Scientists Detect Hantavirus Genetic Material In Semen Nearly Six Years After Infection

Swiss researchers have reported that the Andes strain of hantavirus may persist in a man’s semen for nearly six years after infection. The finding raises new concerns that the virus could potentially be transmitted sexually long after a patient has clinically recovered.

The peer-reviewed study, published in the journal Viruses and reported by The Telegraph, was conducted by scientists at the Spiez Laboratory, a Swiss government institute specializing in biological, chemical, and nuclear threats.

Researchers investigated the case of a 55-year-old Swiss man who contracted Andes hantavirus while traveling in South America.

Viral Material Was Found Years After Recovery

According to the study, no traces of the virus were detected in the patient’s blood, urine, or respiratory samples during examination.

However, viral genetic material remained detectable in his semen 71 months after the original infection, suggesting unusually long-term persistence within the reproductive system.

The researchers say this finding supports concerns that the male reproductive tract may serve as a long-term viral reservoir for certain pathogens.

Why Viruses Can Persist In The Testes

Scientists explain that the testes are treated differently by the immune system because reproductive cells must be protected to preserve fertility.

As a result, immune responses in this area are weaker, potentially allowing some viruses to evade complete clearance and survive for extended periods.

Researchers note that similar persistence has previously been observed with both Ebola and Zika viruses.

A major Ebola resurgence in Guinea in 2021 was linked to a survivor of the 2014–2016 outbreak who is believed to have sexually transmitted the virus years after recovery.

The new study concludes that the Andes hantavirus strain may also carry a potential risk of sexual transmission, although no officially confirmed cases have yet been documented.

The authors stress that the possibility should still be considered seriously in future public health planning.

Experts Call For New Safety Recommendations

Following publication of the study, analysts at health intelligence company Airfinity called for the development of specific safe-sex guidance for male hantavirus survivors after recovery and release from isolation.

They suggested creating recommendations similar to current World Health Organization protocols used for Ebola survivors.

WHO guidance currently advises men recovering from Ebola to undergo semen testing every three months and continue precautions until two consecutive negative test results are obtained.

Until then, patients are advised either to abstain from sexual activity or consistently use condoms.

Researchers say comparable recommendations for Andes hantavirus may help reduce any possible risk of delayed sexual transmission, particularly in areas where the virus circulates naturally.

However, scientists emphasize that additional research is still needed to determine whether persistent viral genetic material in semen necessarily means the virus remains infectious over time.

Growing Attention After Recent Hantavirus Cases

Global interest in hantaviruses has increased following several recent cases associated with the cruise ship MV Hondius.

In the United Kingdom, health authorities have reportedly placed dozens of asymptomatic contacts under precautionary medical monitoring.

The UK Health Security Agency has stated that it is reviewing emerging international evidence on hantaviruses, including research examining viral persistence in bodily fluids.

Officials say patient guidance and recommendations for close contacts could be updated if future evidence suggests a different level or type of transmission risk.

Long-Term Questions Remain

Although hantavirus infections remain relatively uncommon, the study highlights how some viruses may continue posing challenges long after acute illness has ended.

Public health experts are now considering whether future hantavirus response plans should include long-term testing recommendations and sexual health guidance similar to those already used for other persistent viral infections.

Researchers say the findings also underscore the broader scientific question of how viruses interact with immune-protected regions of the body and how long they may remain hidden after apparent recovery.