How climate change may have driven Zika outbreak

By: Staff Reporter

New Delhi, February 20 (G’nY News Service): The Zika virus is a mosquito-transmitted infection, closely related to dengue, yellow fever and the West Nile virus. Although it was first discovered in the Zika forest in Uganda in, 1947 and is common in Africa and Asia, it did not begin to spread in the Western Hemisphere until May 2015, when an outbreak occurred in Brazil. Since then, there have been more than 4,000 births with suspected microcephaly in Brazil, compared with a previous yearly average of 154.

Heavy rain and warm temperatures have helped the mosquitoes carrying Zika thrive. Rains can cause standing water on the ground, which, in turn, breeds mosquitoes. El Niño, which has been spearheading climate change and warmer weather, has had a strong influence in the spread of the Zika virus, since Aedes aegypti, the mosquito that plays host to it thrives in warmer conditions.

Models indicate that the current El Niño could be done by mid-year and the odds favour it being replaced by La Niña. However, a switch to La Niña conditions next year could help the virus spread even further This is because, In terms of severe weather, La Niña usually means more hurricane activity in the tropical Atlantic while the opposite occurs in the tropical Pacific off the coast of Central America and Mexico. Wind shear being suppressed or enhanced in hurricane waters is a major component of this formula.

Finally, while El Niño can bring relief to Tornado or Dixie Alley’s with a less active twister season, La Niña normally enhances instability in the region, which in turn translates into a much more active tornado season.

Besides, most significantly, La Niña often features drier than normal conditions in the US Southwest in late summer, through the subsequent winter. Drier than normal conditions occur typically in the Central Plains during fall and Southeast during winter.

Typical La Niña influence

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In contrast, the Pacific Northwest is more likely to be wetter than normal in the late fall and early winter with the presence of a well-established La Niña.

Additionally, on average, La Niña winters are warmer than normal in the Southeast and colder than normal in the Northwest, as pointed out by The Weather Network (UK).

Warmer conditions up north, can very easily cause the Zika virus to widen the scope of its outbreak, and result in a dangerous situation.

It’s still not clear what role rising temperatures and altered rainfall patterns have had on the spread of Zika. The increased global movement of people is probably as great an influence as climate change for the spread of infectious diseases. But the World Health Organization (WHO) has declared a public health emergency over the birth defects linked to Zika.

“We know that warmer and wetter conditions facilitate the transmission of mosquito-borne diseases so it’s plausible that climate conditions have added to the spread of Zika,” says Dr Diarmid Campbell-Lendrum, a lead scientist on climate change at WHO.

WHO estimates that an additional 250,000 people may die a premature death due to climate change impacts ranging from heat stress to disease by 2050, but Campbell-Lendrum said this is a “conservative estimate”.

Temperatures have been above normal in much of Latin America as a whole since early last year. El Niño has helped warm things up, but climate change is directly responsible for all of last year’s record heat globally. It not only means mosquitoes can incubate the virus, but also that people are also more likely to be outside and have exposed skin for mosquitoes to feast on.
The Centre for Disease Control and Prevention (CDC) suggests that “because Aedes mosquitoes that spread Zika virus are found throughout the world, it is likely that outbreaks will spread to new countries.”

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