Expectoration of flaviviruses during sugar feeding by mosquitoes (Diptera: Culicidae)

van den Hurk, Andrew F., Johnson, Petrina H., Hall-Mendelin, Sonja, Northill, Judy A., Simmons, Russell J., Jansen, Cassie C., Frances, Stephen P., Smith, Greg A., and Ritchie, Scott A. (2007) Expectoration of flaviviruses during sugar feeding by mosquitoes (Diptera: Culicidae). Journal of Medical Entomology, 44 (5). pp. 845-850.

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Abstract

Biological transmission of arboviruses to a vertebrate host occurs when virions are expelled along with saliva during blood feeding by a hematophagous arthropod. We undertook experiments to determine whether mosquitoes expectorate flaviviruses in their saliva while sugar feeding. Batches of Culex annulirostris Skuse and Culex gelidus Theobald (Diptera: Culicidae) were orally infected with Japanese encephalitis (family Flaviviridae, genus Flavivirus, JEV), Kunjin (family Flaviviridae, genus Flavivirus, KUNV; a subtype of West Nile virus), and Murray Valley encephalitis (family Flaviviridae, genus Flavivirus, MVEV) viruses. After a 7-d extrinsic incubation, these mosquitoes were offered sucrose meals via cotton pledgets, which were removed daily and processed for viral RNA by using real-time TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) assays. JEV, MVEV, and KUNV RNA was detected in all pledgets removed from batches of Cx. gelidus on days 7–14 postexposure. In contrast, detection rates were variable for Cx. annulirostris, with KUNV detected in 0.3 M sucrose pledgets on all days postexposure, and JEV and MVEV detected on 57 and 50% of days postexposure, respectively. Higher concentrations of sucrose in the pledget did not increase virus detection rates. When individual JEV-infected Cx. gelidus were exposed to the sucrose pledget, 73% of mosquitoes expectorated virus with titers that were detectable by TaqMan RT-PCR. These results clearly show that flaviviruses are expectorated by infected mosquitoes during the process of sugar feeding on artificial pledgets. Potential applications of the method for arboviral bioassays and field surveillance are discussed.

Item ID: 2549
Item Type: Article (Refereed Research - C1)
Keywords: dengue; mosquito; arbovirus; Japanese encephalitis
ISSN: 0022-2585
Date Deposited: 23 Jul 2009 06:24
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1117 Public Health and Health Services > 111799 Public Health and Health Services not elsewhere classified @ 100%
SEO Codes: 92 HEALTH > 9204 Public Health (excl. Specific Population Health) > 920405 Environmental Health @ 51%
92 HEALTH > 9299 Other Health > 929999 Health not elsewhere classified @ 49%
Citation Count from Web of Science Web of Science 5
Downloads: Total: 2
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