Five cases of locally-acquired malaria have been reported in the U.S., the CDC says—one in Texas and four in Florida. Malaria is a serious, mosquito-borne illness that was eradicated in the U.S. in the 1950s. It’s concerning to see signs that it may be making a comeback.
What is malaria?
Malaria is a life-threatening disease caused by a microscopic parasite, but the parasite is spread from person to person via mosquitoes. Cases of malaria can be mild or can be severe enough to be deadly.
There are five known species of the malaria parasite, and some of them cause more severe disease than others. But all five can cause illness that is potentially life-threatening. Malaria is especially dangerous to young children and to people who have HIV or otherwise have a weakened immune system.
Worldwide, malaria is most common in tropical areas. The parasite uses Anopheles mosquitoes to breed (they actually mate in the mosquito’s gut) and the climate has to be warm enough; the parasite can’t complete its growth cycle if the temperature drops much below 70 degrees. About 95% of malaria cases and deaths occur in Africa.
Malaria is treatable, especially if caught early. There are medications that can kill the parasite, although in some areas the parasite has become resistant to the most commonly used drugs. The CDC has a chart here showing which species of malaria are most common in each country, and which medications are recommended to treat it.
Why is it a big deal that malaria is in the US?
Malaria is a serious illness; it can lead to serious complications like organ failure or severe anemia. Even an “uncomplicated” case of malaria involves severe chills, fever, and sweating, and these attacks may recur every few days. Fortunately, the type of malaria in the recent U.S. cases is Plasmodium vivax, which is one of the slightly less dangerous types.
Malaria has been considered to be eradicated in the U.S. since the mid-twentieth century, but until the 1880s it was a common disease here, too. Especially in the South, deaths due to malaria occurred at a similar rate as in malaria-endemic countries, and malaria killed an estimated 10,000 soldiers during the Civil War. Complications of malaria can cause malnutrition and susceptibility to other diseases, and the presence of malaria is significant in the social and military history of the U.S. It’s a whole thing.
Malaria was eradicated partly via a campaign to drain sources of standing water (mosquitoes breed in stagnant water) and partly by applying enormous quantities of insecticides, including DDT, to houses and by spraying them from airplanes. We do not want to have to do this again, okay?
Unfortunately, climate change is undoing some of that hard work. That’s why five cases of malaria are so significant. It’s not that unusual for people to get malaria on vacation and bring it back to the U.S.; some 2,000 cases occur this way each year. But if malaria is spreading here—that’s what “locally acquired” means in the CDC alert—that’s concerning. Public health officials are paying careful attention to the possibility that malaria may come back in force.
How would I know if I have malaria?
First of all, if you live in the U.S., you’re still far more likely to catch malaria while you’re traveling than to actually pick it up from a mosquito at home. If you travel to a country where malaria transmission routinely occurs, check with your doctor about taking preventive anti-malarial medications.
The symptoms of malaria often include fever, chills, nausea, vomiting, body aches, and a general feeling of malaise. If that sounds like a lot of other illnesses, you’re right—these “flu-like” symptoms aren’t exclusive to malaria. In its recent health alert, the CDC recommends that doctors consider the possibility of malaria whenever they’re trying to figure out the cause of a fever. This was already standard practice for patients who had recently traveled to tropical areas, but doctors in Texas, Florida, and other warmer parts of the U.S. are now aware of the possibility that malaria can be locally acquired as well.
If you think you have malaria, get checked out. Severe cases of malaria are a medical emergency, and the World Health Organization notes that severe symptoms can include extreme fatigue, impaired consciousness, convulsions, difficulty bleeding, dark or bloody urine, jaundice, and abnormal bleeding.
Besides looking out for malaria symptoms, another thing we can all do is make sure not to keep any sources of standing water around (dump out anything that collects water in your yard) and use barriers like window screens and insect repellents to protect ourselves from mosquito bites.
