The Zika virus may have begun its spread through the Western Hemisphere back in 2013, according to genetic evidence put forth by a new study published in Science.
The study's findings have grabbed the attention of news outlets like Medical Daily, NPR and The New York Times. Here are three things to know about Zika's epidemiology in the America's and its potential surreptitious international spread.
1. For the study, researchers collected blood samples from several infected sources associated with the Brazilian outbreak. They used next-generation sequencing to produce seven Brazilian Zika genomes. After comparing these genome sets with current Zika genomes, scientists discovered a pattern that suggests Zika was introduced to the Americas sometime between May and December 2013, according to Medical Daily.
2. This new research changes previously held notions about how the virus spread to the Americas in the first place. Previous studies have linked the outbreak to the influx of international travelers during the 2014 World Cup in Brazil. "I think we can now discount the whole World Cup connection," Kristian G. Andersen, PhD, a disease geneticist at the Scripps Research Institute in La Jolla, Calif., told the Times. Dr. Anderson also said though the number of sequences used in the study was "fairly small but enough so that the main conclusions are likely to be valid."
3. Duane Gubler, an emerging disease expert at Duke-NUS Medical School in Singapore, told NPR the mosquitoes that carry viruses like Zika are typically in place well before the disease is recognized. He added that countries with the right mosquitoes could have Zika spreading in their populations already without anyone the wiser. Dr. Gubler believes countries in Southeast Asia are particularly at risk. Several countries there record several Zika cases each year, and this new research suggests there could be more.
More articles on the Zika virus:
Infographic: Where in the US have Zika cases been reported? [March 25 update]
Congress fails to vote on Zika funds before breaking for Easter
CDC predicts 25 percent Zika infection rate for Puerto Rico within the year