Environmental investigation using cemeteries following a La Crosse encephalitis case fatality in Tennessee, 2012

The mosquito-borne disease La Crosse encephalitis is the leading cause of arboviral disease among children, and was previously limited to the upper Midwest. Unfortunately, the Appalachian region, now has the highest incidence risk in the nation: 228.7 cases per 100,000 children 15 years and younger, and almost 75% of all US cases reported in a year are in Appalachia. In 2012 nine pediatric cases of La Crosse encephalitis occurred in eastern Tennessee, including one death. While Aedes triseriatus has been the historical vector, Ae. albopictus and Ae. japonicus are two invasive species that may be important accessory vectors. All three vectors oviposit desiccant-tolerant eggs in forest stands and opportunistically oviposit eggs in artificial containers. This use of artificial containers may move La Crosse virus (LACv) from the forest’s tree holes and into the urban environment because LACv can be transmitted to mosquito offspring. In an attempt to detect LACv in active mosquito populations, our objective was to detect the same LACv isolate in the active mosquito population as in the child, and to determine if cemeteries were effective sites for monitoring LACv and the vector population; we initiated in in-depth vector ecology study centered around the 2012 fatal case.