Female To Male Transmission Of Zika Virus

The cases of Zika virus infection and resulting complications on fetal well-being made headline news earlier this year. Investigators identified that Zika viral particles can cross placenta and blood brain barrier to cause a multitude of congenital anomalies in the baby such as microcephaly and neural defects (1). Needless to say that the severity of complications and complexity of situation alerted investigators and clinicians to dig deeper and find more clues in the pathophysiology of viral transmission.

First Documented Case Of Viral Transmission From Female To Male

The Zika virus is usually transmitted by the bite of an infected mosquito (Aedes aegypti), as well as via sexual contact with an infected partner. Until July, 2016, all documented cases of Zika virus transmission were from male to female; however, last week only, Centers for Disease Control and Prevention has released the details of the first documented case of Zika virus transmission from an infected, non-pregnant female in her mid-twenties to her healthy partner.

According to the latest available information from the officials, an adult female from New York engaged in unprotected vaginal intercourse with her partner on the day she arrived back from a Zika infected region. She couldn’t engage in frequent sexual encounters as she got her monthly menstrual cycle the same day (2).

Just within a periods of three days, the woman developed the symptoms of Zika virus infection. Her partner developed similar symptoms after a period of seven days despite the fact that he never travelled to the Zika-infected zone. Accelerated viral transmission could be due to menstrual blood or vaginal discharge, according to the health officials.

Health experts believe that there is nothing unexpected or unusual about the mode of transmission, since most sexually transmitted diseases are spread by both males and females.

The Revised Guidelines And Recommendations Of CDC

After the first documented case of Zika virus transmission, the Centers for Disease Control and Prevention (CDC) has issued a new set of guidelines and recommendations. For example, it is suggested that individuals should strictly practice protected intercourse if their partner has visited Zika- prevalent area (2).

Zika virus only induces a mild sickness in the non-pregnant individual (or is asymptomatic in about 80% cases), but the symptoms quickly escalates in the pregnant woman. In addition, the viral infection can also aggravate the risk of serious neuronal birth defects in the baby (1). According to latest data reported by the Government of Brazil, the risk of congenital defects like microcephaly is 20-times higher in areas where Zika infection is endemic (3). Therefore, a pregnant lady (even if she is a bisexual or homosexual) should use protection while engaging in sex with their partner who has travelled to Zika-infected country.

What Else Should You Know About Zika Virus Transmission?

Zika virus is fairly common in Southeast Asia, Latin America, the Pacific Islands, Africa and Brazil. The classic symptoms include:

• Rashes
• Fever
• Conjunctivitis
• Joint pain and inflammation
• Fatigue
• Backache

The treatment is generally supportive and most cases in non-pregnant patients resolve spontaneously within 1 week or less. Along with Unites States, eleven other countries have documented the cases of sexual transmission of Zika virus. According to experts, sexual transmission of this virus from male to female is much more common as compared to female to male because Zika virus stays in semen for 2 months while in vaginal fluid it remains for two weeks only (4).

According to a study reported in the Lancet Infectious Diseases journal (3), investigators suggested that viral load in semen is very high, which can lead to sexual transmission in partners via unprotected sexual intercourse. Moreover, viral transmission from female to male is higher if a man is not circumcised.

References

1. Fiorentino, D. G., & Montero, F. J. (2016). The Zika Virus and Pregnancy. Current Obstetrics and Gynecology Reports, 1-5.

2. Davidson, A. (2016). Suspected Female-to-Male Sexual Transmission of Zika Virus—New York City, 2016. MMWR. Morbidity and Mortality Weekly Report, 65.

3. Campos, G. S., Bandeira, A. C., & Sardi, S. I. (2015). Zika virus outbreak, Bahia, Brazil. Emerging infectious diseases, 21(10), 1885.

4. Mansuy, J. M., Dutertre, M., Mengelle, C., Fourcade, C., Marchou, B., Delobel, P., ... & Martin-Blondel, G. (2016). Zika virus: high infectious viral load in semen, a new sexually transmitted pathogen. Lancet Infect Dis, 16(405), 00138-9.