The number of people with the Zika virus has continued to increase. Millions of people in South America have been infected by the disease-carrying Aedes mosquito, and dozens of cases have been reported in the U.S., mostly by returning travelers who visited countries with active Zika transmission.
But since the outbreak of the disease, most warnings have been geared toward pregnant women. The virus has been linked to a congenital condition that causes newborns to have unusually small heads. Microcephaly, the name of the defect, causes smaller than normal cerebrums in babies and improperly developed brains. One American baby was born with the defect in Hawaii in January.
Reports have told men and nonpregant women they don't need to worry as much. Infected people usually clear the symptoms -- fever, rash, joint pain and red eyes -- in less than 10 days, and there have been no cases in which the virus has been transmitted locally in the U.S.
According to Dr. William Schaffner, a professor at the Vanderbilt University Medical Center and a member of an advisory panel for the Centers for Disease Control and Prevention, as long as a woman isn't pregnant and doesn't become pregnant shortly after being bitten by an infected mosquito, she doesn't run the risk of a passing Zika on to her baby.
"It's not yourself you should be so worried about -- it's your husband," Schaffner said.
Zika has been found in the semen of infected men, and it's unknown how long it stays there and over what period of time a man can transmit the virus through sexual contact. For that reason, a man who visits a country with a large Zika outbreak or who becomes infected puts sexual partners who are pregnant or considering becoming pregnant at risk.
Tom Skinner, a CDC spokesman, said the agency hopes to begin investigating how long Zika lasts in sperm immediately. The organization advises men who've returned from Zika-affected areas to consider abstaining from sex and using condoms until more information becomes available.