When cases of Zika started popping up in people who did not have a documented mosquito exposure, epidemiologists started to wonder if Zika could be transmitted from one person to another through some other way. As it turns out, Zika can be transmitted through sexual contact. Since unborn fetuses are at highest risk for complications from the mother being infected, it is essential that men who have been exposed to Zika use condoms when having sex with a pregnant woman. For how long? Six months.