BEACON TRANSCRIPT – Researchers have recently discovered that the Zika virus could be transmitted sexually, via semen. They performed a study on mice to see why such a transmission occurred and how the virus could affect male fertility.
The study showed how the Zika virus attacked the mouse testicles, namely the cells that are responsible with producing testosterone. In the end, the virus caused the testicles to shrink. These discoveries suggest a persistence of the virus in semen.
Dr. Amesh Adalja, professor at the Johns Hopkins Center for Health Security in Baltimore, talked about the results of the study. He suggested that, if the same effects were produced in humans as in mice, the Zika virus might induce problems with fertility in the infected males.
The typical way of transmission of the Zika virus is via mosquito bites, but the researchers have recently discovered that it can be transmitted via semen. Thus, the researchers drew the conclusion that the virus might be replicating in the testicles.
Ryuta Uraki, a postdoctoral associate at Yale University’s School of Medicine in New Haven and the lead author of the study, decided to test their hypothesis by infecting mice with the virus and looking at how it affected different types of cells.
They discovered that, even after disappearing from the blood cells, the virus replicated in the Leydig cells in the testicles, which are responsible with producing testosterone. They also found traces of the Zika virus in the epididymis, the tube that delivers sperm in the seminal fluid.
The Zika infection caused the inflammation of the mice’s testicles and lower testosterone levels. Also, 21 days after the infection, the testicles of the infected mice became significantly smaller, thus indicating progressive testicular atrophy.
The two possible explanations of this phenomenon are the following. The infection might either cause an immune response that attacks the testicles and causes their shrinking, or the attack on Leydig cells might cause a massive reduction of testosterone levels that eventually leads to the reduction of the testes.
Either of the hypotheses leads to fertility problems. Also, this study might suggest that the Zika virus could have the same effect on humans, although results on animal tests are not necessarily applicable to humans.
The researchers need to perform the same tests on males infected with Zika and see how the replication of the virus is possible in the testicles.
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