The communities most vulnerable to the impacts of climate change are, in many cases, the ones that have the fewest resources to adapt. Mosquito-borne illnesses are no exception.
As temperatures rise globally, previously temperate areas are more likely to experience subtropical and tropical heat. A study authored by New York and New Jersey government researchers and one by researchers in Egypt suggest that many types of mosquitoes will move into the newly subtropical and tropical areas—bringing with them diseases like Zika, dengue, yellow fever, West Nile virus and chikungunya. In many countries, that means more diseases in communities that lack the medical and mosquito-control resources to cope.
Dr. Diego Herrera is a family physician with Andean Health and Development, a Catholic nonprofit serving communities in rural Ecuador. He estimates that 60 to 80 percent of his patients have been infected by disease-carrying mosquitoes—perhaps more, since some people carry mosquito-borne viruses without showing any symptoms of illness.
“It’s not just one disease, one mosquito, one virus,” Mr. Herrera said. In central Ecuador, where A.H.D.’s hospitals are located, chikungunya is particularly problematic, but other mosquito-borne illnesses plague the region as well.
In the United States, incidences of mosquito- and tick-borne infections tripled between 2004 and 2016, in part because of warming temperatures.
And people who have been infected by one virus may experience more severe illness following infection with another. A study published last year by researchers at Mount Sinai Health System in New York shows that mice that have been previously infected with dengue can have more severe symptoms of Zika; the same is true for interactions among various serotypes of dengue.
Some of these diseases can have effects that are long-term or debilitating like birth defects, blindness or severe joint pain. (In the east African language of Makonde, “chikungunya” means “bending over disease” because of the chronic pain it causes some patients.) Particularly among people who already live in poverty, mosquito-borne illnesses can have a huge impact on daily life because of missed days or weeks of work.
“If you’re the father and get these illnesses, the whole family will be impacted,” Mr. Herrera said. He is worried that more and more families will struggle if infection rates in his part of Ecuador rise along with global temperatures.
In the United States, incidences of mosquito- and tick-borne infections tripled between 2004 and 2016, in part because of warming temperatures, according to a study released on May 1 by the U.S. Centers for Disease Control and Prevention. The research suggests places like South Florida and Texas—both of which experienced outbreaks of locally transmitted Zika in the summer of 2016—may see longer mosquito seasons and more mosquito-borne illnesses as temperatures continue to rise.
Catholic health care providers say when those places lack the resources to cope, climate change and mosquito-borne illnesses become issues of social justice.
However, as temperatures in some places rise to optimal mosquito-breeding levels, temperatures in other places may become too hot for mosquitoes to spread disease.
“That pathogen has to basically go through an incubation period within the mosquito—anywhere from a couple of days to over a week,” Erin Mordecai, a Stanford researcher who studied the impact of temperature on mosquito populations, told NPR. Warmer weather causes viruses to mature faster, but it also shortens mosquitoes’ lives. So above a certain threshold, mosquitoes will die before they are able to spread disease. That means overall, the world may not necessarily see an increase in mosquito-borne illnesses, but there may be outbreaks in new places.
Catholic health care providers say when those places lack the resources to cope, climate change and mosquito-borne illnesses become issues of social justice.
“People who are the least responsible for this problem [of climate change] are the people who are bearing the burden, whether it’s in this country or third-world countries,” said Julie Trocchio, a senior director at the U.S. Catholic Health Association, which represents more than 2,200 Catholic hospitals and health facilities. She says the C.H.A. sees mosquito-borne illnesses as one of the many ways climate change has a disproportionately harsh impact on people who lack financial resources and political power.
“[Pope Francis] describes this as a moral issue beautifully in ‘Laudato Si’’—because of what it does to the poor, because of what it does to creation, because of what it does to our resources,” she said.
The C.H.A. has signed onto the Catholic Climate Covenant, a movement of organizations, church leaders, parishes and individuals seeking stronger action on global warming and climate change. It has urged President Trump and Congress to support the Clean Power Plan, the Paris climate accord and the Intergovernmental Panel on Climate Change.
“We’re concerned that when people talk about climate change, health isn’t one of the impacts that comes up,” said Ms. Trocchio. “And it’s huge, not just with the vector-borne diseases…but storms [and] heat events.”
As warming temperatures allow mosquitoes to survive in new areas, there could be one upside, if it could be so described. Mr. Herrera believes mosquito-borne illnesses have garnered more attention—and funding—because of the increasing outbreaks in wealthier nations and cities. When the 2016 Zika outbreak in Miami prompted fears of a public health crisis, it also thrust Zika onto the radar of politicians, reporters and researchers in the United States.
“It’s important that people in the first world care” about mosquito-borne illnesses, Mr. Herrera said, in order for research benefiting poorer countries to be funded. Mr. Herrera said research on the impacts of concurrent infections, along with prevention efforts, would benefit his patients most.
But, he added, new research cannot just focus on travelers who get infected during trips abroad, then bring the viruses back home. And in the United States, the public health implications of climate change cannot be in the spotlight only when a Zika outbreak bridges partisan divides.
“We must speak of how the world interacts, fundamentally,” he said.
This article appears in June 25 2018.
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