The US Centers for Disease Control and Prevention issued an alert Monday after five cases of malaria were confirmed, the first locally acquired cases of the disease in the United States in 20 years.
Four cases of the mosquito-borne illness were confirmed in Florida and one in Texas, the CDC said in its health alert, adding the cases in the two states did not seem to be related.
“All patients have received treatment and are improving,” it said.
Authorities were on the lookout for additional cases and mosquito surveillance and control measures have been implemented in the affected areas, it said.
Florida has issued a mosquito-borne illness alert after cases were discovered in Sarasota County and Manatee County, warning residents to drain standing water where mosquitoes can breed and wear long-sleeved shirts and pants.
Texas also issued a health advisory after a resident who worked outdoors in Cameron County was diagnosed. The Texas health department said no further cases had been identified so far.
“Despite these cases, the risk of locally acquired malaria remains extremely low in the United States,” the CDC said.
However, Anopheles mosquitoes found in much of the United States can transmit the disease if they feed on an infected person, it said.
The last locally acquired malaria case in the United States was in 2003 when eight cases were identified in Palm Beach County, Florida, according to the CDC.
“Malaria is a medical emergency and should be treated accordingly,” it said.
Almost all cases of malaria in the United States are imported by people who have traveled from countries with malaria transmission.
