Zika Virus could cause fertility problems in men, according to the latest study. This result is the confirmation of what previous researchers already have found. Until recently, pregnant women were found to be most at risk from getting the virus through the mosquito bite. After reporting that virus can be sexually transmitted, it was revealed that the virus can persist in the semen of infected men for at least six months. These particularly worried healthcare professionals what’s going on in testicles while they are infected and put it under examination. The final results have show that the virus presence causes testicular atrophy.

After 21 days virus presence in the semen, it was noticed testicles shrinking which further cause infertility problems

Scientists from the Yale University tested genetically modified mouse infected with a non-lethal strain of the Zika virus. They wanted to observe viral replication. Researchers found that virus persists in the part of testicles known as the epididymis ( responsible for sperm transmission from the testes to the urethra ). The virus continued to replicate itself even after it was cleared from the blood. After 21 days of observation, researchers noticed testicle shrinking so-called testicular atrophy, which has an impact on males fertility.

These study findings confirmed previous research on this matter. A similar experiment was conducted by experts from Washington University where is discovered that Zika infections can persist for many weeks in the reproductive systems of male mice. As consequences of infection levels of testosterone and other sex hormones drop, sperm counts fall, and, the testicles shrink to 1/10th of their normal size.

Immunofluorescence staining showing that the tests of Zika-free mice (left) are full of developing sperm (pink), while the testes of Zika-infected mice (right) contain very few sperm. Image Credit: Washington University School of Medicine

While Zika virus is no longer international epidemy, the threat still remains. Its ability to remain in the body for extended periods of time and fast sexually spreading inquire efforts to develop a vaccine. Although the findings have not yet been replicated in humans, experts say that the virus may also have worrying consequences for men who become infected. If Zika turns out to affect male fertility in humans, the good news is that animal studies can speed the search for potential treatments.