 "Study: Guillain-Barre syndrome could be brought about by Zika Virus")
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 Guillain-Barre 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 one in 4,000 people infected with the virus could develop the syndrome.
The Centres for Disease Control and Prevention has said Zika virus is "strongly associated" with Guillain-Barre, 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 Guillain-Barre 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 Marcos A Espinal, the study's lead author and the director of communicable diseases at the Pan American Health Organisation, which collected data on confirmed and suspected cases of Zika infection and on the incidence of Guillain-Barre. "Something is going on."
In Venezuela, officials expected roughly 70 cases of Guillain-Barre 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 Guillain-Barre when there should have been about 100. From September 2015 to March 2016, while Zika infections peaked in El Salvador, cases of Guillain-Barre doubled to 184 from 92.
The researchers included patients with both suspected and confirmed Zika infections, as reported by national health officials.
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 well-developed health systems in place," he said. "They have to have enough ventilators and intensive care unit beds." About one-third of patients with Guillain-Barre require breathing assistance, Gorson said.
Over all, Espinal and his authors found increase in Guillain-Barre 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 Guillain-Barre 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.
©2016 The New York Times News Service
