Female-to-male sexual transmssion of Zika virus infection

Dear Editor,

We read the publication on ‘The challenge given by Zika virus’ with a great interest.¹ Rodriguez and Sebastian mentioned that ‘No sexual transmission of Zika virus from infected women to their partners and from infected people without symptoms has been reported’.¹ Indeed, sexual transmission is a possible mode of Zika virus transmission.² Either homosexual or heterosexual contact might be the starting point of pathogenic virus transmission.³ Regarding female-to-male sexual transmission of Zika virus, there are some reports on this problem. Davidson et al first reported a suspected female-to-male sexual transmission of Zika Virus from New York city in 2016.⁴ This case report had several laboratory evidences showing the possibility of disease transmission.⁴ After that, there are many reports on this issue.⁵ As noted by Sherley and Ong, ‘Unusually for a mosquito-borne virus, sexual spread has also been reported; with cases of male-to-female, female-to-male and male-to-male sexual transmission all now published in the scientific literature’.⁵ According to the summative analysis by Moreira et al on sexual transmission of Zika virus, female-to-male transmission is detected in 3.7%.⁶ Nevertheless, the common difficulty for diagnosis of a male-to-female or female-to-male sexual transmission of Zika virus is the ruling out of the chance of mosquito transmission, mosquito bite, of the two partners.⁷ The diagnosis requires both clinical epidemiological molecular laboratory investigations for final confirmation.⁷