A Critique of West Nile Virus Equine Cases Study (P. Salazar, et al., 2002)

By Jim West and David Crowe

This concerns a study entitled "West Nile Virus: Background Information and a Characterization of Its Equine Cases in Colorado and Nebraska in 2002", by P. Salazar, et. al, which is being heavily promoted throughout the horse industry via press releases. It is online at www.agr.state.ne.us/division/bai/wnvreport.htm

A statement from the study was selected for press releases which promote West Nile virus vaccine:

"The case fatality rate among the WNV [ West Nile virus] cases that had been vaccinated a minimum of one time prior to onset of signs was 20.3 percent, while 36.6 percent of unvaccinated animals had died or were euthanized."

Some press releases provide Salazar's blunt interpretation:

"According to Salazar, the study suggests that vaccinating equids is one very important step toward preventing the disease in horses."

-S askatchewan Horse Federation

However, the actual study declares that it was not designed to support such interpretations:

"The objective of this survey was to describe the equine West Nile virus cases in Nebraska and Colorado in order to better understand the progression of clinical disease, clinical signs, and clinical outcome."


"This study was not designed to evaluate the efficacy of vaccination for preventing WNV infection or decreasing the likelihood of developing clinical disease. While some horses that were reportedly vaccinated according to manufacturer's recommendations developed clinical disease..."

Note that vaccine failure and complications (admitted in the above) are apparently not considered worthy of study.

Essentially, we should disregard the study, and especially the press releases, as propaganda. Much of the study consists of standard uncritical claims describing an assumed pathogenic WNV, mosquitoes as virus vectors, and the vaccination as "a preventative measure." Much of the study's text is regurgitated material completely beyond the stated scope of the study. The professional tone of the study may impress some, but science is more than tone, terminology, and numbers.

We still await empirical and logical proof that diseases caused by the virus can be prevented by the vaccine.

We review here the study on its own terms, except the standard prologue and epilogue claims that recount the highly promoted, a) history of WNV epidemics, b) dangers of the virus, and c) advantages of the vaccine.

The study should have included the following caveats:

Encyclopedia Britannica Macropaedia (1990), p507, defines most viruses as beneficial genetic transfers, not pathogens:

"...most viruses that infect bacteria, plants, and animals (including humans) do not cause disease. In fact, bacteriophages [bacteria viruses] may be helpful in that they rapidly transfer genetic information from one bacterium to another, and viruses of plants and animals may convey genetic information among similar species, aiding the survival of their hosts in hostile environments."

1) Deaths are described, yet little is provided about the various types of illness.

2) The effects of WNV vaccine on horses is not described, apparently because it is assumed to carry little or no risk, which is unusual for a vaccine, and contradictory to reports from horse owners.

3) The study does not consider challenges to the West Nile virus theory, ignoring, for example, that the incidence of WNV symptoms among tested animals is directly proportional to air pollution exposure.

4) The study's own numbers provide a technical argument against WNV vaccination:

a) 47% of WNV cases had been vaccinated previous to acquiring the disease.

b) 50% of WNV cases had not been vaccinated.

Note there is little difference between the two.

Vaccination seems hardly worthwhile, except for another statistic offered: The case fatality rate among non-vaccinated was nearly twice that of vaccinated, i.e., 36.6% versus 20.3% (see quote, at beginning of this article).

However, with vaccination showing no ability to prevent the disease, the case fatality rate appears to be hard evidence of diagnostic inaccuracies. WNV disease is not easily diagnosed since it has symptoms indistinguishable from flu, fever, numerous neurological disorders, GI tract disease, and vaccination induced diseases.

5) Because the study only considered West Nile virus cases, if vaccinated horses became ill or dead due to diagnoses interpreted as non-WNV, then these horses would be excluded from consideration. The study should have included total deaths and total illness among the vaccinated, making the conservative assumption that they might be related to the vaccine, even though the symptoms might be unexpected for a vaccine reaction.

