Avian hosts of St. Louis encephalitis virus in Pine Bluff, Arkansas, 1991
McLean, R.G.; Kirk, L.J.; Shriner, R.B.; Townsend, M.
American Journal of Tropical Medicine and Hygiene 49(1): 46-52
1993
ISSN/ISBN: 0002-9637 PMID: 8352391 Document Number: 407021
An investigation of the extent of St. Louis encephalitis (SLE) virus activity in the avian population of Pine Bluff, Arkansas, USA, was conducted from 30 August 1991 to 5 September 1991, following a SLE epidemic that resulted in 25 human cases. A total of 363 birds of 33 species were captured with ground-level mist nets at 4 sites along the northern edge of the city. No viruses were isolated from the serum of these birds, but 91 birds (25%) of 11 species had detectable neutralizing antibody against the TBH-28 strain of SLE virus in the constant-virus, serum-dilution, plaque-reduction neutralization test in Vero cell culture. No antibody to eastern equine encephalitis virus was detected. The prevalence of antibody to SLE virus varied among the sites from 11 to 44%, but the prevalence at each site was influenced by the avian species composition. The 2 most abundant species captured in the city, the American robin (Turdus migratorius) (43%) and house sparrow [Passer domesticus] (42%), also had the highest prevalence of antibody. Nine other bird species were serologically positive but at significantly lower rates than for the abundant species. The antibody prevalence was higher in immature birds (27%) than in adult birds (15%), but the antibody titres were higher in adult birds than in immature ones. The overall SLE antibody prevalence and the prevalence for house sparrows were significantly higher than the average prevalence for avian hosts studied during previous SLE epidemics. Therefore, house sparrows would be a good choice for a local sentinel species.