An assessment of the biological capacity of a Sacramento Valley population of Aedes melanimon to vector arboviruses.
Daily survivorship, duration of the gonotrophic cycle, absolute abundance and season-long relative abundance were estimated for Aedes melanimon in the Sacramento Valley of California in 1987 and 1988 using mark-release-recapture (MRR) techniques and by monitoring changes in the abundance and parity rate of the native population. One objective of these studies was to determine the extent to which A. melanimon was biologically capable of serving as a horizontal arbovirus vector. Daily survivorship was estimated to be 0.90 and 0.84 in MRR studies conducted in September 1987 and August 1988, 0.89 based on changes in the parity state and abundance of the native population in August 1988 and 0.82 using summer-long parity data in 1988. Gonotrophic cycle length (GCL) was estimated to be five days in three studies. Aedes melanimon densities were estimated to be approximately 1,000,000 and 15,000 females per hectare in September 1987 and August 1988 respectively. Parous A. melanimon females were collected on each sampling occasion from April to November 1988, suggesting that A. melanimon maintained a continuous presence in the study area throughout the summer. The results of these studies suggest that A. melanimon has the potential to be an efficient horizontal vector of western equine encephalomyelitis (WEE), based on high adult survivorship, short GCL, high abundance and a continuous presence across the summer. This supports the concept of a WEE transmission cycle in the Sacramento Valley involving Ae. melanimon as an important vector. Aedes melanimon also can be an efficient horizontal vector of California encephalitis virus (CE), though the importance of horizontal transmission to the maintenance of CE virus is unclear.
Jensen
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University of California, Davis.
Washino
R K
RK
D000330:Aedes / Q000382:microbiology / Q000502:physiology*; D000818:Animals; D002140:California; D004667:Encephalitis Virus, Western Equine; D004683:Encephalomyelitis, Equine / Q000635:transmission*; D005260:Female; D007303:Insect Vectors / Q000382:microbiology / Q000502:physiology*; D008297:Male; D010298:Parity; D011157:Population Dynamics; D012044:Regression Analysis; D012621:Seasons