The Zika virus’s health effects generally are described as mild – flu-like symptoms for those that show symptoms at all – or not yet certain, with references to Guillain-Barré Syndrome, which causes paralysis, or microcephaly, an often devastating birth defect.
But the linkage to Guillain-Barré, an autoimmune disorder first brought to the American public’s attention three decades ago as a reaction to swine flu vaccine, isn’t new to the current outbreak. Researchers raised the likelihood of a Zika-Guillain-Barré connection two years ago after an outbreak of the virus in French Polynesia, the first time the disease had spread to a population that could be tracked and treated.
According to an article in the October 2014 edition of the journal Clinical Microbiology and Infection, the first case of Guillain-Barré was detected just one month after the first Zika cases were reported in French Polynesia in October 2013. The Guillain-Barré sufferer – the syndrome typically causes paralysis that can be so severe as to affect the ability to open one’s eyes and even to breathe – had had a confirmed case of Zika a week earlier.
Over the course of the French Polynesia Zika outbreak, the incidence of Guillain-Barré increased 20-fold, the researchers noted. They called the “temporal and spatial association” between Zika and Guillain-Barré “very suspicious,” though they said they couldn’t prove a causal link.
But they did warn that Zika merited “rigourous clinical monitoring,” despite its reputation for inducing only mild symptoms in most of its sufferers. “The observation that severe clinical complications may occur highlights the need to strengthen surveillance for this emerging virus,” the authors said.
The primary author of that article, Didier Musso, a French infectious disease expert, revisited Zika in a short piece a year later, where he again mentioned the Zika-Guillain-Barré link and said the incidence of Zika infections is probably under-reported.
In an interview this week with the French magazine Le Point, Musso said he believes the Guillain-Barré link is “almost certain” and that the link between Zika and microcephaly in infants is also a near certainty (English version here). And he expressed doubt that those are the only complications that eventually will be linked to what until recently was considered a rather benign infection.
“It is illusory to think that one has already seen the possible complications for a disease that emerged only three years ago,” he said. He said there also have been reports of Zika sufferers having impaired sight and hearing. He called for close monitoring for an extended period of time of anyone whose Zika symptoms have passed.