possible as yet to see
whether the virus would evolve to favour further human to human
contamination. An outbreak of legionellosis is affecting Amsterdam.
8 july 2006.
An outbreak of African swine fever is affecting West and North-West
Cameroon. This disease is caused by a DNA virus of an uncharacterized
type which could be related to Iridovirus and Poxvirus.
It results in high mortality, in particular in young pigs. In general
pig diseases should be monitored very carefully as they might be
source of emerging human diseases. In this case, the similarity with
Poxvirus should be a matter of concern as the infamous small pox virus
belongs to that family. The reservoir of the virus could be wild
African warthogs and bush pigs, where it does not cause much symptoms.
The virus can survive a very long time in contaminated environment. A
great creted grebe has been found infected with the H5N1 flu virus in
Spain.
7 july 2006.
Avian flu has been introduced independently several times in Nigeria.
Although this correlates with some routes of migratory birds the cause
of the outbreaks could still be poultry smuggling. Two interesting
works published in Neuron are likely to have demonstrated that
Down's syndrome is due to a single genetic locus. Most of the impact
of trisomy 21 would be that
reduced retrograde transport or signaling of the neurotrophins NGF
or BDNF account for the mouse model of the disease. This defect
apparently causes degeneracy of a particular class of cholinergic
neurons.
4 july 2006.An
outbreak of the tick-borne
Crimean-Congo Haemorrhagic Fever is affecting the Volgograd
region in Russia. This dangerous disease in lingering in this
part of the world as it was recently found
in Pakistan.
2 july 2006.After
the meeting of the First International Conference on Avian Influenza
in Humans at the Institut Pasteur, the third ministerial meeting of
the Ayeyawady (Irrawaddy)-Chao Phraya-Mekong Economic Cooperation
Strategy (Acmecs) convenes in Laos tomorrow. It will discuss the
situation of avian flu in this part of the continent as Laos has not
reported any outbreak yet, while surrounding countries have. The
Institut Pasteur is part of the reflection on the subject. Research in
progress might put the bird flu scare away: ferrets immunised against
a 2003 form of the virus were protected against the letal action of
more recent forms. If extended to humans this would allow preemptive
action and prevent creation of a pandemic. The virus is now present in
the Taraba state in Eastern Nigeria.
1 july
2006. A new outbreak of H5N1 avian influenza among birds
affects a town in the northwestern region of Ningxia.
28 june 2006. Bird flu is still on the
rise in Siberia, now in the republic
of Tyva.
24 june 2006.The Hong Kong Health
Authority has set up an enhaced surveillance programme on infections
that could be related to avian flu since a human case of avian
influenza H5N1 was discovered recently in Shenzhen. Yesterday
the authority had recorded 102 cases (61 male, 41 female, aged 2
months to 89 years) have been received, an increase of 12 cases on the
day before. These patients have visited Guangdong, Hunan, Hubei,
Fujian and Zhejiang before the onset of symptoms. Sporadic clusters of
human to human transmission of
bird flu have occurred in the past and recently in Indonesia, but,
fortunately the virus did not evolved in a significantly more
efficient form. Widespread vaccination of birds may help control the
disease, as in Vietnam, but it also results in missing one major
indicator of its spread, as mass dying of birds disappears. In Europe,
tick-borne infection by Borrelia
burgdorferi and related bacteria (Lyme disease, a
disease somewhat similar to syphilis in its clinical manifestations)
may be spreading. Unfortunately many European countries do not have
time-series of epidemiological reporting of the disease. 14 june
2006. Since mid-may a pulmonary infection that appears to be
pulmonic plague has killed more than 100 people in the province of
Ituri, North East of the Republic of Congo. The plague bacillus is
endemic in the region at least since february. Data are difficult to
obtain as the region is extremely unsecure. Plague, which is present
in many parts of the world in rodents kills between 1000 and 3000
persons every year.
13 june 2006. China reports a new
suspected human bird flu case in Guangdong province, while an outbreak
in Northern Ukraine leads to mass culling of poultry. The season of
hanta virus infection in the US might be starting at a high pace.
9 june 2006. For several weeks now an
unusual strain of Escherichia coli O157H7 is lingering in the
United Kingdom, where it has caused several severe outbreaks (in
Scotland and in England). This sorbitol fermenting strain, which has
been isolated for the first time in Germany in 1988, does not readily
grow on usual selective media meant to isolate this family of toxin
producing pathogens. It may therefore be more widely spread than
presently assumed. pitalized with flu-like symptoms associated to
lower-limb weakness. Legionellosis is affecting the region of Pamplona
in Spain.
1 june 2006. The chikungunya virus has
probably reached Chennai (Madras) in South East India.
28 may 2006. The way the bird flu
virus is spreading and becoming endemic in the world reflects in a
vivid way the underlying political situation, with some link with the
ecological status of the local region. Romania had to kill more than a
million birds in the past few weeks, and it does not contain the
disease. In the same way the disease is spreading in south west
Siberia, now in
Altaj. This may be linked to bird migration, but most probably
associated to poor control of people's behaviour in the region. This
is in contrast with the situation in Vietnam, where the authorities,
despite the presence of many outbreaks, were able to put the disease
under control. In Africa, as no wild bird is infected, it is clear
that smuggling is the major cause of the spread of the disease, which
is now regularly present in Nigeria, Ivory Coast and Burkina Faso (it
is likely that it is present elsewhere as well). In Indonesia, the
situation is a matter of great concern as not only outbreaks appear
repeatedly, but as some outbreaks may be related to local genetic
susceptibility to the disease (as likely witnessed in the recent death
of several persons in an extended family).
21 may
2006. Seven person of a same family were contaminated by the
dangerous tick-borne haemorrhagic fever Crimean-Congo virus in a
mountain village in Pakistan. One passed away. The H5N1 virus is
present again in Denmark, and the family cluster in Indonesia points
to particular genetic sensitivity. The virus is also present in
Moravia and in Czech republic.
20 may 2006. A cluster of seventeen
cases of trichinellosis, one with neurological consequences, detected
among members of an extended family living in the state of
Mecklenburg-Vorpommern, eastern Germany, reminds us that parasites are
still a matter of great concern, in particular in countries breeding a
considerable number of pigs, such as China. The parasite, Trichinella
spiralis, after crossing the stomach, develops first in
muscle tissue of carnivorous or ominivorous animals, where it causes
pain. It subsequently invades other tissues, progressively
invalidating the host. Bird flu
extended to the province of Novosibirsk on may 16th.
14 may 2006. In contrast with analysis of mutations of
the H5N1 virus from Vietnam and neighbouring countries, indicating
that the virus is resistant to adamantanes, a new study from the
University of Hong Kong shows that most viruses from China and
Indonesia are sensitive to these drugs, improving our arsenal to treat
the disease in the case of a pandemic. Some improvement of the vaccine
against the virus (addition of adjuvants) has been published in this
week's Lancet. Work published last year at the ICDDRB in
Bangladesh, shows that
cholera epidemics are probably related to a dynamic of invasion
of the bacteria, followed by mass destruction of the newly developing
strain by bacteriophages. This was the hypothesis at the basis of
bacteriophage therapy of infectious diseases proposed by
Félix d'Hérelle.
12 may 2006. One third of the Comorean
population appears to have been infected by the Chikunguya virus. The
archipelago is located north-west of Madagascar and north-east of
Mozambique. It seems therefore likely that the virus is lingering in
Madagascar, located between Comoros islands and the island of La
Réunion. The spread of the virus might have retarded identification of
bird flu in Djibouti, where a young girl has been found with the
disease.
8 may 2006. Bird flu is still present
in three provinces of South West Russia, where more than 30 million
birds have been slaughtered. The variant present there appears to be
the variant that appeared
last year in the Qinghai Lake district.
The controversy
about the origin of the disease in Africa is more and more often
pointing to a human origin, through contamination of by contaminated
chicks smuggled from China. Cholera has now killed more than 1000
persons in Angola.
