The CDC is collecting samples from 40 men in the U.S. who've been infected with Zika to better understand how long the virus lives in semen. The agency plans to recruit approximately 210 more volunteers for this study, according to CNN.
Previous research has found the Zika virus lives on in a man's sperm well after symptoms have dissipated. According to the CDC, there have been 14 cases of sexually transmitted Zika virus as of July 6. As of June 30, there have been 320 pregnant women in the U.S. with laboratory evidence of Zika infection and seven infants born with Zika-related birth defects.
Study participants are asked to make approximately a dozen donations from their homes every other week for the first six months post-illness. A courier transfers the donations to the CDC's labs in Fort Collins, Colo. Volunteers receive a $50 gift card every other week of participation.
"I'm happy to say patients really have been quite receptive about volunteering their specimens," Paul Mead, MD, senior epidemiologist at the CDC and leader of the study, told CNN. "They seem to understand the importance of the study."
In a separate study, the CDC is examining the semen of men in Puerto Rico who contracted Zika but never displayed symptoms. The study may prove significant as a majority of those infected with the virus either experience mild symptoms or none at all.
Currently, the CDC recommends men who've been infected with Zika either abstain from sex or use condoms for six months after their illness has subsided.
Learn more about Zika and sexual transmission here.
More articles on the Zika virus:
'It's too late. Mosquito season is here': Houston health official expresses ire over stalled Zika funds
CDC, EPA urge Puerto Rico to start aerial spraying to fight Zika mosquitoes
UPenn researchers say they have a portable $2 test for Zika