The case of a Venezuelan woman and her five-month old child both confirmed to have been infected with Zika adds evidence that the virus can be transmitted through breast milk, according to a report in Clinical Infectious Diseases. While the woman had symptoms of Zika infection and the child, like many found to have the virus, did not, tests identified the same strain of the virus in both, and the virus was found in the mother’s breast milk as well.
The authors of the report, led by Gabriela Blohm of the University of Florida acknowledge that the source of the child’s infection could not be determined, but note that the mother and child lived in an air-conditioned house with window screens, and that the child usually remained indoors. The strain of the virus was one common in Colombia, and while the mother had not traveled there, Barquisimeto, the city where she and the child live lies on route along which large numbers of Venezuelans travel to get goods from that country.
While Zika virus has previously been identified in breast milk, confirmed infant infection through breastfeeding has not been reported. Both the U.S. Centers for Disease Control and Prevention and the World Health Organization continue to recommend breastfeeding infants in areas where the virus is endemic, saying that while information on long-term outcomes from postnatal infections is limited, most children with the virus, like most adults, have mild, or no symptoms and that the benefits of breastfeeding outweigh the risks.