Fresno County has its first case of travel-associated Zika infection, health officials said Tuesday.
The woman patient became infected from a mosquito bite within the past three weeks, said Dr. Kenneth Bird, the county’s health officer. She was not identified, and Bird said she has asked health officials not to disclose the country she visited to protect her identity.
Zika is widespread in portions of southern Mexico, in Central and South American countries and in the Caribbean.
As of July 1, 68 people in California have had confirmed travel-associated Zika infections. Of those, three cases have been confirmed in San Joaquin County and one in Stanislaus County. Nationwide, there have been 934 infections traced to infection during travel.
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“Everyone here needs to be sure they’re protecting themselves from mosquito bites,” Bird said.
Health officials are concerned about the potential for spread of the virus from people who are infected during travel, return home and are bitten by mosquitoes here that can spread the virus.
The Aedes aegypti mosquito, which can carry Zika, has been found in areas of Clovis and Fresno since 2013. In Fresno, the mosquito has been particularly active in the areas of Herndon and Polk avenues and in Old Fig Garden, said Tim Phillips, manager of the Fresno Mosquito and Vector Control District. In Clovis, the mosquito has been concentrated in southeast Clovis.
The infected Fresno County woman lives in an area that is not home to mosquitoes that carry Zika, Bird said. Mosquitoes trapped around her home are not those that can transmit the virus.
68Number of travel-associated Zika cases in California
But since her return to Fresno County from her travels, she has been bitten by mosquitoes that can carry West Nile virus, said Steve Mulligan, manager of the Consolidated Mosquito Abatement District.
People who return from Zika-active countries should use insect repellent for three weeks to prevent its spread, according to federal health guidelines. Bird said the woman is not under quarantine. Health workers have given her information about protecting against mosquito bites and about safe sexual practices. Zika also can be spread through sexual contact. The health department is “taking it on faith” that she is abiding by the health instructions and is protecting herself from further mosquito bites, he said.
The county may have dodged a local transmission this time, but Mulligan remains concerned: “It’s important we don’t have a person who is infected meet up with a mosquito that can transmit it.”
Phillips said the Aedes aegypti mosquito is not going to go away: “Everyone needs to get used to using repellents every day.”
Mulligan said the mosquito can breed in small amounts of water, including in backyard drains, which he said should be screened to keep mosquitoes out.
“These mosquitoes will find water,” he said.
The Central California Blood Center is closely following reports of travel-associated Zika cases, said Leslie Botos, director of community relations and development, who on Tuesday spoke at a health department news conference called about the county’s first travel-associated Zika case.
It’s important we don’t have a person who is infected meet up with a mosquito that can transmit it.
Steve Mulligan, mosquito abatement manager
There is no federally approved test to detect Zika in blood that is universally being used by blood banks. A test has been developed that is in use in Puerto Rico, where Zika is active and blood donations for a time had been suspended, Bird said.
But in the continental United States, people are asked to delay donation for at least one month following return from a Zika-active country, Botos said. Someone who has sexual contact with a partner who in the three months before sexual contact was diagnosed with Zika virus infection or had traveled to an area with Zika transmission must wait a month to donate blood.
“We ask that you give blood before you travel,” Botos said.
However, travelers should not think they no longer can be donors, she said. Deferral does not have to be permanent. Call the blood bank to find out your eligibility to donate, Botos said.
“Every day, we need 250 to 300 donors,” Botos said. “Every time a story about Zika is presented, we see a decline in donations to the point where it takes our blood supply to a very vulnerable position for patients who depend on blood every single day.”