Plant resting site preferences and parity rates among the vectors of Rift Valley Fever in northeastern Kenya. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Arum, Samwel; Weldon, Christopher; Orindi, Benedict; Tigoi, Caroline; Musili, Francis; Landmann, Tobias; Tchouassi, David; Affognon, Hippolyte; Sang, Rosemary
• Is Part Of: Parasites & vectors. Volume 9:Issue 1(2016)
• Page Start: 1
• Page End: 10
• Publication Date: 2016-12
• Subjects: Parity -- Survival -- Resting preference -- Vegetation -- Rift Valley fever vectors; Parasitism -- Periodicals; Parasites -- Periodicals; Vector-pathogen relationships -- Periodicals; Animals as carriers of disease -- Periodicals; Insects as carriers of disease -- Periodicals; 616.96
• DOI: 10.1186/s13071-016-1601-7
• Languages: English
• ISSNs: 1756-3305

Abstract

Abstract Background Mosquito lifespan can influence the circulation of disease causing pathogens because it affects the time available for infection and transmission. The life-cycle of mosquitoes is determined by intrinsic and environmental factors, which can include the availability of hosts and suitable resting environments that shelter mosquitoes from extreme temperature and desiccating conditions. This study determined the parity rates (an indirect measure of survival) and plant resting preference of vectors of Rift Valley fever (RVF) in northeastern Kenya. Methods Resting mosquitoes were trapped during the rainy and the dry season using a Prokopack aspirator from vegetation, whereas general adult populations were trapped using CDC light traps. At each site, sampling was conducted within a 1 km2 area, subdivided into 500 × 500 m quadrants and four 250 × 250 m sub-quadrants from which two were randomly selected as sampling units. In each sampling unit, plants were randomly selected for aspiration of mosquitoes. OnlyAedes mcintoshi andAe. ochraceus were dissected to determine parity rates while all mosquito species were used to assess plant resting preference. Results Overall, 1124 (79 %, 95 % CI = 76.8–81.1 %) mosquitoes were parous. There was no significant difference in the number of parousAe. mcintoshi andAe. ochraceus . Parity was higher in the rainy season than in the dry season. Daily survival rate was estimated to be 0.93 and 0.92 amongAe. ochraceus andAe. mcintoshi, respectively.Duosperma kilimandscharicum was the most preferred plant species with the highest average capture of primary (3.64) and secondary (5.83) vectors per plant, whileGisekia africana was least preferred. Conclusion Survival rate of each of the two primary vectors of RVF reported in this study may provide an indication that these mosquitoes can potentially play important roles in the circulation of diseases in northern Kenya. Resting preference of the mosquitoes in vegetation may influence their physiology and enhance longevity. Thus, areas with such vegetation may be associated with an increased risk of transmission of arboviruses to livestock and humans.