NEW YORK (AP) – Zika virus ravages the testes of male mice, sharply reducing sperm counts and fertility, says a study that raises a new specter about its threat to people.
Experiments found testes of infected mice shrank about 90 percent by weight, while their output of useful sperm fell by three-quarters on average, and often more.
Now it’s time to find out if Zika causes similar damage in men, experts said.
“We just don’t know that yet,” said Michael Diamond of the Washington University School of Medicine in St. Louis, a senior author of the study. The virus is known to infect a man’s reproductive system and persist in sperm and semen, “so it’s in the right place,” he said.
Diamond said he suspects that in mice, the damage is permanent.
But mice are not men, and experts unconnected with the study agreed that it can’t be assumed that the mouse results apply to people.
Shannan Rossi, who studies Zika in mice at the University of Texas Medical Branch in Galveston, noted that the researchers had suppressed the animals’ immune system defense against the virus. That’s a standard step in such experiments but it adds another level of difference from humans, she said.