First case of Zika sexual transmission from female to male reported

The first case of female-to-male Zika virus transmission has been reported in New York City, according a press release from the CDC. Previously, only incidents of male transmission to other partners had been reported. The CDC announced that they are updating their guidelines on sexual activity for those in areas at risk of Zika.


Dr. Mark R. Schleiss, Director, Division of Pediatric Infectious Diseases and Immunology, Center for Infectious Diseases and Microbiology Translational Research, University of Minnesota Medical School (webpage): 

Expertise: Congenital and neonatal viral infections; antiviral agents; fetal infection; antiviral vaccines.

“The constantly-evolving body of knowledge about Zika virus has expanded once again with the new observation that the sexual routes of acquisition of this infection includes female-to-male transmission.

“This is a milestone in our understanding of how this infection can be acquired, and a worrisome one at that. The New York City Department of Health has identified a non-pregnant woman in her twenties who reported she had engaged in a single episode of sexual intercourse with a male partner on the day she returned to New York, after she had been traveling to an area with ongoing Zika virus transmission. No condom was used. Seven days after sexual intercourse the woman’s male partner developed acute Zika infection, with fever, rash, joint pain, and conjunctivitis. Three days after the onset of his symptoms, Zika virus RNA was detected in his urine sample.

“This case demonstrates, for the first time, that female-to-male sexual transmission of Zika virus can occur. This discovery should engender great concern that the disease could spread more widely beyond those countries where it is already endemic. Sexual transmission of Zika to a pregnant woman poses as much of a risk as mosquito-born transmission, and the prospect of bidirectional transmission (man-to-woman and woman-to-man) will accelerate transmission and likely lead to more disabling congenital infections. The CDC recommends that individuals who want to reduce the risk of sexual transmission of Zika virus should abstain from sex or correctly and consistently use condoms.

“An alarming aspect of the sexual transmission of Zika is the observation that virus may be shed in semen for up to six months after infection. Therefore, condom use is recommended for six months in men in whom the possibility of infection is considered. It remains to be seen how long Zika can be shed in vaginal and/or cervical fluid, but prolonged condom use in male partners of Zika-exposed women seems prudent until more information is availale. Up-to-date guidance on prevention of sexual transmission of Zika virus is available on the CDC web site (

“The Zika epidemic has already had a substantial impact in the United States. Over 1100 individuals have been diagnosed with Zika infection, including 320 women. At least seven children have been born with birth defects in the US, and five pregnancy losses related to Zika have been reported. The knowledge that the infection may circulate between men and women by sexual transmission should raise substantial concern. Funding programs focused on research, education, and vaccine development are needed, but Congress has unfortunately refused to act on Zika funding measures. Until this situation can be resolved, great caution should be exercised to take measures to avoid sexual transmission of Zika.”


Dr. Amelia Pinto (webpage) and Dr. James D. Brien (webpage), Assistant Professors, Saint Louis University School of Medicine:

Expertise (Dr. Pinto): Understanding the immune response to arboviruses including West Nile, chikungunya, Zika, and dengue

Expertise (Dr. Brien): Immune responses to arthropod borne viruses, antibody mediated protection against flaviviruses like Zika

“Davidson and colleagues1 have just described the first potential female to male sexual transmission of Zika virus. This work clearly advances our understanding of Zika virus biology and disease, considering that Zika virus out of all studied flaviviruses has the unique potential to be sexual transmitted.

“This case report aligns with multiple publications that document male-to-female2 transmission and male-to-male3 transmission of Zika virus. This case report suggests that an infected female can transmit Zika virus to a male sexual partner, based upon multiple subject interviews and laboratory testing. This has a significant impact on public health infrastructure because it illustrates the potential of Zika virus spread independent of Aedes spp. mosquitoes.

“This also informs research scientists to potential cellular targets of Zika virus infection and may impact the development of antivirals. This work clearly informs the medical, research and public health community, where the speed of viral spread and the unique aspects of sexual transmission make it extremely challenging to provide accurate information to a patient and their physician allowing health decisions to be made.”

1. Davidson A, Slavinski S, Komoto K, Rakeman J, Weiss D. Suspected Female-to- Male Sexual Transmission of Zika Virus — New York City, 2016. MMWR Morb Mortal Wkly Rep. ePub: 15 July 2016. DOI:

2. Foy BD, Kobylinski KC, Chilson Foy JL, et al. Probable non-vector- borne transmission of Zika virus, Colorado, USA. Emerg Infect Dis 2011;17:880–2. CrossRef PubMed

3. Deckard DT, Chung WM, Brooks JT, et al. Male-to- Male Sexual Transmission of Zika Virus — Texas, January 2016. MMWR Morb Mortal Wkly Rep 2016;65:372–374. DOI:

Declared interests (see GENeS register of interests policy):

No interests declared.


CDC press release:

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