A new tool by Japan-based researchers predicts the risk of Zika virus importation and local transmission for 189 countries.
Countries that are well connected to/from Brazil have been at particularly high risk of importation, according to the analysis by a team of researchers from the University of Tokyo, Hokkaido University, and the Japan Science and Technology Agency.
However, subtropical and tropical countries with a history of dengue and other mosquito-borne diseases have the greatest risk of the virus spreading once it arrives in the country. This means many nations in South and Central America and the Caribbean face the highest risk of infection and should take measures to prevent mosquito bites, according to the study. France, southern parts of China and the United Arab Emirates also fall into this category having experienced previous outbreaks.
"We have shown that the predicted risk of local transmission was frequently seen in tropical and subtropical countries with dengue or chikungunya epidemic experience, while the risk of importation was more scattered around the world," said researcher Hiroshi Nishiura.
Professor Nishiura and his colleagues predicted the virus' potential of importation and local transmission by the end of 2016 using a survival analysis model, information about airline transportation networks, and transmission data for dengue and chikungunya viruses, which are also transmitted by the same mosquito species. They collected Zika data up to January 31, 2016, and they note that new cases were confirmed in more countries shortly thereafter.
The authors recommend that a finer scale analysis be done to more accurately predict the spread within regions. For example, models should incorporate ecological information about mosquitoes.
The study is recently published in PeerJ.