title: Isolation of Japanese encephalitis and Getah viruses from mosquitoes (Diptera: Culicidae) collected near Camp Greaves, Gyonggi Province, Republic of Korea, 2000.
abstract: As part of an evaluation of the ecology of arthropod-borne diseases in the Republic of Korea (ROK), we examined 8,765 mosquitoes captured in Paju County, Gyonggi Province, ROK, for the presence of viruses. Mosquitoes were captured in propane lantern/human-baited Shannon traps, Mosquito Magnet traps, or American Biophysics Corporation (East Greenwich, RI) miniature light traps with or without supplemental octenol bait and/or dry ice. Mosquitoes were identified to species, placed in pools of up to 40 mosquitoes each, and tested on Vero cells for the presence of virus. A total of 15 virus isolations were made from 293 pools of mosquitoes. Viruses were identified by reverse transcriptase-polymerase chain reaction and sequencing and consisted of 14 isolations of Japanese encephalitis (JE) virus and one isolation of Getah (GET) virus. All JE isolates were from Culex tritaeniorhynchus Giles, and the isolate of GET was from Aedes vexans (Meigen). The minimum field infection rate for JE in Cx. tritaeniorhynchus was 3.3 per 1,000, whereas the GET virus infection rate for Ae. vexans was 0.2 per 1,000. Isolation of JE and GET indicated that both viruses were actively circulating in northern Gyonggi Province, ROK. The lack of human cases of JE among the Korean population probably is because of an effective government-mandated vaccination program. The reason for no cases among >10,000 United States military and others that reside or train nearby is unknown, but may be related to personnel protection measures (permethrin-impregnated uniforms and use of deet repellent), adult mosquito control, mosquito selection of nonhuman hosts (unpublished data), and the low symptomatic to asymptomatic ratio of disease in adults.
authors.affiliation: Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, MD 21702-5011, USA. michael.turell@det.amedd.army.mil
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Turell
authors.forename: Monica L
authors.initials: ML
authors.lastname: O'Guinn
authors.forename: Leonard P
authors.initials: LP
authors.lastname: Wasieloski
authors.forename: David J
authors.initials: DJ
authors.lastname: Dohm
authors.forename: Wan-Ja
authors.initials: WJ
authors.lastname: Lee
authors.forename: Hae-Wol
authors.initials: HW
authors.lastname: Cho
authors.forename: Heung-Chol
authors.initials: HC
authors.lastname: Kim
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Burkett
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Mores
authors.forename: Russell E
authors.initials: RE
authors.lastname: Coleman
authors.forename: Terry A
authors.initials: TA
authors.lastname: Klein
mesh_terms: D000330:Aedes / Q000821:virology; D000524:Alphavirus / Q000254:growth & development / Q000302:isolation & purification*; D018354:Alphavirus Infections / Q000401:mortality / Q000635:transmission; D000818:Animals; D001483:Base Sequence; D003465:Culex / Q000821:virology; D009033:Culicidae / Q000821:virology*; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004664:Encephalitis Virus, Japanese / Q000254:growth & development / Q000302:isolation & purification*; D004672:Encephalitis, Japanese / Q000401:mortality / Q000635:transmission; D004777:Environment; D006801:Humans; D007303:Insect Vectors / Q000821:virology; D007723:Korea / Q000453:epidemiology; D016133:Polymerase Chain Reaction / Q000379:methods; D013045:Species Specificity
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral