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Though bite of infected Aedes – Wikipedia mosquito is its primary mode of spread, since 2011, several case reports have

  • Suggested Zika can be sexually transmitted.
  • Documented Zika’s prolonged presence in semen of infected men.

In August 2016, the WHO (1) listed a total of 17 published reports on possible sexual transmission of Zika and 8 others on its presence in semen. Thus, as of Oct 2016, there’s plenty of scientific evidence that it’s possible for a Zika-infected man to infect a previously uninfected woman during sexual intercourse, in which case a fetus could also be affected. In other words, counting on a woman remaining uninfected following sex with a Zika-infected man is highly risky, especially for the fetus.

Reports Of Sexual Transmission From Symptomatic Males To Females

In each of these cases, the previously uninfected women developed symptoms suggestive of Zika even though they hadn’t been exposed to Zika-infected mosquitoes, i.e., highly likely they were infected through sexual transmission.

Cases reported from Argentina and France (2), Canada (3), Chile (4), France, where in one case the suspected route was oral sex (5) while the other case suggested male to female sexual transmission occurred 32 to 41 days after the man got infected with Zika (6), Germany (7), Italy (8), a case where Zika virus RNA was found in the man’s semen even 62 days after first symptoms of infection, New Zealand (9), a case where semen samples from the man tested positive for Zika virus RNA even 76 days after symptom onset and only tested negative on days 99 and 117, Peru (10), Spain (11), USA (12, 13, 14, 15).

Other Reports Of Sexual Transmission Include

  • Asymptomatic male to female, one each in France (16) and USA (17). Since ~80% of Zika-infected people remain asymptomatic (18), prolonged presence of potentially infectious Zika in semen makes its sexual transmission a very important means of spreading through the population. Data also shows a pregnant woman being asymptomatic doesn’t preclude Zika virus from affecting the fetus.
  • One case of male to male transmission (anal sex), in Texas, USA (19).
  • One case of female to male transmission in New York City, USA (20).

Documented Cases Of Zika’s Presence In Semen

Live virus: Researchers were able to isolate Zika virus from semen

  • In one case from the 2013 French Polynesia – Wikipedia Zika outbreak (21) two weeks after self-reported symptoms started.
  • In a French case where semen virus load was 100000 times that in blood (22) two weeks after self-reported symptoms started.
  • Even 62 days after first fever symptom in a case from Scotland (23).

Virus RNA: Detectable in a Netherlands patient up to 47 days after symptom onset (24), 80 (25) and 93 days (26) from two cases in France, and even 181 (27) and 188 days (28) in two cases from Italy.

These data suggest live virus is not only present in semen of Zika-infected men but can also stay there for extended periods of time. This is why the WHO recommends (1) that

  • In regions with active Zika virus transmission,

‘Pregnant women should practice safer sex or abstain from sexual activity for at least the whole duration of the pregnancy. Their partners should also be informed about this recommendation.’

  • And in regions with no active Zika virus transmission,

‘a. Men and women returning from areas where transmission of Zika virus is known to occur should adopt safer sex practices or consider abstinence for at least 6 months upon return to prevent Zika virus infection through sexual transmission.

b. Couples or women planning a pregnancy, who are returning from areas where transmission of Zika virus is known to occur, are advised to wait at least 6 months before trying to conceive to ensure that possible Zika virus infection has cleared.

c. Sexual partners of pregnant women, returning from areas where transmission of Zika virus is known to occur, should be advised to practice safer sex or abstain from sexual activity for at least the whole duration of the pregnancy.’

Bibliography

1. World Health Organization. “Prevention of sexual transmission of Zika virus: interim guidance update.” World Health Organization, Geneva, Switzerland (2016). http://apps.who.int/iris/bitstre…

2. Zika virus infection – Argentina and France

3. Statement from the Chief Public Health Officer of Canada and Ontario’s Chief Medical Officer of Health on the first positive case of sexually transmitted Zika Virus – Canada News Centre

4. Zika virus infection – Chile

5. D’Ortenzio, Eric, et al. “Evidence of sexual transmission of Zika virus.” New England Journal of Medicine 374.22 (2016): 2195-2198. http://www.nejm.org/doi/pdf/10.1…

6. Turmel, Jean Marie, et al. “Late sexual transmission of Zika virus related to persistence in the semen.” The Lancet (2016). http://ac.els-cdn.com/S014067361…

7. Frank, Christina, et al. “Sexual transmission of Zika virus in Germany, April 2016.” Eurosurveillance 21.23 (2016). http://www.eurosurveillance.org/…

