*Updated 9/1/2016 at 12:30 PM
An analysis published in the Centers for Disease Control and Prevention (CDC) publication Morbidity and Mortality Weekly Report (MMWR) has produced results that strengthen the link between Zika virus infection and Guillain-Barré syndrome.
The analysis, published on August 26, looked at the cases of 56 patients from Puerto Rico with suspected Guillain-Barré syndrome, from the period of January 1st through July 31st of this year. Puerto Rico has, of course, experienced a large-scale outbreak of the mosquito-born Zika virus since last year, with experts saying there are as many as 2,000 new infections diagnosed per week. Public health officials suggest that one-fourth of the island’s 3.5 million residents could be infected by the end of this year.
The fact that many countries affected by Zika outbreaks over the past 2 years have also seen an uptick in the incidence of Guillain-Barré syndrome in their respective regions led health officials in cash-strapped Puerto Rico to initiate a surveillance program for the autoimmune disorder late in 2015. Of the 56 cases of Guillain-Barré identified through the surveillance program, 34 had evidence of Zika or another flavivirus infection, with 10 confirmed cases of Zika.
“Our findings are the first to publish aggregate data on Guillain-Barré syndrome collected during ongoing Zika virus transmission,” study co-author Emilio Dirlikov, PhD, who works for the CDC in the Puerto Rico Department of Health’s Epidemiology and Research Office, told Contagion. “[However], it’s important to note: Guillain-Barré syndrome is a rare autoimmune disorder, and while our findings are in line with elevated risk of developing Guillain-Barré syndrome, it is still an infrequent outcome of infection with Zika virus.”
The MMWR report adds to the growing list of evidence linking Zika with neurologic complications, including Guillain-Barré and sensory polyneuropathy. Findings such as these are particularly troubling as the virus’ footprint continues to expand into North America and Asia. Significantly, 30 of the patients in MMWR analysis reported an acute illness prior to developing neurologic symptoms (median time of onset was 5 days). And, evidence of Zika or other flavivirus infection was detected in seven patients with neurologic disorders other than Guillain-Barré.
“Previously published reports have also suggested the connection between Zika virus infection and Guillain-Barré syndrome, notably reports from French Polynesia, Brazil, and Colombia,” Dr. Dirlikov explained. “In Puerto Rico, we had the opportunity to act on these initial reports to implement a regular surveillance system, [and] moving forward, the Puerto Rico Department of Health and CDC will continue working together to explore the possible link between Guillain-Barré syndrome and the Zika virus. Our surveillance system is also collecting data from cases of neurologic conditions other than Guillain-Barré syndrome, toward describing a range of conditions potentially associated with Zika virus infection. While our findings do not change prevention strategies, we want to raise awareness that Guillain-Barré syndrome following Zika virus infection is possible. Guillain-Barré syndrome can affect anyone, although people over 50 years of age have a higher risk of developing the condition. Everyone should be concerned about Zika-related Guillain-Barré syndrome, and employ strategies to prevention transmission.”
Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.