332 - How does concurrent ingestion of microfilaria and virus enhance virus transmission

Abstract: Because microfilariae (MF) penetrate the midgut almost immediately after a bloodmeal, concurrent ingestion of microfilariae and arboviruses by mosquitoes may allow a virus to bypass both midgut infection and midgut escape barriers and infect the hemocoel within hours of ingestion. This would not only allow for a much higher dissemination rate but would also greatly shorten the extrinsic incubation period. This has been shown for various Brugia spp. and several viruses including Rift Valley fever, eastern equine encephalitis, Venezuelan equine encephalitis, and dengue viruses. Is this enhancement due to infectious virus leaking out the holes in the midgut created by the MF or by some other means? We have shown that there is an interactive relationship between various Brugia spp. MF and several different arboviruses that indicate that the MF actively transport infectious virus across what might have been a midgut barrier. We will illustrate how the presence of these other pathogens can significantly affect the ability of a mosquito to transmit a virus and even turn an essentially incompetent mosquito into a competent vector.