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David
Crowe, September
2001
West Nile Virus (WNV) is one of the latest
in a string of new disease-causing
organisms that have been brought to the world's
attention by science researchers and public health officials,
most notably the US CDC (Centers for Disease Control).
Although there is sometimes resistance
to the protective measures recommended, there is rarely discussion
of whether the threat really exists. If the claims of these
officials that they know the answers are the legitimate targets
of questioning, why not the claims that they have identified
the problem?
Many recently discovered pathogens, most
often viral, have exploded into the public consciousness,
but then gradually faded from sight. Often a handful of cases
in humans results in a massive reaction that seems out of
all proportion to the danger. Avian flu resulted in the slaughter
of most of the chickens in Hong Kong although
there was no evidence that the first and most publicized
death from this disease in humans, a 3 year old boy, had ever
been in contact with an infected bird [Subbarao 1998].
Nipah disease similarly resulted in the
slaughter of 890,000 pigs in Malaysia [MMWR 1999f]. Foot and
Mouth disease caused the slaughter of 3,881,000 animals in
England, although only 2,023 cases of this mild disease were
found and there is believed to be virtually no risk to humans
[DEFRA 2001]. Legionnaires' disease [MMWR 2000c], and Hantavirus
[MMWR 1999e, MMWR 2000d] have followed a similar pattern of
public panic followed by a steady decline in interest when
the threat does not materialize, although not accompanied
by the slaughter of animals.
Sometimes it is not the supposed animal
vectors, but the current or potential future victims of the
disease, who are the targets of public health attention. Thirteen
occurrences of Swine Flu in February 1976, including one death,
resulted in a recommendation to vaccinate virtually every
American based on a prediction that the 1918 killer flu epidemic
would be repeated towards the end of the year.
When President Gerald Ford convened a
meeting of top scientists in the United States including,
in an uncharacteristically brilliant move, both arch-enemies
Salk and Sabin, there was unanimous agreement that such a
vaccination programme would be safe and effective. Manufacturing
and insurance problems delayed the program so that, by the
time of the expected epidemic only a fraction of Americans
had been vaccinated.
This was fortunate both because the epidemic
did not appear (there was not a single case of Swine Flu after
the original outbreak) but about 50 people died from the Guillain-Barré
polio-like syndrome caused by the vaccine, and hundreds were
injured [Silverstein 1981, Laitin 1997].
In the case of Hepatitis C and AIDS,
the remedy is not a vaccine, but one of several highly toxic
antiviral medications even though, in the case of Hepatitis
C at least, there is increasing evidence that the virus is
not very pathogenic [Cohen 1999, Seeff 2000 and Rodger 2000],
while the medications are
neither highly effective nor very safe.
The public health strategy with West
Nile Virus has so far focused on the vectors - mosquitoes
and birds, rather than on vaccines or therapy for the human
victims.
Opposition to the spraying of wide areas
in the New York City epicenter has been based on the comparison
between the few lives lost due to the virus so far (7 in 1999,
1 in 2000), the millions of people placed at risk by the spraying
of toxic pesticides, the inability of spraying to target only
mosquitoes, the loss of predator species and the possibility
of resistance developing.
While there has sometimes been criticism
of the response of public health officials to a new disease
outbreak, there has rarely been any discussion of the possibility
that the existence of the pathogen, or its connection with
the disease is unproved. Serious concerns over the existence
of West Nile Virus or its causal role in disease would quickly
put an end to attempts to eradicate its carriers, as well
as research funding for tests, vaccines and pharmaceutical
therapies.
Koch's
Postulates
Koch's postulates are a statement of
four logical rules for determining whether a pathogen exists
and is the cause of a disease (e.g. [Cann 1997]). They must
be satisfied before it can be accepted that a pathogen causes
a disease. They state that:
1. The pathogen
must be present in every case of the disease.
2. It must be isolated
from the host and grown in vitro (culture).
3. The disease must be
reproduced when a pure culture of the pathogen
is inoculated into a healthy susceptible host.
4. The same agent must
be isolated once again from the experimentally
infected host.
