Six people in California have been diagnosed with the Zika virus in the past three years, state public health officials said Monday. All of the cases were contracted abroad.
California Department of Public Health Director Karen Smith said Monday that there is no evidence that mosquitoes in California are carrying Zika virus -- which experts think could be causing serious birth defects -- but advised that people take steps to avoid being bitten. There is no vaccine for Zika.
As of last week, officials have confirmed two cases of the Zika virus in Californians who were infected while traveling abroad in 2015. There were three cases in California in 2014 and one in 2013, according to officials.
State officials said the numbers will be updated Friday, and could go up. They would not specify the location of the cases, but L.A. County officials said last week that a young girl had been diagnosed with the illness in the county.
Public health experts became worried about Zika, which usually has no symptoms, when cases of microcephaly skyrocketed in Brazil after a Zika outbreak began there last year. The virus has been rapidly spreading, and cases have since been reported in more than 20 countries in the Americas.
On Monday, the World Health Organization declared the spread of Zika virus an international public health emergency.
So far, all cases in the United States have been in people who traveled to a country with an outbreak.
Zika isn't contagious. It can be transmitted only if a mosquito bites a person who has the virus in his or her blood, and then bites another person.
Because of the suspected link between microcephaly and Zika, authorities are recommending that women who are pregnant consider postponing travel to places where the Zika virus transmission is ongoing, and that women who are trying to become pregnant talk to their doctors about the risk of infection.
The mosquitoes that transmit the virus are not native to California, but have been found here in the last few years. In total, they've been detected in 12 of the state's 58 counties, officials say.
The Asian tiger and the yellow fever mosquitoes -- Aedes albopictus and Aedes aegypti, respectively -- are about half the size of normal mosquitoes and have black-and-white stripes. Unlike mosquitoes more common to California, which usually come out in the evening, these mosquitoes bite during the daytime.
"Although no one has contracted Zika virus in California, mosquito bites can still be harmful and the public should take steps to protect themselves," Smith said in a statement.
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