title: Amplification of the sylvatic cycle of dengue virus type 2, Senegal, 1999-2000: entomologic findings and epidemiologic considerations.
abstract: After 8 years of silence, dengue virus serotype 2 (DENV-2) reemerged in southeastern Senegal in 1999. Sixty-four DENV-2 strains were isolated in 1999 and 9 strains in 2000 from mosquitoes captured in the forest gallery and surrounding villages. Isolates were obtained from previously described vectors, Aedes furcifer, Ae. taylori, Ae. luteocephalus, and--for the first time in Senegal--from Ae. aegypti and Ae. vittatus. A retrospective analysis of sylvatic DENV-2 outbreaks in Senegal during the last 28 years of entomologic investigations shows that amplifications are periodic, with intervening, silent intervals of 5-8 years. No correlation was found between sylvatic DENV-2 emergence and rainfall amount. For sylvatic DENV-2 vectors, rainfall seems to particularly affect virus amplification that occurs at the end of the rainy season, from October to November. Data obtained from investigation of preimaginal (i.e., nonadult) mosquitoes suggest a secondary transmission cycle involving mosquitoes other than those identified previously as vectors.
authors.affiliation: Institut Pasteur de Dakar, Dakar, Senegal. diallo@pasteur.sn
authors.forename: Mawlouth
authors.initials: M
authors.lastname: Diallo
authors.forename: Yamar
authors.initials: Y
authors.lastname: Ba
authors.forename: Amadou A
authors.initials: AA
authors.lastname: Sall
authors.forename: Ousmane M
authors.initials: OM
authors.lastname: Diop
authors.forename: Jacques A
authors.initials: JA
authors.lastname: Ndione
authors.forename: Mireille
authors.initials: M
authors.lastname: Mondo
authors.forename: Lang
authors.initials: L
authors.lastname: Girault
authors.forename: Christian
authors.initials: C
authors.lastname: Mathiot
mesh_terms: D000330:Aedes / Q000821:virology*; D000818:Animals; D003716:Dengue Virus / Q000302:isolation & purification* / Q000472:pathogenicity; D005260:Female; D008297:Male; D011891:Rain; D012675:Senegal