A nearly $1.9 million grant from the National Science Foundation is enabling a Penn State-led group of researchers to continue studies on the potential effects of climate change on the spread of infectious diseases, such as malaria and dengue.

The grant is part of federal stimulus funding authorized under the American Recovery and Reinvestment Act.

Climate change has the potential to affect the dynamics and distribution of vector-borne diseases that impact the lives of millions of people, according to principal investigator Matthew Thomas, professor of entomology in Penn State's College of Agricultural Sciences.

"However, our ability to quantify risk is limited by our poor understanding of the relationship between transmission and environmental parameters," Thomas said. "The central aim of this project is to quantify how environmental temperature influences the transmission of vector-borne diseases, and how this in turn determines disease risk, both now and under future climate-change scenarios."

The researchers plan to evaluate the effect of temperature variation on transmission intensity; to down-scale global climate change projections to the regional level and assess the net effects of both climate change and land-use change on environmental conditions at the regional and local level; and to combine these down-scaled climate models with new biological research data to quantify the effects of environmental temperature on disease dynamics over time and space.

The project will allow scientists to better define the influence of climatic factors on the distribution and dynamics of malaria and dengue, the two most significant vector-borne diseases worldwide. Spread by mosquitoes, malaria and dengue annually infect as many as 500 million people.

"We hope the outcomes of this research can be used to develop appropriate practices for disease prevention and control," said Thomas. "The focus on dengue and malaria will provide general insights that also can be extended to other vector-borne diseases, such as West Nile encephalitis. In addition, scientists trained through this initiative will be well prepared to transfer skills into many areas of social and economic interest, including domestic animal and wildlife diseases, agriculture, fisheries and conservation."

Thomas was the principal investigator in related research published in a leading scientific journal earlier this year.

In the August 3 Proceedings of the National Academy of Sciences, his team reported that daytime temperature fluctuations alter both malaria parasite development in mosquitoes and disease-transmission rates. Consideration of these fluctuations -- rather than relying on average monthly temperatures -- could reveal a more accurate picture of climate change's potential impact on malaria.