Zika causes severe birth defects: US

Experts hope this finding will refocus attention on efforts to stop infections and prompt US lawmakers to fund emergency prevention efforts. “There isn’t any doubt that Zika causes microcephaly,” Dr. Tom Frieden, director of the U.S. Centers for Disease Control and Prevention (CDC), told reporters in a conference on Wednesday.

“There has been so much debate. It lays that to rest now,” said Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota. It had not been declared as the definitive cause until now. The announcement comes at a critical time for the Obama Administration, which has been urging the Republican-controlled Congress to grant nearly $1.9 billion in emergency funds to fight the virus, which is already affecting Puerto Rico and is expected to hit parts of the United States with the coming of mosquito-friendly warmer weather.

In February, the World Health Organization declared Zika a global health emergency based on its suspected link to thousands of cases in Brazil of microcephaly, a birth defect marked by small head size and underdeveloped brains. 

The declaration kicked off a flurry of studies to prove a link. The CDC said its latest conclusions came after all necessary scientific criteria had been met to make the official call. “The data are there. The evidence is there. The pieces of information we have now makes us confident,” said Dr. Sonja Rasmussen, director of the CDC division of public health information and lead author of a New England Journal of Medicine article outlining evidence. 

CDC now believes microcephaly is just one of a range of serious birth defects caused by Zika. Now that the causal relationship has been established, Frieden said several important questions must be answered, such as what percentage of Zika-infected mothers have babies with birth defects. Researchers also want to discover the full range of brain and developmental issues that may crop up later in life for infected babies, Rasmussen said. 

Certainty over whether Zika causes microcephaly should end the debate in the public health community about the potential impact of the virus and focus attention on how to prevent infections, experts said.