Infectious Diseases

22 August 2017

How long can Zika last in your sperm?

It is important to take precautions as the Zika virus can be sexually transmitted. But exactly how long does the Zika virus remain in sperm?


If you are up to date with current affairs, you might have heard of the Zika virus.

According to Health24, the Zika virus is spread to humans mainly through the bite of an infected Aedes aegypti or Aedes albopticus mosquito.

The virus is present in human bodily fluids such as saliva, blood, urine and semen. Zika virus is most often transmitted via mosquito bites. But the virus also can be sexually transmitted, according to the US Centers for Disease Control and Prevention (CDC).

Now, a new small study suggests that the Zika virus might not remain in the semen of some infected men as long as previously thought.

The researchers said Zika may only be present in semen for about a month. Previous research had suggested that Zika virus can be found in semen for as long as 188 days after the onset of symptoms.

Replication in testicles

The new study included 12 men in French Guiana who had Zika virus. Four of the men never had any detectable Zika in their semen. One excreted Zika virus in his semen for at least three days. And seven had Zika-laced semen for at least a month, the researchers reported. The maximum duration of detectable Zika in semen in the study was 45 days.

"These data suggest that not all men who are symptomatically infected with Zika virus will have Zika virus RNA (ribonucleic acid –  nucleic acid present in all living cells and many viruses) detectable in semen," Dr Franck de Laval, of the Military Centre for Epidemiology and Public Health in Marseille, France, and colleagues wrote.

The results also showed that Zika does replicate in the testicles or semen-producing glands, since the amount of Zika in semen was significantly different than the Zika load found in the men's blood.

"More data are needed to better inform public health recommendations," the study authors suggested. The study was published as a letter in the New England Journal of Medicine.

Longer follow-up needed

Women's health specialist Dr Jill Rabin said the small size of the study warrants a larger follow-up.

"The good news is it may last a shorter period in men than recorded previously, but we need to have a larger sample size and follow people for a longer period of time," Rabin said.

Dire effects

Zika causes neurological birth defects, most commonly microcephaly, a condition in which a baby's brain and skull are underdeveloped, Rabin said. She's co-chief of the division of ambulatory care with Women's Health Programs-PCAP Services at Northwell Health in New Hyde Park, New York.

A Health24 article also mentions a study that linked Zika to possible fertility problems in men. However, this study was performed on rats, therefore the human outcome wasn’t clear.

Precaution still necessary

The CDC recommends that men potentially exposed to Zika use condoms or abstain from sex for at least six months, to prevent a Zika-infected pregnancy resulting in neurological birth defects.

It's unlikely the CDC recommendations will change based on these findings, an infectious disease expert said.

And despite these findings, people should still follow the CDC's Zika guidelines for safe sex, health experts said.

According to Dr Amesh Adalja, a senior associate with the Johns Hopkins Center for Health Security, in Baltimore, "Because it is unclear which men will have longer persistence, it is important for Zika-infected/exposed men to practice safe sexual practices for six months post-infection to avoid transmission of the virus."

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