By: Steven Salzberg
Just a few months ago, I warned that travelers to the Rio Olympics should be concerned about Zika virus not only because of its link to microcephaly in newborns, but because it might also cause a deadly paralysis known as Guillain-Barré Syndrome, or GBS. Now we have much stronger evidence of a direct causal link between Zika and GBS.
In a new study published today in the New England Journal of Medicine, my colleague Carlos Pardo together with Beatriz Parra and a consortium of doctors and scientists from Colombia and Johns Hopkins Hospital examined 68 patients from six Colombian hospitals. Of the 68 Guillain-Barré patients, 66 had symptoms of Zika infection before they came down with GBS. They tested 42 of the patients for Zika virus using sensitive molecular assays, and found that 17 of them (40%) had detectable Zika virus.
Guillain-Barré syndrome is a very rare but very deadly illness, with a mortality rate of 5% if you receive the absolute best care–and higher mortality otherwise. Its cause is generally unknown, but now we have strong evidence that Zika virus infection is one of its causes.
Drs. Pardo and Parra also found evidence of a possible link between GBS and both Zika and dengue virus: 32 out of 37 Guillain-Barré patients who were tested had antibodies to both Zika and dengue, suggesting that they may have suffered two successive infections by these viruses, which are genetically similar to one another.
In an editorial accompanying the new study, Jennifer Frontera and Ivan da Silva write that although the new study supports the link between Zika and GBS, confirmatory evidence in more patients will strengthen the (possible) causal association. They warn that “the Zika virus pandemic is just beginning in North America and Africa, and an increase in the incidence of the Guillain-Barré syndrome may follow.”