University of South Florida


John Adams, distinguished university professor in the College of Public Health

John Adams, distinguished university professor in the College of Public Health | Photo by: Allison Long, USF Health

USF infectious disease researcher John Adams provides insight on the recent malaria outbreak

Is the recent outbreak potentially part of a broader infiltration of mosquitoes carrying malaria?

At the moment, this still appears to be isolated to specific areas. Although there are native Florida mosquitoes capable of transmission, the parasite also has to be available in the human population. We are not seeing that yet. 

Which populations are most vulnerable?

Globally, anyone exposed to malaria-carrying mosquitoes is at risk, especially young children and pregnant women. Protective clothing and bug spray should protect the vast majority of at-risk individuals. 

This is the first local spread of malaria in 20 years. What could have caused it?

Malaria cases in Florida are usually a result of people returning to the U.S. after traveling to malaria endemic areas. Malaria is typically found in tropical or equatorial locations. However, vivax malaria can also be a result of the reemergence of dormant parasites hiding in the liver of a person infected in the past. It is unclear which is the case. 

Is there a high risk of contracting malaria in the United States?

There is a relatively low risk of contracting malaria in the U.S.

How do the climates in Florida and Texas play a role in the mosquitoes becoming infected?

Florida has a subtropical climate that is fit for mosquitoes to survive and reproduce year-round. Also, both Texas and Florida have native Anopheles mosquitoes capable of transmission if the parasites are present. Prior to the 1950s, there were many cases of malaria in Florida, transmitted by native mosquitoes.

Can all mosquitoes carry malaria?

Anopheles mosquitoes are the most adequate vectors for malaria transmission. This is different from Ades mosquitos, which dominated the news for transmission of the Zika and Dengue viruses. 

How quickly can malaria spread from mosquito-to-mosquito?

Mosquitoes can give malaria to each other relatively fast, within weeks. 

Is malaria contagious?

Malaria requires a mosquito vector for person-to-person transmission. 

What treatments are available?

There are serval antimalarial drugs and combination therapies available to treat P. vivax malaria (the most common type of malaria.) One of these treatments will work against the dormant liver form of the parasites, but only for some people. There are also two World Health Organization-approved malaria vaccines for Plasmodium falciparum, but they have not been shown to be effective against P. vivax. 

What is the best type of bug spray to repel mosquitoes? Some companies advertise DEET-free or botanical ingredients. Are these still effective?

DEET is the best option for mosquito repellents. Plant-based DEET can still be somewhat effective, but there can be variations in results between batches and companies.  

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