Peru battles worst dengue outbreak as climate warms - The Washington Post
Peru battles worst dengue outbreak as climate warms - The Washington Post
Peru is taking extraordinary measures such as banning households from filling vases with water, as it battles its worst dengue outbreak on record, a crisis that experts have linked to increased rainfall and warmer temperatures as the climate changes.
The outbreak is a warning sign for countries in the tropics, where dengue and other insect-borne illnesses are increasingly prevalent as a rapidly changing climate brings more instances of warm and wet weather, which provide ideal breeding conditions for mosquito hosts. At its worst, dengue can cause high fevers, serious organ failure and death. The number of reported cases increased roughly tenfold from about 500,000 in 2000 to 5.2 million in 2019, according to the World Health Organization, which in March declared dengue a “major public health problem” for the Americas region.
The latest wave comes as northern parts of Peru experienced record rainfall in March. “In terms of climatic change, certainly increased precipitation, higher temperatures and higher humidity all favor the mosquito,” Raman Velayudhan, who leads the WHO’s program on Neglected Tropical Diseases, said at an April news conference.
The epidemic has been exacerbated by the beginning of the El Niño weather pattern, a regular occurrence that begins with warm water developing off the Pacific coast of South America and a weakening of trade winds that cause the water to flow toward the continent. This warming typically occurs every three to five years, before a period of cooler ocean water and stronger winds known as La Niña.
Climate change has increased rainfall expected during El Niño in Peru because more water evaporates into the air from a warmer ocean, which may then fall all at once when it reaches land, according to the U.S. Environmental Protection Agency, as opposed to less rain falling over a longer, steadier period of time.
Jason Mackenzie, professor of virology at the University of Melbourne’s Doherty Institute, said there is a clear link between increased rainfall and outbreaks of mosquito-borne illnesses. “Increased rainfall leads to increased accumulated water and so therefore you get more mosquitoes laying eggs,” he said.
A study published by U.S. and Peruvian public health experts in the journal PLOS Neglected Tropical Diseases last year found a “strong” link in Peru between dengue fever outbreaks, warmer weather and the El Niño Southern Oscillation.
“Dengue fever cases have increased substantially in the past four decades, driven largely by anthropogenic factors including climate change,” the authors wrote, adding that “climate change is expected to increase the frequency of El Niño events.”
Peru also prohibited storing still water in open containers, while rushing to opening a field hospital in one of its worst-affected regions. Residents have also been prohibited from trying to treat suspected dengue cases at home, and are instead being told to attend clinics.
“Dengue kills,” said Health Minister Rosa Gutiérrez Palomino in a Tuesday statement. “Because of that, help me eliminate mosquito breeding sites.”
Mackenzie, the Australian professor, said there have been several instances of increased rainfall leading to outbreaks of mosquito-borne illnesses in places where they were not known to spread. Japanese encephalitis has appeared 2,000 miles farther south than ever before— reaching Australia — after record flooding in usually cool and dry areas last year.
The West Nile virus also often resurfaces in the United States after a burst of mosquito breeding activity in a wet period, followed by a dry period that pushes mosquitoes into urban areas in search of water, Mackenzie said.
Related Knowledge Center: Climate economics
Climate change is now a driver of the world’s economy. The impact is profound:
- Catastrophic weather events — hurricanes, floods, droughts, high temperatures — are more frequent and more extreme. The cost can be measured in both the initial damage caused and the longer-term impact on the economy.
- Vulnerable communities are increasing climate-related investments, hardening infrastructure and taking other protective measures.
- Investment in carbon capture and storage technologies is increasingly rapidly.
- Governments are making investments and crafting regulations to reduce emissions of carbon dioxide and other greenhouse gases.
On top of all of this is the cost of uncertainty. As the Fourth National Climate Assessment, released in 2018 by the U.S. Global Change Research Program, says, “The assumption that current and future climate conditions will resemble the recent past is no longer valid.”