**An Analytical Study of the Perceptions, Prevention Strategies,
Treatment and Economic Impact of Equine West Nile Virus**

**Robert Galvan, MPH, MS, DrPH~ABD~, Associate Dean**

Department of Health Management & Policy, School of Public Health,
University of North Texas Health Science Center at Fort Worth, Fort
Worth, Texas 76107-2699, USA

E-mail: <bgalvan@hsc.unt.edu>, Tel: 817-735-2372, FAX: 817-735-0324

**Antonio Rene, Ph.D., Assistant Professor**

Department of Epidemiology, School of Public Health, University of North
Texas Health Science Center at Fort Worth, Texas 76107-2699, USA

E-mail: <arene@hsc.unt.edu>, Tel: 817-735-0327, FAX: 817-735-0324

**K.P.Singh, Ph.D., Professor and Chair**

Department of Biostatistics, School of Public Health, University of
North Texas Health Science Center at Fort Worth, Texas, 76107-2699, USA

E-mail: <ksingh@hsc.unt.edu>, Tel: 817-735-0490, FAX: 817-7352314

***Abstract:*** Since the introduction of the West Nile Virus (WNV) in
the United States in 1999, WNV has been the cause of disease and deaths
in humans, wild birds, zoo birds, and horses. In 2002, more than 15,000
equines in 40 states were diagnosed with illness associated with WNV.
Approximately one third of those horses died or was euthanized. Horses
are infected with the WNV more often than humans or any other mammal. It
is becoming one of the fastest growing health threats to horses
nationwide. Texas responded to the discovery of WNV by expanding their
surveillance systems in the eastern counties of the state. Positive
reports for WNV were announced in 2002, which prompted an increase in
public education and equine vaccination recommendations. Although much
has been reported on the economic impact WNV has on human health and
hospital care facilities, documentation is lacking on these issues in
the equine population. Understanding the biology, epidemiology, economic
impact, and how WNV affects the equine industry are important aspects to
public health programs and prevention activities.

***Objectives:*** The objectives of this study are to: (1) examine WNV
cases in the equine population in Texas in order to better understand
the distribution of clinical disease, signs, treatments and outcomes;
(2) to provide information regarding the knowledge, concerns, and
treatment of the WNV by Texas veterinarians; and (3) to determine the
economic impact of the WNV on the equine population in the state.

***Methods:*** A 14 question survey was mailed to licensed veterinarians
in Texas in an effort to gather information about their perceptions and
beliefs of the WNV, recommended treatment preferences, and the estimated
cost of treatment. Outcomes included case fatality rate, descriptive
data, veterinarians' knowledge of WNV, veterinarians'
beliefs/perceptions of WNV, and the economic impact of WNV. Descriptive
analyses were performed by using SPSS version 11. The methods used for
analysis of WNV data were primarily simple descriptive statistics
including summations and frequencies. A cross-tabulation was performed
between the results of Questions 1, 2, and 3 and a variable created to
approximate the number of veterinarians that actually treated cases of
WNV (treat). A cross-tabulation and Chi-square analysis was performed
between the treatment variable (treat) and derived variables of
Questions 1, 2, and 3 to examine differing beliefs and knowledge between
veterinarians who had treated WNV and those who had not.

***Results:*** Seven hundred of 4,177 surveys returned yielded a
response rate of 16.8 percent. Among the veterinarians, 73.4% (514/691)
believed that they are knowledgeable about WNV. Only 49.7% (348/691)
believed that they are receiving or received enough training and/or
education concerning WNV. The vaccination regimen is believed to be
effective and reliable by 56.1% (393/691) of the respondents. There were
1,256 cases of equine WNV reported confirmed via laboratory testing.
There were also 766 cases reported that were not confirmed via
laboratory testing. Among the 2,022 diagnosed cases, 257 were vaccinated
against WNV prior to illness; and, 159 cases were vaccinated after signs
of illness. A total of 441 horses died as either a direct cause of the
disease or by owner or veterinarian elected euthanasia. The most common
criteria used to decide euthanasia in these horses was prolonged
recumbency as reported by 44.2% (87/197) of the veterinarians. Fifty-two
percent (233/448) of the veterinarians did not recommend prevention
strategies to equine owners. The cost of the vaccination regimen was
reported by 62% (269/434) of the veterinarians to be \$25 or less.

***Conclusions:*** The results of the survey suggest that there could be
a need for WVN education among veterinarians in areas of prevention,
control, and treatment. Future studies should be conducted to examine
owner knowledge and beliefs of WNV vaccinations and prevention
strategies. Values for lost horses were not solicited in the survey,
thus, a total economic impact could not be completely estimated.
However, a formula to approximate the aggregate economic impact of the
WNV on the Texas equine industry was employed.