THE EFFECT OF MULTIPLE HOST CONTACTS ON THE INFECTIVITY OF DENGUE-2 VIRUS-INFECTED AEDES-AEGYPTI

This study was designed to determine if transmission rates for dengue- 2 virus by Aedes aegypti are altered by mosquitos probing a host for b lood or imbibing blood prior to attempting transmission. Aedes aegypti is known to contact multiple hosts during each egg-laying cycle and m ultiple host contacts might diminish the amount of virus in infected m osquito's salivary glands or ducts and render them functionally uninfe ctive. Probing a host 5, 10, or 20 consecutive times did not significa ntly alter the infectivity of parenterally infected mosquitoes. Howeve r, orally infected Ae. aegypti that probed 20 times transmitted dengue viruses at a significantly higher rate than controls. Infectivity of orally infected Ae. aegypti was unaffected by blood feeding. Our data suggest that (1) dengue virus-infected Ae. aegypti remain infective re gardless of their probing or engorging history, and (2) once Ae. aegyp ti become infective they are extremely efficient disseminators of deng ue virus.