However, they maintained that more research was needed before they could conclusively say it is causal.
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Until now, the CDC has suggested that evidence shows that there is a link between Zika and birth defects, but was never definitive with their statements.
Dr. Patterson says the virus is still new to most health experts, which makes it scary when trying to understand how to prevent and treat the virus.
According to The Washington Post, there is still a great deal that is unknown about the Zika virus, including the rate of infection and further risks that the virus may pose to pregnant women.
Frieden said the lifelong cost of caring for a baby with microcephaly is estimated to be $10 million.
Among the evidence that clinched the case: Signs of the Zika virus, which is spread primarily through mosquito bites but can also be transmitted through sex, have been found in the brain tissue, spinal fluid and amniotic fluid of microcephaly babies. Their partners should either use condoms or abstain from sexual contact while the woman is pregnant. Additionally, numerous fetuses that are exposed to Zika have followed the same, specific pattern: they are born with abnormally small heads or have other brain anomalies.
In response to a question at a press briefing today, Dr. Sonja A. Rasmussen, the CDC’s director of the division of public health information and dissemination, said women who are infected with the Zika virus and get pregnant later should not be overly concerned. Nor do they know what stage of pregnancy poses the greatest risk, or whether another infection that occurred at the same time might affect the risk of birth defects, she said.
As the microcephaly cases rose in Latin America, a number of alternative theories circulated through the public.
The Zika virus has always been thought to cause microcephaly. Cases of Guillain-Barre syndrome have increased in countries where there is a Zika Virus outbreak.
These include smaller head measurements than expected and a condition called fetal brain disruption sequence in which the virus has a destructive effect on the brain. In another experiment, the researchers grew brain organoids-another bundle of brain cells used to model brain development, this one with more structures that resemble a real brain-then infected them with Zika. Their analysis is published in the New England Journal of Medicine.
Earlier outbreaks of the Zika virus, in the Pacific Islands, did not result in adverse reports related to pregnancy. Health officials said the last infectious virus to cause “a major epidemic of congenital birth defects” was rubella, or German measles, in the 1960s.
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“This is an unprecedented situation”, Frieden said. Until more is known, CDC continues to recommend that pregnant women and women trying to become pregnant take the following precautions. But while Zika remains in the blood longer than the 10 days initially believed, after six months a woman or man who has had the virus should be able to conceive without the potential of microcephaly complications, the CDC said.