29 april 2006. Frightening diseases
such as those caused by the Ebola or Marburg viruses do not have a
considerable impact on the human population at large. This means that
there is no pressure for the development of a vaccine that would be
commercially viable. However, when there is an outbreak, the medical
personnel is in great danger, while it can also be a factor of
contagion, and it is therefore of the utmost importance to protect
doctors and nurses from getting infected. A vaccine has been shown
last year to be fully effective in protecting monkeys from both
viruses. Now, The Lancet reports a study showing that a vaccine
was active after being injected to monkeys 30 minutes after
infection. This is of course remarkable, as this could be used by
medical or research laboratory personnel in case of suspected
contamination. The mode of action of the protection is not yet
understood, and monkeys are not humans, so that much work still needs
to be done to develop the vaccine, but this is a promising information
for the rapid control of a deadly disease.
28 april 2006. Huang long bing (yellow
dragon disease) has eradicated cultivated citrus trees is some parts
of Asia. This disease, caused by an uncultivated bacterium tentatively
named Liberibacter asiaticus, causes citrus greening,
considerably altering the development of the trees. The disease may
now be spreading in America, where it will add to the destruction
promoted by Xanthomonas campestris pv citri (causing
citrus canker) or by Xylella fastidiosa.
27 april 2006. Two outbreaks of the
H5N1 avian flu have been uncovered in the outskirts of Abidjan, Ivory
Coast. The disease seems also present in East Africa, in Mozambique.
26 april 2006. After the infamous
"envelopes" with anthrax spores sent to US administration (the origin
of which, american, not yet publicly revealed), it became particularly
important to find an antidote to the most serious toxin (the "letal"
toxin) of the bacteria. The magazine Nature Biotechnology, publishes
interesting results which show that lipid vesicles, liposomes,
containing peptides chosen to interact and neutralise the toxin, can
be demonstrated to be active in vivo in an animal model. This same
study has been extended to the cholera toxin, and here again, it
appears to work as an excellent antidote.
20 april 2006. Since mid-march a
severe outbreak of cholera is affecting Angola, while several cases
have been reported in Cameroon. An International Course on Emergency
Response to Cholera and Shigella Epidemics is ending at the Sasakawa
International Training Centre, ICDDR,B, Dhaka, Bangladesh. The purpose
of this course is to strengthen the capacity of international
organizations and NGOs in managing epidemics due to cholera and
shigella following disasters. Avian flu reached Sudan.
16 april 2006. The disease that
killed chicken near Bondoukou, Ivory Coast, is probably not bird flu.
A new outbreak is affecting Pakistan.
15 april 2006. Avian flu may have
reached the north-east of Ivory Coast, in the region of Bondoukou. A
suspect human case is investigated in Denmark. The way the virus is
propagated in the world is not clear, and there is much discussion
about the relative contribution of fowl smuggling and migratory birds.
Strict measures that would restrict destruction of wetlands and
marshes would certainly limit contact between Anatidae, the birds most
affected, and poultry. A new epidemic of fever affects Maurice; it
looks like chikungunya in its symptoms, but has a shorter course.
13 april 2006. Dengue fever, which
was somewhat less intense last year in Vietnam than preceding years is
on the rise again, with 20% more cases since the beginning of the year
than at the same time last year. The capacity of malarial infection to
suppress the patient's immune responses both to the parasite and to
other antigens has long puzzled researchers. It has now been
demonstrated that the pigment hemozoin inhibits the major sentries of
the immune response, dendritic cells. Hemozoin is a crystalline
substance produced in the digestive food vacuole of blood-stage
malaria parasites formed from the heme group that makes the red color
of hemoglobin. An undiagnosed apparently contagious disease has
affected high school students in the province of Shanxi at the end of
march and one student died of the disease, which is apparently is
neither SARS nor influenza. The only reported symptom is high fever,
so that it is impossible to have an idea of the cause of the disease.
10 april 2006. The annual epidemic of
meningitis is affecting sahelian region (Burkina Faso and Niger where
a vaccination campaign is underway.
7 april 2006. Chikungunya is
spreading in southern India, with some 40,000 people infected in
several places. It is likely that the epidemic will reach considerable
proportions, knowing the enormous population of India. A remarkable
discovery published in Nature yesterday has uncovered in
insects a gene coding for a protein responsible for enacting movements
(a particular type of myosin) which controls symmetry in the animal.
We all remember that Pasteur, when working as a chemist, discovered
that life was strongly associated to asymmetry ("asymmetry is life")
as the hallmark of life; indeed, at the molecular level there is a
disproportionate number of one form of a molecule with respect to its
mirror-symmetrical counterpart. And, as a matter of fact, we are not
spheres. Animals are constructed on two major axes, the
antero-posterior axis, which defines the head and the tail, and the
dorso-ventral axis which defines the back and the face of the
organism. There is a third axis, which defines how organs are
distributed inside the body. Most of us have their liver on the right
and their heart on the left. In a rare condition, named situs
inversus viscerum, the place of the organs is reversed. It is
not yet clear whether the discovery in insects will extrapolate to
vertebrates, but the discovery of some elements of the control of the
third axis of development of the embryo is fascinating.
6 april 2006. The Aedes
mosquito-borne viral fever chikungunya is affecting several hundred
persons in a coastal village of Malaysia. It is also present in India.
Bird's flu continues slowly expanding in the world. After West Africa,
new cases are found in Egypt, Cambodia, Indonesia (where it is now
well established, and where, unfortunately, authorities burn alive all
kinds of birds including species on the verge of extinction, without
discrimination nor evaluation of risk). Until recently, the standard
"humanisation" of the influenza virus is from
ducks to pigs to humans. We need to consider now another
possible route that should be monitored carefully, from chicken, to
domestic cats, to humans, as the number of infected cats is on
the increase everywhere (felines
have been known to be infected very early on).
4 april 2006. An outbreak of avian
flu is affecting Gampèla, 15km east of the capital, Ougadougou,
Burkina Faso.
2 april 2006. An imported case of
chikungunya viral infection has been diagnosed at the Prince of Wales
Hospital in Hong Kong, affecting a man just returning from Mauritius.
Hong Kong is regularly affected by dengue fever episodes, the virus of
which is also transmitted by mosquitoes of the same family (Aedes) as
that which transmits chikungunya.
1 april 2006. An interesting study
published by the fashionable magazine Nature will reignitate
the debate about the meaning of the widely spread Intellectual
Quotient (IQ) and its relation to human intelligence. While what IQ
measures is indeed controversial (the best definition of intelligence
is the number of backward steps a person can go to infer causes of an
observable, as defined by Jean Piaget, something that can only be
indirectly related to IQ) it is of considerable interest that there is
a strong correlation between the measure of IQ and the physical
development of human-specific brain structures. One important feature
of this work is that it shows that IQ is related to brain development,
from childhood to adolescence, with a strong correlation with the time
when the skills of language and writing are acquired and developed,
suggesting a correlation between brain development, skills measured by
IQ, and, for example the active vocabulary available to a person (i.e.
the number of the words that spontaneously come to mind at a given
time to speak about something). As can be expected, this emphasizes
not the genetic background of a person, but its epigenetic unfolding,
a property that, unfortunately, is not widely understood by those who
either emphasize the role of genes or the role of the environment in
the becoming of a human being.
30 march 2006. The
first study of a human vaccine similar to the annual vaccine against
the influenza virus H5N1 is somewhat disappointing as it showed
that only half of the inoculated persons would be protected, even with
a fairly large dose. However this result is promising as protection
was demonstrate, suggesting that more complex protocols (such as
including an H5 component in the annual usual vaccine) might be
rewarding.
29 march 2006. Creation of Genetically
Modified Organisms may have interesting outcomes: an American
group of investigators created pigs that are able to transform part of
their omega-6 fatty acids into the omega-3 variety. These animals will
be used as models to understand better the role of these fashionable
lipids in the well-being of animals (and perhaps humans). It can be
predicted, if the outcome is positive, that these animals will soon be
used for human consumption! Avian flu is continuing to spread: now in
a kibboutz in Israel and in Jordan, while the situation in sub-Saharan
Africa remains difficult to monitor. A surge in tuberculosis is
witnessed in Kenya where more than 100,000 people were affected by the
disease last year.
