The Seasonality and Ecology of the Anopheles gambiae complex (Dipetra: Culicidae) in Liberia Using Molecular Identification.
Members of the Anopheles gambiae sensu lato (Giles) complex define a group of seven morphologically indistinguishable species, including the principal malaria vectors in Sub-Saharan Africa. Members of this complex differ in behavior and ability to transmit malaria; hence, precise identification of member species is critical to monitoring and evaluating malaria threat levels. We collected mosquitoes from five counties in Liberia every other month from May 2011 until May 2012, using various trapping techniques. A. gambiae complex members were identified using molecular techniques based on differences in the ribosomal DNA (rDNA) region between species and the molecular forms (S and M) of A. gambiae sensu stricto (s.s) specimens. In total, 1,696 A. gambiae mosquitoes were collected and identified. DNA was extracted from legs of each specimen with species identification determined by multiplex polymerase chain reaction using specific primers. The molecular forms (M or S) of A. gambiae s.s were determined by restriction fragment length polymorphism. Bivariate and multivariate logistic regression models identified environmental variables associated with genomic differentiation. Our results indicate widespread occurrence of A. gambiae s.s., the principal malaria vector in the complex, although two Anopheles melas Theobald/A. merus Donitz mosquitoes were detected. We found 72.6, 25.5, and 1.9% of A. gambiae s.s specimens were S, M, and hybrid forms, respectively. Statistical analysis indicates that the S form was more likely to be found in rural areas during rainy seasons and indoor catchments. This information will enhance vector control efforts in Liberia.
U.S. Naval Medical Research Unit No.3, 3A Imtidad Ramses Street, Adjacent to Abbassia Fever Hospital, Abbassia, Postal Code 11517, Cairo, Egypt. nermeen.fahmy.eg@med.navy.mil.
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Fahmy
U.S. Naval Medical Research Unit No.3, 3A Imtidad Ramses Street, Adjacent to Abbassia Fever Hospital, Abbassia, Postal Code 11517, Cairo, Egypt.
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Villinski
Liberian Institute for Biomedical Research, P.O. Box 31, Charlesville, Margibi County, Monrovia, Liberia.
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Bolay
Navy Entomology Centers of Excellence, Box 43, Building 937, Jacksonville, FL 32212-0043, USA.
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Stoops
U.S. Naval Medical Research Unit No.3, 3A Imtidad Ramses Street, Adjacent to Abbassia Fever Hospital, Abbassia, Postal Code 11517, Cairo, Egypt.
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Tageldin
Liberian Institute for Biomedical Research, P.O. Box 31, Charlesville, Margibi County, Monrovia, Liberia.
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Fakoli
U.S. Naval Medical Research Unit No.3, 3A Imtidad Ramses Street, Adjacent to Abbassia Fever Hospital, Abbassia, Postal Code 11517, Cairo, Egypt.
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Okasha
Navy Entomology Centers of Excellence, Box 43, Building 937, Jacksonville, FL 32212-0043, USA.
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Obenauer
U.S. Naval Medical Research Unit No.3, 3A Imtidad Ramses Street, Adjacent to Abbassia Fever Hospital, Abbassia, Postal Code 11517, Cairo, Egypt.
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Diclaro
D063147:Animal Distribution; D000818:Animals; D000852:Anopheles / Q000145:classification / Q000235:genetics / Q000502:physiology*; D021901:DNA, Intergenic / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007303:Insect Vectors / Q000145:classification / Q000502:physiology*; D007988:Liberia; D008288:Malaria / Q000469:parasitology / Q000635:transmission; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011156:Population Density; D012339:RNA, Ribosomal, 28S / Q000235:genetics / Q000378:metabolism; D012621:Seasons
D021901:DNA, Intergenic; D012339:RNA, Ribosomal, 28S
Anopheles gambiae; PCR-RFLP; hybrid; molecular form