Cathy Barnette, DVM, a paid consultant for Covetrus®

There’s no doubt that West Nile virus (WNV) is a serious threat for horses. WNV is the leading cause of encephalitis in horses, with over 25,000 reported cases since its introduction in 1999.¹

In our interview with Kevin Hankins, DVM, MBA, senior technical services veterinarian for Zoetis Animal Health,² he points out that WNV “is now considered an endemic disease in the United States, so the horse owner needs to remain concerned about the disease even though it has been around for over 20 years.“

In 2018 alone, the United States Department of Agriculture identified 220 equine WNV cases in 34 different states.³ The virus has been identified in all 48 continental United States; its wide distribution is likely attributable to the fact that it has many potential mosquito vectors.

Current estimates suggest that WNV has a 33% mortality rate, accompanied by a 40% likelihood of residual neurological deficits (lasting six or more months) in surviving horses.¹ Additionally, Dr. Hankins notes that the mortality rate is 70% in horses that are recumbent at the time of diagnosis. Given these factors, it’s no surprise that WNV is now regarded as a core vaccine by the American Association of Equine Practitioners.¹ However, gaining an equine client’s compliance with recommended vaccination strategies can sometimes present a challenge that requires creativity and information to overcome.

Emphasizing Value in West Nile Virus Vaccination

Equine clients, like many veterinary clients, are often price-conscious. When debating whether to pay for a recommended service, such as WNV vaccination, they want to know whether the service provides value. Fortunately, WNV vaccines are an affordable and effective solution for many equine clients.

Depending on the vaccine you carry and your practice’s pricing strategies, the price of a single WNV vaccination will likely be $50/year or less. This vaccine is often administered at the same time as other preventive care services, so there is rarely a need for a separate farm call charge.

Contrast the cost of vaccination against the cost of WNV infection. According to Dr. Hankins, “The cost [of treatment] can reach into the thousands of dollars and there is still no guarantee that the horse will survive.”

Mild cases may only require outpatient care, but moderate and severe cases could require weeks of hospitalization. Some patients require treatment in a specialty hospital with access to slings and other materials appropriate for treating horses with neurological conditions, further increasing the cost of treatment. While specific data regarding the cost of treating WNV are limited, a 2002 North Dakota study estimated the cost of treatment at approximately $1,500 per horse.⁴ That study was performed 20 years ago; when adjusted for inflation, we can expect the average cost of treatment to be at least $2,500 today.

Vaccine Guarantees as an Additional Benefit of Vaccination

WNV vaccines provide effective protection against disease. Leading WNV vaccines are estimated to be over 95% effective, with unvaccinated horses being 30 times as likely to develop symptoms of WNV.⁵

However, in the event that a horse does experience a break in vaccine coverage, vaccines offer an additional advantage. Vaccine manufacturers often may reimburse horse owners for a significant portion of their treatment costs, with verification that the vaccine was administered in an appropriate manner.

Zoetis, for example, offers an Equine Immunization Support Guarantee for horses that have received their vaccine from a licensed veterinarian in the context of a valid veterinarian-client-patient relationship. In the event that a horse contracts WNV after appropriate vaccination, Zoetis will reimburse the client up to $5,000 for costs associated with the diagnosis.⁶

Dr. Hankins emphasizes, “This is only available to horses that are vaccinated by a licensed veterinarian and is not available to horses that are vaccinated by the horse owner or with vaccines purchased through catalog sales, over the counter sales or other sources.”

While we all certainly hope that we will never need to rely on a vaccine guarantee (and we shouldn’t, given the excellent efficacy of most equine vaccines), these guarantees may provide an additional assurance for clients. Remind clients of these vaccine guarantees, to ensure them that they are truly “getting their money’s worth” when allowing you to administer recommended vaccines to their horse.

Read more about vaccinations for horses in the vector-borne diseases resource center.

About the author: Cathy Barnette, DVM is a veterinarian and freelance writer, based in Southwest Florida. After graduating from the University of Florida in 2006, Dr. Barnette spent 14 years working in small animal general practice. Her current professional focus is veterinary writing, creating educational content for veterinary teams and their clients. Dr. Barnette is a paid Consultant for Covetrus.

References

1. American Association of Equine Practitioners. West Nile Virus. Accessed April 17, 2023. https://aaep.org/guidelines/vaccination-guidelines/core-vaccination-guidelines/west-nile-virus
2. Kevin Hankins, DVM, MBA, email communication [interview], April 24, 2023.
3. USDA APHIS. (2022). 2021 Summary of West Nile Virus Equine Cases in the United States. Accessed April 17, 2023. https://www.aphis.usda.gov/animal_health/downloads/animal_diseases/2021-wnv-report-summary.pdf
4. Ndiva Mongoh, M., Hearne, R., Dyer, N. W., & Khaitsa, M. L. (2008). The economic impact of West Nile virus infection in horses in the North Dakota equine industry in 2002. Tropical animal health and production, 40(1), 69–76.
5. Epp T, Waldner C, West K. (2005). Efficacy of vaccination for West Nile virus in Saskatchewan horses, in Proceedings: 51st Annual Convention of the American Association of Equine Practitioners, 180-182. Accessed April 17, 2023. https://www.ivis.org/library/aaep/aaep-annual-convention-seattle-2005/efficacy-of-vaccination-for-west-nile-virus-saskatchewan-horses
6. Zoetis. Equine Immunization Support Guarantee. Accessed April 17, 2023. https://www.zoetisus.com/content/_assets/docs/Equine/Equine_ISG_certificate.pdf.