Koch's postulates are merely a statement of the minimal
evidence necessary to have confidence in the existence of
a pathogen and its causal link to a disease. It is important
to note that these postulates are not based on experimental
evidence, but on simple logic.
They have not been satisfied for West
Nile Virus.
How Virus
Existence Should Be Proven
A critical part of Koch's postulates
is proving the existence
of a pathogen before its association with a disease can be
established. If West Nile Virus exists in biologically
significant quantities, virus particles must be present in
the body in large quantities. It should be able to separate
them from body fluids such as blood through a process of filtration
using ultra-fine pores that no other pathogen is small enough
to pass through. This is how the first viruses were discovered
[MMWR 1999d].
After filtration, a portion of the resulting
material can be examined under an electron microscope to show
that the sample is composed of particles of exactly the same
size and shape, to an acceptably high degree of purity. The
remainder of the sample, having been verified as pure, can
be analyzed for its protein and DNA (or RNA, in the case of
a retrovirus) constituents.
Isolating (or purifying) a virus is therefore
an essential step in Koch's second and fourth postulates.
Without this it is not possible to state that a virus is present
in organisms that have the disease, it is not possible to
know what the virus is composed of, and it is not possible
to know whether it, and it alone, is sufficient to cause disease
in another organism.
Isolation
of West Nile Virus
The 1999 papers on West Nile Virus in
the journal Science [Anderson 1999, Lanciotti 1999] claim
that it has been isolated, but their frequent use of this
word in no way corresponds to the normal definition of separating
one thing (the purported virus) from everything else (including
the cells that it might infect).
The researchers instead abuse the term,
disguising the fact that their evidence is non-specific and
indirect, and that at no
point during their research do they have any evidence that
they had purified virus.
Co-Culturing
Viruses
can only reproduce within cells, so a pure culture
of virus on an inert medium is not possible. Instead a co-culture
must be established, whereby (ideally) purified virus is added
to a cell culture, both are allowed to grow, and then a larger
quantity of virus is removed from the CO-culture than was
initially added.
The process used to establish a virus
CO-culture by both [Anderson 1999a] and [Lanciotti 1999] does
not involve the addition of purified virus to the CO-culture,
nor extraction of pure virus from the CO-culture
[Anderson 1999a] established a culture
by filtering ground up crow brains or mosquitoes through a
0.22 micrometer filter, even though flavivirus particles are
about 0.04 micrometers in size [Lanciotti 1999].
The resulting material obviously contains
much material that is of cellular origin, but was directly
added to a cell culture after filtration without any further
attempt at purification, and without attempting to validate
that the material was already pure (which seems extremely
unlikely given the process used).
Similarly, to establish Koch's fourth
postulate, the putatively infected cell culture was centrifuged,
without any attempt at separating the virus from the cell
culture. The material that was analyzed included the cells
in the culture as well as the virus.
The use of the word isolate is so prevalent
in the Anderson paper that I attempted to clarify their use
of it.
Anderson replied to my query that "Viruses
can only be isolated in cells" [Anderson 1999b]. This
is obviously not true, because viruses
must exist as particles outside cells in order to infect cells,
and they must harness the machinery of a cell to produce more
virus particles so that they can travel through the body to
infect more cells.
If West Nile Virus exists in the body
of a person, a mosquito or a crow, or even in a CO-culture,
it must be possible to purify the particles, and separate
them from all other organic materials.
[Lanciotti 1999] used similar 'Vero'
cell cultures, but also claimed to culture the virus by inoculating
"necropsy samples" from birds into chicken eggs.
Again, there is no evidence that these samples had in any
way been purified.
The method for determining whether a
CO-culture is producing virus is similarly nonspecific [Anderson
1999a] looked for cell death occurring, and for the ability
for unpurified materials from these cell cultures to cause
sickness in laboratory animals [Anderson 1999b, no details
given]. Without purification, one can never be sure that the
cytopathic effects are due to a virus, and not just due to
exposure to foreign cellular constituents from a sick animal
or person or due to an immune system reaction.