The vaccine could produce a wide variety of disease symptoms, some occurring quite long after vaccination, and accordingly, vaccinated horses suffering non-WNV symptoms should not be eliminated from the study at the whim of diagnosticians.

Veterinarians who are critical of the vaccine do not feel free to express or act on their opinion for various reasons, and so a strong bias permeates the entire vaccination program.

6) Nothing has been done to minimize this diagnostic confusion, as noted in the following:

a) A well-publicized result of the study is, "The case fatality rate among the WNV cases that had been vaccinated [versus] unvaccinated animals."

b) The focus should simply be, "The fatality rate of WNV vaccinated versus WNV unvaccinated."

This simplification would remove the diagnostician and his dilemma, and reveal problems with the vaccine.

7) The WNV horse vaccine study notes that few horses were fully vaccinated. This could very well be an indication of the presence of unacceptable vaccine side effects and should be reported as a failure of the vaccine. In these cases the owners should be queried as to why full vaccination status was not acquired.

8) Government agencies, designed ostensibly to protect the public, are too strongly influenced by industrial interests to be able to objectively evaluate any vaccination program. This problem is well documented by Dan Fagan, et al., "Toxic Deception" (1996). Fagan cites, for example, Judge J. R. Elliot, federal district court, 1995, who paraphrased the CEO of Dupont, "When DuPont says what the science means, that is what the science is." Fagan also cites large numbers of completely faked studies, and helps us to understand the vulnerability of government agencies to industrial influence.

9) Our article ("West Nile Virus: Horse Puckey?", published in Natural Horse , Volume 4, Issue 6) asks for evidence of a properly characterized WNV virus. The WNV horse study should tell us that WNV lab samples are contaminated with extraneous matter, i.e., not actually isolated, as admitted by USGS and by papers published in the prestigious journal Nature .

10) Obvious environmental factors are not even mentioned, let alone discounted. A study of 62 New York State counties found that MTBE and associated air pollution correlated in time and place with " West Nile virus" case incidence. Worldwide, the severity of WNV and SLE (St. Louis Encephalitis, WNV's twin virus) epidemics (over 20 reviewed) are proportional to industrial emissions exposure, mainly oil refinery emissions. See www.geocities.com/noxot.

11) The study was not a clinical trial, meaning that the environment of each horse, both its natural and care environment (type of care and feeding), represents uncontrolled variables that could have biased the study. The gathering of data cannot be standardized in this type of remote data gathering operation.

12) Data is significantly biased when it is obtained from a third party (veterinarian) that gains financial benefit from vaccination and may be legally liable for vaccine-related injuries. Vets will be more likely to report a) injury in vaccinated animals as non-vaccine related, and b) illness or death in non-vaccinated animals as WNV related.

13) Euthanasia should not be reported under "survival status". Euthanasia results from diagnoses that, as described, are problematic. The only way euthanasia should be reported is if a horse health expert who is blinded to the vaccination status makes the decision.

This article is a discussion of issues, not medical advice, which requires professional consultation. For more information, see the Salazar document itself, and discuss the issues with a knowledgeable, trusted veterinarian.

About the authors:
David Crowe is an analyst of the science behind modern medicine, particularly virology. He has an HBSc in Biology and Mathematics, and lives in Calgary with his wife and 3 children, where he works as a self-employed communications consultant. He publishes often in "Alive" magazine and redflagsweekly.com. He can be reached by email at David.Crowe@aras.ab.ca.

Jim West's background is engineering and computer science. Since 1999, he has served as Chairman of the Science Committee for the NoSpray Coalition in New York City . The group has organized environmentalists against the city's pesticide spray campaigns for ' West Nile virus' mosquito vectors, and is engaged in an ongoing suit against the NYC in federal court. For details, see www.nospray.org. Jim was recently published in The Weston A. Price Foundation's journal, "Wise Traditions".

Related info:

www.geocities.com/noxot (WNV critique)

www.geocities.com/harpub (Poliovirus critique)