The Zika virus is responsible for the increase in cases of Guillain-Barre syndrome, a post-infectious neurological disorder, according to a study conducted by a group of Colombian physicians published in the New England Journal of Medicine.
A link between this complication — causing progressive paralysis — and the Zika virus was suspected since the outbreak of the epidemic in 2013 in French Polynesia. This first outbreak affected half of the population, and 42 cases of Guillain-Barre syndrome were identified. But at the same time, the Dengue fever was also raging on the island, making difficult to confirm that Zika was responsible.
Three years later, the danger of Zika virus has resurfaced. Over sixty countries are affected by the outbreak of Zika since 2015. Eleven of these countries have reported an anomalous proportion of people suffering from the Guillain-Barre syndrome. Brazil, the epicenter of the outbreak, was hit really hard. Soon, Colombia is also greatly affected by the epidemic.
In Colombia, between November 2015 and March 2016, nearly 60,000 people have been infected with Zika. To this is added 400 patients with neurological complications, including 270 cases of Guillain-Barré. Usually, the country experiences 250 cases a year.
To conduct their research, the team of Colombian doctors studied medical records, blood and urine samples from 68 people with the syndrome. Of these, 66 showed typical symptoms of infection (rash with or without fever, joint pain, conjunctivitis). Blood tests and cerebrospinal fluid performed on 42 patients revealed the presence of the Zika virus in 17 of them.
Furthermore, the researchers’ observations revealed that the syndrome can appear 4 days after the onset of the Zika symptoms and up to 48 days. Along with limb weakness and tingling, paralysis of half of the face is one of the most common signs. In addition, Electromyography (examination of the muscles and nerves) conducted in 46 patients shows nerve damage: the myelin sheaths around neurons are destroyed. Result: the transmission of nerve signals is slowed down, causing muscle weakness and paralysis.
For the Colombian researchers, all these elements combine to prove the responsibility of the Zika virus. However, they stress that the mechanism behind the cause/effect relation remain unknown.
In a commentary accompanying the study, two experts have meanwhile reminded the public that the epidemic is not yet over and that many cases of Guillain-Barre could be identified on the American continent in the coming months.