Tracking Zika Through the Female Genital Tract

Researchers in Guadeloupe, the French territory in the southern Caribbean Sea, have reported, for the first time, the presence of Zika infection in the genital tract of a woman with the virus.

In a patient case published online by The Lancet Infectious Diseases on July 11, 2016, physicians at the Centre Hospitalier Universitaire de Pointe à Pitre in Guadeloupe describe a 27-year-old female patient whose Zika virus infection was confirmed in May 2016. Guadeloupe has officially been recognized as an outbreak region for Zika since April.

The patient presented to the hospital with the clinical symptoms of Zika (fever, maculopapular rash, and conjunctivitis), and the diagnosis was confirmed with real-time PCR. Three days after the onset of the patient’s symptoms, physicians collected a genital swab, an endocervical swab, and a cervical mucus sample for RNA Zika virus analysis, and all tested positive for the presence of Zika virus RNA. Interestingly, though, according to the authors of the Lancet paper, on day 11 after the onset of symptoms, the patient’s blood and urinary samples tested negative, whereas her cervical mucus still tested positive for the presence of Zika virus RNA.

Zika is increasingly being viewed as a sexually transmitted infection, with the first case of a woman passing the virus to a sexual partner confirmed in New York City on July 14. Lancet case report co-author Nadia Prisant, MD, of the Centre Caribéen de Médecine de la Reproduction (CCMR)/CECOS Caraïbes, Pôle Parents Enfant at the Centre Hospitalier Universitaire de Pointe à Pitre, told Contagion that while Zika’s “presence in the vaginal tract is not a surprise, as the virus has been described in several compartments, including blood, urine, [breast] milk, saliva, and sperm, the duration of this presence” is significant.

In The Lancet, Dr. Prisant and her colleagues write that Zika’s “very presence in the female genital tract poses notable challenges, implying that sexual transmission from women to men could occur, as is the case for other viral infections. Zika virus presence in the female genital tract also means that vertical transmission from mother to fetus needs to be assessed, since this virus is a member of the Flaviviridae family, which includes hepatitis C, in which vertical transmission from mother to child can occur in up to 10% of pregnancies.”

Furthermore, they note that their findings “raise the threat of a woman potentially becoming a chronic Zika virus carrier.” The team is presently performing follow-up research to assess the “duration of Zika virus persistence in the female genital tract and its clearance after the disappearance of the symptoms.” Dr. Prisant said that this research could help clinicians and others better understand the physiopathology of Zika’s transmission route to the fetus.

“It is important to find out how long the virus stays in the vaginal tract in order to know how long a woman can be contagious through sexual encounter,” Dr. Prisant told Contagion. “Also, we need to know if there are some places in the woman body where the virus could ‘hide,’ as it does in the sperm, where it has been shown to stay as long as several months. The idea that a woman can be a chronic carrier of this virus is not an easy one to consider in view of its effect on fetuses, and it is very important that in epidemic areas or in contact with people coming back from these areas, sexual encounters should be protected via condoms.”

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.