Smallpox in monkeys, virus in testicles: “Sexual transmission hypothesis”

Scientists have verified its presence for the first time in macaques

A team of researchers first found il Monkeypox virus in the testes of non-human primates – macaques – during the acute phase of the infection. It also found preliminary evidence of persistent infection in two specimens that survived the challenge with the virus. The findings are published online in the journal ‘Nature Microbiology’ and highlight the potential for sexual transmission of the virus in humans, explain the authors, researchers from the US Army Medical Research Institute of Infectious Diseases (Usamriid).

The interest in investigating whether this path of contagion was possible stems from the fact that the monkeypox epidemic underway in 2022 was linked to sexual contact in patients with laboratory confirmed infection. Because the virus can be transmitted through direct contact with body fluids and skin lesions, the experts note, understanding the biology of testicular infection and spread of the virus in sperm “has substantial public health implications.” Usamriid researchers performed a retrospective analysis of monkeypox virus infection in archived tissue samples of crab-eating macaques, a non-human primate model used to study the disease and evaluate the effectiveness of medical countermeasures. , such as vaccines and treatments.

By analyzing the samples, “we detected monkeypox virus in the interstitial cells and seminiferous tubules of the testes, as well as in the epididymal lumina, which are the sites of sperm production and maturation,” explained senior author Xiankun Zeng. Focusing on the course of the disease, the team found that while the monkeypox virus was cleared from most organs and skin lesions that healed during convalescence, it could be detected in macaque testes for up to 37 days after exposure. pathogen.

“Our data provides evidence that monkeypox virus can spread in sperm during the acute and convalescent phases of the disease in macaques,” said Zeng. “It seems plausible, therefore, that human transmission can also occur” through sperm. ” The authors then noted that the persistent virus can be eliminated over time. As this was a retrospective study, isolation of the virus in semen was not possible, said Jun Liu, first author. Further studies are now needed to understand the origins, dynamics and implications of viral DNA shed in sperm, and to confirm whether the viruses contained in this body fluid are indeed infectious, especially after the lesions have healed.

Additionally, the crab-eating macaque model may not fully reflect monkeypox in humans, according to the authors. In fact, animals show a more serious and lethal disease than that observed in humans and the incubation period is shorter. Additionally, this study used animal samples exposed to different viral isolates than the currently circulating strain.