Aedes albopictus is an Asian vector of dengue that has expanded its range over the past decade to include the Americas. As a potential dengue vector in the Western hemisphere, it is important to identify factors that affect this immigrant species and its interactions with the indigenous Ae. aegypti The effect of nutrients and Ascogregarina taiwanensis infections on the bionomics and vector potential of a New Orleans strain of Aedes albopictus were evaluated. Larvae were infected with oocysts and reared under optimal and deficient nutrient conditions using leaf litter as a detritus source. Mortality, development time, wing length and reproductive potential were measured for infected and uninfected groups. Parasitism and low nutrients caused a 35% increase in the rate of larval mortality and doubled the development time, of females. Parasitized adults were 5% smaller and produced 23% fewer eggs. While small body size is correlated with a lowered reproductive capacity, ascogregarine infections caused an additional decrease in fecundity Large, ascogregarine-infected females fed on blood infected with Dirofilaria immitis, had a higher (70%) filaria yield and a lower (22%) post blood meal mortality than single infected females. In large females it is possible that coinfection enhanced the immune response allowing fewer filaria to develop with less host mortality. In small females the lower vector potential may have resulted from low food reserves that limited filarial development, while further reductions in coinfected females may have been caused by ascogregarine damage to tubules Aedes aegypti cross infected with A. taiwanensis showed larval mortality, reduced size and extended development time. Responses varied according to the geographic origin of host and parasite strains, but indicated that the geographic expansion of Ae. albopictus may be aided by ascogregarine infections of the non natural host, Ae. aegypti The combined effects of nutrient levels and parasitism therefore regulate the population density of tire pile Ae. albopictus so the carrying capacity of the habitat is not exceeded. Thee factors also influence the vector capacity of this species for D. immitis. Finally, ascogregarines may play a role in the expansion of Ae. albopictus into habitats occupied by Ae. aegypti / acase@tulane.edu
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_25713 |
| Date | January 1997 |
| Contributors | Comiskey, Nora Mary (Author), Wesson, Dawn M (Thesis advisor) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Rights | Access requires a license to the Dissertations and Theses (ProQuest) database., Copyright is in accordance with U.S. Copyright law |
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