For the first time, scientists have detected the monkeypox virus in the testes of macaques during the acute phase of infection. This is shown by an investigation published in the journal “Nature Microbiology” in which, in addition, preliminary evidence of persistent infection is found in two animals that survived the virus. The results highlight the potential for sexual transmission of the virus in humans..
The monkeypox outbreak has been linked to sexual contact in patients with laboratory-confirmed infection. Since the virus can be transmitted through direct contact with body fluids and skin lesions, understanding the biology of monkeypox infection of the testis and virus shedding in semen has important public health implications.
What this team from the US Army Medical Research Institute of Infectious Diseases, or USAMRIID, has done is a retrospective analysis of monkeypox virus infection in tissue samples from a type of macaques that they are a widely used non-human primate model for studying the disease and evaluating the efficacy of monkeypox vaccines and treatments.
“We examined tissue samples obtained during the acute phase of the disease, when the infection is at its peak, and the convalescent phase, when it gradually declines,” explains the lead author. Xiankun Zeng. “We detected monkeypox virus in the interstitial cells and seminiferous tubules of the testes, as well as in the lumen of the epididymis, which are the sites of sperm production and maturation.”
Zeng notes that they have also found preliminary evidence of persistent monkeypox virus infection in two convalescent macaques that survived the virus.
Using histological analysis to microscopically analyze the course of the disease in tissue samples, the team found that despite the monkeypox virus being cleared from most organs, and skin lesions healed , during convalescence, could be detected up to 37 days after exposure in the testicles of macaques.
Ebola, Marburg…
This group of researchers had previously shown that the viruses of the hemorrhagic fever of the Ebola, Marburg, Nipah and Crimea-Congo they can persist in certain nonhuman primate organs where the immune system is suppressed. These immune privileged sites are similar in humans, and include the eyes, brain, and testes.
In the case of the monkey virus, although close contact through sexual activity has been associated with its spread, it was unclear whether the virus replicated in the testicles or was transmitted through semen.
“Our data provide evidence that monkeypox virus can pass into semen during the acute and convalescent stages of the disease in macaques,” Zeng said. Therefore, he continues, “human transmission in convalescent male patients via semen seems plausible».
The authors also noted that the persistent virus may go away over time.
However, the researchers acknowledge that this macaque model may not reflect monkeypox in humans. Animals show more severe and lethal disease than humans, and the incubation period in animals is shorter. Furthermore, this study used samples from animals exposed to different viral isolates than the currently circulating strain.