1 Arboviral Disease Section, Ecological Investigations Program, Center for Disease Control, Health Services and Mental Health Administration, Public Health Service, U. S. Department of Health, Education, and Welfare, Post Office Box 551, Fort Collins, Colorado 80521
A study was made of the role of house sparrows in the epidemiology of arboviruses in Hale County, Texas, during a 5-year period (1965-1969). Virus isolation attempts on bloods of 3,964 wild sparrows yielded 234 western equine encephalitis (WEE), 15 St. Louis encephalitis (SLE), 15 Turlock (TUR), and 2 Flanders-Hart Park (FLA-HP) viruses. Virus recovery rates from viremic nestling house sparrows varied directly with human attack rates of WEE and SLE, and provided the most reliable of several indices used to measure human risk of contracting clinical WEE infection. Rates of WEE virus recoveries were greatest in nestlings found dead in the nest or live nestlings 8 to 12 days old. Arboviruses were not detected in bloods of artificially hatched nestlings, or in fecal specimens of wild nestlings (with or without viremia). WEE virus was recovered from oral swabs of some naturally infected nestlings, but probably originated from blood contamination. These and other results are discussed in terms of WEE virus overwintering and amplification during epizootic seasons in Hale County, Texas.
Deceased 15 May 1972.
Present address: Vector Biology and Control, World Health Organization, 1211 Geneva 27, Switzerland.