Potential New Zika Virus Association

April 18, 2016
Samantha J. Peterson

In addition to microcephaly, evidence suggests the Zika virus may be linked to another neurological condition, according to a report from the AAN Annual Meeting.

A possible association between the Zika virus and Guillain-Barré syndrome (GBS) was discussed by James Sejvar, MD, with the Centers for Disease Control and Prevention (CDC) in Atlanta during a press conference at the American Academy of Neurology Annual Meeting on Friday, April 15, 2016.

Although the Zika virus has been reported since 1947, the virus was only seen in isolated isolated cases or small clusters in Africa and parts of Asia. Most people experienced no symptoms with Zika. Those who did show symptoms had only a mild rash illness.

In 2013, health officials in French Polynesian reported a concerning increase in GBS cases that coincided with the largest outbreak of Zika up to that point. At least 12 countries in Central and South America and the Caribbean have since reported increases in GBS following the introduction of Zika into their countries.

“This is the strongest evidence to date that Zika and GBS are linked,” stated Sejvar. “As the outbreak continues we are learning more and we hope to be able to better understand the relationship between these two conditions.”

The CDC and local health partners are performing investigations to learn if Zika can trigger GBS and other neurologic symptoms. In January 2016, the CDC and the Brazilian Ministry of Health conducted a case control investigation in northeast Brazil, one of the hardest hit areas affected by Zika.

“Our preliminary analyses are already revealing some troubling trends,” explained Sejvar. Almost 90% of the GBS patients reported a Zika-like illness prior to their GBS illness. “It also appears that cases of GBS in Brazil are nearly five times the number that we’d expect. About half of GBS patients in our study were still experiencing moderate to severe symptoms 6 months after they initially became ill.”

CDC labs are testing blood and urine samples collected in Brazil and hope to learn if GBS cases coincided with a recent Zika infection and how that compares to Zika infections in controls who did not get GBS.

Another study is beginning in Columbia, the second-most heavily affected country, which is also experiencing large numbers of GBS cases. In addition, the CDC is conducting GBS surveillance in Puerto Rico in advance of an anticipated large Zika outbreak this spring and summer. “By setting up surveillance ahead of the anticipated Zika outbreak, we hope to gain more information about the development and progression of GBS in real time.”

Sejvar concluded by stating, “As a neurologist, I’ve never seen anything like what we are seeing in the ongoing outbreak in Central and South America. CDC and other public health officials in the United States will continue to work tirelessly to learn about Zika virus and its potential complications. We will remain vigilant for the possible emergence of locally transmitted Zika virus infection. As always, in our mission to protect the public’s health we’ll disseminate new information on the emerging features of this virus as soon as they become available.”

Reference: Update on Zika virus and the brain press conference. AAN Annual Meeting, Vancouver, British Columbia. Apr 15, 2016.

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