A Deadly Mosquito-Borne Illness Rises as the U.S. Cuts All Climate-Health Funding

Brazil, where dengue is a near-constant threat. The NIH has also funded studies that bring the world closer to finding medical and technological interventions: more effective vaccines and genetically engineered mosquitoes that can’t develop dengue, among other solutions.

“Disease doesn’t have national borders,” said an American vector biologist who has received funding from the NIH in the past. She asked not to have her name or affiliated academic institution mentioned in this story out of fear of reprisal from the Trump administration. “I’m worried that if we’re not studying it, we’re just going to watch it continue to happen and we won’t be prepared.” 

Americans aren’t just bringing cases of dengue fever home with them from trips abroad; the disease is also spreading locally with more intensity in warmer regions of the country and its territories. Last March, Puerto Rico declared a public health emergency amid an explosion of cases on the island. By the end of 2024, Puerto Rico registered over 6,000 cases — passing the threshold at which an outbreak officially becomes an epidemic. More than half of the known infections led to hospitalization. Close to 1,000 cases have been reported there so far this year, a 113 percent increase over the same period in 2024. California and Florida reported 18 and 91 locally-acquired cases of dengue, respectively, last year. California registered its first-ever locally-acquired case of dengue in 2023. 

“Dengue is already found in many places in the U.S. that have never seen this disease before,” said Renzo Guinto, a physician and head of the Planetary Health Initiative at the Duke-NUS medical school in Singapore. “To combat this emerging climate-related health threat, U.S. scientists must collaborate with others working in dengue overseas. With no resources and capacity, how can such collaboration occur?”

There are limited non-government sources of funding for climate and health research. The money that is available to American researchers is primarily offered by private foundations like the Gates Foundation and the Wellcome Trust. The grants these philanthropies offer annually pale in comparison to the $40 million Congress made available annually through the NIH for climate and health research in the two years before Trump took office. Researchers will be forced to compete for a small pool of funding in the coming years, which will likely lead to fewer studies and less innovation in the years to come. “The end result will be that much less of this work would be done — we would all tell you to the detriment of Americans long term,” said the vector biologist.   

As dengue spreads with more intensity in the countries where it is already common and slips across borders into zones like North America where the disease is still comparatively rare, it’s clear countries need to expand their arsenals of disease-fighting weapons. But the U.S. appears to be leading a charge in the opposite direction, with thousands of lives at stake. 

“We’re at a time when we need acceleration of innovation and solutions to very pressing global problems,” said O’Neill, whose organization receives funding from governments around the world, including the U.S.“It’s not the time to let ideology drive science rather than let science drive itself.”

Zoya Teirstein is Staff Writer at Grist. This story was originally published by Grist. You can subscribe to its weekly newsletter here.