Male Fertility and Zika – Is There a Reason to Fear?

Healthy Living

March 29, 2017

The New Concerns About the Zika Virus for Men

A recent research study, funded by the National Institutes of Health (NIH), was published that reported the effects of the Zika virus on male mice’s reproductive abilities. The results of the study found that the virus may produce a marked reduction in the sperm count of male mice and that the effects may be long term, or in some cases permanent.

Prior to the NIH study there was only a few things known about the Zika virus in terms of negative effects on males, that being that Zika can be sexually transmitted and that men who’re infected with the Zika virus can carry the virus in their semen months after being infected. The revelations of the NIH mice study have brought a newfound urgency for the need of additional testing and research studies to be conducted to understand the full extent of the possible health hazards Zika presents for all people; men, women and children.

In the NIH mouse study, it was alarming for researchers to realize that the Zika virus not only was found in the semen of male mice weeks after infection, but that the virus caused a marked decrease in sperm levels and testosterone. An additional finding was that the testes in some of the lab mice shrank to 1/10th of their normal size prior to infection, and in some instances permanently.

The conclusions drawn from the mice study showed that male mice infected with the Zika virus were dramatically less able to reproduce than Zika free mice; Zika-infected mice produced approximately one quarter the amount of healthy offspring as the Zika-free mice. The lead researcher, Michael Diamond of Washington University School of Medicine, St. Louis, noted that the virus quickly spread through the reproductive systems of the adult male mice, with long term negative effects.

Zika was found in the reproductive parts and testicles of the test mice as well as in mature sperm cells; primary spermatocytes, Sertoli cells, and spermatogonia all of which are integral in producing sperm. It was also noted that one week later the Zika-infected mice’s testicles still appeared normal, but after two weeks a marked decrease in size was observed (this occurred as infected reproductive tissue died). After three weeks the testicles of the infected mice were essentially destroyed.

Lead researcher, Diamond said that even though the infected mice cleared the virus several weeks later, the damage to their reproductive systems (spermatogenesis) had already been done and that he and the other researchers doubted that the mice could recover from such severe injury. But, he also stated longer term studies would be required to confirm their findings.

Not only will long term studies in mice be necessary, but the researches are studying if the viral dosage of Zika the study mice were given would be equal to, or at least similar to what a human male would receive if they’re bitten by a Zika carrying mosquito. The researchers are now collecting evidence from men who’ve tested positive for the Zika virus to see if they’ve experienced similar damage to their reproductive systems and drastic shrinkage of the testicles as was seen in the Zika infected mice.

While all of this sounds very grim for men, there is a light at the end of the tunnel; animal studies typically speed up the process for potential treatments and cures in humans. Diamond and his research team have begun tests in their male mice to see if treating the mice with highly neutralizing antibodies can neutralize the Zika virus in the reproductive system of the mice before it can cause cellular destruction and infertility.