Malaria in Florida: What to know

Malaria remains one of the most significant global health challenges. Each year, over half a million people die from the disease, many being children, with an average of 290 million infections worldwide. The disease is caused by five species of protozoan parasites from the genus Plasmodium.  

P. falciparum and P. vivax pose the greatest threat, with the former being the most prevalent on the African continent. P. malariae, P. knowlesi and P. ovale are the other species that can infect humans. While infection from the latter three is less severe, the parasites can live dormant in the liver for years before causing reinfection. The parasites are spread through the bites of Anopheles mosquitoes. 

Malaria is not endemic in the United States, meaning it doesn’t regularly occur. Typically, the U.S. reports around 2,000 cases annually, most of which are in individuals who contracted malaria abroad and then returned. On average, Florida reports 71 cases of internationally acquired malaria each year — roughly 4% of the national number. 

Occasionally, local transmission can happen when an imported case leads to disease spread within a community.  

Malaria basics

Malaria is an ancient disease, with records dating back over 5,000 years. Clay tablets with cuneiform script from Mesopotamia mention deadly periodic fevers suggestive of malaria. Malaria antigen was also detected in Egyptian remains dating from 3200 and 1304 B.C.E. Furthermore, the Greek poet Homer, circa 750 B.C.E., mentions malaria in “The Iliad.” 

Charles Louis Alphonse Laveran, 1845-1922, a French army doctor, is credited with discovering the parasites that cause malaria. The disease’s namesake stems from the Latin term for bad air, or “mal’ aria.” 

Some varieties of malaria parasites, which typically cause milder forms of the disease, can persist for years and cause relapses. 

Malaria can be fatal, particularly when caused by P. falciparum. Malaria deaths are usually related to one or more serious complications, including: 

Malaria in Florida

Malaria is not endemic in Florida. However, Florida is home to mosquitoes that can transmit malaria. Therefore, travelers returning from malaria-endemic areas should take precautions to prevent mosquito bites. The largest locally-acquired outbreak in recent Florida history occurred in Palm Beach County in 2003, with eight cases reported. 

In 2024, the Florida Department of Health reported 68 travel-associated cases of malaria caused by the P. vivax species. As of August 2025, 30 cases have been reported in individuals with a travel history to a malaria-endemic area. Counties reporting cases were Alachua, Brevard, Broward, Collier, Duval, Hillsborough, Lake, Leon, Marion, Miami-Dade, Nassau, Orange, Palm Beach, Polk, St. Lucie and Volusia.  

There have been occasional cases of locally acquired malaria in the state, usually in travelers returning from malaria-endemic regions. In 2023, a local outbreak occurred in which seven cases were reported in Sarasota County, causing the state health department to issue a mosquito-borne illnesses advisory. 

In Florida, Malaria is transmitted through infected Anopheles mosquitoes. Individuals with symptoms of fever, chills, sweating, nausea/vomiting and headache should seek immediate medical attention. Effective treatment is readily available through hospitals and other health care providers. 

Malaria transmission

Most people contract malaria through a bite from an infective female Anopheles mosquito carrying a malaria parasite. These mosquitoes become infective after biting a person or an animal already infected with the parasite. Approximately a week later, the same mosquito bites another person and transmits the parasite through its saliva. This cycle of infection then repeats. 

People can’t spread malaria to other people like a cold or the flu. You can’t get malaria through physical contact or sexual contact with an infected person. However, if bitten by an infected mosquito, anyone can become infected with malaria.  

Symptoms of malaria

After being bitten by an infected mosquito, the parasites, called sporozoites, travel through the bloodstream to the liver. There, they mature and release another form of parasites, called merozoites. The merozoites enter the bloodstream and infect red blood cells before multiplying inside them. Within 48 to 72 hours, the cells will break open and infect more red blood cells.  

The first symptoms usually occur two to four weeks after an infection, though they can appear as early as eight days or as long as a year after infection. The symptoms occur in cycles of 48 to 72 hours. 

Symptoms

• Fever 
• Chills 
• Headache 
• Nausea and vomiting 
• Diarrhea 
• Abdominal pain 
• Muscle or joint pain 
• Fatigue 
• Rapid breathing 
• Rapid heart rate 
• Cough 

If left untreated, the infection can cause more severe complications, like kidney failure, seizures and coma. 

People most vulnerable to malaria infections

Malaria is endemic in many tropical and subtropical regions, primarily in sub-Saharan Africa, parts of South America and Southeast Asia. Sub-Saharan Africa accounts for the vast majority of global malaria cases and deaths. People living in and traveling to these areas are more at risk for malaria exposure. 

Infants and children under five years face a high risk of mortality from malaria due to their undeveloped immunity to pathogens. Pregnant people are also at a high risk for mortality due to the complications the malaria infection can cause, such as hypoglycemia, fluid in the lungs, premature labor, stillbirths and post-birth infections. 

Anyone with a compromised immune system, such as the elderly and people with HIV or AIDS, is at higher risk of severe infection. 

Malaria diagnosis

Only a lab test will confirm a malaria parasite infection using a small blood sample. 

There are three kinds of diagnostic tests health care providers can run to determine if the malaria parasite is present: 

Malaria treatment

Starting treatment immediately is the best way to treat malaria and prevent serious and life-threatening issues. The type of drugs prescribed and the length of treatment depend on: 

• The type of malaria-causing parasite. 

• The geographic location where the infection likely happened, and the likelihood of drug resistance. 

• The patient’s age. 

• Whether the patient is pregnant or breastfeeding. 

• How sick the patient is at the start of treatment. 

Patients in the U.S. are typically hospitalized for malaria treatment. 

Identifying the species of malaria-causing parasite is paramount in effective and safe treatment. For example, P. vivax and P. ovale infections also require treating the parasites that remain dormant in the liver and can cause relapsing episodes. In addition, P. falciparum and P. vivax species have different drug resistance patterns in different geographic regions. 

Malaria prevention

Mosquito-bite prevention is the best way to prevent malaria infection. Be sure the area around your home is not hospitable for mosquitoes to breed. This includes removing any standing water near your home, maintaining screens on windows and doors and utilizing repellants. While outdoors, wear insect repellent and loose-fitting, long-sleeved clothing.  

Malaria vaccines have been under development since the 1960s, with significant advancements in the past decade. Oct. 6, 2021, was a milestone when the World Health Organization recommended the widespread use of the RTS,S/AS01 malaria vaccine for children in sub-Saharan Africa and other areas with moderate to high P. falciparum transmission. Two years later, the WHO approved a second vaccine, R21/Matrix-M, for use in regions where malaria is endemic. 

A new vaccine for infants and newborns, Coartem Baby, received approval from Switzerland in July 2025, and is expected to be rolled out in eight African countries.  

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