Yet another
very important update on sexual transmission of Zika virus from CDC was published
online in CDC's Morbidity and
Mortality Weekly Report[1]
Till now it was known that sexual transmission of ZIKA virus only takes
place from male to female partner. But, The New York City Department of Health
and Mental Hygiene (DOHMH) today identified the first case of a female transmitting
the Zika virus to a man through sex in New York city.
This surprising new announcement have prompted the CDC to update its
guidelines on the sexual mode of transmission of the virus.
A 20-year-old non-pregnant woman had condomless vaginal intercourse with
male partner on the day she returned from a country where Zika virus infection
is ongoing. She was completely symptomless on the day of return, but was down
with Zika-like symptoms, including fever, rash, fatigue and muscle pain, along
with numbness and tingling in her fingers and toes. On the next day she visited
her primary health care provider, who confirmed the illness as Zika virus after
getting the results of her urine and blood test. ((rRT-PCR).
A week after the sexual contact, the male partner also had similar
symptoms and was also diagnosed with Zika infection. On detailed history he
ruled out other mode of Zika transmission. He has not travelled outside the
country since 1 year, only had one sexual encounter since a week and did not
have any mosquito bite.
Both the
partners tested negative for Zika virus IgM antibodies by the CDC Zika
MAC-ELISA assay performed at the New York State Department of Health Wadsworth Center.
CDC report
concluded that “The timing and sequence of events support female-to-male Zika
virus transmission through condomless vaginal intercourse.” The woman was most
likely viremic when she had sex with her partner, and the virus was transmitted
through uretral mucosa or penile abrasion or cut from woman’s vaginal or menstrual
blood.
A case
report published on May 2016 in Lancet has already documented the presence of Zika
virus in female genital tract.[2]
Non-Human studies in primates have shown the presence of the virus in genital
tract up to 7 days after subcutaneous inoculation.[3]
This case is
very important from public health perspective as until now, it was assumed that
the Virus is transmitted from a male partner to a receptive partner, now ongoing
surveillance will be needed to combat the additional risk of reverse
transmission. CDC is also advising protection for pregnant women with female
sex partners who might have travelled to Zika endemic areas, though woman to woman
transmission is not known till now.
The report
stressed the need for further studies to determine the amount of time of virus
survives in female genital tract.
The Aedes aegypti
mosquitos still is the major source of infection.
