Zika-linked brain disorder in adults identified by Brazilian scientists

Zika has already been linked with the autoimmune disorder Guillain-Barré​ syndrome, which attacks peripheral nerves outside the brain and spinal cord, causing temporary paralysis that can in some cases require patients to rely on respirators for breathing.

The findings add to the growing list of neurological damage associated with Zika.

Brazil said it has confirmed more than 940 cases to be related to Zika infections in the mothers. Brazil is investigating nearly 4,300 additional suspected cases of microcephaly.

"Though our study is small, it may provide evidence that in this case, the virus has different effects on the brain than those identified in current studies," Dr. Maria Lucia Brito, a neurologist at Restoration Hospital in Recife, Brazil, said in a statement.

Brito presented her findings on Sunday at the American Academy of Neurology meeting in Vancouver. Research presented at meetings should be viewed as preliminary until published in a peer-reviewed medical journal.

The study involved  151 patients who visited her hospital between December 2014 and June 2015. All had been infected with arboviruses, the family of viruses that includes Zika, dengue and chikungunya.

All six patients tested positive for Zika, and all had lingering effects after being discharged from the hospital, with five patients reporting motor dysfunction, one with vision problems, and one with cognitive decline.

Why does Zika virus appear to be strongly associated with disease of nervous system?

Dr. James Sejvar, a neuroepidemiologist for the U.S. Centers for Disease Control and Prevention, said the ADEM cases linked with Zika do not appear to be occurring at the same accelerated rate as cases of Guillain-Barré​, but said doctors should be on the lookout for ADEM and other central nervous system illnesses.

Sejvar, who has studied Guillain-Barré​ Syndrome (GBS) in Brazil and is involved in a major clinical trial of Guillain-Barré​ in Puerto Rico, said he hopes future studies will shed more light on such questions. 

In Guillain-Barré​, the immune system attacks the nervous system, resulting in muscle weakness and sometimes paralysis, according to the U.S. Centers for Disease Control and Prevention.

Zika, which is prevalent in Latin America and the Caribbean, is mainly transmitted through the bite of infected Aedes aegypti mosquitoes. Most healthy people infected with the virus experience no symptoms, but babies whose mothers were exposed to the virus in pregnancy appear to be at special risk for microcephaly.