Geographic Distribution and Breeding Site Preference of Aedes albopictus and Aedes aegypti (Diptera: Culicidae) in Cameroon, Central Africa
ABSTRACT Presence in Cameroon of the recently introduced Aedes (Stegomyia) albopictus (Skuse) in association with the indigenous Aedes aegypti (L.) raises public heath concerns because it might alter the risk of arbovirus transmission. The breeding site and distribution of the two Stegomyia species are updated and reported following entomological surveys carried out in 22 localities throughout Cameroon, with a total of 1,353 containers with water visited. Ae. aegypti was found in every location sampled, showing higher infestation rates in northern Cameroon. Breeding populations of Ae. albopictus were observed in all 19 southern localities, up to the Adamaoua mountains, but the species was not recorded further north. In the area where both species are present, they were often sampled in the same larval developmental sites, suggesting convergent habitat segregation. The most frequently encountered artificial and natural breeding sites were used tires, discarded tins and plastic containers, abandoned car parts, brick holes, dead leaves on the ground, tree holes, and rock pools. Further monitoring of the demographic as well as geographic expansion of Ae. albopictus in this Afrotropical environment and its relationships with indigenous Ae. aegypti should provide insight into the biology of this highly invasive species and help to implement arboviruses surveillance programs in the area.
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- "tins and plastic containers, abandoned car parts, brick holes, dead leaves on the ground, tree holes, and rock pools; Simard et al. 2005). Ae. albopictus prefers to lay eggs in stagnant or nonturbulent waters containing microflora and fauna, debris of plant and animal origin (Clements 1963, Becker et al. 2010). "
ABSTRACT: In this study, we evaluated the larvicidal activity of four citrus essential oils (EOs; sweet orange, mandarin, bergamot, and lemon) against the arbovirus vector Aedes albopictus (Skuse) (Diptera: Culicidae) under laboratory conditions. Through gas chromatography-mass spectrometry (GC-MS) analyses, we found that in sweet orange, mandarin, and lemon EOs, limonene was the most abundant compound, whereas linalyl acetate was the most abundant in the bergamot EO. All tested EOs showed a marked larvicidal activity, in particular sweet orange, lemon, and bergamot that killed all treated larvae. After 24 h of exposure, the LC50 values of the tested citrus EOs ranged from 145.27 (lemon EO) to 318.07 mg liter(-1) (mandarin EO), while LC95 ranged from 295.13 to 832.44 mg liter(-1). After 48 h of exposure, the estimated LC50 values decreased to values ranging from 117.29 to 209.38 mg liter(-1), while LC95 ranged from 231.85 to 537.36 mg liter(-1). The results obtained from these evaluations, together with the large availability at reasonable costs of citrus EOs, are promising for the potential development of a new botanical mosquitocide.Journal of Economic Entomology 09/2015; DOI:10.1093/jee/tov270 · 1.51 Impact Factor
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- "albopictus because the accumulation of water at domestic and peridomestic sites can increase the number of artificial and natural breeding sites for mosquitoes (Chen & Hsieh 2012). Aedes aegypti is the principal vector of important arboviruses such as Yellow fever virus, Chikungunya virus, Zika virus, La Crosse virus and the four serotypes of Dengue virus (DENV1-4) (Simard et al. 2005; Paupy et al. 2009; Rezza 2012). Laboratory studies have demonstrated the competence of Ae. albopictus to become infected with and to transmit approximately 26 arboviruses , including Japanese encephalitis virus, West Nile virus, Yellow fever virus and Chikungunya virus (Gratz 2004; Ponce et al. 2004). "
ABSTRACT: Objective To entomologically monitor Aedes spp. and correlate the presence of these vectors with the recent epidemic of dengue in Divinopolis, Minas Gerais State, Brazil.Methods Ovitraps were installed at 44 points in the city, covering six urban areas, from May 2011 to May 2012. After collection, the eggs were incubated until hatching. In the 4th stage of development, the larvae were classified as Ae. aegypti or Ae. albopictus.ResultsIn total, 25 633 Aedes spp. eggs were collected. February was the month with the highest incidence, with 5635 eggs collected and a hatching rate of 46.7%. Ae. aegypti eggs had the highest hatching rate, at 72.3%, whereas Ae. albopictus eggs had 27.7%. Climate and population density influenced the number of eggs found. Indicators of vector presence were positively correlated with the occurrence of dengue cases.Conclusion These data reinforce the need for entomological studies, highlight the relevance of Ae. albopictus as a possible disease vector and demonstrate its adaptation. Ae. albopictus, most commonly found in forested areas, comprised a substantial proportion of the urban mosquito population.Tropical Medicine & International Health 10/2014; 20(1). DOI:10.1111/tmi.12402 · 2.33 Impact Factor
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- "In tropical African surveys, ecological and population studies have highlighted the importance of mosquitoes as vectors of lymphatic filariasis  . The contaminated water in pit latrines, septic tanks and drains which constitute good breeding habitats for Culex quinquefasciatus has led to an increase in the prevalence of urban filariasis. The spread of rural filariasis has been enhanced by the development of dams, reservoirs, etc, which are ideal, all-season habitats for the vector, Anopheles gambiae s.l.. "
ABSTRACT: The dearth of information on the epidemiology of Bancroftian filariasis in Akwa Ibom State, Nigeria, necessitated a 2-year study on filarial infection rates in humans and mosquitoes in rural (Abat, Odot, Nung-Udoe, and Oko-Ita) and urban (Ikot Ebok, Edisiong, Iba-Oku and Ibiakpan) communities across ecovegetational zones (Mangrove swamp forest, Lowland rainforest, Freshwater swamp forest, Moist savanna woodland). The spray catch method was used for mosquito collection. They were age-graded and filarial species identified by standard keys. Blood was obtained from consenting outpatients at hospitals and health centres at study locations. Two methods were used for the examination of blood samples (thick smear and concentration). Age grading yielded 42.1% nullipars and 57.9% parous; about 50.0% of the parous females had ovulated once, while 16.25-17.01% ovulated more than twice. The infection rates in An. gambiae s.l. and Cx. quinquefasciatus were 0.10 and 0.02% respectively. The overall infection rate in humans was 4.75%; the infection rates were 5.5 and 0.4% in rural and urban locations respectively. Wuchereria bancrofti, Loa loa and Mansonella persitans were identified; W. bancrofti was dominant. Filariasis prevalence was highest in the ≥60yr age-group and zero in the 0-19yr age-group. Longevity of mosquitoes in both seasons met the threshold for the complete development of the filarial worms to the infective stage. Infection rates in mosquitoes and humans were generally low, with highest prevalence was recorded in rural areas. Keywords Wuchereria bancrofti, Culex