sexta-feira, 29 de janeiro de 2016

Climate Change Could Tell Us Where the Zika Virus Will Spread Next

Warming temperatures and extreme weather are making more of the world breeding grounds for the mosquitoes that carry the disease.
Larvae of the Aedes aegypti mosquito, which transmits the Zika virus, as seen in a lab in Brazil on Jan. 26. (Photo: Mario Tama/Getty Images)

It sounds like the plot for a horror movie: A virus with subtle, easily overlooked symptoms (cough, fever, rash) that has the potential to cause serious birth defects and long-term neurological problems is carried by a tiny mosquito that’s rapidly spreading throughout the world.

Global travel and climate change are creating conditions perfectly designed to increase that mosquito’s breeding potential and lengthen its biting season, leading scientists to use the term “pandemic” to describe the Zika virus’ potential for destruction. On Thursday, the director of the World Health Organization warned that the virus is “spreading explosively” in the Americas.

“There are two things most surprising about Zika,” said Peter Hotez, dean of the National School of Tropical Medicine at Baylor University in Houston. “First is the rapid spread—it’s alarming how quickly it’s going across all the Caribbean into Central America and Mexico.” There’s also concern about the virus’ potential spread to Southern Europe.

Second, said Hotez, is the “vertical transmission from mother to child—we haven’t seen that before with one of these arboviruses.” While scientists are still trying to pinpoint causality, there has been a shocking spike in cases of microcephaly—a central nervous system deformity causing an abnormally small head and brain—among babies born to mothers in Brazil, where Zika has infected as many as 1.5 million people in the past year.

In just the week ending Jan. 16, Brazilian health officials announced that 363 babies had been born with Zika-linked microcephaly, and on Wednesday they said there were 287 new suspected cases in the week ending Jan. 23. There have been a total of 4,180 cases of Zika-associated microcephaly since October, when the country instituted mandatory reporting. A spike in microcephaly had previously been noted in French Polynesia, tied to a Zika outbreak there.

Both outbreaks have also been linked to an increase in the incidence of Guillain-Barré syndrome, a little-understood autoimmune disease in which the body attacks its own central nervous system, causing long-term neurological consequences, including paralysis.

Named for a forest in Uganda where researchers first identified the virus in monkeys in 1947, Zika has only in the past eight months been considered a threat beyond a narrow slice of equatorial Africa and Asia where it appeared to be safely contained for decades.

To read more go to takepart

by Melanie Haiken a San Francisco Bay Area–based health, science, and travel writer who contributes regularly to and numerous national magazines.

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