NYTimes: Study Finds Increase in Temporary Paralysis Accompanied Zika Outbreaks

Study Finds Increase in Temporary
Paralysis Accompanied Zika Outbreaks
By CATHERINE SAINT LOUIS AUG. 31, 2016
In seven countries that recently experienced Zika outbreaks, there were also sharp
increases in the numbers of people suffering from a form of temporary paralysis,
researchers reported Wednesday.
The analysis, published online in The New England Journal of Medicine, adds
to substantial evidence that Zika infections — even asymptomatic ones — may bring
on a paralysis called Guillain­Barré syndrome.
The syndrome can be caused by a number of other factors, including infection
with other viruses. Researchers studying the Zika epidemic in French Polynesia had
estimated that roughly 1 in 4,000 people infected with the virus could develop the
syndrome.
The Centers for Disease Control and Prevention has said that the Zika virus is
“strongly associated” with Guillain­Barré, but has stopped short of declaring it a
cause of the condition.
The new data suggest a telling pattern: Each country in the study saw unusual
increases in Guillain­Barré that coincided with peaks in Zika infections, the
researchers concluded.
“It’s pretty obvious that in all seven sites there is a clear relationship,” said Dr.
Marcos A. Espinal, the study’s lead author and the director of communicable
diseases at the Pan American Health Organization, which collected data on
confirmed and suspected cases of Zika infection and on the incidence of GuillainBarré.
“Something is going on.”
In Venezuela, officials expected roughly 70 cases of Guillain­Barré from
December 2015 to the end of March 2016, as mosquitoes were spreading the virus.
Instead, there were 684 cases.
Similarly, during five months in which the Zika virus was circulating in
Colombia, officials recorded 320 cases of Guillain­Barré when there should have
been about 100. From September 2015 to March 2016, while Zika infections peaked
in El Salvador, cases of Guillain­Barré doubled to 184 from 92.
The researchers included patients with both suspected and confirmed Zika
infections, as reported by national health officials.
Dr. Kenneth C. Gorson, professor of neurology at Tufts University School of
Medicine, who was not involved with the new analysis, called it compelling.
“This is a substantial public health burden for countries that may not have welldeveloped
health systems in place,” he said. “They have to have enough ventilators
and I.C.U. beds.” About one­third of patients with Guillain­Barré require breathing
assistance, he said.
Over all, Dr. Espinal and his authors found increases in Guillain­Barré that were
two to 10 times what would normally be expected. Roughly 500 million people in
Latin America and the Caribbean are at risk for Zika virus infection, so even modest
increases in the incidence of Guillain­Barré are worrisome.
The nations in the study included the Dominican Republic, El Salvador,
Honduras, Suriname, Venezuela and Colombia, along with the state of Bahia in
Brazil. (National data from Brazil was not available until February 2016.)
Collectively, they reported a total of nearly 1,500 cases of temporary paralysis.
The reported incidence was 28 percent higher for men and increased with age for
both sexes, in line with previous research.
Temporary paralysis is a potential neurological complication of dengue
infection, too. But Dr. Espinal and his colleagues looked for a similar link to dengue
and found none.
Dr. Gorson noted that the continental United States has no formal monitoring
system for Guillain­Barré. As the number of Zika cases in Florida and elsewhere
increases, he said, “you won’t know if a Guillain­Barré case is related to Zika
infection.”
“We can do it,” he said of such surveillance. But “there’s no funding from
Congress to do it.”
A version of this article appears in print on September 1, 2016, on page A14 of the New York edition with
the headline: Researchers Find Increase in a Temporary Paralysis Accompanied Zika Outbreaks.
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