With mosquitoes spreading the Zika virus in sections of Miami Beach and Wynwood, Florida health officials on Tuesday confirmed three more local infections in Miami-Dade County — including one on the beach, and two cases outside of the designated zones.
An additional 16 travel-related cases also were reported, including five in Miami-Dade, three in Palm Beach, two in Broward, two in Orange, one in Polk and three involving pregnant women, whose counties of residence are not disclosed.
In total, Florida has confirmed 558 travel-related Zika infections and another 78 cases involving pregnant women, who are considered to be at greatest risk from the virus because it can cause microcephaly, a birth defect characterized by an abnormally small head, and other neurological complications.
But it’s the growing number of locally transmitted Zika infections — now at 46 Floridians statewide — that has health officials scrambling to contain the virus. The Florida Department of Health is conducting 12 investigations into local cases, including one in Pinellas, two in Palm Beach and the remainder in Miami-Dade.
The federal Centers for Disease Control and Prevention and the state health department first identified a one-square mile area of Miami’s Wynwood neighborhood on July 29 as the only place in the nation with active spread of Zika by mosquitoes. At least 29 cases have been linked to that area.
A second zone of ongoing transmission in Miami-Dade was confirmed on Aug. 19 in a 1.5-square-mile area of Miami Beach, with links to at least five infections.
At least nine Zika infections, however, have been reported in Miami-Dade outside of those identified areas, leading to investigations.
Two cases are now closed, determined to be single infections with no additional spread. Seven cases remain under investigation in Miami-Dade. Health officials have not identified the areas in Miami-Dade where those Zika infections occurred.
As health officials work to contain the virus’ spread in Florida, the CDC issued Zika travel notices for two new locations: the British Virgin Islands and Singapore.
In the Virgin Islands, local transmission of Zika was reported on the island of Tortola, which includes Cane Garden Bay and Havers, though it is not clear from the CDC’s guidance how many people have been infected by mosquitoes.
In Singapore, the health ministry has reported at least 41 cases of locally transmitted Zika virus.
Also Tuesday, the CDC released a report that found a heightened risk for hearing loss among infants born with microcephaly after their mothers contracted Zika while pregnant.
Researchers looked at 70 children in Brazil born with microcephaly and found that congenital Zika infection appears to be associated with hearing loss caused by damage to the inner ear or the nerve from the ear to the brain.
Hearing loss varied in severity, but researchers reported that at least four of the children had hearing loss with no other potential cause than Zika infection. Those children all had severe microcephaly, the researchers reported.
There was no significant association between hearing loss and severity of Zika symptoms, although the researchers noted that hearing impairment occurred mostly in infants whose mothers had a rash during the first trimester.
Researchers cautioned that their study was limited to children born with microcephaly and added that it’s possible that children without the birth defect might also suffer hearing loss as a result of congenital Zika infection.
As researchers race to learn more about Zika, federal health officials and pharmaceutical companies this week announced progress in the search for a vaccine and a more effective diagnostic test for the virus.
On Monday, Inovio Pharmaceuticals of Pennsylvania announced that it will launch a clinical trial for a DNA-based vaccine using 160 adult volunteers in Puerto Rico, which has been hard hit by Zika infections. Officials on the island have reported more than 14,000 cases, including 1,244 among pregnant women.
And on Friday, the Food and Drug Administration gave emergency approval for the pharmaceutical company Roche to begin using a diagnostic blood test for people with Zika symptoms. The FDA has granted emergency use approval for nine other Zika diagnostic tests since February.
Zika infections reported in Florida as of Aug. 30
Number of Cases
Total cases not involving pregnant women
. . .
. . .
Cases involving pregnant women regardless of symptoms*
* Counties of pregnant women are not disclosed.
** Does not include local cases.
Source: Florida Department of Health