The first known cases of locally transmitted Zika virus in the continental U.S. have
been found in Florida, federal health officials said Friday.
Four people appear to have contracted the infection in Miami, according to the Centers
for Disease Control and Prevention (CDC).
“All the evidence we’ve seen indicates that this is mosquito-borne transmission that
occurred several weeks ago,” said CDC Director Tom Frieden, M.D., M.P.H.
Zika virus is spread primarily through infected Aedesaegypti and Aedesalbopictus mosquitoes, although it also can be sexually transmitted.
For months, CDC experts have been monitoring cases spreading throughout Latin America
and the Caribbean and preparing for the possibility of local transmission in the states.
Their focus has been on pregnant women who can pass on the infection to their fetus,
potentially resulting in microcephaly and other brain abnormalities.
In U.S. states and Washington, D.C., there already have been 1,658 cases among travelers
and their sexual partners, including 433 pregnant women, according to the CDC. When
an infected person is bitten by a mosquito, the insect then can infect another person.
“If we were to see continuing spread in this area or somewhere else or explosive spread,
we would absolutely issue travel guidance,” Dr. Frieden said. “That’s not the situation
we’re in today, but we will reassess that every single day.”
For the 20% of those infected who display symptoms, the illness is mild and may include
fever, rash, joint pain and conjunctivitis. Dr. Frieden said he would not be surprised
to see additional cases and possibly clusters.
“We believe that widespread transmission in the continental U.S. is unlikely, but
it’s not impossible and that’s why we’re aggressively keeping our guard up and investigating
every possible incident that may represent widespread transmission,” he said.
The virus is a nationally notifiable disease and should be reported to local, state
or territorial health departments to facilitate testing. The CDC also is asking health
care providers to contribute data to its Zika pregnancy registry that will follow children exposed to Zika for up to 1 year of age.
President Barack Obama has requested $1.9 billion from Congress to combat the virus,
but lawmakers have not reached an agreement on how much funding to provide. In the
meantime, the CDC is borrowing $589 million, largely from Ebola funds.
“We are doing the best we can with the resources we have available to us …” Dr. Frieden
said. “If we had more resources, we would be able to mount a more robust response.”