Florida officials today confirmed another active Zika transmission area, a 1.5-square-mile section of Miami Beach, which prompted an expanded travel advisory and an alert to health providers from the US Centers for Disease Control and Prevention (CDC).

The affected area of Miami Beach is the second Miami-Dade County neighborhood with confirmed active transmission, and with its high-rise buildings, skin-baring tourist population, and oceanfront location it poses unique response challenges.

The Florida Department of Health (Florida Health) said in its daily update today that a cluster of five already-confirmed cases are linked to the Miami Beach transmission area.

Considerations for pregnant women

CDC Director Tom Frieden, MD, MPH, said in a press briefing today that CDC investigators are working closely with state health officials on an aggressive response. He warned officials to anticipate more local cases, along with more Zika illnesses linked to travel to the affected Miami areas, such as recent cases detected in Texas and Taiwan.

He said the situation in the Miami area is evolving as the CDC expected for limited vulnerable areas of the continental United States: multiple individual local cases and some clusters.

Though the CDC's travel recommendation for pregnant women applies to the two active transmission areas around Miami, Frieden said pregnant women and their partners who are concerned about possible Zika exposure may also consider postponing nonessential travel to all of Miami-Dade County.

The CDC outlined its additional warnings today in a Health Alert Network (HAN) health advisory to clinicians.

Women or men who live in or traveled to the affected area of Miami Beach since Jul 14 should be aware of the active Zika transmission, and pregnant women who were in the area should see their health providers about getting tested for Zika virus, the CDC said today. It added that those who were in the areas and have pregnant sex partners should consistently use condoms or abstain from sex during the duration of the pregnancy.

"Florida and Miami-Dade County are taking appropriate steps to control mosquitoes and protect pregnant women. It is difficult to predict how long active transmission will continue," Frieden said in a CDC news release today.

Mosquito-battle challenges

Frieden said characteristics of the Miami Beach area prohibit aerial spraying, which was done for the Wynwood neighborhood. Planes involved with aerial spraying need to fly relatively low and in wind-free conditions to effectively deliver the insecticide, which isn't possible in Miami Beach with its many high-rise buildings and oceanfront environment.

He said mosquito control workers in the Miami Beach transmission area will be limited to backpack spraying.

Aerial spraying has been about 90% effective thus far, Frieden said. "We're impressed by the effectiveness of aerial spraying in Wynwood, but we're also impressed by the resilience of the mosquitoes."

Health officials are always concerned about the possibility of mosquito resistance to insecticides, Frieden said, adding that the impact of the aerial spraying in Wynwood has made it difficult to collect mosquito eggs to do resistance testing.

One new local case

Florida Health said it has confirmed one more local case, an individual from outside of the two active transmission areas, raising the total number of locally acquired cases to 36.

Also, the department announced 14 more travel-linked cases, lifting that total to 488, and 5 more cases involving pregnant women, putting that number at 68.

Officials said they have cleared three more blocks in the first transmission area as being free of Zika in the Wynwood neighborhood just north of downtown.

Gov Rick Scott said in a statement today, "The ability to continue reducing that area where we believe local transmission is occurring shows that our efforts to aggressively spray for mosquitoes and educate the public are working."

He said he asked the CDC for 5,000 more antibody test kits, which Frieden said will arrive in Florida on Aug 23.

Updated guidance on infants

In other Zika developments today, the CDC released updated interim guidance for clinicians on caring for babies born to potentially Zika-infected mothers. Today's update, published in an early online edition of Morbidity and Mortality Weekly Report (MMWR), walks physicians through the early evaluation and testing of newborns whose mothers have lab-confirmed evidence of Zika. It also includes new scientific information that has surfaced since the CDC released its first recommendations in February.

The CDC said the guidance also covers recommendations for management, referral to services, and follow-up for infants with congenital Zika infections, with or without obvious birth defects.

In a media advisory that highlights the main changes, the CDC said it no longer recommends dengue testing and recommends against cord blood testing. The guidance includes information on how to interpret lab tests.

The new guidance now recommends cranial ultrasound for all potentially affected newborns, not just the ones who had abnormal findings on prenatal third trimester ultrasounds.

Also, the CDC added more recommendations for follow-up during the first year of life to include repeat eye and hearing screenings, plus a new one for endocrine evaluation. Because care of infants with congenital Zika infections is so complex, the CDC recommends that medical treatment be coordinated through a multidisciplinary team and an established medical home.

The CDC has a Web page for affected families, and the Department of Health and Human Services (HHS) has a planning resource to help health departments prepare and respond to the need for special services for Zika-affected families.

To assist clinicians with the new recommendations, the CDC yesterday announced an Aug 23 Clinicians Outreach and Communication Activity (COCA) conference call.

Other developments

The US Food and Drug Administration (FDA) on Aug 17 issued an emergency use authorization (EUA) for the first commercially available serologic test for Zika virus. The test, produced by InBios International, based in Seattle, detects Zika immunoglobulin M antibodies in human sera. The FDA has now issued nine EUAs for Zika diagnostic tests.





Federal health regulators are evaluating a proposal for human Zika challenge tests headed by researchers from Johns Hopkins University Bloomberg School of Public Health, the Associated Press reported today. If approved, the trials would begin in December with paid healthy, nonpregnant volunteers who would be monitored at a Baltimore hospital. The studies are designed to yield information about human response to the virus for vaccine development purposes and for studying Zika's impact on the body at different levels of infection, according to the report.

See also:

Aug 19 Gov Rick Scott statement

Aug 19 Florida Health daily Zika update

Aug 19 CDC press release on Miami Beach transmission

Aug 19 CDC HAN advisory

Aug 19 MMWR report

Aug 19 CDC media statement

Aug 23 CDC COCA call information