In the treatment of horses suffering from West Nile virus (WNV), vets have only a few choices besides supportive care. A novel WNV serum antibody product received conditional approval from the USDA in November 2004. Colorado Serum Company (CSC) announced the product’s availability on Dec. 13, 2004.

Serum antibody products help animals that have been exposed to a disease by increasing the antibody level against the disease in the circulatory system, thereby enhancing the animal’s ability to neutralize virus. The product is the third WNV serum or plasma product to receive conditional approval from the USDA. Randall J. Berrier, DVM, director of Veterinary Services at CSC, explained that the product is ready to use straight from the bottle (once it has been warmed to room or body temperature), and it doesn’t require pre-treatment with non-steroidal anti-inflammatory drugs. The serum antibody is developed from horses that have been hyperimmunized with inactivated WNV antigen and have high antibody levels to WNV.

To receive a conditional license, the company had to prove the product’s purity, safety, and a reasonable expectation of efficacy (for information on efficacy studies and specifics on the treatment method, see www.TheHorse.com/ViewArticle.aspx?id=5360).

Berrier says the product is processed so that it is very “clean,” sterile, and safe for IV use in the horse, and each batch is tested for purity, safety, potency, and endotoxin content. As with any treatment, it can’t be expected to be a cure-all and is best given as soon as WNV infection is suspected. It is available to veterinarians only