Researchers Report Zika and Guillain-Barré Syndrome Are Related

Guillain-Barré Syndrome outbreak may be associated with the Zika virus
man over 50
Africa (Zika News)

Johns Hopkins Medicine researchers report what they believe to be the strongest biological evidence to date linking the Zika virus and Guillain-Barré syndrome.

This new study's results, published in The New England Journal of Medicine, support the correlation with immunologic and viral evidence of Zika infection in a substantial number of people with Guillain-Barré.

These researchers said the study is believed to be the largest of its kind to document the role of Zika infection with increased rates of Guillain-Barré.

A so-called post-infectious immune condition, Guillain-Barré syndrome (GBS) occurs when a person's own immune system attacks the myelin sheaths that protect the body's nerve cells, often resulting in muscle weakness, pain, sensory deficiencies and, in very acute cases, paralysis. GBS symptoms appears days to weeks after infection with viruses or bacteria.

Anyone can develop GBS.

However, it is more common among older adults. The rate of GBS increases with age. People older than 50 years are at greatest risk for developing GBS. Each year, between 3,000 and 6,000 people in the United States get GBS, regardless of vaccination.

Guillain-Barré, which affects an estimated one or two out of 100,000 people after infections, is diagnosed with electrodiagnostic neurological tests that measure the conductive speed and activity of nerve signals.

Scientists do not know why it strikes some people and not others.

"At the beginning of the Zika outbreak in South America, my colleagues in Colombia contacted me with concern about the increasing number of patients with neurological complications," says Carlos A. Pardo, M.D., associate professor at the Johns Hopkins University School of Medicine.

The researchers say that almost one-half of the study participants complained of neurologic symptoms within four days of the onset of Zika symptoms.

Approximately 500 million people in Latin America and the Caribbean are at risk for Zika infection, because they live in areas that are less than 2000 m above sea level, where competent aedes vectors mosquitoes are found.

Researchers say it's clear that increases in the incidence of the Guillain–Barré syndrome to a level that is 2.0 and 9.8 times as high as baseline, impose a substantial burden on populations and health services.