PBS and NPR for Southwest Florida
Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Eighth malaria case confirmed in Sarasota equals largest U.S. outbreak of the disease in decades

The same mosquito that can harbor malaria takes a blood meal out of a volunteer
CDC's Division of Parasitic Diseases and Malaria
The same mosquito that can harbor malaria takes a blood meal out of a volunteer

A seventh Sarasota-area resident has been infected with malaria acquired by a mosquito bite in town, which adds an eighth person to tie the largest U.S. group to become infected with the parasitic virus in nearly a century.

Malaria remains one of the world’s greatest public health concerns, infecting about 219 million people each year. Untreated, the virus is often deadly and kills on average about 660,000 of those infected — mostly children in Africa.

Malaria is transmitted by a parasite left behind in the saliva of an infected mosquito during a sting.

The first case of malaria in Sarasota County this year was diagnosed on May 26 and more followed; nearly a month later a Cameron County, Texas, man was identified with the virus. There is no evidence that the cases are related, health officials say, and everybody involved has been treated at hospitals and are recovering.

The majority of malaria cases diagnosed in the United States are imported, usually by people traveling overseas to countries where malaria is endemic and then feel the flu-like symptoms back here.

The Centers for Disease Control and Prevention says those at greatest threat are overseas travelers, members of the military, and citizens living and working abroad. Typically, about 2,000 malaria cases are brought home to the U.S. and diagnosed each year.

Nausea, vomiting, and diarrhea are common with malaria, followed by anemia and jaundice. If not promptly treated, the infection can become severe causing kidney failure, seizures, confusion, coma, and death.

The possibilities in Southwest Florida are serious enough that the CDC has joined state and local health agencies in Florida and Texas to figure out how the mosquitos here became infected with malaria, and why now.

What is known is nearly all of the Florida cases are from mosquito bites in northern Sarasota County neighborhoods including DeSoto Acres south of University Parkway, where most homes were built long ago, often acres apart, with heavily wooded mini-forests between.

Malaria eliminated?

The effort to eradicate malaria in America began in earnest in the early 1900s. The focus was on controlling malaria around military training bases in the southern U.S. and its territories where malaria was still problematic.

Many of the bases were established in areas where mosquitoes were abundant, and housed soldiers returning from countries overseas where malaria was rampant.

Malaria cannot be passed from person-to-person, but a mosquito could sting someone who has the virus, then transfer it to someone nearby with its next sting.

Clinicians should consider a malaria diagnosis in any person with a fever of unknown origin regardless of their travel history.

Over the next several decades scientists figured out how malaria spread –- a bite by an infected mosquito -– and federal health officials trained state and local health departments in mosquito control strategies such as pouring out standing water and applying new pesticides.

By 1947, home-grown malaria in America was considered eliminated.

But in 2003, eight people in Palm Beach County were proven to have locally acquired malaria. Everyone involved worked outdoors into the evening hours, and all were treated and recovered.

Still, being infected with malaria at home is very rare.

All the same, the CDC reminded Florida healthcare professionals in a recent alert that malaria is a medical emergency and anyone with symptoms should be "urgently evaluated.

“Clinicians practicing in areas of the United States where locally acquired malaria cases have occurred should follow guidance from their state and local health departments,” the CDC wrote. “Clinicians should consider a malaria diagnosis in any person with a fever of unknown origin regardless of their travel history. Prompt diagnosis and treatment of people with malaria can prevent progression to severe disease or death and limit ongoing transmission.”

Climate change a factor?

Some scientists say climate change is a factor in the resurgence of malaria-infected mosquitos in Florida, as the planet and its climate warm mosquitos chase their comfort zone as it shifts.

Stat, an international journal on health and medicine, published an article in March titled, “West Nile, Lyme, and other diseases are on the rise with climate change. Experts warn the U.S. is not prepared” on the rising prevalence of mosquito-born diseases in areas where they had been eradicated.

“With climate change accelerating, however, shifting the ranges of many disease-carrying species and sharply increasing infections, scientists and others warn that the nation’s public officials, as well as hospitals and doctors, are underprepared for a potentially devastating surge in infections,” wrote author Sara Van Note. “Research on vector-borne diseases and disease surveillance, they note, are underfunded by federal and local governments, leaving the country vulnerable to outbreaks.”

The state of Florida has issued a mosquito-borne illness alert and recommended that residents drain standing pools of water, make sure their window screens do not have holes in them, and use insecticides that contain DEET to repel mosquitoes.

Long-sleeved shirts and pants are also recommended when mosquitoes are present, which can be all day and night but the insects are especially active at dawn and dusk.

The Florida Department of Health is working with local mosquito control agencies in Sarasota and Manatee counties to try to prevent further transmission of malaria, spraying in the neighborhoods where the infections occurred.

The state of Texas has also issued a health alert, advising clinicians to routinely obtain a travel history to determine if a patient with symptoms of malaria has spent time outdoors and been bitten by mosquitoes in an area with malaria activity.

Environmental reporting for WGCU is funded in part by VoLo Foundation, a non-profit with a mission to accelerate change and global impact by supporting science-based climate solutions, enhancing education, and improving health. 

Sign up for WGCU's monthly environmental newsletter, the Green Flash, today.

WGCU is your trusted source for news and information in Southwest Florida. We are a nonprofit public service, and your support is more critical than ever. Keep public media strong and donate now. Thank you.