23 march 2006. As in the case of the
infamous SARS coronavirus, a kind of which infected pigs in a
1983-1984 episode by changing tropism from
the intestine to the lung, the H5N1 influenza virus shifts
tropism from birds' gut to human lungs. This accounts for the
contamination spread by some migratory birds as the virus is stable
for some time in birds' dejections. It is therefore important to
monitor the way the virus attaches to epithelial cells. The viral
hemagglutinins (the "H" marker in H5N1) bind to host cell receptors
decorated by complex sugars with a terminal acidic end, sialic acid
which attaches to the sugars via a variety of specific links. Avian
viruses bind to receptors of intestinal cells with a-2,3-linked
sialoglycan, while human flu viruses are usually specific for the 2-6
sialoglycan link of the lungs cells. It is therefore expected that a
change in the receptor binding properties of the avian virus will lead
to a virus which would communicate between humans in their respiratory
tract. An intermediate host is possible, as often the case and
pigs are important candidates as they interact often both with humans
and with birds in small farms. Monitoring the change of tropism
between the digestive tract and the respiratory tract is therefore of
the utmost importance. Two research international collaborations have
independently uncovered the target of the H5N1 virus in humans deep in
the lungs, explaining why human patients do not shed the virus in the
environment.
21 march 2006. The H5N1 flu outbreak
that recently affected the south of Israel (where two more sites have
been found in the Negev desert) is likely to have been brought in by
somebody coming from Egypt (contaminated shoes or clothes are the
likely vector). Flu is confirmed in Myanmar, Pakistan, Afghanistan and
Denmark. Five persons died of the disease in Azerbaijan and one in
Egypt.
18 march 2006. In line with our
concern, avian flu is on the rise in Africa: more than 200 cases of
suspect birds deathshave been recorded in Tshikapa, Congo Democratic
Republic, Kasaï province (centre) and in Kinshasa-Kingabwa six pigeons
and a cat which ate one of the pigeons have been found dead. Congo is
also witnessing a cholera epidemic in the region of Uvira (South
Kivu). The familial cases of flu uncovered in Azerbaijan were indeed
caused by the H5N1 virus. Fortunately, this was not the result of
interhuman contamination. Human cases keep being recorded in
Indonesia. In Denmark, a wild common buzzard (Buteo buteo) was
found contaminated on Svinø beach on the southern coast of the island
of Zealand. The question of a possible pandemic remains open if one
considers that, despite the fact that there has never been any human
flu caused by a H5 virus (the only recorded cases are the result of
direct contamination from birds), the descent of the virus groups
together the H5 marker, with markers H1 and H2, both at the origin of
a pandemic (1918 and 1957).
12 march 2006. Poliomyelitis, which
had been almost eradicated in 2001 thanks to the WHO eradication
programme, when less than 500 cases were recorded worldwide, is on the
rise again, mainly due to sub-optimal vaccine coverage. Several large
outbreaks were recorded recently in Yemen, Somalia and Indonesia
(almost 2000 cases have been reported in 2005). As can be seen this
covers areas where the avian flu H5N1 is now setting up and probably
becoming endemic (Africa has now cases in the south of Nigeria – in
fact in 11 out of its 37 states – and the north of Cameroon),
demonstrating that it will be impossible to control dangerous diseases
reservoirs in the near future even when vaccination is available
because of poverty and political instability. Polyomyelitis is
particularly illustrative as the reservoir is Man. As is unfortunately
common during this hot and dry season, Burkina Faso is affected by an
outbreak of bacterial meningitis.
10 march 2006. "Vaccinating"
mosquitoes against a disease they transmit has long been a dream. This
is now reality for one type of dengue viruses. American
scientists have succeeded in reprogramming the genome of Aedes
aegypti mosquitoes so that they would destroy the dengue virus
as it replicates. The idea was to use an in-built mechanism of animal
cells which controls the amount of RNA when it is forming a double
helix (which is not the most usual functional form of RNA) by cutting
it into pieces. Indeed the dengue virus has an RNA, not a DNA genome
and it must replicate it, going transiently through a double helix
form. As the genetically modified mosquitoes have already seen part of
that double helix (this is what is reprogrammed to be expressed from
their genome), they destroy the replicative form of the virus. The
long term idea, now, is to replace the population of contaminated
mosquitoes by the new ones, a strategy that has been successfully used
(in a different way however) to control the transmission of the New
World screwworm fly Cochliomyia hominivorax when it invaded
North Africa. From 2002 to 2005, 21 countries which were previously
polio-free were affected by cases imported from what were the six
remaining six countries with endemic wild polio virus (WPV) type 1
circulation (Afghanistan, Egypt, India, Niger, Nigeria, and Pakistan).
Most of these were from Nigeria, while three importations were from
India. For eight countries, imported WPV cases did not result in
sustained transmission, but in the remaining 13, WPV caused multiple
outbreaks. In 2005, 1983 cases of poliomyelitis were reported
worldwide, and 50 were caused by vaccine-derived polioviruses.
9 march 2006. Evidence seems to be
accumulating showing that Aedes mosquitoes are not only the vectors
for the chikungunya virus, but also one of their reservoirs. This
opens a new avenue for investigating reservoirs of vector-borne
pathogens such as the widespread dengue virus.
6 march 2006. While, dengue fever is
highly active in the island, the chikungunya virus is confirmed in
Madagascar. The size of the island will probably make it
uncontrollable for a fairly long period of time.
4 march 2006. The Department of Health
of Hong Kong has informed on march 3rd that a 32-year old man most
probably died from bird flu in Guangzhou (Canton). A man died of the
disease recently in Iraq, and an outbreak is affecting Azerbaijan
again, where the governement decided to cull 500,000 birds. In Burkina
Faso (West Africa), fowls are dying massively west of Ouagadougou.
This is probably not due to avian flu however. The WHO will convene on
march 6th, an international meeting to discuss influenza pandemic
containment strategy.
28 february 2006. For the first time,
an experimental
study has demonstrated a direct genetic effect on the brain
sexual dimorphism that is not mediated by the sole effects of gonadal
hormones, as believed until now. The product of gene SRY, which is
specific to the male chromosome Y is expressed in the brain and
controls synthesis of the important neuromediator dopamine. Present in
Europe in Sweden, and probably the cause of the death of a cat in an
island of Northern Germany, avian flu is likely to have reached Niger
and Ethiopia in Africa.
26 february 2006. The epidemic of
chikungunya virus (a member of Togaviridae) infection affected at
least one person in six in the island of La Réunion. Starting for
Comoros Islands early 2005 it spread also to Ile Maurice and Mayotte
and is behind a recent mystery fever in the state of Andrah Pradesh in
India. It is not yet clear whether it has affected Madagascar, but
this looks inevitable (cases have even be recorded in France, from
persons infected in La Réunion). The disease was first identified in
East Africa in 1953 and is transmitted by mosquitoes (typically of the
Aedes group). Its reservoir is not known but may be primates of
tropical African forest. The reasons for the recent epidemic are not
clearly understood, although it is apparent that people in La Réunion
were often reluctant to see their places spread with insecticides. The
virus has regularly been the cause of outbreaks in Asia, as far as
Thailand and Indonesia. As often the case, it is not understood how
the virus can reappear after several years of silence. One must
probably include Swizerland in the list of European countries affected
by avian flu... An
interesting study from the USA and Germany shows that vitamin D
is important to stimulate the innate immune response against the
bacilli responsible for tuberculosis. This study is not only
interesting because it explains at least in part the larger
susceptibility of Afro-Americans to the disease (they have less
vitamin D in their blood stream), but also because it reminds us that
mice are not a good model to describe some of the aspects of innate
immunity in Man.
25 february 2006. The enormous
emphasis by media on avian flu may trigger inappropriate responses and
may mask other outbreaks (this was the case, back in february 2003 at
the onset of the large SARS epidemic). While we know that we will be
able to construct a vaccine if and when a variant of the bird's virus
will propagate between humans, the way we will construct the vaccine
should be considered with extreme care. Our best experience is with
vaccines built using fertilized eggs, but the enormous amount of doses
needed to get enough eggs will pose a serious logistics problem. This
is why many advocate the use of animal cell cultures: we should exert
in this domain the utmost care, as cell cultures are prone to
propagate many unknown viruses, and, of course prions (the cause of
Transmissible Spongiform Encephalopathies, such as the Mad Cow
disease). This is of particular concern, as TSE's incubation time is
extremely long, sometimes several decades. In the mean time
surveillance may have useful outcomes: for example the Centre for
Disease Control in Taiwan, while implementing measures to control
persons entering the country with high fever (infrared cameras
monitoring) in the hope to control H5N1 flu, detected several cases of
dengue fever, thus showing that the latter disease needs to be
monitored seriously.
