After a sexual infection, the replication of the virus in the female genital tract is favored, thus increasing the risks for the fetus.
Zika infection is usually not dangerous, except for pregnant women. Babies of women who carry the virus are at high risk of developing microcephaly, a brain defect that causes severe disabilities.
And the risks to the fetus may be even greater when mothers contract the infection sexually, compared to conventional transmission through mosquito bites, according to a study from UC Davis University (United States). ), published in the review PLOS Pathogens.
Promoted viral replication
The American researchers carried out experiments on female rhesus macaques, which they infected vaginally. By following the evolution of the amount of virus in the reproductive organs, they noticed that its replication was much higher than that observed after infection by a simple bite.
“These results suggest that the fetuses would be more at risk of being infected in turn, and of developing the complications associated with the disease, when women are infected through sexual contact”, summarize the authors.
Long life in sperm
The information is not trivial, because the means of combating the disease mainly focus on vector control, that is to say, the elimination of mosquitoes and protection against bites. But little against sexual transmission.
Yet studies have shown that the virus can survive in semen six months (at least) after infection. Wearing a condom therefore remains essential in case of suspicion of contamination of one of the two partners, in order to avoid contaminating the other. It is even more so for couples whose wife is pregnant.
Almost 50% risk of malformation
But it becomes more of a nuisance for those with a desire for children. For the moment, no treatment has made it possible to eliminate the risk to the fetuses, and the only means of prevention is to postpone the pregnancy.
Deformities occur in about 10% of cases, according to a study by the US CDC. If the mother is infected during the first trimester of her pregnancy the risk could rise to 15%. And up to 42% when taking into account all the anomalies caused by the virus.
Knowing for example that in French Polynesia, two thirds of the population has been affected by the virus, caution is in order.
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