While earlier CDC guidance had focused almost exclusively on the risks to women, last month's Update: Interim Guidelines for Prevention of Sexual Transmission of Zika Virus — United States, 2016 contained the following subtle change in the definition of what constitutes potential sexual exposure to Zika:
These guidelines define potential sexual exposure to Zika virus as any person who has had sex without a condom (i.e., vaginal intercourse, anal intercourse, or fellatio) with a man who has traveled to or resides in an area with ongoing Zika virus transmission.
Not completely unexpectedly, given the above changes, today we have an MMWR report that describes sexual transmission of the Zika virus between two males.
First, the summary, followed by a link to the full report and some excerpts.
SummaryWhat is already known about this topic?
Although Zika virus is spread primarily by Aedes species mosquitoes, published case reports have documented sexual transmission from infected men to their female sex partners through vaginal sex.
What is added by this report?This is the first report of transmission of Zika virus from an infected man to a sex partner through anal sex.
What are the implications for public health practice?
Sexual transmission through both vaginal and anal sex is an emerging mode of Zika virus infection that might contribute to more illness than was anticipated when the outbreak was first recognized. Cases of sexually transmitted Zika virus infection should be reported to public health agencies and can help inform recommendations to prevent Zika virus infections.
Male-to-Male Sexual Transmission of Zika Virus — Texas, January 2016
Weekly / April 15, 2016 / 65(14);372–374
Zika virus infection has been linked to increased risk for Guillain-Barré syndrome and adverse fetal outcomes, including congenital microcephaly. In January 2016, after notification from a local health care provider, an investigation by Dallas County Health and Human Services (DCHHS) identified a case of sexual transmission of Zika virus between a man with recent travel to an area of active Zika virus transmission (patient A) and his nontraveling male partner (patient B). At this time, there had been one prior case report of sexual transmission of Zika virus (1).
The present case report indicates Zika virus can be transmitted through anal sex, as well as vaginal sex. Identification and investigation of cases of sexual transmission of Zika virus in nonendemic areas present valuable opportunities to inform recommendations to prevent sexual transmission of Zika virus.
In January 2016, 2 days after returning to Dallas, Texas, from a 1-week visit to Venezuela, patient A developed subjective fever, pruritic rash on his upper body and face, and conjunctivitis lasting 3 days. Both 1 day before and 1 day after his symptom onset (Day 0), patient A had condomless insertive anal sex with patient B. Patient A reported that during and after illness he experienced no symptoms of prostatitis or dysuria, and noted no macroscopic hematospermia.
On Day 7, patient B developed a subjective fever, myalgia, headache, lethargy, and malaise; a few days later, he developed a slightly pruritic rash on his torso and arms, small joint arthritis of his hands and feet, and conjunctivitis. All symptoms resolved after 1 week. On Day 11, while still symptomatic, patient B visited his primary care provider for evaluation. Suspecting Zika virus infection, the provider obtained serum specimens from patient B on Day 11 (4 days after patient B’s illness onset), and from both patients A and B on Day 14 (14 and 7 days after respective illness onsets). On Day 24, semen, urine, and saliva specimens were collected from both patients (24 and 17 days after respective illness onsets).
Patient A had traveled regularly to Central and South America for many years. During his recent trip to Venezuela, he reported that multiple persons in the area he visited were experiencing symptoms consistent with Zika virus disease; autochthonous transmission of Zika virus had been confirmed in Venezuela in late November 2015.* Patient B had not recently traveled outside of the United States and had never traveled to countries with active autochthonous Zika transmission. Neither patient had a history of prior known arboviral infection nor had they received yellow fever or Japanese encephalitis vaccinations. The men had been mutually monogamous for more than 10 years and had no major medical illnesses or history of sexually transmitted infections. Neither patient reported ulcerative anal or genital lesions.