20 february 2006. Correlation is not
cause: this should be repeated again and again. The fact that
migratory birds have been identified carrying the H5N1 virus does not
mean that they are the cause of the spreading of the disease: they are
simply sentries showing that the disease is present. In fact the
presence of the disease is tightly linked with widespread fowl trade
and large breeding centers (where one finds also other influenzae,
such as H7N7 or H5N2). Remarkably, the disease did not spread in
countries where there is a tight control on poultry trade. Large
aviaries often breed highly consanguinous animals, and it is expected
that this creates a dangerous niche for animals susceptible to
emerging diseases.
19 february
2006. Until now the spread of human influenza in Europe is
on the low range, but not exceptionally low (the widespread
vaccination of people afraid by the H5N1 virus and who thought they
might be protected by a vaccine against a somewhat similar virus might
have played the role of herd protection, however the statistics do not
support that hypothesis). This is of interest as the avian flu virus
H5N1 is spreading throughout Europe, raising fears that it might
infect somebody already infected by human flu and allowing
recombination into a new virus (see the analysis
of the H5N1 virus origin back in 2001). This year it corresponds
in Europe to two virus types, A and B, with A of the H1N1 and H3N2
types, with many different variants.The distribution in the USA is
totally different, with only a very small proportion, this year, of
type B viruses. It may be useful to recall some of the facts about the
influenza virus, a usual commensal of birds, with preference for
Anatidae (ducks and geese). This cytopathic
orthomyxovirus is made of 8 single stranded RNA fragments (7 for
influenza C), making enveloped virions 80-120nm in diameter. The RNA
is associated into a helical structure with a nucleocapsid protein
(NP). NPs can be separated by immunochemical techniques into three
types, A, B and C, which makes the classification of human influenza
viruses. Four major antigens are recognized by the infected hosts, the
hemagglutinin, made of two subunits which mediate the attachment of
the virus to the host cells (the "H" symbol in H3N2 or H5N1),
neuraminidase (N), the nucleocapsid protein (NP), and the matrix
protein (M). Other components are less interesting from the
immunological point of view but are extremely important for the
multiplication (and hence virulence) of the virus. This is the case of
the subunits of the polymerase. Type B and C
viruses are specific to humans: they have probably evolved from a
bird's virus origin, but adapted to humans and now infect people on a
regular basis. Influenza A is most probably still in its adaptation
phase, being continuously transmitted from birds to mammals, usually
via the food chain (for humans this means breeding practices, with the
standard route from ducks to pigs
to humans, at least at the time of small farms).The usual cycle
has been: a large-scale epidemic followed by one or several decades of
adaptation of the virus with milder epidemics in parallel with
evolution of the major antigens of the virus, then a new large-scale
epidemic etc. It appears that pandemics are usually associated with a
change in the H antigen: the Spanish flu of 1918-1919 was due to a
H1N1 virus (the progeny of which is probably still circulating, after
several decades of disappearance), the 1957 episode was H2N2 and the
Hong Kong flu of 1968 was caused by a H3N2 virus, the progeny of which
is still active world-wide.The cause of this particular kind of
variation is still not completely understood: it may result from
reassortment/recombination of two viruses in a common host (animal or
human), from revival of a virus circulating at a low level in the
human population somewhere and taking the opportunity of the
population becoming susceptible again after a few decades, or from a
direct transmission from animal to humans of an animal adapted virus.
The latter hypothesis appears to fit with many emerging diseases such
as SARS for example. In that case, the fact that no known human flu
epidemics was caused by a virus of type H5 would not mean that it
cannot spread to humans in a transmissible fashion.The virus has now
reached Iran and India and is probably present at several places in
Africa, not only in Nigeria, but also in Egypt and perhaps in Niger.
17 february 2006. Dengue fever is on
the rise in South East Asia and in Yogjakarta in Indonesia, and the
epidemics sometimes overlaps with that of avian flu. Newcastle disease
kills many birds in Turkey and Ukraine, also overlapping with avian
flu. A patient probably died from the disease in Iraq. Iran is
affected. Many birds have been infected throughout Europe (noticed
mostly in wild swans as they are bid animals, easy to spot when dead).
Retrospective analysis and surveillance in different parts of the
world indicate that the virus is well established in South East Asia
and China, where it evolves slowly and infect mammalian predators and
scavengers. No human to human contamination has been noticed yet.
France will vaccinate its poultry in some areas in the South of the
country using a H5N2 vaccine produced by the company Intervet and
assumed to provide wide protection against the H5 type viruses.
Scientists are investigating family clusters, apparently somewhat more
frequent than expected, to explore whether there is a genetic
contribution to sensitivity to the disease. The numbers are small
however and probably not statistically significant.
13 february 2006. There is no need to
write long developments about the spread of the influenza H5N1 virus,
as the topic is highly covered world-wide: the virus is now present in
Greece and Italy, continuing is expansion westwards. The most
worrisome is its spread in Africa, where it is likely to become
endemic. For the time being the economic consequences of the disease
begins to be considerable in poultry industry, and as chicken are
perhaps the main source of proteins in sub-saharian Africa, this is
likely to be highly damaging for the population's health. Bacterial
meningitis is spreading in the United Kingdom and in the USA for some
time; an epidemiological study has shown that, as might be expected,
this is due to the behaviour of teenagers having multiple partners. It
has long been known that a significant transmission of the
Epstein-Barr virus - the "kissing disease" - follows the same route in
teenagers. However, meningococcal meningitis is mostly a severe
disease that affects sahelian regions every year at the end of the
winter, when hot dry weather dominates. It is now already affecting
Ethiopia, where a vaccination campaign has begun.
9 february 2006. The Chikungunya
virus is still spreading in the island of Réunion, Maurice and
Seychelles. It might have reached Madagascar, where many patients
suffering from fever are flooding the hospital of Toamasina. Greece
may have its first H5N1 cases in wild swans.
8 february 2006. The battle against H5N1
flu seems to be a victory in Turkey, as almost 10 million fowl has
been culled to control the spread of the disease. Unfortunately more
birds appear to be infected in Hong Kong (where households have been
banned to raise chicken), and, worse, the virus may have reached
Africa. The World Organisation for Animal Health (OIE) has released
information that a massive infection was reported in Jaji, Igabi,
Kaduna State, in Nigeria in a poultry layers commercial farm in which
ostriches and geese were also kept. The geographical position of
Nigeria is such that this would mean that the virus is present in many
places of the continent. It is unfortunately clear that this means
that the disease will remain out of control for a long time (as it is
in Indonesia for example). The only positive side is that, as for now,
there has never been known large human outbreaks of influenza in
humans caused by a virus of the H5 type.
2 february 2006. Several wild birds have
recently been found infected with the H5N1 virus in Hong Kong
(including a crested myna in a playground), but some concern was
visible when a chicken smuggled from the Mainland was also found to
carry the virus. Persons in contact with the dead bird are being
investigated. The natural birds reserves have been closed by the
authorities.
1 february 2006. The area of H5N1 flu is
slowly extending, with the virus now present at several places
bordering Turkey: Iraqi Kurdistan, where a young girl died and Cyprus
where birds were found to be infected. Central China is witnessing
outbreaks in Sichuan and in Northern areas. There is still no
indication of any person to person contamination, and it must be
stressed again that we do not have yet cases of epidemics triggered by
an H5 virus in humans. While there are many outbreaks of cholera in
Africa and in Asia, the International Centre for Diarrhoeal Disease
Research, Dhaka, Bangladesh (ICDDR,B), popularly known as the Cholera
Hospital locally, will host a conference on "Combating Malnutrition
and Intestinal Diseases in Children: Are We Doing Enough?”, next week
(6-8 february). In guerilla torn Ivory Coast, a survey by the National
Programme for the Fight against Mycobacterial Ulcers has discovered
that 22,000 cases of Buruli ulcers affected the country last year, a
marked increase on the number recorded in 1997 (4,642). Buruli ulcer,
which often requires amputation of the affected limbs is caused by Mycobacterium
ulcerans, a close kin of the bacteria causing tuberculosis and
leprosy.
26 january 2006. Viruses come in a
variety of forms (as do computer viruses). In particular they are
small genome programs that may be made either of RNA or of DNA
protected into a more or less complex envelope: are these "flavours"
of a piece of genetic program recognized in the same way by the first
level of the host defence (the so-called innate immunity)?
