West Nile Virus: Up the Nile Without a Virus?

David Crowe
Alive Magazine
April 2003

2002 was the year West Nile Virus (WNV) fever hit Canada, after three years of spreading reports of illness and death in humans and birds in the United States. Mosquitoes are believed to be the main carrier of the disease. Consequently, most debate has been over whether aerial spraying is justified but little discussion of the evidence that West Nile Virus is the cause of the disease, and virtually none on whether it has been proven to exist.

Questioning the existence of a virus usually elicits a response similar to an adult declaring a belief in the Tooth Fairy. Yet, we believe in WNV because we are told by the media, who were told by Canadian public health officials, who were told by the US Centers for Disease Control (CDC), who were told by virologists that the virus exists and is the cause of an associated encephalitis (brain inflammation brain). Few have critically examined the published scientific evidence. Those who do will find a less than convincing story.

Proving the existence of a virus requires purification from humans or animals believed to be infected (and absence in the uninfected). West Nile virologists often report ‘isolation’, but only by completely debasing this word compared to its normal meaning (e.g. “To place or set apart or alone” – OED). John Anderson and colleagues, in a 1999 paper in the prestigious journal Science, made this claim, but the process described was to grind up whole mosquitoes or samples of a crow brain, pass the material through a filter with pores much larger than virus particles, centrifuge, then add this impure material, along with stimulating chemicals to a cell culture. ‘Isolation’ of WNV was the detection of “cytopathologic effects” (cell death), antibodies or particles of the expected size within this artificial system. This was obviously not equivalent to purification. According to Anderson “viruses can only be isolated in cells”, which is to say that viruses (according to him) cannot be purified, and any evidence that can possibly be interpreted as the footprints of a virus is accepted as proof of the presence of the virus. [Anderson, 1999]

Most virologists are happy to accept detection of non-specific phenomena generated by the addition of unpurified materials to a cell culture as proof that a pathogenic virus is present. But, Dr. Etienne de Harven, a retired University of Toronto virologist, believes that virology lost its way years ago by neglecting the need for purification. “To obtain virus specific reagents, purification is essential. But the success of such purification should be demonstrated. And the best way to demonstrate the achieved level of purification is to study, by electron microscopy thin sections of pelletized [centrifuged] virus!” The reagents he refers to are the RNA and proteins (antigens) needed for West Nile Virus tests. Without obtaining them from purified virus, there is no proof that they came from any virus, let alone a specific virus. [de Harven, 2002]

It was not until December, 2002 that a report claimed the“first time that infectious WNV has been recovered from a patient with encephalitis in North America” [Huang, 2002], indicating that the evidence for causation is weak, even without considering the flaws in the methods used to detect it.

If a virus is not causing the observed bird and human illness and death, something else must be. Jim West, a researcher with the No Spray Coalition [NoSpray], based in New York City (the supposed beachhead of the virus in North America) found a strong correlation between petrochemical emissions and both bird and human disease. For example, half the dead birds collected in the New York State counties with severe air pollution tested positive, less than 5% of those in moderately polluted counties and none in the least polluted counties. Excessive bird deaths were first noticed during a June 1999 air pollution peak in New York City, and human illness and deaths started during a second, even worse peak in late August. [West]

In Canada, Health Canada statistics for 2002 indicate a similar environmental connection. In Quebec 2% of dead birds found in the most rural areas of the province tested positive, but 37% of those tested from Montreal/Laval. In Ontario, about 5-11% of birds in rural areas were found to be positive (e.g. 5.6% in Porcupine district) but from 15-75% in the more industrialized areas (e.g. 35% in Toronto).

The disease is thought to be most prevalent in the corvid family – Crows, Ravens, Magpies and Jays and the highest rates are found in crows (18% of those tested in 2002). Surprisingly, however, the lowest rates are found in Ravens (2.5%), even lower than in species not believed to be at risk. While Crows and Ravens are closely related, Crows are much more common in heavily urbanized areas, including scavenging along highways. [CCWHC, 2002]

Human cases of disease with positive West Nile tests are even more urbanized. Greater Toronto has 44% of Ontario’s population, but 82% of the 65 cases in 2002 that were confirmed positive. The only other significant hotspot is Windsor which has 3.3% of the population yet 10.7% of the West Nile cases. It also has “anomalously high rates” of disease, death and congenital abnormalities, blamed on local pollution, and proximity to Detroit [Gilbertson, 2001].

