How long does Zika remain in semen?

With growing concern about the spread of the Zika virus, new evidence reveals that the virus can survive in sperm for up to six months, according to a new study.

An Italian man tested positive for Zika in his sperm six months after initially experiencing symptoms of the virus such as a skin rash, fatigue and fever during a trip to Haiti. That is twice as long as a French man who tested positive for Zika three months after his initial infection.

Doctors at the Spallanzani Institute for Infectious Diseases in Rome said their analysis suggests the possibility that Zika reproduces itself in the male genital tract.

The Zika virus is a mosquito-borne virus (similar to West Nile virus) that causes birth defects including microcephaly, a rare condition characterized by incomplete brain development and an abnormally small head.

While it is most commonly transmitted by infected mosquitoes to people, there have been rare cases of it being transmitted through sexual contact. The Centers for Disease Control (CDC) reports that Zika can be passed through intercourse, even if the infected person does not have symptoms.

Symptoms of the virus typically occur within a couple of weeks of infection and include fever, rash, joint pain, red eyes, muscle pain and headache.

But Dr. Susan Mitchell, an obstetrician and gynecologist at Advocate Good Samaritan Hospital in Downers Grove, Ill., says that only 20 percent of adults infected with the Zika virus actually experience symptoms.

“When we first became aware of Zika, the focus was on keeping pregnant women from traveling to areas in the world where there was active Zika transmission,” says Mitchell. “But now that we realize men can acquire the virus and pass it on to a partner even months after exposure, it is extremely important for everyone to understand the danger of having unprotected intercourse with anyone who has traveled to an endemic area within the previous six months. This is especially important for men who have had symptoms of Zika, like a rash or fever, even after the symptoms have completely resolved.”

The CDC recommends men diagnosed with Zika wait six months before having unprotected sex so that they do not infect their partner. Infected men who have a pregnant partner are advised to wear a condom during the pregnancy.

“Especially now that active transmission of Zika has been confirmed in Miami and as Americans are returning home from the Rio Olympics, it is essential that everyone understands the risk of Zika transmission from unprotected sex. The birth defects that Zika can cause are devastating,” says Mitchell.

While researchers continue to study the complex virus, there is no specific treatment nor vaccine to protect against infection.