Malaria is spreading locally in the US

Malaria is a mosquito-borne disease that can cause fever, chills, headache, nausea, vomiting, muscle pain, and more. Although the disease is preventable and curable, it can sometimes be life-threatening if left untreated, leading to jaundice, kidney failure, seizures, and even death.

According to the World Health Organization, there were around 247 million cases of malaria worldwide in 2021, with an estimated 619,000 deaths from the disease. Per CDC, in the United States, around 2,000 cases of malaria are reported every year, but almost all of them are from travelers who visited other countries. Of these infections, 95% of them are acquired in Africa.

However, CDC on Monday announced that local transmission of malaria had been detected in the United States for the first time in 20 years. The last time the United States saw a local outbreak was in 2003 when eight cases were reported in Palm Beach, Florida.

So far, five local cases of malaria have been reported. Four cases have been identified in Florida over the last two months, as well as one case in Texas. According to CDC, "[a]ll patients have received treatment and are improving."

In an alert, CDC said that malaria is considered a medical emergency and that anyone experiencing symptoms should be "urgently evaluated."

Climate change is making malaria more widespread

As temperatures continue to rise worldwide, malaria and other vector-borne diseases will become more widespread, expanding to regions where they may have not been before.

According to a 2021 study published in The Lancet, climate change will increase the suitability of several environments for both malaria and dengue, another mosquito-borne infection. "Rising global mean temperature will increase the climatic suitability of both diseases particularly in already endemic areas," the researchers wrote. "The predicted expansion toward higher altitudes and temperature regions suggests that outbreaks can occur in areas where people might be immunologically naive and public health systems unprepared."

Estelle Martin, an entomologist at the University of Florida, has expressed a similar sentiment, saying that climate change is "definitely playing a role in vector-borne disease" throughout the United States.

A CDC spokesperson also acknowledged the potential impact of climate change on vector-borne diseases, but noted that growing worldwide migration may also play a role. "Today, global travel and trade allow vector-borne diseases to be moved around the world and transmitted by local mosquitoes or ticks, especially in places where those diseases may have once been common," the spokesperson said.

How to protect yourself from malaria

According to CDC, the risk of malaria in the United States remains low, but people should still take steps to keep themselves safe from the disease. Some ways to protect yourself from malaria include:

• Using insect repellants that have been registered with the Environmental Protection Agency
• Wearing loose-fitting, long-sleeved shirts and pants
• Use screens on windows and doors
• Drain items that can hold water, such as tires, buckets, and trash containers, at least once a month

Outside of personal measures, local health departments and agencies in areas where cases have been identified are also taking efforts to target and kill mosquitoes in the area, such as by spraying insecticides. CDC has also recommended hospitals have malaria tests available and stock up on treatments.

Overall, "[i]t's not panic time," said Brian Grimberg, an associate professor of pathology and international health at Case Western Reserve University. "I think the message is to be aware. I mean, Americans never think about malaria unless they travel abroad." (Millson, TIME, 6/27; Westerman, NPR, 6/27; Falconer, Axios, 6/27; Bernstein, Reuters, 6/26; Lallanilla, New York Post, 6/26; Getahun, Insider, 6/26; Shammas, Washington Post, 6/26)

Over time, climate change has caused several disease-carrying species to become more widespread in the United States, significantly increasing the risk of certain diseases, such as West Nile virus and Lyme disease. However, experts say the United States isn't prepared for future outbreaks, Sara Van Note writes for STAT.