Antibodies
Antibodies are often used to show that
a virus is present in a host, largely because they are quick,
simple and cheap. Antibodies, however, persist after an active
infection, and so cannot be taken as proof of an active infection.
Even with virus isolation, it is impossible to prove that
antibody reactions are specific and are immune from cross-reactions
with other pathogens, or indeed with non-infectious conditions.
Furthermore, one could only be sure that
antibodies are even associated with the virus by injecting
animals or humans with purified virus to
ensure that the antibodies only arise afterwards.
Even if antibodies are closely correlated with a disease they
could be caused by processes resulting from the disease, they
could be caused by opportunistic infections or they could
be similar antibodies from another pathogen that cross-react.
[Anderson 1999a] admit that their West
Nile antibodies are nonspecific, because they used St. Louis
Encephalitis antibodies to detect infections with West Nile
Virus.
The use of antibodies to detect a virus
then, at a minimum, requires that the virus has been purified,
and even then can only be used as a less than perfect indicator
of past infection, and can never be used as proof that Koch's
first postulate has been established.
Antigens
Antigen testing is theoretically more
direct than antibody testing, since an antigen is the constituent
of a pathogen (usually a protein) that the body produces antibodies
to. Detecting an antigen from a person suspected of having
a disease can be an indication
of the presence of current infection - but can
only be taken as proof if cross-reactions with other antigens
are eliminated and if the antigens have been obtained from
purified virus.
[Anderson 1999a] show that antigens are
obtained merely by lysing cells (digesting the cell walls)
resulting in all cellular constituents being obtained along
with, possibly, virus particles that were within the cell.
Such materials cannot properly be described as viral antigens,
because this implies that they exclusively come from a virus.
At best the virus would be a small part of these materials.
Detection
of DNA or RNA
The detection of genetic material seems
like another way to avoid the deficiencies of antibody testing
since, as with antigens, it is more direct evidence. If the
genome of a virus has been identified, a test that can reach
into a sample and detect its presence or absence seems foolproof.
Even here, however, there are significant
problems. First of all, the ability to detect genetic material
in sick animals or people that is not found in the healthy
does not constitute proof that this material comes from a
virus. It could come from the rearrangement of genetic material
within the body, or as breakdown of cells resulting from the
disease.
Secondly, the Polymerase Chain Reaction
(PCR), widely used as a genetic probe, is highly sensitive
to false positive reactions as even a molecule of genetic
material that matches trigger a chain reaction. Thirdly, genetic
probes are only a small fraction of the genome, so cross-reactions
with related viruses are possible.
The genome of WNV is claimed to be just
over 11,000 nucleotides long [Lanciotti 1999], but there are
no techniques to detect this directly unless purified viral
particles can be obtained. Consequently, without this, very
short primers (21 or 23 bases in Anderson 1999a] are used
to lock onto what is believed to be viral genetic material
in non-purified materials.
There
is no proof that what is fished out of this cellular/viral
stew came from a virus and not from within the cell.
Even then the genome had to be reconstructed from six overlapping
pieces [Lanciotti 1999].
The ability to send short primers into
an unpurified mixture assumes that these gene sequences can
uniquely identify a species of virus without error. But, this
assumes a stability of the genome that may be unsupportable
in healthy people, let alone in sick people where it can be
expected that destruction of cells is occurring, resulting
in damaged and rearranged genomes.
As Dr. Mae-Wan Ho showed in [Ho 1998],
the atomistic view of the genome is not warranted, and there
are many processes in cells that result in significant modifications
to the genome in response to its environment. It has also
been noted that the human genome contains endogenous retroviral
elements that can only be distinguished from infectious virus
particles by the "presence of infectious, extracellular,
membrane-enveloped particles in the retroviruses" [Boeke
1989].
Without purification it is simply not
possible to tell whether one is dealing with a poorly understood
cellular process or an infectious virus.
Proof of
Causation
Even if the existence of a virus or other
pathogen is shown in 100% of a sample of people with a particular
illness, and in none of a sample of people without the illness
(including a number of people with illnesses with similar
symptoms or believed to be caused by similar pathogens), it
does not prove that the pathogen causes the disease.