West Nile is more a test than a disease. The CDC case definition [CDC, 1999] admits that the symptoms (fever, headache, altered mental state, stiff neck or various signs of brain dysfunction) are clinically indistinguishable from other viruses. Furthermore, the vast majority of people who test positive have none of these symptoms. One study found that 2.6% of a New Yorker sample tested positive, yet none had symptoms worse than a recent fever [Mostashari, 2001]. When more serious symptoms are associated with a positive test it is assumed that this is proof that the virus is the cause of the symptoms. There has even been a recent attempt in two separate New England Journal of Medicine papers to add polio-like paralysis to the clinical spectrum, based on positive tests in a handful of people with this condition [NEJM, 2002].

As testing extends further in Canada and the US, inevitably more people and animals will test positive. But, without baseline data, it is impossible to say whether we are seeing the spread of a virus, or merely of testing.

The CDC case definition requires that illness and a positive West Nile test occur during a time when virus transmission is believed likely (e.g. when mosquito populations are active). This is also when the collection of dead birds is encouraged. These policies reinforce the association between the disease and its purported carrier. The inability to find a mosquito connection in some cases has led to speculation that the virus can be transmitted via blood transfusions or organ transplants.

In the rare cases when serious disease or even death occurs, other explanations are also possible. The victims were usually elderly (average age 58 in Ontario, in 2002), had serious pre-existing health conditions (e.g. diabetes, cancer) and lived in heavily polluted areas.

You do not have to accept the story you are being told by Health Canada. Read the 1999 papers in Science (especially the fine print) and make your own decisions about the validity of the isolation they describe. You have the right to ask for proof that West Nile Virus has been purified, proof that tests have been constructed from RNA and proteins obtained from purified virus and proof that the virus can be purified from the bodies of animals and people whose sickness is blamed on the virus. You also deserve evidence that environmental connections have been thoroughly investigated, and eliminated.

Only when you are comfortable with the science of West Nile do you need to consider whether the prescription (aerial spraying for mosquitoes) is the lesser evil, or whether it will just increase the burden of chemicals to which we are exposed, while doing nothing to eliminate the root cause.


  1. [Anderson, 1999] Anderson JF et al. Isolation of West Nile Virus from Mosquitoes, Crows and a Cooper’s Hawk in Connecticut. Science. 1999 Dec 17; 286: 2331-3. Also, personal communications.
  2. [CCWHC, 2002] http://wildlife.usask.ca/WestNileAlertHTML
  3. [CDC, 1999] Encephalitis or Meningitis, Arboviral (includes California serogroup, eastern equine, St. Louis, western equine, West Nile, Powassan); 2001 Case Definition. http://www.cdc.gov/epo/dphsi/casedef/encephalitis_arboviral_current.htm.
  4. [de Harven, 2002] Personal communications (email: pitou.deharven@wanadoo.fr).
  5. [Gilbertson, 2001] Gilbertson M et al. Community health profile of Windsor, Ontario, Canada: anatomy of a Great Lakes area of concern. Environ Health Perspect. 2001 Dec; 109 Suppl 6: 827-43.
  6. [Huang, 2002] Huang C et al. First isolation of West Nile virus from a patient with encephalitis. EID. 2002 Dec; 8(12).
  7. [Mostashari, 2001] Mostashari F et al. Epidemic West Nile encephalitis, New York, 1999: results of a houshold-based seroepidemiological survey. Lancet. 2001 Jul 28; 358(9278): 261-4.
  8. [NEJM, 2002] Glass JD et al. Poliomyelitis Due to West Nile Virus. NEJM. 2002 Oct 17 and Leis AA et al. A poliomyelitis-like syndrome from West Nile Virus infection. NEJM. 2002 Oct 17.
  9. [NoSpray] Anti-spraying group based in New York City: http://www.nospray.org.
  10. [West] Jim West’s West Nile Virus website: http://www.geocities.com/noxot

Copyright © David Crowe, Wednesday, June 2, 2004.