What happened to Zika?

From PBS News Hour
July 6, 2018

Last week, biologists reported the most detailed structure of the Zika virus to date, a finding that could help the effort to develop vaccines or anti-viral medicines. And Monday, a nationwide group of researchers reported in Nature Medicine that Zika causes miscarriages and stillbirths in a quarter of pregnancies in non-human primates.

The urgency to fight Zika reached a fever pitch two summers ago when a massive outbreak struck South and Central America and the Caribbean causing more than half a million suspected cases and more than 3,700 congenital birth defects. Some scientists suspect a mutation in the virusmade the disease more harmful and triggered the epidemic. It also landed in an ideal climate, where tropical mosquitoes — namely of the Aedes family — helped propel Zika to such large numbers.

But then last summer, the virus declined sharply in its hotspots and all but disappeared in the U.S. In 2016, Puerto Rico, the U.S. Virgin Islands and American Samoa saw more than 36,000 cases of locally transmitted Zika virus. By 2017, the number had dropped to 665. In 2017, the continental U.S. saw only seven cases of local mosquito-borne Zika, down from 224 the previous year.

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