Even if the first two of Koch's postulates
had been satisfied for WNV, it would still be necessary to
expose an animal to purified virus and ensure that it acquired
the same disease, and that virus could again be purified from
it. Without starting with purified virus, it is impossible
to perform the experiments necessary to establish this.
If
not West Nile Virus, Then What?
It is difficult to say what has really
caused the illnesses currently blamed on West Nile Virus if
we accept that it does not exist or is not pathogenic.
Lynn Gannett, a researcher from New York City, has found that
all the people who died in 1999 were over 60 and all but two
over 75.
It is suspicious that virtually no information
has been released about these victims (unlike the victims
of traffic accidents), making it impossible to determine what
their health was before their supposed infection. It may well
be that these cases had nothing in common except that they
all tested positive for West Nile Virus.
Jim West, another activist, has focused
his attention on the use of MTBE (Methyl Tertiary Butyl Ether)
as a gasoline additive to reduce smog, noting that the majority
of cases in birds and humans were in areas with high levels
of pollution, where MTBE is used.
Conclusions
It is quite clear that West Nile Virus
has never been purified,
and that without purification not only is it impossible to
say whether it is the cause of the disease that it is associated
with, but it is impossible to say whether it even exists.
Even ignoring the lack of purification,
scientists still cannot
agree on what it is that they have found. One paper
constructed a phylogentic tree ('family tree' based on analysis
of genetic material from the 'isolates') to claim that the
1999 New York virus was closest to Kunjin [Briese 1999]. This
virus has never been known to cause disease in humans, and
so could hardly be used to create a public health alert and
intense spraying programs.
However, just two months later, the same
researchers published three new genetic trees that showed
that the New York virus was more closely related to West Nile
Virus [Jia 1999], which is blamed for previous outbreaks of
disease - enough justification for a public health alert.
Even though [Anderson 1999a, Jia 1999
and Lanciotti 1999] show in five phylogentic trees that the
New York isolates are more closely related to some West Nile
isolates than Kunjin, all the trees also show that the New
York isolates are more closely related to Kunjin than several
other West Nile isolates, which brings the concept of West
Nile virus as a species into question.
Even
the size of the virus genome is subject to significant disagreement.
[Lanciotti 1999] claim that it is 11,029 nucleotides long,
while [Jia 1999] claim that it is only 10,945 nucleotides
long. While the genomes of Chimpanzees and Humans are about
98% identical, the genome of two 'isolates' of the same virus
species are about 10% different.
There
are significant financial interests that discourage questioning
of the evidence for the existence of West Nile Virus too closely.
Public Health officials and virologists
get increased funding, status, attention and new facilities
from being involved in a 'deadly' epidemic. Politicians can
appear to be making tough decisions based on sound science.
Pesticide companies can show that their
products are essential to maintain good health. Biomedical
researchers and companies may get government or stock market
funding for the development of new drugs, tests, reagents
and vaccines, and can anticipate enormous future profits.
Even environmentalists are often satisfied
with the argument that the emergence of new viruses is a consequence
of globalization, overpopulation and disruption of ecosystems.
There is something in the existence of West Nile Virus for
almost everyone.
If people are injured by the pesticide
spraying or by adverse reactions to vaccines or drugs, they
will only be a few quiet voices that cannot be heard above
the din of people struggling to be seen as leaders in the
response to a public health emergency.
A great danger is that the
symptoms of pesticide poisoning (to combat mosquitoes
that are believed to be the vector for West Nile Virus) will
be similar enough to the rather vague symptoms of the disease
itself, which are encephalopathy (inflammation of the brain),
weakness and neuropathy (peripheral nerve damage, leading
to symptoms such as numbness) [Briese 1999]). This could cause
more cases and create calls for ever more intense spraying
programs.
Opponents to 'public health' initiatives
such as spraying mosquitoes with malathion should take a broader
view. Not only should they consider the dangers of these interventions,
but demand that the existence
of West Nile as a pathogenic virus must be proven.
They can argue that, not only are the
interventions dangerous, but that they might be completely
misguided, and are only delaying recognition of the true,
underlying health problems.
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