Abstract
Climate change and variability influence temperature and rainfall, which impact vector abundance and the dynamics of vector-borne disease transmission. Climate change is projected to increase the frequency and intensity of extreme climate events. Mosquito-borne dis-eases, such as dengue fever, are primarily transmitted by Aedes aegypti mosquitoes. Freshwater availability and temperature affect dengue vector populations via a variety of biological processes and thus influence the ability of mosquitoes to effectively transmit dis-ease. However, the effect of droughts, floods, heat waves, and cold waves is not well under-stood. Using vector, climate, and dengue disease data collected between 2013 and 2019 in Kenya, this retrospective cohort study aims to elucidate the impact of extreme rainfall and temperature on mosquito abundance and the risk of arboviral infections. To define extreme periods of rainfall and land surface temperature (LST), we calculated monthly anomalies as deviations from long-term means (1983–2019 for rainfall, 2000–2019 for LST) across four study locations in Kenya. We classified extreme climate events as the upper and lower 10% of these calculated LST or rainfall deviations. Monthly Ae. aegypti abundance was recorded in Kenya using four trapping methods. Blood samples were also collected from children with febrile illness presenting to four field sites and tested for dengue virus using an IgG enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). We found that mosquito eggs and adults were significantly more abundant one month following an abnor-mally wet month. The relationship between mosquito abundance and dengue risk follows a non-linear association. Our findings suggest that early warnings and targeted interventions during periods of abnormal rainfall and temperature, especially flooding, can potentially con-tribute to reductions in risk of viral transmission.
| Original language | English |
|---|---|
| Article number | e0009182 |
| Journal | PLoS Neglected Tropical Diseases |
| Volume | 15 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2021 |
| Externally published | Yes |
Funding
This research was supported by National Institutes of Health (NIH) grant R01AI102918 (ADL). The Stanford REDCap platform (http:// redcap.stanford.edu) is operated by Stanford Medicine Research IT team. The REDCap platform services at Stanford are subsidized by a) Stanford School of Medicine Research Office, and b) the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through grant UL1 TR001085⤉. JMC was supported by a Stanford Woods Institute for the Environment-Environmental Ventures Program grant. The funders had no role in the collection, analysis, or reporting of the data.This retrospective study assesses the effect of extreme climate events on mosquito abundance and DENV transmission in Kenya using data from a study performed by the LaBeaud Lab, Technical University of Mombasa, and the Kenya Medical Research Institute (KEMRI). Vec-tor, climate, and disease data is housed in the Research Electronic Data Capture Database (REDCap) at Stanford University. The Stanford REDCap platform (http://redcap.stanford. edu) is operated by Stanford Medicine Research IT team.
