Meeting Abstract

P2.74  Sunday, Jan. 5 15:30  Fitness conflict between vector and parasite: an investigation of fecundity and survivorship in parasitized Aedes aegypti SCHUMACHER, MS; Illinois State University mkschum@ilstu.edu

Evolutionary considerations predict that vector-borne parasites have less effect on vector fitness than on the fitness of the vertebrate host, because reduced vector fitness would likely result in a reduction in the parasites’ fitness. This prediction has led to the misconception that vector borne pathogens have no fitness effect on the vector. However, it is also true that parasites exploit their vectors, growing, developing, and sometimes replicating in the vector. Thus, the vector must remain healthy and live long enough to transmit the pathogen to a vertebrate host despite pathogen exploitation; however, vector fecundity is not essential for the parasite to survive or to be transmitted. If exploitation of the vector by the pathogen is energetically costly to the vector, vector fecundity may be reduced. Conversely, a parasite might manipulate vector fecundity by accelerating egg production to stimulate oviposition, which would in turn cause the vector to seek a blood-meal more frequently compared to non-infected females, thus enhancing probability of parasite transmission. Brugia spp. are blood-dwelling, filarial nematode parasites that are vectored by mosquitoes in the genera Aedes and Culex, and are the primary causes of lymphatic filariasis in mammals. Detrimental effects of Brugia on vector fitness, including fecundity and longevity of female mosquitoes were tested for a relationship to Brugia titer in the blood meal. The results illustrate the fitness conflict between vector and parasite, which arises because the parasite must exploit the vector to be transmitted successfully. The outcome of this conflict may be important to our understanding of vector-borne disease dynamics.