CDC officials have found traces of the Zika virus in the tissue of two babies in Brazil who had microcephaly and died.
"This is the strongest evidence to date that Zika is the cause of microcephaly," Tom Frieden, MD, PhD, director of the CDC, told a congressional panel, according to a HealthDay report.
Microcephaly is a condition in which a baby's head is much smaller than expected, causing neurological problems. While the new findings suggest a strong link between Zika virus and the birth defect, more tests are needed before the link is formally proven, according to a USA TODAY report.
Most people who contract the Zika virus, which is spread mainly through mosquitoes but has also been transmitted sexually, are not greatly affected by the virus. The main concern is protecting pregnant women and their unborn children, Dr. Frieden told the congressional panel, according to USA TODAY.
The World Health Organization declared Zika and its suspected link to microcephaly a Public Health Emergency of International Concern, and the Obama administration is seeking roughly $1.8 billion in funds to combat the growing Zika virus crisis.