GENEVA/BRASILIA, (Reuters) – The World Health Organization voiced concern on Wednesday over the reported sexual transmission of the Zika virus in Texas amid worries that such infections could make battling it even tougher. There is no vaccine or treatment for Zika.
The virus, spreading quickly across the Americas, is usually transmitted by mosquitoes, but Dallas County reported on Tuesday that the first known case contracted in the United States was a person infected after having sex with someone who had returned from Venezuela.
The WHO declared a global health emergency on Monday, citing a “strongly suspected” causal relationship between Zika infection in pregnancy and microcephaly, a condition marked by abnormally small head size that can cause permanent brain damage in newborns.
Health ministers from across South America gathered in Uruguay’s capital, Montevideo, to discuss the public health emergency and how the region could coordinate its fight against the outbreak.
Sexual transmission could add a new dimension to the threat Zika poses, but WHO spokesman Gregory Hartl stressed that “almost a 100 percent of the cases” are transmitted by the bite of a mosquito.
“This reported case in the U.S. of course raises concerns,” Hartl said at the U.N. agency’s headquarters in Geneva. “This needs to be further investigated to understand the conditions and how often or likely sexual transmission is.”
But he said that for the WHO “the most important thing to do is to control people’s exposure to mosquitoes.”
The WHO estimates as many as 4 million people could become infected in the Americas.
Hartl called the Texas case only the second worldwide linked to sexual transmission, referring to media reports about a case of an American man who returned from Senegal in 2008 and is suspected of having infected his wife. The medical literature also has a case in which the virus was detected in semen.
“If you swap enough bodily fluid, most viruses can probably be sexually transmitted to some extent,” said Ben Neuman, a virologist at Britain’s University of Reading.
Florida Governor Rick Scott declared a public health emergency in four counties with travel-related cases of the Zika virus, and ordered state officials to increase mosquito control efforts in some of the southeastern U.S. state’s most heavily populated locales including Miami and Tampa.
Scott directed state officials to pay special attention to mosquito spraying in residential areas.
In addition, the U.S. Centers for Disease Control and Prevention, which has urged pregnant women to consider delaying travel to locations with ongoing Zika transmissions, added Jamaica and Tonga to its travel alert.
Despite already being on the CDC’s travel alert, Mexico’s health ministry downplayed Zika’s threat to tourism on Wednesday, saying its 34 confirmed cases are far from tourist areas while conceding it was “inevitable” the virus would spread.
The WHO said at least 26 countries in the Americas have a Zika outbreak, and countries such as Ireland, Australia and Canada have reported cases of travelers testing positive for the virus after visiting an infected area.
Late on Tuesday, the Brazilian health ministry said the number suspected microcephaly cases that may be linked to the virus had increased to 4,074 as of Jan. 30, from 3,718 a week earlier.
Researchers have identified evidence of Zika infections in 17 of these cases, either in the baby or in the mother, but have not confirmed that Zika can cause microcephaly.
