The Florida Department of Health has reported two new cases of locally acquired malaria in Sarasota County this past week.
There have now been six people who have contracted the mosquito-borne illness in the county.
Officials say all of the cases reported this year came from mosquitoes in the Sarasota area, and not from insects in another country. This is unusual because a vast majority of malaria cases in the U.S are detected after someone has traveled internationally.
A statewide mosquito-borne illness alert remains in effect.
In late June, a similar health alert was also issued nationally by the Centers for Disease Control and Prevention due to the cases in Sarasota County and another in Texas, by a man working for the National Guard along the Rio Grande.
Dr. Manuel Gordillo, an infectious disease specialist at Sarasota Memorial Hospital, told NBC News that the hospital treated four of the county's malaria infections.
Two of the patients were homeless, he said, and all four were admitted with fever and dehydration.
"Some of the cases were sort of neglecting the symptoms and they presented way late with other complications," he said.
Gordillo told NBC the Florida’s cases were transmitted in a northern region of the county, which has wooded areas and has experienced rain.
Sarasota County said it has increased treating areas with insecticides, particularly in the northern area.
No cases have been reported in Manatee County, but officials there are spraying with a focus on the southwestern part of the county.
The CDC says that the patients had contracted P. vivax, a strain of malaria that typically produces milder symptoms or can even be asymptomatic but still can prove fatal, especially in those who are pregnant and in children.
People should take precautions like applying mosquito spray, avoiding areas with high mosquito populations such as retention ponds, and wearing long pants and shirts when possible - especially during sunrise and sunset when mosquitos are most active.
The seven patients are the most locally acquired malaria cases in the U.S. in 20 years.
Information from WGCU was used in this report.
