by The summary
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Nearly 12 million cases of dengue fever have been recorded in America this year, almost three times as many as last year.
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New research suggests that climate change is responsible for almost a fifth of the global dengue burden.
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According to the results, this proportion is likely to increase significantly in the future.
It’s been an exceptionally bad year for dengue fever: As of October, nearly 12 million cases had been recorded in America, nearly triple last year’s total of 4.6 million.
Research presented Saturday at the annual meeting of the American Society of Tropical Medicine and Hygiene quantifies the role climate change has played in the trend, attributing nearly a fifth of the existing dengue burden to rising temperatures.
The study predicts that climate change could be responsible for a 60 percent increase in dengue fever incidence by 2050 if emissions continue at a rapid pace, with spikes in some places – such as parts of Peru, Mexico, Bolivia and Brazil up to 200% can be recorded. .
Public health experts have long warned that global warming is allowing mosquito-borne diseases to spread to new places because it expands the geographic range in which the insects that serve as vectors live and thrive. Mallory Harris, co-author of the new research and a postdoctoral researcher in the biology department at the University of Maryland, said her team’s findings provide evidence of the significant role that climate change has played in the spread of dengue. More broadly, she said, research underscores the connection between greenhouse gas emissions and specific health outcomes.
“Dengue fever is a growing health threat that can have really serious consequences. We have to prepare for that,” Harris said. “We should expect such large epidemics in the future and think about how we can respond to them.”
The United States and its territories have seen more than 7,200 dengue cases so far this year – more than double last year’s total and the highest since 2013.
In June, the Centers for Disease Control and Prevention issued a health alert warning of an increased risk of dengue infections. After two locally acquired cases were discovered in the Florida Keys, the Monroe County Health Department issued its own alert the next month. According to the CDC, 53 locally acquired cases have been recorded in Florida so far that have not been linked to travel to a country where dengue fever is prevalent. California has recorded 15 such cases.
But the vast majority of U.S. cases this year have been in Puerto Rico, which declared a public health emergency in March amid an alarming rise in dengue infections. More than 4,500 locally acquired dengue cases have been reported in Puerto Rico, compared with fewer than 1,300 last year and even fewer the year before.
The new study, which has not yet been published or peer-reviewed, analyzed temperature records and dengue incidence data in 21 countries in Asia and the Americas over an average of 11 years. The researchers compared the data with a simulation of what would have happened during that period without human-caused climate change.
The resulting estimates are likely to be on the lower end of the spectrum, according to a press release accompanying the results, because dengue data is not available for some areas such as sub-Saharan Africa and South Asia. Additionally, predictions for the southern United States are difficult because the virus has only recently become a local threat.
The researchers found that the mosquitoes that transmit dengue fever – called Aedes aegypti – transmit the virus most efficiently when temperatures are between 20 and 30 degrees Celsius. They concluded that even if global greenhouse gas emissions were significantly reduced, the majority of countries analyzed would still see climate-related increases in dengue disease.
“The risks will still increase, so we need to think about mitigation measures,” Harris said, suggesting a focus on vaccines and efforts to control mosquito populations.
The maker of the only dengue vaccine approved by the Food and Drug Administration discontinued it earlier this year, according to the CDC.
More than half of people who contract dengue fever, a viral fever, remain asymptomatic. Most of the others are mild cases with symptoms such as fever, headache and joint pain, nausea and vomiting. Serious infections — about 2% of cases in U.S. territories from 2010 to 2020, according to the CDC — can cause bleeding under the skin, in the nose or in urine or stool, as well as a sudden drop in blood pressure or even death.
The disease is most common in places with humid, tropical climates throughout Latin America.
Derek Cummings, a professor of epidemiology at the Johns Hopkins Bloomberg School of Public Health who was not involved in the new research, said it needed “something we all knew – that temperature matters – but quantify how much.” and how important it is.” the changes we are seeing.”
Cummings, who has published his own research on dengue, added that he sees a global need to prioritize vaccinations, better control mosquito populations and ensure hospitals and health care providers are prepared for a surge in dengue cases.
Harris emphasized that the new research shows how the impacts of climate change are affecting different parts of the world.
“The greatest impacts of historical climate change on dengue burdens have been in places like Peru, Bolivia and Mexico, which are not necessarily the hottest places overall. They are not necessarily the places where heat deaths are increasing the most,” she said. “In places where it is a little cooler, there may be impacts that also need to be taken into account.”
This article was originally published on NBCNews.com
