Top veterinarians and the USDA dispute allegations made in a May 30 article in The Denver Post that the West Nile virus (WNV) vaccine might have caused widespread abortions and deformed foals. Mare owners calling themselves the “Lost Foals Group” claimed the vaccine caused up to 1,200 abortions and nearly 300 deformed or dummy foals.

A news release from the USDA stated: “Some recent stories have suggested that the Fort Dodge Animal Health (FDAH) West Nile virus vaccine approved by the USDA may cause pregnant mares to abort or give birth to deformed foals. The misleading information in those articles has sparked many anxious phone calls from horse owners, veterinarians, and others involved with horses. Unfortunately, as a result, the USDA is concerned that horse owners may not use an effective preventive measure against West Nile virus available to them, that of vaccinating their horses.

“Horse owners should be assured that the vaccine is safe, and it should be used as protection against West Nile virus (emphasis from USDA).” (For the complete press release visit www.aphis.usda.gov/lpa/issues/wnv/wnv_vaccine.html.)

Tom Riddle, DVM, of Rood and Riddle Equine Hospital in Lexington, Ky., (which has 38 equine veterinarians on staff) said, “I can tell you that my practice has vaccinated thousands of mares with the West Nile virus vaccine, and we have seen no relationship between the vaccine and abortions