Cases of a mosquito-borne illness known as dengue are rapidly increasing throughout the world possibly due to climate change.
A health emergency has been declared in may parts of the world including Puerto Rico, Brazil and Peru. Dengue, also known as break-bone fever, is a viral infection that is most commonly found in tropical and subtropical climates.
More than 6.5 million cases of dengue were recorded worldwide in 2023, according to the World Health Organization. In the Americas, there was a record high of 4.6 million cases in 2023. Alarmingly, in 2024, there have been than 7 million cases reported in the Americas through the end of April.
There have been 13 reported cases of dengue in Virginia in 2024, and more than 2,500 cases throughout the United States, according to the Centers for Disease Control. Most dengue cases reported in the 49 continental U.S. states occur in travelers infected elsewhere.
Michael Robert, an assistant professor in the Department of Mathematics at Virginia Tech, is working with a team of Argentinian collaborators to learn more about the spread of dengue and the impact of climate change on the transmission of the disease.
“The mosquito’s entire life cycle is highly regulated by temperature, and so part of what’s happening is that the mosquito species is moving farther south of the equator and farther north of the equator,” said Robert. “Environmental conditions are becoming more suitable for the mosquito species in these places, and so it’s having an easier time getting established.”
Robert is working with two graduate students from Virginia Commonwealth University and four undergraduate students and a recent graduate from Virginia Tech.
Robert provides expertise in mathematical modeling; other colleagues bring knowledge in areas such as epidemiology, entomology, ecology, geospatial analyses, climate science and public health.
“As a mathematical biologist and mathematical modeler, my role in this is going to be working on building predictive models, but also building models that can help us better understand why transmission has been happening and what’s driving these outbreaks,” said Robert. “The goal is that we want to use an all-hands approach.”
One goal of Robert’s research in Argentina is to create an early warning system for dengue transmission that can be turned over to public health officials.
“The idea behind an early warning system is kind of like a weather forecast,” said Robert. “We look at relationships between things like climate and disease outbreaks and we can use that information to generate a warning basically that the climate conditions are favorable for an outbreak, so we should be on the lookout over this period of time.”
What is happening in central Argentina could be an indicator of what is to come closer to home, Robert said.
“We need to be paying more attention to what’s happening in other places, in part because we’re not necessarily going to be safe from these issues,” said Robert. “The climate in the region we are studying is not unlike the climate in some of the southern U.S. states. From this project, I think we can learn a lot about dengue fever and the relationship between climate and why it’s sort of creeping into temperate areas and use that to get a head start in other places.”
Mosquitos are also responsible for diseases including malaria, yellow fever, Zika, West Nile virus and chikungunya.