AsianScientist (Jun. 3, 2016) – Subtropical and tropical countries with a history of mosquito-borne diseases have the greatest risk of the Zika virus spreading once it arrives in the country, according to a team of researchers in Japan.
Besides many nations in South and Central America and the Caribbean, areas in France, southern China and the United Arab Emirates also fall into this category.
The study, carried out by researchers from the University of Tokyo, Hokkaido University, and the Japan Science and Technology Agency, is published in the journal Peer J.
“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 Professor Hiroshi Nishiura from Hokkaido University, the corresponding author on the study.
The virus first emerged in Uganda in 1947, and was subsequently detected in 39 countries around the world, including the United States, India and Japan. In early 2015, a Zika virus outbreak in Brazil was soon followed by a high number of microcephaly cases, in which babies are born with abnormally small heads. The link between the two is not definitively understood, but is strongly suspected.
Since the Brazil outbreak, Zika virus has been detected in an additional 39 countries, including in Europe, the UK, South America and Asia.
With thousands of visitors set to attend the Olympics in Rio de Janeiro this summer, global concern and attention are elevated, especially given that the virus can be carried by lightly-infected travelers and then passed onto others by mosquitoes.
Using a survival analysis model, information about airline transportation networks, and transmission data for dengue and chikungunya viruses up to January 31, 2016, Nishiura and colleagues predicted the virus’ potential of importation and local transmission by the end of 2016.
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.
“Despite a clear need to improve predictions in the future, the present study successfully devised a simple global risk prediction of importation and local transmission,” Nishiura said. “Countries at low risk may focus on prevention among pregnant women who must travel to epidemic areas.”
The article can be found at: Nah et al. (2016) Estimating Risks of Importation and Local Transmission of Zika Virus Infection.
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Source: Hokkaido University; Photo: Shutterstock.
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