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 blood or imbibing blood prior to attempting transmission. Aedes aegypti is known to contact multiple hosts during each egg-laying cycle and multiple host contacts might diminish the amount of virus in infected mosquito's salivary glands or ducts and render them functionally uninfective. Probing a host 5, 10, or 20 consecutive times did not significantly alter the infectivity of parenterally infected mosquitoes. However, 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 regardless of their probing or engorging history, and (2) once Ae. aegypti become infective they are extremely efficient disseminators of dengue virus.