Which species is not susceptible to infection with FMD virus?

• A. Pigs
• B. Cattle
• C. Horses
• D. Water buffalo

Answer: (D)

FMDV has a limited host range and preferentially infects cloven-hooved livestock. The virus targets epithelial cells in the mouth and feet and spreads systemically, so species that are naturally permissive to replication and disease—like cattle, pigs, and water buffalo—show classic vesicular disease and strong susceptibility. Horses, on the other hand, are relatively refractory to FMDV infection in natural settings. They tend to resist productive viral replication, and clinical disease is rare unless exposure is unusually high or experimental routes are used. This makes horses the species not susceptible under typical exposure conditions, whereas water buffalo are indeed susceptible and can develop the disease.