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United States Department of Agriculture

Agricultural Research Service

Title: Epizootiology and Transmission of a Newly-Discovered Baculovirus from the Mosquitoes Culex Nigripalpus and Culex Quinquefasciatus

Authors
item BECNEL, JAMES
item White, Susan
item Moser, Bettina
item Fukuda, Tokuo
item Rotstein, Margaret - NC STATE UNIVERSITY
item Undeen, Albert - RETIRED USDA/ARS/CMAVE
item Cockburn, Andrew - WEST VIRGINIA UNVERSITY

Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 26, 2000
Publication Date: N/A

Interpretive Summary: A naturally occurring virus that kills mosquitoes has been dicovered by ARS scientists at the Center for Medical, Agricultural and Veterinary Entomology, Gainesville Florida. This new virus kills larval mosquitoes quickly and over extended periods of time. We have discovered that magnesium is required for transmission and that calcium inhibits transmission of the virus. This fundamental knowledge contributes to our basic understanding of these pathogens and will enable the evaluation and development of viruses as biopesticides for the control of mosquitoes that vector deadly diseases of man and animals.

Technical Abstract: Reports of mosquito baculoviruses are extremely uncommon and epizootics in field populations are rarely observed. We describe a baculovirus that was responsible for repeated and extended epizootics in field populations of Culex nigripalpus and Culex quinquefasciatus over a two year period. These mosquito species are important vectors of St. Louis and Eastern equine encephalitis in the United States. Our initial attempts to transmit this baculovirus to mosquitoes in the laboratory were unsuccessful. A salt mixture similar to that found in water supporting infection in the field was used in laboratory bioassays and indicated that certain salts were crucial to transmission of the virus. Further investigations revealed conclusively that transmission is mediated by divalent cations: magnesium is essential, whereas calcium inhibits virus transmission of baculoviruses in mosquitoes and will allow characterization of the virus in the laboratory. In addition, they can explain, in great part, conditions that support epizootics in natural populations of mosquitoes that vector life-threatening diseases of man and animals.

Last Modified: 9/10/2014
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