Fragments of the monkeypox virus have been detected in semen in a handful of patients in Italy, raising questions over whether sexual transmission of the disease is a possibility, scientists said on Monday.

The monkeypox virus is understood to spread through close contact with an infected person, who may shed the virus via its hallmark skin lesions or large respiratory droplets. Many of the monkeypox cases confirmed in the current outbreak are among sexual partners who have had such close contact.

However sexually transmitted diseases such as HIV/AIDS, chlamydia, and syphilis are understood to be caused by pathogens that pass from one person to the next specifically in semen, vaginal secretions or other bodily fluids.

Researchers at the Spallanzani Institute, a Rome-based hospital and infectious disease research facility first highlighted evidence of the monkeypox virus in semen in four patients in Italy in a report on June 2.

They have since identified six out of seven patients at the facility with semen containing the virus' genetic material. In particular, a sample tested in the lab from a single patient suggested that the virus found in his semen was capable of infecting another person and replicating.

This data, which is being submitted for publication, is not enough evidence to prove that the virus' biological traits have changed, such that its mode of transmission has evolved, Francesco Vaia, the institute's general director, told Reuters.

"However ... having an infectious virus in semen is a factor that tips the balance strongly in favour of the hypothesis that sexual transmission is one of the ways in which this virus is transmitted," he said....