Zika virus may be linked to acute disseminated encephalomyelitis (ADEM), an autoimmune disorder that attacks the brain and spinal cord, a new study found.
ADEM is an autoimmune disorder similar to multiple sclerosis. Among ADEM patients, the immune system attacks the myelin, which coats the spinal cord and the brain's nerve fibers.
Previous reports already linked the Zika virus to two diseases – microcephaly, a birth defect characterized by an infant's small head, and Guillain-Barre syndrome, which causes temporary paralysis. Now, a new condition has been added to the list.
"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," said study author Dr. Maria Lucia Brito Ferreira from the Restoration Hospital in Brazil.
For the study, the researchers analyzed six people who developed neurologic symptoms following their arrival at a hospital in Recife, Brazil. All six patients were positive for Zika virus. None of them tested positive for chikungunya and dengue. They were admitted between December 2014 and June 2015.
Their documented symptoms – severe itching, joint and muscle pain, red eyes and fever – were similar to the ones linked to the family of viruses to which dengue, chikungunya and Zika belong.
Some patients experienced these symptoms almost immediately, while some started 15 days after they were admitted.
Two patients developed ADEM while four developed Guillain-Barre syndrome. After their hospital release, five patients still suffered problems with movement. One still had vision problems while another still had thinking and memory issues.
Ferreira noted that the study does not suggest all individuals who tested positive for Zika will develop these brain diseases. In the study, some who have issues in the nervous system do not have brain problems.
"However, our study may shed light on possible lingering effects the virus may be associated with in the brain," added Ferreira.
The study is considered "preliminary" until it is published in a peer-reviewed journal. However, the results released on April 10 will be presented at the American Academy of Neurology's annual meeting on April 15 in Canada.