A study published in the journal Immunity, involving the
bacterial pathogen Legionella pneumophila (the cause of
the infamous legionellosis, "legionnaire's disease", after multiplying
in the cytoplasm of host cells) has shown that DNA triggers a
first line response that completely differs from that triggered by
RNA. DNA of the pathogens is recognized because in contrast to that of
the animal hosts, it is usually not
chemically modified when it contains CG dinucleotides. The study
of this new defence pathway may help design new drugs to interfere
with DNA viruses and intracellular bacterial pathogens.
22
january 2006. Many viral diseases, such as dengue fever,
endemic in subtropical regions, are transmitted by
mosquitoes. Several outbreaks of infection by the Chikungunya
virus (in swahili "to walk bent", because of the terrible joint pain
it causes), transmitted by mosquitoes of the genus Aedes, have
been recorded by the surveillance system in the French island of the
Réunion. More than 7000 cases have been registered in the island
during the past year. Since the end of december, one witnesses an
important increase in the number of new cases, with the climate
becoming favorable for the development of the vector mosquitoes. As
usual, the control of such outbreaks depends on the elimination of
niches convenient for larvae in particular in subuurban areas (empty
cans, old tyres, flowerpot saucers, buckets, etc...). Twenty grave
forms (13 infants and 7 adults) with hospitalisation in an intensive
care unit have been recorded. On the front of avian influenza, the
situation continues to evolve, but it must be noted that we have no
experience ever of a human epidemic caused by a H5 virus, which makes
any prognosis about the future of the possible pandemic extremely
hasardous.
20 january 2006. Hong
Kong, which regularly witnesses
the presence of the H5N1 virus in dead birds, but did not have
such cases recently, discovered the virus in a dead magpie robin near
the bird's reserve at Tai Po. The authorities were somewhat concerned
as we are approaching the Chinese New Year, because people in the
region prefer eating fowls that they bought alive, keeping very active
the live birds markets.
17 january 2006. The Lancet
publishes a study based on evidence gathered from Zanzibar showing
that, contrary to common belief, giving generalised iron
and folic acid supplements to young children in malarial areas
results in a slight increase in the likelihood of those children being
admitted to hospital for diseases. Malaria causes severe anemia, and
it has been believed that in order to improve the condition of
patients it would be good practice to restore their iron supplement as
well as cell multiplication by intake of folic acid. It now appears
that the remedy could be worse than the disease, as, perhaps, anemia
protects against further multiplication of the parasites. However a
parallel study in Nepal did not show any adverse effect of the
supplementation. The comment of the editors of The Lancet is
that, at this point, it remains likely that iron and folate
supplementation in regions of malnutrition may probably be beneficial
on the long term.
15 january
2006. A picture of the evolution of the H5N1 avian flu virus
is emerging. As we recalled recently, hemagglutinin (H) and
neuraminidase (N) aside, several other features of
the virus are of major importance for its virulence. In
particular, the
polymerase B2 gene (PB2), involved in viral replication, seems to be
crucial. Last summer's outbreak in the Qinhai region in China
showed that the PB2 gene carried a G–>A mutation, at its codon 627,
changing a glutamate amino acid residue in the protein into a lysine.
This type of change (from G or C to A or T) is frequent
in parasites, including viruses, for metabolic constraints in the
host cell . Remarkably, this same mutation had been observed
earlier in infection of mammals (tigers
in Thailand in 2004), and it seems to be present in Turkey. This
is consistent both with epidemiology (with migratory birds migrating
westwards from the Qinhai region) and with the apparently more
infectious phenotype of the virus, which, in addition to alteration of
replication efficiency, seems to have often acquired a tropism for
nerve cells with this mutation. It is remarkable that this same
mutation was present in the H1N1 virus which caused the 1918 pandemic.
Consistent with this observation, a Dutch study just appeared in the
American Journal of Pathology, shows in cats that the virus can be
spread from animal to animal, and that the route of infection is much
more varied than simple pulmonary infection.
10 january 2006. At a time when avian flu
seems to be spreading in Turkey, including to the Istanbul region, and
cause more fatalities in China, a retrospective study in Vietnam by
Swedish epidemiologists is "consistent with transmission of mild,
highly pathogenic avian influenza to humans and suggest that
transmission could be more common than anticipated, though close
contact seems required. Further microbiological studies are needed to
validate these findings." This indicates that it may be that many more
people have been infected by the H5N1 virus with no or only mild
symptoms. The unusual clustering of fatalities in families, involving
children or young adults is however a matter of concern.
7 january 2006. An unusually large cluster
of human cases of avian flu is active in the region of Van in the east
of Turkey. Three children from the same family died from the disease
after having been in close contact with poultry. A fourth child of
that family is still in hospital. The reason of the worry is that 19
other persons are ill in the same region. However a child who died
yesterday, from an unrelated family tested negative for the virus, but
this might be a false negative result. The WHO is monitoring closely
this outbreak as the size of the cluster might indicate that the virus
is becoming able to spread from person to person. However people are
in close contact with poultry throughout that region. Two wild ducks
have been found carrying the virus in central Turkey, suggesting that
migratory birds could be spreading the virus.
31 december 2005. At a time
when avian flu outbreaks are found everywhere it may be important to
recall that flu viruses, even with the same name, are
not equivalent to each other. Many variant proteins of the
surface of the virus envelope, sixteen hemagglutinins (the "H" in the
name) and nine different neuraminidases (the "N") have been identified
to date. Before genomics, immunochemical and biochemical tests were
used to identify pathogens: hemagglutinin and neuraminidase were the
first antigens of the flu virus to be identified, and the nomenclature
was built around them. The virus types are numbered according to when
they were discovered; H1 was identified first. When the genes were
identified it appeared that the virus was made of discontinuous
segments which can be reassorted
when two different viruses infect the same host cell and that
they code for eight proteins. A H5N1 virus can therefore harbour a
panoply of six other genes, coming from various sources. Some
combinations are innocuous, some are letal and the virulence is, of
course, different for birds and humans. This is why there is a strong
controversy about the creation of a live vaccine to vaccinate poultry:
while the vaccine virus might be innocuous, it might reassort with
another virus and create a dangerous variant. The Chinese authorities
– another victim in the country was apparently never in contact with
fowls – have recently claimed to have created a live vaccine for
their huge poultry flocks: fortunately it appears that the vaccine
uses the Newcastle virus, not the flu virus, which has been
genetically engineered to display the flu virus antigens on its
surface and therefore trigger both an anti-Newcastle disease and
anti-flu immune response.
28 december 2005.Cholera is back in Douala,
Cameroon, and one fears that an epidemic will start from there in
january. Fowls died again in Turkey, affected by type H5 flu. The
final diagnostic is not yet available but several parts of the village
of Köprüler, near the town of Aralik have been quarantined.
27 december 2005. For some time there has
been a controversy about the efficiency of vaccinating poultry to
prevent emergence of a H5N1 human variant pandemic. A
study from Wageningen University in Netherlands studied the
effect of vaccination on transmission of the less dangerous variant
H7N7 that has led to several serious episodes in the past few years.
The showed that vaccination was able to reduce the transmission level
to such an extent that a major outbreak would be prevented. This is a
very optimistic view for the control of the dangerous H5N1 virus.
While there is no final analysis of the cause of death of wild birds
in Malawi it is unlikely that it was due to the avian flu virus.
17 december 2005. Birds may be suffering
from bird's flu in the south-east African republic of Malawi, where
thousands of migratory birds have been found dead. The cause of the
death is not yet known. The disease is still developing in China with
new human cases. In the same issue of the magazine Science,
where the Corean cloning investigator Woo-suk Hwang retracts
his paper on patient-specific human stem cells (which made
headlines recently), Keith C. Cheng from Penn State University,
describes a gene he has discovered in the model zebra fish (Danio
rerio) which controls skin pigmentation. The remarkable
observation he makes is that this gene is conserved in vertebrates,
and that a single polymorphism (a single base change, a G to an A,
changing an alanine of the gene coded protein SLC24A5 into a
threonine) controls dark pigmentation in humans. The alanine variant
is present in dark skinned people, while the partially dominant
threonine variant makes skin color much lighter. This variation,
uncovered by the Hapmap
consortium, corresponds to a single change in the 3 billion letters
human genome. It is amusing to see that such a minute difference could
have such important sociological and political consequences, with the
widespread positive sexual selection associated to lighther skin
complexion.
