In controlling BVD, what is the recommended strategy for animals with persistent infection?

In controlling BVD, what is the recommended strategy for animals with persistent infection?

• A. Vaccinate all animals
• B. Cull PI animals and vaccinate others
• C. Do nothing
• D. Isolate and monitor

Answer: (B)

The key idea is that animals with persistent infection continuously shed the BVD virus and act as the main source of transmission in the herd. The most effective control is to remove these lifelong sources by culling them, which drastically reduces the viral reservoir. Once the PI animals are gone, vaccinating the remaining animals helps protect susceptible animals and lowers the chance of fetal infection in future pregnancies, preventing new PIs from being born and slowly building herd immunity. Vaccinating all animals without removing PIs won’t eliminate the problem because the virus would still be shed by the PI animals. Isolating and monitoring alone isn’t enough to stop transmission since the persistent shedders remain in the population. Do nothing would allow ongoing spread and losses to continue.

The key idea is that animals with persistent infection continuously shed the BVD virus and act as the main source of transmission in the herd. The most effective control is to remove these lifelong sources by culling them, which drastically reduces the viral reservoir. Once the PI animals are gone, vaccinating the remaining animals helps protect susceptible animals and lowers the chance of fetal infection in future pregnancies, preventing new PIs from being born and slowly building herd immunity. Vaccinating all animals without removing PIs won’t eliminate the problem because the virus would still be shed by the PI animals. Isolating and monitoring alone isn’t enough to stop transmission since the persistent shedders remain in the population. Do nothing would allow ongoing spread and losses to continue.