May 21 - July 30
The Thermal Potential for the Spread of Mosquito Borne Diseases Due to Climate Change in Oklahoma
Jenelle Edwards, Mike Wimberly, and Jason Davis
What is already known:
- The mosquito, Aedes aegypti, is a known vector for disease-causing viruses including Zika and dengue.
- There is a specific range of temperatures at which Aedes aegypti can transmit Zika and dengue.
- Future temperature characteristics of Oklahoma can be projected using climate models.
- Are temperatures in Oklahoma suitable for the transmission of Zika and dengue via Aedes aegypti? If temperatures shifts due to climate change, how will that affect the length of the transmission season of these viruses?
What this study adds:
- Recent meteorological data (1999 to 2018) indicated that there were about 91 to 110 days per year suitable for Zika transmission and 164 to 183 days per year suitable for dengue transmission.
- The number of days suitable for Zika and dengue transmission in Oklahoma via Aedes aegypti increased 20 to 35 for dengue and 25 to 40 days for Zika days in several future climate scenarios.
Abstract:
One possible outcome of climate change is the spread of vector borne diseases. According to the World Health Organization, vector borne diseases account for more than 17% of all infectious diseases, killing more than 700,000 people annually. Warming temperatures can cause vectors to spread into more favorable environments, increasing the rate that mosquitoes and viruses reproduce, mature, and spread. A particularly important mosquito vector is Aedes aegypti, known as the “Yellow Fever” mosquito. We explored the temperatures at which Aedes aegypti can transmit Zika and dengue, predicted where in Oklahoma temperatures are suitable for Aedes aegypti to carry out this process, and determined the potential effects of temperature fluctuations due to climate change on transmission potential (days out of the year where R0 > 0). Using daily temperature data collected by the Oklahoma Mesonet since 1999, we determined where there were suitable conditions for Zika and dengue transmission by Aedes aegypti by comparison with upper and lower temperature limits for each virus. Using downscaled climate projections developed by the Climatology Lab at the University of Idaho, we evaluated the average temperature shift throughout the state, determining a delta value, and added that to the current temperatures to analyze where the transmission potential for ZIKV and DENV could be in the years 2070 to 2099. For Zika transmission, it increased from 112 days to 136 days with RCP 4.5 and to 153 days with RCP 8.5. The number of days out of the year for dengue transmission increased from 171 to 191 days with RCP 4.5 and to 206 days with RCP 8.5.