IMPACT OF DENGUE VIRUS-INFECTION ON FEEDING-BEHAVIOR OF AEDES-AEGYPTI

In addition to heavily infecting the salivary glands of Aedes aegypti (L.) mosquitoes, dengue viruses produce a significant infection of the nervous system, involving the brain, Johnston's organ, compound eye, and thoracic and abdominal ganglion. To determine if dengue infection affects feeding behavior of Ae. aegypti we measured feeding times, cou nted the number of feeding delays or interruptions, and by in situ imm unocytochemistry techniques determined the spatial and temporal distri bution of dengue infections in females parenterally infected with deng ue 3 virus. The mean of the total time required for feeding by infecte d mosquitoes was significantly longer than the time required by uninfe cted mosquitoes. Similarly, the mean of the time spent probing was sig nificantly longer in infected mosquitoes than in uninfected mosquitoes when day after inoculation was considered. Significant increases in t he length of feeding activity in infected mosquitoes corresponded to v irus infection in organs that are known to control or influence activi ties associated with blood feeding. Sequential infections of the saliv ary glands (five days postinoculation [PI]), brain and compound eye (e ight days PI), and Johnston's organ and midgut and abdominal ganglion (11 days PI) of most mosquitoes were observed. The increased time requ ired by infected Ae. aegypti mosquitoes to acquire a blood meal may co ntribute to the efficiency of Ae. aegypti as a vector of dengue virus. Longer feeding periods are more likely to be interrupted by the host, which increases the chance that an infected mosquito will probe or fe ed on additional hosts.