EXECUTIVE SUMMARY
The Centers for Disease Control and Prevention reports that sexual transmission of the Zika virus is possible and is of particular concern during pregnancy. There is an apparent increased incidence of microcephaly in babies born to mothers infected with the virus.
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The virus has spread through 18 Latin American countries and the Caribbean. It is predicted that the virus could affect more than 4 million people in the Americas in 2016.
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Men who have lived in or traveled to an area with Zika virus should abstain from sex or use condoms consistently and correctly for vaginal, anal, and oral (fellatio or mouth-to-penis) sex for the duration of their partner’s pregnancy. Pregnant women should talk with their healthcare providers about their male partner’s potential exposures to Zika virus and symptoms of Zika-like illness.
News of the rapid spread of the Zika virus through 18 Latin American countries and the Caribbean has captured headlines. The World Health Organization predicts that the virus could affect more than 4 million people in the Americas in 2016 alone. Public health officials at the Centers for Disease Control and Prevention (CDC) report that sexual transmission of Zika virus is possible and is of particular concern during pregnancy.1
Information about possible sexual transmis-sion of Zika first was raised based on reports of three cases, notes the CDC. The first case was probable sexual transmission of the Zika virus from a man to a woman, in which sexual contact occurred a few days before the man’s symptom onset.2 The second case of sexual transmission, reported Feb. 2, 2016, by the Dallas County (TX) Health and Human Services, is under investigation.3 The third was a single report of replication-competent Zika virus isolated from semen at least two weeks and possibly up to 10 weeks after illness onset. Reverse transcriptase-polymerase chain reaction testing of blood plasma specimens collected at the same time as the semen specimens did not detect Zika virus.4 The man had no sexual contacts. Because no further testing was conducted, the duration of persistence of Zika virus in semen remains un-known.
“In all three cases, the men developed symptomatic illness,” the CDC reports. “Whether infected men who never develop symptoms can transmit Zika virus to their sex partners is unknown.”
At press time, the CDC and state public health departments were investigating 14 new reports of possible sexual transmission of Zika virus. At the present time, sexual transmission of Zika virus from infected women to their sex partners has not been confirmed. The CDC recommends that men who have lived in or traveled to an area with Zika virus should abstain from sex or use condoms consistently and correctly for vaginal, anal, and oral (fellatio or mouth-to-penis) sex for the duration of their partner’s pregnancy. Also, the CDC recommends that pregnant women talk with their providers about their male partner’s potential exposures to Zika virus and symptoms of Zika-like illness.
For non-pregnant women, and men with non-pregnant sex partners who live in or have traveled to Zika-affected areas, the CDC advises that for those who are concerned about sexual transmission of Zika virus, they may consider using condoms the right way every time during sex or abstaining from sexual activity.
The Zika virus is primarily spread to people through mosquito bites. Its most common symptoms are fever, rash, joint pain, and conjunctivitis. The illness is usually mild, with symptoms lasting several days to a week. Severe disease requiring hospitalization is uncommon.
A major concern associated with this infection is the apparent increased incidence of microcephaly, a serious birth defect, in babies born to mothers infected with the virus. “We are working with the Ministry of Health in Brazil and other international public health partners to investigate an unexpected increase in the number of babies being born with microcephaly to mothers who were infected with Zika virus during their pregnancy,” said Lyle Petersen, MD, MPH, director of the CDC’s Division of Vector-Borne Diseases.
The New England Journal of Medicine has published the report of an expectant mother who had a febrile illness with rash at the end of the first trimester of pregnancy while she was living in Brazil. Ultrasonography performed at 29 weeks of gestation revealed microcephaly with calcifications in the fetal brain and placenta. After the mother requested termination of the pregnancy, a fetal autopsy was performed. Microcephaly was observed, and the virus was found in the fetal brain tissue on reverse transcriptase–polymerase-chain-reaction assay, with consistent findings on electron microscopy. The complete genome of the virus was recovered from the fetal brain.5 (Read the article at http://bit.ly/1Q9u2hE.)