16 december 2005. A thorough summary about
the situation of H5N1 flu raises hopes and concerns. Curiously, it
does not seem to consider the episode of february 2003, which
overlapped with the onset of SARS.
After a relative decline in 2004, infections due to the mosquito-borne
West Nile virus have increased again this year in the United States.
15 december 2005. Many strains of the
influenza virus are propagating at the moment in the Northern
hemisphere. In a routine check health authorities in Taiwan found two
mild strains of the virus in feces of birds at the Guandu reserve.
These strains, H5N2 and H7N3 have been recorded earlier in Japan or in
Taiwan. The dangerous H5N1 strain is still active in Indonesia, South
East Asia, and at the border of Europe, in Ukraine and in Romania.Year
2005 will probably be a record year for dengue fever, in particular in
South East Asia. Malaysia, Thailand, and even Singapore have been
seriously hit. The disease is usually more dangerous upon the second
infection. There is no good vaccine at present although this would be
the best protection, as the symptoms of the disease usually appear
after the virus has disappeared from the body, precluding
efficient use of antivirals.
7 december 2005. Apparently, a school
teenager in China GuangXi province has been confirmed with H5N1 avian
flu infection. Surprisingly she had no contact with poultry, and there
was no birds mortality in the region.
3 december 2005. The
Lancet publishes the work of a team of researchers from
Cambodia, France and Senegal showing that some resistance to the newly
available drug against malaria, artemisin, is already emerging in
French Guiana (South America) and Senegal (West Africa). Artemisin,
isolated from Chinese Traditional Medicine, was a promising drug to
replace treatments that have become ineffective.
2 december 2005. The normal hosts of avian
flu are ducks, geese and related birds (Anatidae). However it can also
infect many other bird families. A recent study from China shows that
free-living
tree sparrows collected in 2004 harboured a H5N1 variant virus.
This observation gives some flesh to the concern of authorities in
Ethiopia that are checking for the presence of the virus in dead
pigeons. We know that our Homo sapiens ancestor reached Asia
through the South of the Arabic peninsula, and it is quite reasonable
to think (and in fact known) that migratory birds are moving in the
opposite direction. When the virus will be established in Africa,
unfortunately, it will be very difficult to control.
1 december 2005. A team of investigators
working in Gabon has identified the Ebola virus in three different
species of Fruit bats, where it is asymptomatic. This suggests that
these animals are the elusive reservoir of the virus.
29 november 2005. Sonja Olsen and her
colleagues at the International Emerging Infections Program in
Thailand, showed that forty-one of 109 H5N1 flu cases (38%) identified
between January 2004 and July 2005 occurred in 15 families, with
between two and five cases per family. While there is an obvious
common environment in families, this could be consistent with some
propagation of the virus from person to person. Monitoring clusters of
infected people is extremely important to evaluate whether the disease
becomes apt to spread. According to the WHO Indonesia's 12th human
case of bird flu had two brothers who died from similar symptoms a few
days before he was taken to hospital. The cause of their death was not
investigated.
25 november 2005. Most diseases result from
the combination of social practices and pathogenic agents, often
starting from more or less innocuous organisms. In this respect, the
extremely fast urbanisation process we are witnessing all over the
world, in China and India in particular, involve such a high number of
people that we should be concerned by the new microbiological niches
this creates. In China in 2005, poverty and lack of local job
opportunities and the belief of chances of finding work in cities
drove an estimated 120 million people to migrate from rural areas to
urban areas. Men constitute the bulk of the migration. This creates a
huge gender imbalance in a country that already lacks some 30 million
women because of a tradition that could not be eradicated by
communism, and that was enhanced by the — necessary — one-child
demographic policy, favoring boys over girls. The consequence is that
there is a considerable traffick of poor girls in the urban areas. It
is not difficult, unfortunately, to understand that this situation
results in sexual exploitation, with inevitable consequences in terms
of diseases transmitted by sexual promiscuity. The All China
Women's Federation (ACWF) is trying to set up a series of programmes
to help young migrating women (often even children) in particular in
the rich Pearl River Delta to be aware of the risk of trafficking and
to find means to escape it. The International Labour Organisation
(ILO) has set up several programmes to help preventing girls
trafficking within China. At a time when 26 bird flu outbreaks have
been identified in China, any type of trafficking becomes a matter of
extreme concern.
19 november 2005. The fourth Multilateral
Initiative on Malaria (MIM) PAfrican Malaria Conference 2005 in
Yaoundé, Cameroon, closed yesterday after one week of interesting
discussions about the future of malaria research. More than 1,500
investigators met. A study conducted by researcher Afumbom Kfutwah of
the Pasteur Center in Yaoundé and his colleagues, suggested that
mother-to-child HIV transmission peaked three months after the peak of
the rains in Cameroon. As this is the time when mosquitoes multiply,
this is consistent with a link between malaria and HIV "vertical"
transmission. A student from Cameroon now at the department of
Biology, Georgetown University in Washington DC, USA, Geneviève Fouda
Amou’ou won the MIM 2005 Young Malaria Scientist Award for her work on
antimalarial antibodies in infants.
17 november 2005. There are not yet signs
that avian flu can spread from person to person, but as the extent of
the area covered by the virus increases more persons are at risk and
indeed more are infected. This is the case in the past few days in
China and in Indonesia. A difficult situation will be reached when the
usual winter human flu types will spread, as we can expect that the
most dangerous form of the H5N1 virus will appear when it will be less
letal (and therefore more like the "ordinary" flu) while propagating
from person to person (also allowing reassortment and recombination
between human and bird flu viruses).
14 november 2005. China unfortunately does
not differ, in terms of interperson fights, from Western countries. At
a dangerous moment where millions of birds had to be slaughtered in
several provinces as new outbreaks of H5N1 flu cannot be contained,
the various authorities, at the local and national level, compete to
avoid being caught in error, or to get the glory of the control of the
disease (or identification of a new strain). As avian flu is a
zoonotic disease it is dealt with by the Ministry of Agriculture, but,
naturally, the Ministry of Health, the Ministry of Science and
Technology and the Chinese Academy of Sciences (to name a few
institutions) should also be involved in a general collaboration. This
is not (yet) the case. We see a situation similar to that during the
SARS episode where hospital in Hong Kong fought a bitter fight instead
of collaborating. It would be inappropriate to point our finger at the
Chinese authorities: we simply have to witness the behaviour of the US
Department of Energy versus the National Institutes of Health in
genomics to understand that the situation is not specifically Chinese.
And what could we say about the Centre for Diseases Control in the
1997 episode and in its creation of the 1918 flu virus?
11 november 2005. The enigmatic
correspondence between the brain development and structure and animal
behaviour is under intense investigation. After the recent studies
indicating that human brain is under ongoing
selection pressure, and evolving, a behavioural study suggests
that there is a correlation
between the IQ level and lower mortality rates. The study shows
that the association between childhood IQ and mortality exists even
among people with very high IQ scores. The authors claim that the
result is independent of childhood social position. There have been
several suggestions about why higher childhood IQ might be associated
with longevity and the fact that the observation still holds at the
higher range of IQs will trigger debates. As usual the intrinsic flaw
of correlation studies is that correlation is not cause. However, even
considering IQ as irrelevant to define what intelligence is, it
monitors some brain activity. And as brain is the basic organ
controlling behaviour, any correlation deserves to be investigated in
depth. A genetic study on the male courtship behaviour in Drosophila
flies identifies a remarkable brain circuitry at work. The gene
fruitless (fru) is differently expressed in females and males.
The functional Fru protein is present only in males and Fru is
necessary and sufficient to induce normal male courtship behaviors in
flies. Work by a group of scientists at Hokkaido University of
Education in Iwamizawa, Japan, established that neurons in females
undergo cell death because they lack the Fru protein. This is the
first explicit demonstration of sex determination of neuronal
patterns, with direct influence on behaviour. Insects are far from
mammals, but it has been repeatedly found that ancestral rules present
in insects — including in body plan construction — have (much more
evolved) counterparts in vertebrates. We can expect that this is
another type of work which will trigger interesting debates. Avian
flu, probably in its H5N1 form has been discovered in a migrating
flamingo in Koweit. Newcastle disease is active in several European
countries (Greece, Slovaquia and France) and in Turkey, and it can be
mixed up with avian flu by some. A yellow fever outbreak has been
confirmed in the Kayes region of western Mali.
