Adult women in Puerto Rico are contracting Zika at higher rates than men, according to the CDC's Morbidity and Mortality Weekly Report.
For the study, researchers examined 29,000 laboratory confirmed Zika cases on the island contracted since November 2015 — the start of the virus' outbreak in Puerto Rico. Of the cases, 18,384 (63 percent) occurred in females, which represents a pattern of infection comparable to what's been reported in Brazil and El Salvador. Differences in infection rates may relate to how the virus is transmitted sexually.
"Although male-to-female and female-to-male sexual transmission has been documented, data from Rio de Janeiro suggest that differences in infection rates between men and women might be explained by male-to-female sexual transmission," wrote the study's authors. "The relative contribution of sexual transmission of Zika virus to rates of Zika virus disease is only beginning to be explored, including relative risk of developing disease in men and women, and through sexual transmission versus mosquito-borne transmission."
In addition to microcephaly, a neurological birth defect characterized by babies born with abnormally small heads, Zika can cause a host of other developmental problems and birth defects in children born to women infected with the virus while pregnant.
As of Nov. 3, the CDC has reported 1,057 cases of Zika in pregnant women in U.S. states and 2,357 in U.S. territories.
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