The CDC reports similar results in four cases in Brazil, where two infants born with microcephaly at 36 and 38 weeks’ gestation died within a day of birth and two fetuses were lost at 11 and 13 weeks’ gestation. All four mothers had signs of Zika infection but were not tested for antibodies. All cases tested positive for Zika and negative for dengue virus.6
Some countries that are experiencing Zika virus outbreaks are recommending that women postpone pregnancy. Women in affected countries face pregnancies that may be impacted by the Zika virus. Three countries (the Dominican Republic, El Salvador, and Nicaragua) provide no legal access to abortion under any circumstances. Six countries (Guatemala, Haiti, Honduras, Paraguay, Suriname, and Venezuela) provide access to abortion only to save a woman’s life.7
The CDC has developed interim guidelines for U.S. providers who are caring for women during the Zika outbreak. The information includes recommendations for pregnant women considering travel to an area with Zika transmission and recommendations for screening, testing, and management of returning pregnant travelers. (Access guidance for providers at http://1.usa.gov/1VuapPd.)
Pregnant women in any trimester should consider postponing travel to an area where Zika virus transmission is ongoing, advises the CDC. If they travel, they should strictly follow steps to avoid mosquito bites. These steps include wearing long-sleeved shirts and long pants, staying in places with air conditioning or that use window and door screens to keep mosquitoes outside, and sleeping under a mosquito bed net if outside and not able to protect from mosquito bites. Insect repellents registered with the Environmental Protection Agency (EPA), when used as directed, are proven safe and effective, even for pregnant and breastfeeding women. (Check repellents at the EPA site: http://1.usa.gov/1PD0qaf.)
Researchers with the National Institute of Allergy and Infectious Diseases (NIAID) are working on vaccine candidates to prevent Zika virus infection, said Anthony Fauci, MD, NIAID director, at a January telebriefing. Scientists have the advantage of existing vaccine platforms to use in finding a suitable approach, said Fauci.
The first potential candidate is a DNA-based vaccine using a strategy similar to what has been employed for the West Nile virus, said Fauci. This vaccine was found to be safe and immunogenic in a Phase I trial. The second candidate is a live vaccine that builds on similar and highly immunogenic approaches used for the closely related dengue virus, he reported. The University of Georgia in Athens has entered into a collaborative research agreement with GeoVax Labs in Smyrna, GA, to develop and test a Zika virus vaccine. (Robert Hatcher, MD, MPH, editorial board chairman of Contraceptive Technology Update, weighs in on the Zika virus later in this issue.)
REFERENCES
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Oster AM, Brooks JT, Stryker JE, et al. Interim guidelines for prevention of sexual transmission of Zika virus — United States, 2016. Morb Mortal Wkly Rep 2016; 65:120-121.
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Foy BD, Kobylinski KC, Chilson Foy JL, et al. Probable non-vector-borne transmission of Zika virus, Colorado, USA. Emerg Infect Dis 2011; 17:880-882.
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Dallas County Health and Human Services. DCHHS reports first Zika virus case in Dallas County acquired through sexual transmission. Press release. Accessed at http://bit.ly/1PT0iWe.
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Musso D, Roche C, Robin E, et al. Potential sexual transmission of Zika virus. Emerg Infect Dis 2015; 21:359-361.
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Rubin EJ, Greene MF, Baden LR. Zika virus and microcephaly. N Engl J Med 2016; doi: 10.1056/NEJMe1601862.
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Martines RB, Bhatnagar J, Keating MK, et al. Notes from the field: Evidence of Zika virus infection in brain and placental tissues from two congenitally infected newborns and two fetal losses — Brazil, 2015. Morb Mortal Wkly Rep 2016; http://dx.doi.org/10.15585/mmwr.mm6506e1er.
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Kates J, Michaud J, Valentine A. Zika Virus: The Challenge for Women. Accessed at http://kaiserf.am/1PQhbKU.
