(REUTERS) - Florida officials removed part of Miami Beach from an active Zika transmission zone on Tuesday (Nov 22), saying more than 45 days had passed since the last local case of the mosquito-borne virus that has been linked to microcephaly, a rare birth defect.
Popular areas in the southern part of the seaside tourist destination, however, remain in a designated zone of active Zika transmission.
The area of active transmission in Miami Beach is now about 1.5 square miles (2.4 km). The newly cleared area covers about three square miles, Florida Governor Rick Scott said in a statement.
State officials believe Zika is still being transmitted in another small area of Miami-Dade County, in addition to the remaining section of Miami Beach.
Mosquitoes began spreading the virus this summer in Florida, bringing local Zika transmission to the continental United States.
"Until we have a vaccine, this is going to be something we're going to deal with," Scott said at a news conference in Miami Beach. "We're going to be active, and we've learned a lot," he added.
On Tuesday, the US Centers for Disease Control and Prevention said as of Nov 16 there were 4,255 cases of Zika reported in the continental United States and Hawaii. Of the total reported Zika cases, 35 are believed to be through sexual transmission and one case from lab exposure.
Florida on Tuesday separately said it has seen 1,201 cases of Zika, and 236 of them were locally acquired infections, according to the state health department.
The CDC also updated its travel guidance for the Miami area, urging continued caution. It has suggested that pregnant women consider postponing travel anywhere in Miami-Dade County, but it expressly directs pregnant women to avoid travel to areas within the county that are still designated as Zika transmission zones.
Zika infections in pregnant women have been shown to cause microcephaly - a severe birth defect in which the head and brain of babies are undersized and underdeveloped - as well as other brain abnormalities.
A report on Tuesday raised new concerns about the hidden effects of pre-natal exposure to Zika, showing some babies in Brazil gradually developed microcephaly in the months following birth.
The developments come after the World Health Organization declared the global Zika emergency over on Friday, because the link between Zika and microcephaly has been confirmed. WHO intends to continue studying Zika as a serious infectious disease that will require years of research.
The connection between Zika and microcephaly first came to light last year in Brazil, which has since confirmed more than 2,100 cases of microcephaly.
In adults, Zika infections have also been linked to a rare neurological syndrome known as Guillain-Barre, as well as other neurological disorders.