Brazilian President Dilma Rousseff on Wednesday called for more efforts to eliminate mosquito breeding grounds to prevent the spread of the Zika virus, describing it as a "real threat" against the country.
In a taped message aired on Brazilian television, Rousseff said the government was mobilizing to develop a vaccine and vowed to protect women who have given birth to babies with microcephaly, a birth defect that causes abnormally small heads, affecting brain development, the Associated Press reported.
Researchers in Brazil have linked microcephaly to the Zika virus. But international health officials told the AP they have been hamstrung from doing their own research into the link, as well as potential treatment or vaccines, this despite the World Health Organization declaring the outbreak a global health emergency.
So far, scientists in Europe and the U.S. have not received enough data or samples from Brazil to conduct research, according to the AP, noting that it is against Brazilian law to share blood samples containing the virus or other genetic material.
The Global Post reported that cases of microcephaly have peaked in Recife, the northeastern city considered the epicenter of Brazil's Zika outbreak. Questions remain about how widely the virus has spread; Brazilian officials have estimated the number of cases at around 1 million.
Officials said earlier this week that since some people may show no symptoms of infection, the virus may be more prevalent than previously thought.
Scientists are also researching how the virus can be transmitted. On Tuesday, health officials in Texas confirmed a sexually transmitted case of Zika, which is more commonly transmitted by mosquito bites. It remains unknown how long the virus can stay alive in a person's body fluids.