The Centers for Disease Control and Prevention recommended on Monday that pregnant women avoid unnecessary travel to an area near downtown Miami in light of new locally transmitted cases that surfaced over the weekend and the possibility that mosquitoes in the area may be resistant to insecticide.
Officials also recommended that anyone who had been to the area after June 15 should wait at least eight weeks before trying to conceive. The virus, which can be spread sexually as well as through mosquitoes, is believed to stay in semen for at least two months, so men who have had Zika should wait at least six months before trying to impregnate their partner, given that the virus causes the birth defect microcephaly, CDC said.
CDC is dispatching additional staff to Florida after the state’s governor, Rick Scott, on Monday called for a federal emergency response team. Members of the team will be assisting with measures like lab testing and mosquito control. Officials believe the virus began spreading in a small area just north of downtown Miami in early July.
Officials are especially concerned that mosquitoes have not dissipated despite insect-control efforts. Scientists are are trying to discover whether the mosquitoes are resistant to insecticides or if larvae are hiding in places that are difficult to reach.
During the weekend the number of people who were infected in Florida by mosquitoes carrying the Zika virus increased from four to 14. Even more are likely infected but don’t know it, given that only a fifth of those who have the virus will experience any symptoms, including fever and rash. Six people who tested positive had no symptoms and were found because officials went door to door to test people.
Health officials first confirmed the existence of Zika-carrying mosquitoes in Florida on Friday. Prior to the Florida cases, all Zika infections in the continental U.S. were believed to have occurred through people who had traveled to other countries that had mosquitoes carrying the virus or through sex with a partner that had been infected. Officials are also investigating a case in Utah in which they believe another mode of transmission is possible.
Health officials are most concerned about pregnant women becoming infected because the virus causes microcephaly in a fetus, and the birth defect can’t be detected until later in a pregnancy. Scientists still don’t know all the conditions that result from this type of microcephaly. It can cause children to be born with abnormally small heads, as well as possible blindness, seizures and brain damage. Rare cases have also caused neurological disorders in adults.
Dr. Tom Frieden, director of the CDC, said in a call with reporters Monday that people should take the threat of Zika seriously.
“The tragedy of a preventable case of a severe birth defect is something we have to make very clear to people,” he said. Medical costs for babies born with the condition can cost $10 million over the course of their lives.
Congress left for its summer recess without providing emergency funding for Zika, and private funding also has been insufficient, officials say.