Zika May Also Cause This Neurological Disorder

Photo: Felipe Dana/AP Photo.
The Zika virus hits just keep on comin' this week. New research published in The Lancet suggests that the virus may trigger Guillain-Barré syndrome, a rare but potentially severe neurological disorder that can cause paralysis.

Guillain-Barré syndrome
is relatively rare and mysterious. Experts don't totally understand what causes it, but it tends to show up a few weeks after otherwise mild viral or bacterial infections. It's unclear why it affects some people and not others. But it is thought that an infection might be able to change immune cells in a way that causes the body's own immune system to attack nerve cells, leading to weakness and tingling sensations that can sometimes progress to life-threatening total paralysis. Although experts have observed an increase in the syndrome during the recent Zika outbreaks in the past two years, the new study is the strongest evidence that the two are related. Researchers looked into data from an outbreak of Zika in French Polynesia between October 2013 and April 2014, which, at the time, was the biggest recorded outbreak of the virus. According to data collected during that outbreak, 42 people had been diagnosed with Guillain-Barré syndrome. The researchers went back and matched those patients with 70 people who had Zika but did not have any neurological symptoms and 98 people who had non-fever-related illnesses using samples and records from the same hospital. After they crunched the numbers, the researchers found that almost all (88%) of the 42 people with Guillain-Barré had come to the hospital complaining of Zika symptoms before developing neurological symptoms (e.g., muscle weakness or facial palsy). And they were able to determine that all of the 42 people also had immune system markers in their blood confirming they'd been exposed to Zika. On top of that, only about 54% of those control patients who came to the hospital without a fever had been exposed to the virus, suggesting that Zika has a far stronger association with Guillain-Barré than other illnesses without fevers. Guillain-Barré can be devastating because it's sudden, severity varies widely (an estimated 30% of those affected will experience life-threatening paralysis), and so little is known about it. But people can get better, with recovery taking anywhere from a few weeks to a few years. About 30% will have lingering muscle weakness. There is no cure, but prompt treatment can lessen the severity. Usually that involves getting immunoglobulin therapy and plasma exchange. Each of these involves injections of certain blood proteins that seem to lessen severity and duration of the illness. Physical therapy is also a huge part of the process. It is also worth underscoring that Guillain-Barré remains rare. In fact, most people who contract the Zika virus won't ever have symptoms and will clear the virus on their own. Still, this is another thing in a long line of things that you should know about the potential risks of the virus.

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