Examining data from a succession of settings that have seen Zika outbreaks followed by rising rates of microcephaly among babies born to women infected with the virus during pregnancy, Harvard researchers now say risks of maternal infection leading to the birth defect ranges from 1- to 13 percent.
Based on data from Brazil and French Polynesia, researchers wrote in a study published Wednesday in the New England Journal of Medicine they had found the highest risk of a child being born with a stunted head and brain occurring when the mother was infected during the first three months of her pregnancy.
Their findings appeared on the same day House science committee members were told that at any given moment, 28,000 women are pregnant in Puerto Rico, which confirmed its first Zika-related case of microcephaly last week.
Witnesses, as well as some legislators at a hearing on the science surrounding the ongoing outbreak urged Congress to take action immediately and expressed frustration at the lack of sustained preparation to respond to infectious disease outbreaks.
As the holiday weekend heralding the approach of summer begins, the House and Senate, however, remain divided on even an emergency response to the outbreak, for which the Obama administration in February requested $1.9 billion. (Click here to read the Center for Global Health Policy’s most recently updated paper on Zika impacts and responses).
“The world is a much smaller place now, and viruses move more quickly,” Congressman Ami Bera (D-CA) said. “We need to provide adequate resources to support the places where viruses originate.”
Scientists are continuing to seek a basic understanding of how Zika interacts with the host’s body, how it moves within the mosquito, and other science behind the virus, Dr. Daniel Neafsey of the Genomic Center for Infectious Disease at Massachusetts Institute of Technology told legislators. His team at MIT and Harvard are working to sequence and map the DNA of the aedes aegypti mosquito to finds ways to disrupt Zika, and other viruses (including dengue and chikungunya) within the vector.
The head of a British biotech company shared another approach. Hadyn Parry, CEO of Oxitec, briefed the Committee on his company’s work to breed a genetically modified aedes aegypti mosquito. The GMO male mosquitoes are released into a small area (while unmodified Aedes aegypti mosquitos have a range of one or two miles, the GMO version has a range of about 200 yards) where they mate with female mosquitoes, and produce offspring that die before reaching maturity. The GMO mosquitoes, according to Parry, have reduced targeted populations of Aedes aegypti by up to 90 percent in field tests. This approach is not without controversy. While Oxitec is seeking FDA authorization for field testing in the U.S. in the coming months, a change.org petition has gathered more than 160,000 signatures asking Florida officials to block release of the firm’s mosquitoes in Florida, and on Wednesday a woman sitting behind Parry wore patches on her sleeve that read “Say no to GMO mosquito release.”