LABORATORY TRANSMISSION OF EASTERN EQUINE ENCEPHALOMYELITIS VIRUS TO CHICKENS BY CHICKEN MITES (ACARI, DERMANYSSIDAE)

Pools of adult female chicken mites, Dermanyssus gallinae (De Geer), were allowed to feed on chicks that had been inoculated with eastern equine encephalomyelitis (EEE) virus and that had a viremia level of 10(6.2)-10(6.6) plaque-forming units per milliliter of blood. Virus remained detectable by plaque assay in samples of these mites for 30 d after the infectious blood meal. Virus was not recovered from any of 151 progeny of virus-exposed female mites. Mites that had fed on viremic chicks were allowed to feed on naive chicks 3, 7, 11, 15, or 30 d later. EEE virus was transmitted to chicks by these mites on days 3 (one transmission in four trials) and 7 (one transmission in four trials). Both transmissions were confirmed by the presence of virus in chick blood 24-72 h after mites had fed, and by plaque-reduction neutralization assays of 21-d convalescent chick sera against the original viral strain.