As the Zika virus has spread across the Americas these past few months, there has been more and more evidence that its greatest dangers are neurological. It’s been linked to the birth defect microcephaly, and the autoimmune nervous disorder Guillain-Barré pretty much from the beginning of the outbreak, but scientists are starting to see connections to other neurological conditions as well.
The outbreak has led to a rush on research to solidify these links, and in the cases of microcephaly and Guillain-Barré, the connection is finally strong enough to be called causal. In its Zika situation report on Thursday, the World Health Organization used the word “cause” to describe the relationship between Zika and these two conditions.
“Based on a growing body of preliminary research, there is scientific consensus that Zika virus is a cause of microcephaly and Guillain-Barré syndrome,” the report reads.
But this confirmation is hardly the end of Zika’s neurological mysteries. There have been recent case reports of people exposed to the virus who’ve come down with different kinds of infections of the brain and spinal cord. In Guadeloupe, there was a case of acute myelitis (an inflammation of the spinal cord) in a 15-year-old girl; there was a French case study of a man who came down with meningoencephalitis (inflammation of the brain and its outer membranes); and new research out of Recife, Brazil, presented at the American Academy of Neurology annual meeting, has found two people who, after presenting with symptoms consistent with Zika or another flavivirus, came down with acute disseminated encephalomyelitis (ADEM). ADEM is a “brief but widespread attack of inflammation in the brain and spinal cord,” according to the National Institutes of Health.