Zika Update: Virus Could Negatively Affect Male Fertility

A new study revealed that men who are exposed to the dreaded Zika virus might develop some serious reproductive problems, leading to infertility.

The study, published in the journal Nature, showed that the virus could travel into the testes of male mice and destroy the internal structure of the testicles, shrinking reproductive organ by 90 percent. Additionally, the virus greatly reduced the sperm count and testosterone levels of the mice.

"We undertook this study to understand the consequences of Zika virus infection in males," said Dr. Michael Diamond, associate director of the school's Center for Human Immunology and Immunotherapy Programs and co-author of the study, in a report from CNN. "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."

For the study, the researchers injected the virus into male mice. A week after the injection, the virus has already reached to the testes, boring microscopic signs of infections. After two weeks, the researchers observed that the testicles are significantly smaller and the internal structure started to collapse.

At three weeks, the testes are already one-tenth of its normal size with its internal structure completely destroyed. Six weeks after the initial introduction of the virus, the mice had cleared the virus from their system. However, the damage done in the testicles did not heal.

The researchers found that the Zika virus primarily attacks the Sertoli cells, which is responsible for the internal structure of the testes and maintains the barrier between the testes and the bloodstream. These Sertoli cells also help nourish developing sperm cells. While it plays a crucial role in the overall health of the male reproductive system, Sertoli cells don't have the ability to regenerate.

Furthermore, the researchers observed that the sperm count and testosterone levels of the mice drop as the virus destroy the male organ. Due to this, male mice infected with the virus are four times less likely to reproduce compared to healthy male mice.

The research team noted that while the study is conducted on mice, the findings might well be applied to man. However, further human studies are needed to full understand the negative impact of Zika virus to male reproductive system.