The CDC are investigating 14 new potential cases of sexual transmission of Zika virus from traveling men to non-traveling women in the US.
The news appears in a Centers for Disease Control and Prevention (CDC) statement about following guidance to prevent sexual transmission of Zika virus.
The federal agency emphasizes that while sexual transmission of Zika virus is possible, being bitten by virus-carrying mosquitoes in countries where Zika circulates remains the main way to contract the infection, and adds:
"Because there currently is no vaccine or treatment for Zika virus, the best way to avoid Zika virus infection is to prevent mosquito bites."
An outbreak of Zika virus in Brazil has been linked to a recent surge in cases of birth defects in babies.
The new CDC statement follows an earlier release of interim recommendations after lab tests confirmed a case of sexual transmission of Zika virus in a US non-traveler who got it from an infected sexual partner.
According to the World Health Organization (WHO), the Zika virus is known to circulate in Africa, the Americas, Asia and the Pacific.
14 suspected cases of sexual transmission of Zika
In the latest announcement, the CDC gave details of the 14 suspected cases of sexual Zika virus transmission:
- In all suspected cases, the travelers were men who reported symptoms starting within 2 weeks before their non-traveling female partner's symptoms began
- In two cases, Zika virus infection has been confirmed in women whose only known risk factor was sexual contact with ill male partners who had recently returned from countries with Zika transmission - confirmation that the male partners were infected with Zika virus is still pending
- In four other cases, preliminary lab results (IgM antibody test) are available for the women, but these are awaiting confirmation by further tests
- In eight additional suspected cases, the investigation is ongoing.
The CDC also note that:
"At this time, there is no evidence that women can transmit Zika virus to their sex partners; however, more research is needed to understand this issue."
Until further information comes to light about sexual transmission of Zika virus, the CDC recommend people follow the interim guidance they published earlier this month that details recommendations for pregnant women and men with pregnant sex partners who live in or have traveled to areas affected by Zika.
A global public health emergency
Zika virus is carried by the Aedes mosquito - the same insect that spreads dengue and chikungunya.
On February 1st, the WHO declared that the Zika situation "meets the conditions for a Public Health Emergency of International Concern."
The WHO declaration follows a recent surge in Brazil of babies born with microcephaly - a birth defect caused by abnormal or arrested brain growth in the fetus - that coincides with an increase in Zika virus infections. The situation in Brazil follows a similar event in French Polynesia in 2014.
Babies born with microcephaly have smaller-than-normal heads, and their brains fail to grow as they develop. The condition often leads to serious neurological and development problems and sometimes early death.
Experts say while evidence is mounting of a link, there is as yet no proof that antenatal infection with Zika virus actually causes the birth defects.
Meanwhile, Medical News Today recently learned about a new study that strengthens the case for a causal link between Zika and microcephaly. Researchers in Brazil found Zika virus in the amniotic fluid of two pregnant women carrying fetuses diagnosed with the birth defect, showing the pathogen can cross the placental barrier.