13 research outputs found
Dengue and yellow fever virus vectors: seasonal abundance, diversity and resting preferences in three Kenyan cities
Isolation of Tick and Mosquito-Borne Arboviruses from Ticks Sampled from Livestock and Wild Animal Hosts in Ijara District, Kenya
Detection of West Nile virus in wild birds in Tana River and Garissa Counties, Kenya
Background West Nile fever virus is a zoonotic arboviral infection maintained in a sylvatic cycle involving mosquito vectors and birds. It is one the arboviruses whose geographical range is expanding because of climate and land use changes that enhance the densities of mosquitoes and promote mosquito-bird-human interactions. We carried out a survey to determine the reservoirs of WNV among wild birds in Tana River and Garissa counties, Kenya. Methods Blood samples were obtained from 361 randomly trapped wild birds. Using real-time polymerase chain reaction (PCR), all samples were screened for WNV using gene specific primer sets amplifying a portion of the E region of the genome encoding the envelope protein. Results Sixty five (65) out of 361 birds screened tested positive for WNV on real-time PCR assay. Sequencing of the selected positive samples reveals that the isolated WNV were most closely related to strains isolated from China (2011). A regression analysis indicated that sampling location influenced the occurrence of WNV while species, age, weight and sex of the birds did not have any effect. Conclusions This study provides baseline information on the existing circulation of WNV in this region among wild bird reservoirs that could spill over to the human population and points to the need for implementation of surveillance programs to map the distribution of the virus among reservoirs. Awareness creation about West Nile fever in this region is important to improve its detection and management
Vector competence of Aedes aegypti in transmitting Chikungunya virus: effects and implications of extrinsic incubation temperature on dissemination and infection rates
Whole genome phylogenetic investigation of a West Nile virus strain isolated from a tick sampled from livestock in north eastern Kenya
âWe do not bury dead livestock like human beingsâ: Community behaviors and risk of Rift Valley Fever virus infection in Baringo County, Kenya
Cell fusing agent virus (Flavivirus) infection in Aedes aegypti in Texas: seasonality, comparison by trap type, and individual viral loads
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Evolution of mosquito preference for humans linked to an odorant receptor
Female mosquitoes are major vectors of human disease and the most dangerous are those that preferentially bite humans. A âdomesticâ form of the mosquito Aedes aegypti has evolved to specialize in biting humans and is the major worldwide vector of dengue, yellow fever, and Chikungunya viruses. The domestic form coexists with an ancestral, animal-biting âforestâ form along the coast of Kenya. We collected the two forms, established laboratory colonies, and document striking divergence in preference for human versus animal odour. We further show that the evolution of preference for human odour in domestic mosquitoes is tightly linked to increases in the expression and ligand-sensitivity of the odorant receptor AaegOr4, which we found recognises a compound present at high levels in human odour. Our results provide a rare example of a gene contributing to behavioural evolution and provide insight into how disease-vectoring mosquitoes came to specialise on humans