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Zika Causes Infertility In Mice, But Does It Do The Same To Human Men Too?

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If you thought that, just because the weather was finally cooling off, Zika wasn't going to be much of an issue anymore — think again. A new study revealed that Zika causes infertility in male lab mice and it could theoretically do the same to human males as well. Yup, although most of the research surrounding the virus and its effects has so far centered around pregnant women and their babies, it looks like men might have something to worry about, too. Don't start freaking out just yet, gentlemen, the study still needs to be corroborated. But it's still not exactly great news.

Here's the deal. Scientists know that Zika virus can be sexually transmitted and that is can stay in semen for up to six months, which is why the Centers for Disease Control and Prevention recommended that men who travelled to Zika infected areas have protected sex with their female partners, putting a stop to any plans of getting pregnant or starting a family. But that might not be the only risk.

The study, which was done at Washington University in Louis, injected male mice with the virus. After a week, the testes of the mice were pretty normal. But after three weeks, things were not great. The researchers found that the testes of the Zika infected mice had shrunk to a tenth of their size and were pretty much destroyed. They also found that the virus had killed the Sertoli cells, the cells that help sperm grow, in the testes. The Sertoli cells don't regenerate. The Zika infected mice also had lower testosterone.

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According to Dr. Michael Diamond, an author of the the study, the study hasn't been replicated on humans, but the findings aren't promising in the mice. He told The Telegraph in a statement, "While our study was in mice, and with the caveat that we don't yet know whether Zika has the same effect in men, it does suggest that men might face low testosterone levels and low sperm counts after Zika infection, affecting their fertility."

Diamond added, "We don't know for certain if the damage is irreversible, but I expect so, because the cells that hold the internal structure in place have been infected and destroyed.” There have been Zika infected, male humans already reported (no reports of shrinking testicles yet, and that's something men would probably notice and tell their doctors about), but that doesn't mean that Zika could affect a human male's fertility. Mice are tiny and could biologically be affected more than their human counterparts.

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Co-author co-author Dr Kelle Moley, professor of obstetrics and gynecology at the University of Washington explained, "We don't really know how the severity in men might compare with the severity in mice. I assume that something is happening to the testes of men, but whether it's as dramatic as in the mice is hard to say.”

So men, don't fret, because your testicles are probably not going to shrink. But there might be some more serious side effects for Zika infected men in the long run. Hopefully, there will be ways to find out exactly what they are soon as well.