10 november 2005. Mass media, as usual,
have a very short memory, and they all stress that China now has its
"first" cases of human avian flu, while confusion about the origin of
SARS in Hong Kong began because of the simultaneous presence of deadly
contamination by a H5 flu virus of a father and his son from
the Mainland. In a very dangerous move, scientists in the USA have recreated
the 1918 pandemic flu virus. Authorities now will permit
exchange of the virus between laboratories, while the National
Laboratory in Winnipeg, Canada, plans to recreate the virus for its
own purpose! Human
hybris is such that we can unfortunately be certain that
accidents will happen some day, if not malevolent actions. In parallel
with the bird flu scare, mosquito-borne dengue fever affected millions
this year, without much public concern. In one of the latest outbreaks
Sudan recorded at least 71 deaths from the disease.
9 november 2005. The outbreak of bird flu
which affects China is not over. It seems that the number of birds
affected in the Liaoning province is so large that millions have to be
culled, a task that the local governments appear to have difficulties
to apply. In Japan the epidemic is of the H5 type, but the apparent
relatively mild infection suggests that it is not of the N1 type.
6 november 2005. Avian flu is still
infecting people in Indonesia, where a woman died of the disease after
having been infected by dead chicken, a young boy of her family is
also hospitalized and it is not clear how he got infected. At least
three persons in China are suspected to have caught the disease in one
of the recent outbreaks that forced the government to slaughter more
than one million birds in an effort to contain the spread of the
virus. Honolulu international airport has initiated voluntary tests
for airflight passengers.
1 november 2005. An outbreak of Escherichia
coli O157H7 affected 18 persons in the South of France. This
variant of commensal E. coli, which is a normal host of the
human gut, produces dangerous toxins and is the source of recurrent
food-borne infection all over the world. The pathogen is often found
associated with bovine and may contaminate the food chain when
unproperly processed. Bird flu is reappearing at various places in the
world (Romania, Thailand in particularn and the virus found in swans
in Croatia seems to be of the H5N1 type), but one must be open to
other bird infection (such as Newcastle disease) or other variants
(the virus in Japan is apparently a H5N2 variant, significantly less
dangerous than the H5N1 variant). A control of migratory birds in
Tunisia did not show yet the presence of the virus.
26 october 2005. Many diseases are
transmitted by mosquitoes, which transport the pathogenic agent from
an infected host to a naive one. These insects multiply rapidly and
are impossible to control easily. For this reason, investigators
explored for some time ideas to make mosquito mutants that would not
be able to be infected by the pathogenic agent. In a collaboration
between the Johns Hopkins University, the European Molecular Biology
Laboratory, Imperial College in London and the University of Texas,
scientists uncovered a gene (SPRN6) that is involved in the protection
of the Anopheles mosquito against invasion by the Plasmodium
malaria parasite. Inactivation of the gene increases the parasite load
of the mosquito. There is hope that making this insect immunity
pathway more active might prevent mosquitoes to be carrying the
malaria parasite. Subsequently, it might be possible to breed
mosquitoes with this property and make them replace their counterpart
in the environment, thus interrupting the dangerous Plasmodium
cycle.
25 october 2005. At a two days meeting on
the management of bird flu in Canada, health ministers and authorities
of the WHO try to agree on a common reaction to the possible pandemic
triggered by the H5N1 virus. Among the most important reaction is the
rapid identification of the virus, which can be mistaken in some
places for another virus affecting fowl. For example, at this very
moment two foci of Newcastle disease affect the North of France (where
300 pheasants died and 1200 had to be slaughtered) and in Denmark.
They also discuss the mode of transmission, which is not entirely
clear (the same is true for transmission of the paramyxovirus of
Newcastle disease), together with containment measures which must be
associated with the outbreaks. Many local outbreaks of avian flu are
now affecting Europe, Russia and China, perhaps because of the
unusually warm autumn. When migratory birds will go south it seems
likely that northern Africa will be affected. This is a matter of
great concern as implementing measures to eradicate the virus there
will be as difficult as in South-East Asia.
21 october 2005. While avian flu seems to
be present in inner Mongolia in China, south of Moscow in Russia and
extending westward in Europe, Taiwan reported its first cases of avian
flu, discovered in a cargo of exotic birds smuggled from China.
Smuggling of wild animals should be punished more severely as it deals
with endangered species and is a very important source of emerging
diseases.
19 october 2005. The first antibacterial of
the same class as the innate immunity "defensins" of insects has been
isolated in a fungus, Pseudoplectania nigrella. Named
"plectasin", it is a peptide that targets bacterial envelopes, in
particular killing antibiotic resistant Steptococcus pneumoniae.
Plectasin appeared to have very low toxicity in mice, and it might be
the first efficient new antibiotic discovered for a long time.
18 october 2005.
Rather than duplicate information about the H5N1 viruses at the border
of Europe and now probably in Greece, we shall summarize a few
concepts needed to understand why this virus is worrying. In short
virus families can be split into two broad clusters. A large number,
including the influenza virus, are extremely toxic for cells as they
multiply fast and kill the cells they invade. They are loosely called
cytopathic viruses. Animals have evolved very specific
responses to cope with that challenge: they need to have a very fast
and efficient response to prevent a major cell death, which would
result in the death of the infected individual. The remaining virus
cluster is very heterogeneous and comprises viruses which circumvent
the host defenses by multiplying more slowly — so as to become less
visible — and give rise to persistent infections during which there is
plenty of time for the virus to mutate in the host, hence avoiding the
host immune defenses. This is the case of the AIDS virus, HIV. After
contact with a cytopathic virus, the host evolves first a complex and
mechanistically diverse innate immunity response, some of
which present as early in evolution as in the insects, to try to get
rid of the pathogen. This often succeeds to protect the individual, at
least when the number of invading virus particles is not too large.
The second response involves a complex interaction between classes of
immune system cells, the T and B cells. Following an interaction with
T-cells, the B cells produce the well known antibodies which, in the
case of cytopathic viruses, begin to neutralize the virus (i.e. stick
to it and make assemblies that can be ingested by other types of cells
of the immune system and destroyed). This synthesis becomes to be
effective after about four days. The concentration of neutralizing
antibodies increases very much in a few days, and the individual is
cured of the infection, while retaining memory of this event, yielding
protection against similar infections usually for several years. This
remarkably efficient process, selected through the ages of
co-evolution of viruses and organisms, has a drawback: it is extremely
selective. The part of the coat of the virus which is recognized by
the immune system is but a tiny region. This is the price that had to
be paid to construct such an efficient response out of a very complex
set of interactions. Now, in turn, the game of evolution, from the
virus point of view, is to make this recognized surface structure
evolve fast, and therefore avoid protection memorized by possible
hosts. This is typically the situation with flu: two surface
architectural motifs, named H and N are recognized by the
anti-cytopathic viruses response. Under selection pressure they are
doomed to evolve: only those mutants of the virus that have escaped
the neutralizing antibodies that destroyed their ancestors can
propagate, triggering a new epidemy. This is how variants of the H and
N motifs, labeled 1, 2, 3, etc in turn invade the bird and human
population. More subtle variants superimpose on the major classes.
Fortunately, not all combinations are equally efficient for allowing
the virus to invade cells, so that it always takes time for a virus to
evolve a new virulent form, with a large variation in virulence, and
the forms are often somewhat related to one another, so that there is
a weak response in any individual, making the virus less pathogenic.
However, from time to time, a completely new form appears, for which
no protection whatsoever (except of course the innate immunity) is
present. This is exactly the situation which is feared in the case of
the H5N1 influenza virus complex.
16 october 2005. As mass media widely cover
the extent of H5N1 bird flu in Romania we shall not further comment,
except to warn against irrational panick. It is clear however that the
disease is now likely to remain endemic on the Eastern border of
Europe, slowly moving westwards, and, next spring to Northern places.
But what may be more worrying is that many of the migrating birds
which are the reservoir of the virus will reach Africa, where control
measures will be impossible. It is clear, witnessing the situation in
Indonesia, that the virus can become endemic in tropical climate.
14 october 2005. Two fatal cases of yellow
fever have been recorded in the past few weeks in Senegal at the
border with Guinea. The local population has been vaccinated. Cholera
keeps its letal progress in Guinea Bissau.
13 october 2005. Romanian ducks have been
confirmed infected by a H5-type flu virus. Wild ducks appear to be
dying en masse in Iran at the frontier with Azerbaijan, no cause
recorded yet.
