Economic impact of an epizootic of bovine vesicular stomatitis in California.

A recent outbreak of vesicular stomatitis in California's San Joaquin Valley caused economic loss at 2 dairies of $225,000 during a 2-month period. These losses amounted to $202/cow for dairy 1 and $97/cow for dairy 2. The most notable economic losses were associated with high cull rates. The rapid spread of the disease (attack rates were 72% in 66 days for dairy 1 and 38% in 41 days for dairy 2) suggests that high-density herds particularly may be vulnerable to the disease. Factors that may have accounted for this rapid spread included common water troughs, open corrals, and inability of the dairy operator to isolate cows due to lack of space.