A recent report by the CDC has bolstered the previously suspected theory that the Zika virus – a virus receiving global attention for its connection to deformities in newborns of infected women – is sexually transmittable from men to women. [3] Prior to the CDC’s recent report of 14 potential infections through sexual activity, only a handful of such transmissions were reported, bolstered in addition by the discovery of the virus in one infected man’s semen. [1][2][3] No cases of women transmitting the virus sexually to their partners have been documented. [4]
Approximately 80% of those infected by the Zika virus do not display symptoms, and those who do are often only mildly affected. [2] However, Zika infections in pregnant women have been linked to deformities in newborns, and transmission of the virus can occur between infected mothers and their fetuses.[3] The CDC has thus advised that “people returning from Zika-infected areas use condoms or abstain from sex for the duration of their partner’s pregnancy.”[3] Proper use of latex condoms reduces the risk of infection through sex. [4] The primary mode of infection, however, remains the mosquito, and the CDC advises that those traveling to areas with Zika infection should take steps to prevent mosquito bites, such as wearing long sleeves and avoiding areas near standing water. [3][5]
The CDC is currently investigating the 14 reported potential sexual transmissions of Zika, which should better indicate the risk and scope of the problem. [3] Thus far, approximately 100 cases of Zika have been reported in the US, mostly in Florida, Texas, and California, with the vast majority of those cases being mosquito-borne, and every case imported from countries currently experiencing Zika outbreaks [6]. There is currently no known mosquito transmission of Zika in the US, but the Aedes mosquito that transmits the virus does inhabit the southern and eastern United States, and could further transmit the virus if it became prevalent.
Acknowledgments: Thank you to Sarah M (ScM Student, Infectious Disease Epidemiology, Harvard) and Rachel C (PhD Candidate, Harvard Immunology Program) for their insights on Zika.
Managing Correspondent: Sam Dillavou
[1] http://wwwnc.cdc.gov/eid/article/21/2/pdfs/14-1363.pdf
[2] http://www.cdc.gov/mmwr/volumes/65/wr/mm6505e1.htm
[3] http://www.nytimes.com/2016/02/24/health/zika-virus-sexual-transmission.html
[4] http://www.cdc.gov/zika/transmission/sexual-transmission.html
[5] http://www.cdc.gov/zika/prevention/index.html
[6] http://www.cdc.gov/zika/geo/united-states.html