Can We Stave Off Vector-Borne Diseases From Encroaching Into New Areas?

The sustained rise in temperatures combined with extreme and more frequent weather events has expanded the natural habitats of mosquitos and ticks and increased the possibility of rare vector-borne diseases being discovered in previously unfounded areas.

For example, the CDC released a report last week that babesiosis, a rare, zoonotic-tickborne parasitic disease, had increased dramatically in Maine, Vermont, and New Hampshire, which were previously nonendemic places. And after such findings, the CDC decided to reclassify the states as having endemic babesiosis.

Lyme disease is another example of a tickborne disease expanding in North America. 

“With vectors like mosquitos, ticks, and sandflies, they are driven by temperatures and rainfall, and these indicators are going to be changing over time with the climate,” Andrea Thomas, PhD, director of epidemiology, BlueDot, said. “We know that the range where mosquitos may be suitable to survive, breed, and spread viruses will be changing over time. Ticks will also be moving into new areas where they had not previously been able to survive—and they will be active for longer.”

BlueDot uses data to model potential changes that could influence vector-borne diseases and illnesses and works with governments and public health officials in identifying these threats. The company recently released the results of their report showing that climate change is likely to turn northern hemisphere cities like New York, Toronto, and London into breeding grounds for dengue- and Zika-carrying mosquitoes over the next 10 years. This type of data is critical to understanding future at-risk populations who will be in need of related vaccinations, therapeutics, and education related to the tropical diseases.

BlueDot describes itself as a disease intelligence company, and has a data platform that provides public and private sector organizations information to identify, understand, and effectively respond to global biothreats.

For the report, the company used a gradient-boosted regression tree model to forecast global climatic suitability for the vectors, Ae. albopictus and Ae. aegypti mosquitoes, under the projected climate over the next 10 years with five-by-five-kilometer granularity. Precipitation, surface temperature, and elevation are used, along with historical mosquito occurrence data, to fit the models. They also evaluated three different climate scenarios which looked at best-case, most-likely, and worse-case changes.

BlueDot also predicted that the Zika virus would enter Florida 6 months before it occurred. The company is using data and modeling information to be one part of increasing infection prevention methods.

Thomas is optimistic for the long-term, and believes we can work towards staving off the more severe consequences and possibly limit the spread of such diseases. “Fortunately we do have a lot of tools that we can use, and I think that is the positive side of this,” Thomas said. “We can use science and technology and try to get ahead of where the frontier might be and the areas of risk.”

Contagion spoke to Thomas who offered more information about how the company does its modeling, and how uncovering this information can work towards infection prevention.