El Niño fuelled Zika outbreak

A new study has found that a change in weather patterns brought on by the strong El Niño of 2015 fuelled the Zika outbreak in South America.

Scientists at the University of Liverpool used a new epidemiological model that looked at how climate affects the spread of the Zika virus by its two main vectors: the yellow fever mosquito and the Asian tiger mosquito.

They also looked at temperature-dependent factors including mosquito biting rates, mortality rates and viral development rates within mosquitos in a bid to predict the effect of climate on virus transmission.

The model showed that in 2015, when the Zika outbreak occurred, the risk of transmission was greatest in South America.

The researchers believe that this was likely due to a combination of El Niño and climate change, which created conducive conditions for the mosquito vectors.

Dr Cyril Caminade, a population and epidemiology researcher who led the work, said: “It’s thought that the Zika virus probably arrived in Brazil from Southeast Asia or the Pacific islands in 2013.

“However, our model suggests that it was temperature conditions related to the 2015 El Niño that played a key role in igniting the outbreak – almost two years after the virus was believed to be introduced on the continent.”

According to the University of Liverpool, the model can also be used to predict the risk of future outbreaks and help public health officials tailor mosquito control measures and travel advice.

“Zika is not going away,” said Professor Matthew Baylis, from the University of Liverpool’s Institute of Infection and Global Health. “The development of tools that could help predict potential future outbreaks and spread are extremely important.”


Image credit: preventable diseases, flickr/Creative Commons

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