Wednesday, October 26, 2016

Zika virus - a new sexually transmitted infection?

Media attention has emphasized the importance of the sexually transmittable nature of Zika, especially in the US and Europe. These countries don’t have naturally endemic areas, and thus travelers from outside areas are able to bring in Zika. By September 9, 12 countries has reported cases of non-mosquito-borne Zika virus. ‘

However, through publicly available CDC data it was reported that only 23 out of 2,381 cases were transmitted through sexual contact with a person who had traveled to an endemic area. Math models has estimated that 3% of overall R0 (reproduction number) are due to sexual transmission, with the upper limit more around 45%.  

One reason that Zika will probably not be a sustainable STI is becuase R0 for sexual transmission must be greater than one, when considering the product for infectious duration and sexual transmission rate. 

The article has a call for action for follow up studies of sexually-transmitted Zika-virus. They claim that those small groups with frequent change of sexual partners could undergo Zika infection, as well as those who don’t have endemic areas, but do have travelers. This could lead to viral persistence and reservoir potential to pass through areas with no mosquitos. However, Zika is still not a designated sexual transmitted infection - yes, sexually transmissible -  but not yet a sexually transmitted infection due to low proportion of Zika infections through this method. 

- Gianna Nino-Tapias (’18)


  • Althaus CL, Low N (2016) How Relevant Is Sexual Transmission of Zika Virus? PLoS Med 13(10): e1002157. doi:10.1371/journal

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