The first instance of female-to-male Zika sexual transmission has been announced by the CDC. Previously, only incidents of male transmission of Zika virus to other partners had been reported.
The CDC also 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, said:
“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.”
Zika Sexual Transmission
Zika virus RNA was detected in both serum and urine by real-time reverse transcription–polymerase chain reaction (rRT-PCR) performed at the NYC Department of Health and Mental Hygiene (DOHMH) Public Health Laboratory using a test based on an assay developed at CDC. The results of serum testing for anti-Zika virus immunoglobulin M (IgM) antibody performed by the New York State Department of Health Wadsworth Center laboratory was negative using the CDC Zika IgM antibody capture enzyme-linked immunosorbent assay (Zika MAC-ELISA).
“This case demonstrates, for the first time, that female-to-male sexual transmission of Zika virus can occur,” Dr. Schleiss explained. “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.”
Zika has already made an impact in the United States. More than 1100 individuals have been diagnosed with Zika infection, including 320 women. At least seven children have been born with birth defectshttps://sciencebeta.com/invasive-testing-birth-defects/ in the US, and five pregnancy losses related to Zika have been reported.
Mosquitoes Not Required For Epidemic Spread
This case report aligns with multiple publications that document male-to-female2 transmission and male-to-male3 transmission of Zika virus, according to Dr. Amelia Pinto and Dr. James D. Brien, Assistant Professors, Saint Louis University School of Medicine. This case, they add, suggests that an infected female can transmit Zika virus to a male sexual partner, based upon multiple subject interviews and laboratory testing.
This has significant implications for public health infrastructure because zika sexual transmission 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,” they conclude. “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.”
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: http://dx.doi.org/10.15585/mmwr.mm6528e2