Four cases of Zika virus infection in Florida have been confirmed as the first cases of local transmission of the Zika virus in the continental United States, the Centers for Disease Control and Prevention announced.
“As we have anticipated, Zika is now here,” CDC Director Tom Frieden, MD, MPH, said during a conference call with the media. “These cases are not unexpected [as] we’ve been saying for months, based on our experiences with chikungunya virus and dengue – which are viruses spread by the same mosquitoes that spread Zika – that individual cases and potentially small clusters of Zika are possible in the U.S.”
The cases in question occurred within several blocks of each other in Miami. The individuals were infected in early July, became symptomatic within a few days, and were diagnosed a few days later. Frieden explained that the CDC is proceeding as though these are confirmed cases of local mosquito-borne transmission, which he emphasized is not the same as simply confirming that a person has Zika virus infection.
“We’ve been working closely with Florida and we’ve been impressed by the comprehensiveness of their investigation,” Dr. Frieden said.
Since these cases became diagnosed, Florida officials have implemented “aggressive” mosquito control protocols, which include trying to significantly reduce the local mosquito population by spraying both adult and larval mosquitoes. Dr. Frieden reiterated that killing mosquitoes is one of the most effective ways to ensure local transmission does not occur. Screening of travelers coming into Florida has also been ramped up. Teams are also going door-to-door to eliminate any standing water that may be harboring mosquitoes.
“We’re coordinating closely with Florida, and will continue to support their efforts to assess the situation on a daily basis,” he said.
To reduce the chances of an individual contracting the virus through mosquitos, the CDC continues recommending mosquito repellent; wearing clothing that covers as much of the body as possible; avoiding any areas with still water; and staying in rooms that have air conditioning, fans, or mosquito nets.
“We have been working with state and local governments to prepare for the likelihood of local mosquito-borne Zika virus transmission in the continental United States and Hawaii,” said Lyle R. Petersen, MD, MPH , Director of the CDC’s Division of Vector-Borne Diseases and Incident Manager for the CDC’s Zika Response efforts, in a statement. “We anticipate that there may be additional cases of ‘homegrown’ Zika in the coming weeks. Our top priority is to protect pregnant women from the potentially devastating harm caused by Zika.”
To combat the growing domestic Zika burden, the American Public Health Association called on Congress to allocate more funding, saying that the lack of Congressional support is directly leading to the disease’s incursion into the United States.
“Sadly, we knew this outcome was probable with each passing day that Congress failed to fund Zika protection and response [and] now Congress has adjourned for summer recess.” said Georges C. Benjamin, MD , Executive Director of the APHA, adding that “when Congress comes back in September, it must make sending bipartisan Zika legislation to the president a top priority.”
The American Medical Association echoed that position. “This should be a wake up call to Congress and the Administration that they must resolve their differences and immediately make the necessary resources available for our country to combat the growing threat of the virus,” Andrew W. Gurman, MD , AMA President, said in a statement.
The announcement of locally transmitted Zika virus cases in the continental U.S. comes on the heels of the CDC’s latest Morbidity and Mortality Weekly Report, which found that cases of Zika virus have increased dramatically in Puerto Rico. There have been 5,582 individuals diagnosed with Zika virus so far in 2016, as of July 7. That figure includes 672 pregnant women, with the rate of positive tests increasing from just 14% in February to 64% in June, according to the MMWR ( doi: 10.15585/mmwr.mm6530e1 ).
“Puerto Rico is in the midst of a Zika epidemic. The virus is silently and rapidly spreading in Puerto Rico,” Dr. Peterson said in a separate statement. “This could lead to hundreds of infants being born with microcephaly or other birth defects in the coming year. We must do all we can to protect pregnant women from Zika and to prepare to care for infants born with microcephaly.”