Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates
Abstract The coastal region of Kenya has emerged as a focal point for urban dengue virus transmission driven by Aedes aegypti as the primary vector. To gain a deeper understanding of the epidemiological situation, we carried out a year-long longitudinal study (December 2021- November 2022) of the po...
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Nature Portfolio
2025-07-01
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| Online Access: | https://doi.org/10.1038/s41598-025-05408-z |
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| author | Josephine Osalla Louis-Clement Gouagna Gilbert Rotich Maureen Nzilani Penina Safari Kennedy Senagi Francis Mutuku Baldwyn Torto David P. Tchouassi |
| author_facet | Josephine Osalla Louis-Clement Gouagna Gilbert Rotich Maureen Nzilani Penina Safari Kennedy Senagi Francis Mutuku Baldwyn Torto David P. Tchouassi |
| author_sort | Josephine Osalla |
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| description | Abstract The coastal region of Kenya has emerged as a focal point for urban dengue virus transmission driven by Aedes aegypti as the primary vector. To gain a deeper understanding of the epidemiological situation, we carried out a year-long longitudinal study (December 2021- November 2022) of the population dynamics of A. aegypti through weekly mosquito surveys using ovitrap and CO2-baited Biogents (BG) mosquito traps in Ukunda, an urban township in the coastal region. Aedes eggs laid in ovitraps were exclusively A. aegypti with 80.8% mean hatch rate. A total of 35,109 adult A. aegypti were captured, with twice as many females than males. The density of adult A. aegypti trap captures varied monthly, but there was no discernible delineation by season. Aedes aegypti fed more on humans (human blood index = 0.72). Two dengue-2 virus RNA was detected in two blood-fed specimens that had fed on humans. Multiple linear regression model indicated 59% variation in adult female abundance explained by weather variables including daily range in wind speed (82.9%) and temperature (17.1%). In contrast, random forest model revealed 83% variation in egg abundance attributed to weather variables, being positively influenced by mean daily temperature, wind speed, relative humidity and negatively by total precipitation. Our results confirm year-round vector presence and active circulation of dengue virus indicative of endemicity in urban Kenya. The findings highlight the importance of short-term climatic factors as predictors of A. aegypti dynamics of value in surveillance and control of arboviral diseases such as dengue. |
| format | Article |
| id | doaj-art-30c75bf60a0c431abe7ae6fe8d57fffc |
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| issn | 2045-2322 |
| language | English |
| publishDate | 2025-07-01 |
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| series | Scientific Reports |
| spelling | doaj-art-30c75bf60a0c431abe7ae6fe8d57fffc2025-08-20T03:03:28ZengNature PortfolioScientific Reports2045-23222025-07-0115111110.1038/s41598-025-05408-zLongitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection ratesJosephine Osalla0Louis-Clement Gouagna1Gilbert Rotich2Maureen Nzilani3Penina Safari4Kennedy Senagi5Francis Mutuku6Baldwyn Torto7David P. Tchouassi8International Centre of Insect Physiology and EcologyMIVEGEC, Université de Montpellier, IRD, CNRSInternational Centre of Insect Physiology and EcologyInternational Centre of Insect Physiology and EcologyInternational Centre of Insect Physiology and EcologyInternational Centre of Insect Physiology and EcologyTechnical University of MombasaInternational Centre of Insect Physiology and EcologyInternational Centre of Insect Physiology and EcologyAbstract The coastal region of Kenya has emerged as a focal point for urban dengue virus transmission driven by Aedes aegypti as the primary vector. To gain a deeper understanding of the epidemiological situation, we carried out a year-long longitudinal study (December 2021- November 2022) of the population dynamics of A. aegypti through weekly mosquito surveys using ovitrap and CO2-baited Biogents (BG) mosquito traps in Ukunda, an urban township in the coastal region. Aedes eggs laid in ovitraps were exclusively A. aegypti with 80.8% mean hatch rate. A total of 35,109 adult A. aegypti were captured, with twice as many females than males. The density of adult A. aegypti trap captures varied monthly, but there was no discernible delineation by season. Aedes aegypti fed more on humans (human blood index = 0.72). Two dengue-2 virus RNA was detected in two blood-fed specimens that had fed on humans. Multiple linear regression model indicated 59% variation in adult female abundance explained by weather variables including daily range in wind speed (82.9%) and temperature (17.1%). In contrast, random forest model revealed 83% variation in egg abundance attributed to weather variables, being positively influenced by mean daily temperature, wind speed, relative humidity and negatively by total precipitation. Our results confirm year-round vector presence and active circulation of dengue virus indicative of endemicity in urban Kenya. The findings highlight the importance of short-term climatic factors as predictors of A. aegypti dynamics of value in surveillance and control of arboviral diseases such as dengue.https://doi.org/10.1038/s41598-025-05408-zAedes aegyptiDengue-2 virusUrbanizationFeeding patternsClimate changeArbovirus surveillance |
| spellingShingle | Josephine Osalla Louis-Clement Gouagna Gilbert Rotich Maureen Nzilani Penina Safari Kennedy Senagi Francis Mutuku Baldwyn Torto David P. Tchouassi Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates Scientific Reports Aedes aegypti Dengue-2 virus Urbanization Feeding patterns Climate change Arbovirus surveillance |
| title | Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates |
| title_full | Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates |
| title_fullStr | Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates |
| title_full_unstemmed | Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates |
| title_short | Longitudinal surveillance of Aedes aegypti (Diptera: Culicidae) in urban coastal Kenya: population dynamics, blood feeding frequency and dengue virus infection rates |
| title_sort | longitudinal surveillance of aedes aegypti diptera culicidae in urban coastal kenya population dynamics blood feeding frequency and dengue virus infection rates |
| topic | Aedes aegypti Dengue-2 virus Urbanization Feeding patterns Climate change Arbovirus surveillance |
| url | https://doi.org/10.1038/s41598-025-05408-z |
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