PULLMAN, Wash. — Large animal veterinarians at Washington State University are informing the region’s llama and alpaca owners of confirmed West Nile Virus (WNV) disease in camelids.
The action follows information released Tuesday (Sept. 17) from the Iowa State University Veterinary Diagnostic Laboratory stating that samples from a Suri Alpaca tested positive for WNV. Results were confirmed at the National Veterinary Services Laboratory in Ames, Iowa.
“We think it is important to let the animal owning public know of any changes we see in any emerging disease,” explained Dr. Steve Parish, head of the WSU veterinary teaching hospital’s agricultural animal service. “By doing this early on, stock owners can decide how best to manage any risk they believe their animals are exposed to.”
Clinical signs of the disease in alpacas and other New World camelids consists of a contracture of the neck muscles, incoordination, lying down, and vocalizing in pain. The infected Iowa animal exhibited clinical signs for three and one-half days prior to its death. The alpaca also had a mild to moderate brain inflammation.
The Iowa case extends the range of domestic livestock at risk for WNV infection. In 2000, two llamas were reported WNV-positive in Connecticut, and one unconfirmed case was believed to have occurred in Massachusetts in 2001.
According to the Iowa group, the equine WNV vaccine has been tested in llamas and found to cause an immune response thought to provide some level of protection when using the same dosage as in horses. In addition, llama owners and breeders are using the vaccine in some states.
“However, the vaccine is not approved for use in these species and cannot be recommended for camelids,” Parish said.
Currently, the horse vaccine is available on a USDA conditional use permit. This means that, although it is safe, not all of the testing has been completed to determine how well it prevents disease. The vaccine can only be dispensed by a veterinarian.
There is no evidence to suggest that West Nile virus can be spread from person to person or from animals to people.