Plague surveillance by serological testing of coyotes (Canis latrans) in Los Angeles County, California.

Sera from 19 (5.6%) of 338 coyotes (Canis latrans) collected in Los Angeles County, California between 1986 and 1990 had antibodies against Yersinia pestis using the passive hemagglutination test. Coyotes were excellent sentinels of plague activity in Los Angeles County. Enzootic plague declined dramatically in the county during the 5-yr period.