Detection of the bloodmeal origin of mosquitoes collected at alligator farms, and West Nile Virus activity in mosquitoes collected from alligator farms, sentinel chicken surveillance sites, and larval habitats
Doctor of Philosophy (PhD)
A three year study was conducted to determine if testing mosquitoes collected in modified sentinel chicken boxes for West Nile Virus (WNV) or testing sentinel chickens for WNV antibody would detect WNV activity prior to reports of human cases in East Baton Rouge (EBR) Parish, Louisiana. In one year we also compared the effectiveness of CDC light traps, gravid traps, and sentinel chicken box traps for collecting WNV positive mosquitoes. In all three years, we detected WNV activity in mosquito collections from sentinel chicken box traps prior to the onset of human cases, while there were no seroconversions in the chickens prior to human cases. In order to incriminate mosquitoes as vectors of WNV for captive alligators, mosquitoes were collected using Centers for Disease Control (CDC) light traps, gravid traps, backpack aspirators and resting boxes at three commercial Louisiana alligator farms from 2004 to 2006. The bloodmeal origins of 237 field-collected mosquitoes were identified based on cytochrome B (cytb) sequence homology. Alligator blood was detected in 24 mosquitoes representing six species of mosquitoes. This is the first study that identified alligator blood from mosquitoes at Louisiana alligator farms. Mosquitoes also were collected from the commercial Louisiana alligator farms and tested for WNV RNA. A total of 2, 404 mosquito pools were tested using reverse transcriptase polymerase chain reaction. West Nile virus was detected in 41 pools of females of 11 mosquito species. A comprehensive survey for vertical transmission of WNV was conducted. Male mosquitoes and mosquito larvae were collected in EBR Parish, Louisiana, using CDC light traps, gravid traps, backpack aspirators, resting boxes, and from larval habitats. West Nile virus was detected in 15 pools of male Culex specimens (collected as adults). West Nile virus also was detected in 2 pools of Cx. quinquefasciatus nulliparous females, 1 pool of Ae. albopictus nulliparous females and 2 pools of Culex species males. This is the second report of WNV vertical transmission in nature for Cx. quinquefasciatus and the first study that detected WNV from field collected nulliparous Ae. albopictus females.
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Unlu, Isik, "Detection of the bloodmeal origin of mosquitoes collected at alligator farms, and West Nile Virus activity in mosquitoes collected from alligator farms, sentinel chicken surveillance sites, and larval habitats" (2007). LSU Doctoral Dissertations. 184.