The four previously reported non–travel-related cases of Zika infection have now been confirmed to be locally acquired in Miami-Dade county, Florida.
*Updated on 11/01/2016 at 5:00 PM EST
An investigation into four non—travel-related Zika cases led both Centers for Disease Control and Prevention (CDC) and Florida Department of Health (DOH) officials to confirm what many had feared: active Zika transmission in Florida. Since the first case was identified on July 19, 2016, there have been more than 70 cases of locally acquired Zika in Miami-Dade, Palm Beach, Broward, and Pinellas counties in Florida. As a result of active Zika transmission, the US Food and Drug Adminis­tration (FDA) has urged blood establishments in the infected areas to stop blood collection efforts. More recently, the FDA approved the release of the genetically modified Aedes Ae­gypti mosquito, OX513A, in Key Haven, Florida, in an effort to reduce Zika-carrying mosquito prevalence.
In a teleconference, Tom Frieden, MD, MPH, director of the CDC, confirmed that “Zika is here.” The four Florida cases are the first locally acquired cases of Zika in the United States. The CDC is working closely with the DOH to investigate the geographical origins of each case presenting with non—trav­el-related Zika in Florida. The investigation will use epidemi­ological analysis to report the origin of infection.
Zika is confirmed to cause microcephaly and other neu­rological complications in developing fetuses. However, the CDC is not advising women residing in Florida to post­pone pregnancy; the CDC calls it a “highly personal deci­sion.” Nonetheless, the CDC recommends that all pregnant women, including those who do not present with Zika-like symptoms, be tested for the Zika virus, “even if the odds [of infection] are low.” Because Ae. aegypti mosquitoes, which transmit Zika, only travel around 150 meters in a lifetime, ac­tive Zika transmission in these areas is a “focal problem that needs to be addressed locally.” Based on past transmission of mosquito-borne viruses in Florida, Dr. Frieden notes that local Zika transmission within the state is “not unexpected.” According to the CDC, active Zika transmission has been ongoing in Florida since early July. However, efforts to con­firm local Zika transmission require extensive investigation through testing of the Zika vector, Ae. aegypti, which is diffi­cult. Dr. Frieden described the process as “looking for a nee­dle in a haystack.” Thus far, there have been approximately 3,132 travel-related cases of Zika in the United States, and now 92 locally acquired cases of Zika-infected individuals in Florida. The Florida DOH reports that a total of 90 of the to­tal number of Zika-infected individuals in the state are preg­nant women.
Upon confirmation of local Zika transmission, Florida health officials took measures to reduce the mosquito pop­ulation within the areas where infected individuals reside. Furthermore, the DOH investigated possible routes of trans­mission, including travel and sexual intercourse with infect­ed individuals. Once these possibilities were ruled out, the DOH began to suspect local transmission.
The Florida DOH has been aggressive in its efforts to min­imize the Ae. aegypti population in Miami. According to the CDC, Zika is not a concern unless there continue to be more cases of locally acquired Zika after mosquito control efforts have been taken.
In addition to the $25 million Zika funds the CDC provid­ed to areas at risk of outbreaks in early July, on August 2, the CDC also granted a total of $16 million in Zika funds to all US states and territories.
The CDC recommends that all individuals residing in or traveling to areas where there is an Ae. aegypti mosquito population use DEET-containing mosquito repellent. The CDC suspects that Zika will continue to spread throughout South America and the Caribbean.
*Information contained in this article is accurate at the time of publishing.