title: Detection of dengue viruses in field-caught Aedes aegypti (Diptera: Culicidae) in Maracay, Aragua state, Venezuela by type-specific polymerase chain reaction.
abstract: Virological surveillance of dengue viruses in Aedes aegypti populations constitutes a powerful tool for early prediction of dengue outbreaks. We have standardized a protocol for viral RNA extraction from individual and pools of mosquitoes that permits a sensitive detection of dengue virus without RNA degradation or PCR inhibition when we apply a semi-nested RT-PCR. The limit of detection for each dengue serotype was 0.1 PFU. In a prospective field study conducted from November 2000 to December 2001, adult female A. aegypti mosquitoes from several municipalities with high dengue transmission in Maracay, Aragua State, Venezuela were collected and screened for dengue viruses using RT-PCR. We analyzed a total of 296 A. aegypti pools (1,632 mosquitoes); of these, 154 pools (469 mosquitoes) were collected from houses with persons with clinical diagnosis of dengue (dengue houses), and 142 pools (1,163 mosquitoes) from adjacent residences (neighbour houses). From the dengue houses, eight mosquito pools (5.2%) were positive for DENV-1 (0.7%), DENV-3 (3.2%) and DENV-4 (1.3%) viruses. From the neighbour houses, 18 mosquito pools (12.7%) were positive for DENV-3 (12%) and DENV-4 (0.7%) viruses. From these 26 RT-PCR positive mosquito pools (containing 1-25 mosquitoes each), 22 pools (84.6%) were positive for DENV-3. The most prevalent serotype in the 2001 dengue outbreak was also DENV-3. The minimum infection rate in both A. aegypti collections, from dengue houses and neighbour houses was 17 and 15 per 1,000, respectively. The relevance of these results for dengue surveillance is discussed.
authors.affiliation: Sección de Biología Molecular del Centro de Investigaciones Biomédicas (BIOMED), Apartado 2351, BIOMED, Universidad de Carabobo-Núcleo Aragua, Maracay, Venezuela. ludmel@telcel.net.ve
authors.forename: Ludmel
authors.initials: L
authors.lastname: Urdaneta
authors.forename: Flor
authors.initials: F
authors.lastname: Herrera
authors.forename: Martha
authors.initials: M
authors.lastname: Pernalete
authors.forename: Normig
authors.initials: N
authors.lastname: Zoghbi
authors.forename: Yasmín
authors.initials: Y
authors.lastname: Rubio-Palis
authors.forename: Roybel
authors.initials: R
authors.lastname: Barrios
authors.forename: José
authors.initials: J
authors.lastname: Rivero
authors.forename: Guillermo
authors.initials: G
authors.lastname: Comach
authors.forename: Matilde
authors.initials: M
authors.lastname: Jiménez
authors.forename: Maria
authors.initials: M
authors.lastname: Salcedo
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D003716:Dengue Virus / Q000145:classification / Q000302:isolation & purification*; D005260:Female; D007303:Insect Vectors / Q000821:virology; D012367:RNA, Viral; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014687:Venezuela
chemical_list: D012367:RNA, Viral