CHICAGO – With no specific federal guideline yet in place to control the spread of the Zika virus in the United States, some mosquito-heavy states like Florida are stepping up spraying and education programs. But the North and West have yet to boost prevention.
Only one out of the more than 30 confirmed cases of Zika in the country appears to have been transmitted locally, in Dallas, Texas. Public health officials are bracing for the time when warmer weather increases the number of mosquitoes that can transmit the virus by biting an infected person and spreading it to others.
The types of mosquitoes carrying the Zika virus, Aedes aegypti and Aedes albopictus, are common in Florida, where mosquito season is year-round, and along the coast of the Gulf of Mexico, including Houston.
Florida seems to be leading so far in intensifying efforts. Hillsborough County, located on Tampa Bay on Florida's west coast, is paying workers overtime as it steps up spraying, mosquito monitoring, and misting in the area of the home of someone who had Zika, said Carlos Fernandes, director of county mosquito control.
In west-central Florida, in Pinellas County, officials plan to educate people about removing standing water where mosquitoes breed, and are looking into expanding spraying to specifically target mosquitoes that transmit Zika. Pest control efforts are focused around people's homes.
"She doesn't fly very far at all. She's a real homebody," said Dr. Mark Whiteside, medical director for the Florida Department of Health in Monroe County.
The U.S. Centers for Disease Control and Prevention has said it is working on a specific U.S. program for Zika. Until then, the CDC is circulating guidelines developed for combating chikungunya, a close cousin to Zika that is carried by the same types of mosquitoes.
Texas, which has had eight cases of Zika, has not changed mosquito control efforts at this point but is asking healthcare providers to monitor cases. Dallas County already has robust anti-mosquito programs in place and Houston is stepping up mosquito control education.
But elsewhere in the United States, such as in Illinois, New York and Los Angeles County, officials are maintaining normal mosquito abatement programs. Travelers have returned to Minnesota, New York and Illinois with the virus, but health officials say it is unlikely mosquitoes will spread the virus in the winter in those areas.
Since the 1960s, the increase in international travel and decline in the use of pesticides such as DDT, has spread the outbreaks of mosquito-borne illnesses such as West Nile, dengue, malaria and chikungunya to countries such as the United States, where the diseases are not endemic.
The CDC recommendations for fighting mosquitoes carrying all those viruses are the same - cover skin with clothing and insect repellant, cover windows with screens and stay in air conditioning.
"No mosquito is a good mosquito," Dr. Laurene Mascola, chief of the Los Angeles County public health department's acute communicable disease control program. "It's true. Sorry, mosquitoes."
The insecticides for Zika-carrying mosquitoes are the same as those for other mosquitoes, officials said.
But for Zika, local officials have received an additional CDC recommendation, that women who are pregnant or considering becoming pregnant defer travel to Zika-outbreak countries because the risks are unknown. Zika is suspected to have a causal relation with clusters of microcephaly, a birth defect, in Brazil, according to the World Health Organization.
In Houston, officials are upping efforts to inform residents about prevention and notify doctors about the possibility of Zika, to take down patients' travel histories and talk to pregnant patients, Houston Health Department spokesman Porfirio Villarreal said.
Available insecticides had a limited impact during a major dengue outbreak in Key West, Florida, in 2009 and 2010, state health official Whiteside said. So the health department mobilized a door-to-door education campaign, leaving door hangers and refrigerator magnets reminding residents to check their yards regularly for containers with standing water.
(Additional reporting by Ben Klayman in Detroit and Letitia Stein in Tampa, Florida; Writing by Fiona Ortiz; Editing by Jonathan Oatis)