11 october 2005. A possible outbreak of the
deadly Crimean-Congo haemorrhagic Fever is affecting South Africa.
This zoonose caused by a Nairovirus spread by a tick vector sometimes
affects humans.
9 october 2005. The extent of dengue fever
this year is particularly worrying as it is on the increase. Even in
the very clean Singapore environment more than 10,000 cases have been
recorded so far this year. The area breeding the mosquito vectors
covers region with some 2.5 billion persons. More anecdotal but
significant, an infection by the bacteria causing American foulbrood
of honeybees (Paenibacillus larvae subsp. larvae) has
caused the destruction of serveral bee hives in Norway. The origin of
the disease is unknown. Turkish turkeys have been confirmed hit by a
H5-type flu virus.
8 october 2005. Several sources indicate a
mass dying of birds in Turkey (farm turkeys) and in Romania (wild
ducks and farm fowls), that may be caused by a strain of avian flu,
perhaps coming from migratory birds coming from Siberia or Kazhakstan.
If this were the case, this would likely be the H5N1 variant. 7
october 2005. Investigators at the Armed Forces Institute
of Pathology in Rockville, Maryland, USA have sequenced the 1918
influenza virus and scientists from the Centers for Disease Control
and Prevention in Atlanta have recreated a functional virus, showing
its extreme virulence. This triggers a huge controversy (see
our position about small pox, which would probably differ in
the present case, as the flu viruses reservoir is immense and out of
human control, implying that, in contrast to small pox, flu cannot
be eradicated) as it is clear that making the sequence public may
allow recreation of the virus. The very fact that militaries are
involved is a demonstration that the research does have military
implications.
6 october 2005. In a series of articles
published in the Nature and Science magazines
investigators demonstrate, using tissues preserved from two soldiers
and an Alaskan woman who died in the 1918 flu pandemic that the
virus apparently jumped directly from birds to humans. This is
exactly the scenario which is feared for the present H5N1 avian flu
episode.
5 october 2005. For two weeks now an
outbreak of infection with a highly pathogenic Escherichia coli
is affecting schools Wales in UK. More than 150 persons have been
affected and a young boy died of the disease. Several local
outbreaks are affecting the USA. While E. coli is a normal
and innocuous (perhaps even beneficial) host of the human gut (a
commensal) some strains can become highly pathogenic and either
cause gut, bladder or kidney diseases, and even sometimes septicemia
and brain infections. Australia will host in Brisbane, october 31st,
a regional meeting to study how to ensure a swift and co-ordinated
regional response to contain the expected outbreak of avian
influenza.
1 october 2005. A new report, published
on line by the magazine Science, shows again
that bats are the likely reservoir of the SARS virus.
27 september 2005. Dengue
fever is so widely spread in the world that it may affect 100 million
people or more every year. It is so common that one is reluctant to
mention its outbreaks except when it is locally higher than usual, or
new. This year it is affecting the French Department of West Indies,
Martinique where more than 6,000 persons have got infected. It is also
much stronger than usual in Singapore, despite drastic measures to
control mosquito populations. Another viral disease, also transmitted
by mosquitoes, Japanese encephalitis, continues to spread in the state
of Uttar Pradesh in India as well as in Nepal, where it has
contaminated almost one thousand people.
23 september 2005. The World Health
Organisation (WHO) is launching a vast immunisation programme for more
than half a million people in response to four confirmed new cases of
yellow fever, one of them fatal, in southern Burkina Faso near the
border with Ivory Coast. Yellow fever is endemic in the region
(northern Ivory Coast, Togo, Benin and southern Niger, in particular
near the game reserve of Pendjari (Porga), Arly and the Niger W) with
a reservoir in rodents. The vaccine is remarkably effective, but the
disease, transmitted by mosquitoes, is often fatal. The
fatalities caused by the disease were the reason for the selling
of Louisiana to the United States at the beginning of the XIXth
century.
21 september 2005. After the zoo of Jakarta
has been closed when 19 captive birds were found to be infected by the
flu H5N1 virus, three members of the personnel are thought to have
been contaminated and are hospitalized with suspected H5N1 avian
influenza. Since August an epidemic of cholera is affecting the
Fujiang province in China. In Africa many foci are still highly active
from Senegal, Guinea Bissau to Congo.
18 september 2005. Japanese encephalitis, a
mosquito borne viral disease, has killed almost 1,000 people in India,
mostly in the Uttar Pradesh state. Fortunately the peak of the
outbreak seems to have been reached.
14 september 2005. A
series of articles published in this week's magazine Science
suggest that the human brain is still undergoing evolution under
positive selection. The most remarkable observation is that
polymorphism of some genes involved in the construction of the brain
results from recent mutations. One type of mutation happened
apparently just before humans began to produce artistic artefacts,
while another one would be even more recent, just at the time of the
neolithic revolution. Of course correlation is not cause, and one
should be extremely cautious about interpretation of these data, which
are certainly doomed to trigger controversy. However it is fascinating
that one of the genes of interest codes for Microcephalin, a protein
most probably directly involved in the spectacular increase of brain
mass witnessed in humans as compared to non-human primates. Patients
without the gene have a brain several times smaller than the normal
brain, especially in cortex regions, with normal brain tissue however.
Previous studies have shown that Microcephalin is a specific regulator
of brain size and that it has evolved under strong positive selection
in the lineage leading to Homo sapiens. One of the haplotypes
of this gene apparently spread during a very short period of time.
Avian flu is present in Indonesia. A detailed study by an Italian
group of human sera from exposed poultry workers in Italy shows that
seropositivity occurs in poultry workers who were exposed during
outbreaks in poultry caused by some avian strains (H7N7, H7N3, and
H5N1) but not by others (H7N1 and H5N2). This suggests that some avian
influenza viruses are more likely than others to infect humans. More
worrying is the observation that both H7N7 and H5N1 strains are more
adaptable than other strains. Even worse is the observation that avian
flu viruses have more chances than previously suspected to mix with
human flu viruses, potentially creating hybrids that could trigger a
pandemic. Since june, more than 15,000 people were infected by the
cholera vibrio in Guinea-Bissau and more than 250 died from the
disease.
11 september 2005. A
team led by Yuen Kwok-Yung at the University of Hong Kong found a
virus highly related to the SARS-CoV, responsible of the Severe Acute
Respiratory Syndrome in 2003-2004, in horseshoe bats. This is a
further indication that civet
cats are not the reservoir of the virus, as suggested by a
previous study that showed that the virus
evolved in civets exactly in parallel with evolution in humans.
However the way the virus might have come into contact with humans is
not clear. Bats are used for traditional medicine and the local
population has the habit to eat all kinds of animals. However, among
many possible scenarios, they might have been victims of a predator,
like civets (bats are frequently the victims of domestic cats), which
might then have passed the virus onto humans. This discovery may be
revealing as bats are not related to rodents (despite their name as
"flying mice" or "flying rats" in several languages), but to Primates,
in the superorder Archonta.
8 september 2005. Japan is, once again,
affected by the H5N2 avian flu virus. In contrtast to what has been
repeatedly stated by proponents of a general use of human embryonic
stem cells, these cells have been shown to accumulate many more
changes in their genomes than expected, an international team of
scientists report in the October issue of Nature Genetics. It
is obvious that, rather than pursue experiments on human cells,
despite many therapeutical and ethical caveats, much is needed
performing research on animals. The situation is paradoxical, as it is
often easier now to perform experiments with human living material
than with animal material.
2 september 2005. Among drugs developed
against cancer, a new one presented at the national meeting of the
American Chemical Society, an analog of a carbohydrate (sugar)
important for the cell envelope and connection to the outside, a
ganglioside, appears to interfere strongly with tumor growth,
providing some new hope in improving cancer treatment. Furthermore
this compound seems to restore some of the immune system which has
been suppressed by the development of the tumors. This could be placed
in relation with the observation that membrane
turnover and DNA synthesis must be coupled in the cells of
higher organisms, an observation that was previously
suggested to be important for creating new drugs against cancer.
1 september 2005. Another patient passed
away from avian flu in Vietnam. The disease keeps on being contagious
from birds to humans, but does not spread between humans, while it
stays highly letal. A sign of danger will appear when the disease will
become less letal: at that point interhuman
contamination might happen.