8. Venturi, G., et al. “An autochthonous case of Zika due to possible sexual transmission, Florence, Italy, 2014.” Euro Surveill 21.8 (2016): 30148. http://www.eurosurveillance.org/…

9. Harrower, Jay, et al. “Sexual transmission of Zika virus and persistence in semen, New Zealand, 2016.” Emerging Infectious Diseases 22.10 (2016): 1855. http://wwwnc.cdc.gov/eid/article…

10. Zika virus infection – Peru

11. Spain records first case of sexually transmitted Zika virus

12. Foy, Brian D., et al. “Probable non–vector-borne transmission of Zika virus, Colorado, USA.” Emerging infectious diseases 17.5 (2011): 880. http://www.ncbi.nlm.nih.gov/pmc/…

13. Sex After a Field Trip Yields Scientific First. Martin Enserink, Science, April 6, 2011. Sex After a Field Trip Yields Scientific First

14. Zika Infection Transmitted by Sex Reported in Texas. The New York Times, Donald G. McNeil Jr., Sabrina Tavernise, Feb 2, 2016. Log In – New York Times

15. Hills, Susan L. “Transmission of Zika virus through sexual contact with travelers to areas of ongoing transmission—continental United States, 2016.” MMWR. Morbidity and mortality weekly report 65 (2016). http://www.cdc.gov/mmwr/volumes/…

16. Fréour, Thomas, et al. “Sexual transmission of Zika virus in an entirely asymptomatic couple returning from a Zika epidemic area, France, April 2016.” Eurosurveillance 21.23 (2016). http://www.eurosurveillance.org/…

17. Brooks, Richard B. “Likely sexual transmission of Zika virus from a man with no symptoms of infection—Maryland, 2016.” MMWR. Morbidity and Mortality Weekly Report 65 (2016). http://www.cdc.gov/mmwr/volumes/…

18. Duffy, Mark R., et al. “Zika virus outbreak on Yap Island, federated states of Micronesia.” New England Journal of Medicine 360.24 (2009): 2536-2543. http://www.nejm.org/doi/pdf/10.1…

19. Deckard, D. Trew. “Male-to-male sexual transmission of Zika virus—Texas, January 2016.” MMWR. Morbidity and mortality weekly report 65 (2016). https://www.cdc.gov/mmwr/volumes…

20. Davidson, Alexander. “Suspected female-to-male sexual transmission of Zika virus—New York City, 2016.” MMWR. Morbidity and mortality weekly report 65 (2016). http://www.cdc.gov/mmwr/volumes/…

21. Musso, Didier, et al. “Potential sexual transmission of Zika virus.” Emerg Infect Dis 21.2 (2015): 359-61. https://www.researchgate.net/pro…

22. Mansuy, Jean Michel, et al. “Zika virus: high infectious viral load in semen, a new sexually transmitted pathogen.” Lancet Infect Dis 16.405 (2016): 00138-9. https://www.researchgate.net/pro…

23. Atkinson, Barry, et al. “Detection of Zika virus in semen.” Emerg Infect Dis 22.5 (2016). Emerging Infectious Disease journal

24. Reusken, Chantal, et al. “Longitudinal follow-up of Zika virus RNA in semen of a traveller returning from Barbados to the Netherlands with Zika virus disease, March 2016.” Eurosurveillance 21.23 (2016). http://www.eurosurveillance.org/…

25. Matheron, Sophie, et al. “Long-lasting persistence of Zika virus in semen.” Clinical Infectious Diseases 63.9 (2016): 1264-1264. Long-Lasting Persistence of Zika Virus in Semen

26. Mansuy, Jean Michel, et al. “Zika virus in semen of a patient returning from a non-epidemic area.” The Lancet Infectious Diseases 16.8 (2016): 894-895. http://www.thelancet.com/pdfs/jo…

27. Barzon, Luisa, et al. “Infection dynamics in a traveller with persistent shedding of Zika virus RNA in semen for six months after returning from Haiti to Italy, January 2016.” Eurosurveillance 21.32 (2016). http://www.eurosurveillance.org/…

28. Nicastri, Emanuele, et al. “Persistent detection of Zika virus RNA in semen for six months after symptom onset in a traveller returning from Haiti to Italy, February 2016.” Eurosurveillance 21.32 (2016). http://www.eurosurveillance.org/…

 

https://www.quora.com/If-a-child-is-conceived-while-the-father-has-Zika-but-the-mother-never-gets-infected-can-the-fetus-be-affected/answer/Tirumalai-Kamala

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