Proceedings of the Vertebrate Pest Conference

Since the report on our understanding of plague in California as reported in 1964, the largest outbreak in the state since the early 1940s occurred, which largely proved the assumptions stated in the earlier report. An infected chipmunk was found on the north shore of Lake Tahoe (Nevada) in August 1965; a human plague case occurred at Viola, southeastern Shasta County in September 1965, that was linked to an epizootic in California grounds squirrels nearby; and in 1966 plague was confirmed in three woodrats in the Tulare County foothills, where California ground squirrels were found also be involved at several locations. By late spring, plague was detected in chipmunks and golden-mantled ground squirrels in Shasta and Mono Counties. The role of various species serving as reservoirs and casualties of plague infection is discussed in detail, along with a description of investigations and actions taken by county and state public health personnel. The role of wood rats, the occurrence of epizootic migrations, and the effectiveness of control measures are discussed.