Zika outbreak: Possible local transmission in Florida investigated

Evaristo Miqueli, a natural resources officer in Florida, looks through a microscope at Aedes aegypti mosquito larvae in June in Florida. Health officials in the state are distributing Zika prevention kits and repellent. (Lynne Sladky/Associated Press)

Florida health officials said they are investigating a case of Zika virus infection that does not appear to have stemmed from travel to another region with an outbreak.
 
Tuesday’s statement from the Florida Department of Health did not specify whether the Zika case was believed to have been transmitted via mosquito bite, sexual contact or other means.
 
The department said the case was reported in Miami-Dade County and that it is working with the U.S. Centers for Disease Control and Prevention (CDC) on an epidemiological study.
 
The department also reiterated guidance to Florida residents on protecting themselves from mosquitoes that may carry the virus.

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“Zika prevention kits and repellant will be available for pickup … and distributed in the area under investigation,” the Health Department said in a statement. “Mosquito control has already conducted reduction and prevention activities in the area of investigation.”
 
Zika, which can cause a rare birth defect and other neurological conditions, has spread rapidly through the Americas. A small number of cases of Zika transmitted between sexual partners have also been documented.
 
There has yet to be a case of local transmission by mosquitoes in the continental United States, though more than 1,300 people in the U.S.  have reported infections after traveling to a Zika outbreak area.
 
U.S. officials have predicted local outbreaks to begin as the weather warms, particularly in southern states such as Florida and Texas.

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There are three steps in local transmission:

• Someone who is infected with Zika while travelling and has high enough level of the virus returns home to the U.S.
• The person then gets bitten by a local mosquito that is able to carry the Zika virus.
• The local mosquito then bites and infects someone else.

Experts with the CDC have previously said if local spread of the virus occurs in the U.S., it is not likely to be as widespread as in Latin America and Caribbean.

They point to what happened when Aedes mosquitoes spread dengue and chikungunya, cousins of Zika virus. Locally transmitted outbreaks of dengue occurred in Florida, Hawaii and Texas. In 2014, there were 12 cases of locally acquired  chikungunya reported in Florida, the CDC said. 

In the continental U.S., greater use of air conditioning, window screens, mosquito control, and less densely populated areas than in Central and South America are all thought to lessen the likelihood of widespread outbreaks, CDC officials have said.