In recent months, we have become increasingly aware of the existence of bovine viral diarrhea BVD) virus infections within our llama and alpaca herds. It has long been suspected that BVD virus could infect these camelids with a similar frequency to cattle (0.5-1.0% Persistently Infected (PI)). The current management styles of many of our camelid herds, which do not emphasize herd biosecurity, have certainly increased the risk of infection. So far, the problem appears to be worse in the alpaca population. The purpose of this article is to help clear up any misconceptions concerning the disease and its potential effects.

BVD is caused by a virus that has traditionally been found in cattle, but variants of the virus are found in many species. The virus can cause severe diarrhea but this condition has become rare in recent years. It is noted primarily to cause decreased fertility, abortions and mild respiratory disease. These conditions are somewhat slow developing and nonspecific; thus they continue to occur within a population and often go unnoticed. The disease is easily transferred to naïve animals within 30-45 days of exposure and it is maintained in the herd with the presence of a persistently infected animal. PI animals occur when a naïve animal is exposed to the virus while she is pregnant. Usually these animals are between 45 and 120 days gestation when their fetus becomes infected. This fetus will be born PI and will always shed the virus to others. Most will die before they reach two years of age. Some will remain as normal animals within the population and will always be contagious to others. The animal that is first exposed to the virus after birth will develop an immune response and clear the virus. These animals will only be contagious to others for a short time.

Many diagnostic tests are available to help us determine recent infection or PI. It is best to test animals via a Serum Neutralization (SN) test to determine if antibodies are present in the serum which would indicate exposure to the virus. If determining PI status is the goal, I recommend using a whole blood PCR (Polymerase Chain Reaction test). This test looks for virus and if present for greater than 3 weeks, the animal is probably PI. These tests are a little confusing and we will be glad to discuss a testing plan within your herd.