Zika virus may cause temporary paralysis, in addition to birth defects, new findings suggest

Scientists may have the first evidence that Zika can cause temporary paralysis, according to a new study of patients who developed the rare condition during an outbreak of the virus in Tahiti two years ago.

Zika is currently spreading with alarming speed across the Americas. The World Health Organisation declared the epidemic to be a global emergency several weeks ago based on suspicions it may be behind a surge in disturbing birth defects including microcephaly, and in Guillain-Barre syndrome, a neurological illness causing paralysis that mostly lasts a few weeks.

Before reaching South America last year, the mosquito-spread Zika had triggered outbreaks in the South Pacific on Yap island in Micronesia and in French Polynesia, including its largest island, Tahiti.

Researchers in Tahiti, France and elsewhere went back and analysed blood samples from all 42 adults diagnosed with Guillain-Barre syndrome from the 2013-14 outbreak; nearly everyone showed signs of a previous Zika infection.

They were compared with patients who did not have the condition and did not have any Zika symptoms but were treated at the same hospital for other illnesses. Tests showed only half of that group of 98 had apparently been infected with the normally mild virus.

The research was published online Monday in the journal Lancet.