The Zika virus has been linked to a second type of autoimmune disorder, according to a small study released today.
Doctors have known that Zika is associated with Guillain-Barre syndrome, a condition in which the immune system attacks the nervous system, causing paralysis, since the Zika outbreak in French Polynesia in 2013-2014.
Now, scientists have linked Zika to a condition similar to multiple sclerosis, called acute disseminated encephalomyeltis, or ADEM, a swelling of the brain and spinal cord that affects the myelin, the coating around nerve fibers, according to a paper to be presented this week at the annual meeting of the American Academy of Neurology in Vancouver.
Authors of the study followed people who were hospitalized in Recife, Brazil because of symptoms that could be caused by Zika, dengue or chikungunya — which are all spread by the same species of mosquito, the Aedes aegypti — between December 2014 and December 2015. All of the people had fever followed by a rash. Some also had severe itching, muscle and joint pain and red eyes.
Six of those people develop neurological problems that were consistent with autoimmune diseases. Four developed Guillain-Barre syndrome.
The other two developed ADEM, according to the paper. Unlike multiple sclerosis, a chronic illness, ADEM usually consists of a single attack and most people recover within six months. In some cases, the disease comes back.
Five of the six people still had problems with their muscles when they were discharged from the hospital, according to the report. One had vision problems and one had issues with memory and thinking. Tests showed all had Zika virus and none had dengue or chikungunya.
Doctors have been most concerned about Zika's effects on the brains of developing fetuses. Brazil's Zika epidemic has been accompanied by a surge in cases of microceophaly, in which babies are born with abnormally small heads.
Zika also has been linked to meningoencephalitis, a dangerous inflammation of the membranes that surround the brain, as well a type of sudden paralysis called myelitis, or inflammation of the spinal cord.
"Before the outbreak of Zika in the Western Hemisphere, the medical world knew very little about this infection and it was mostly regarded as travel-medicine trivia," said Amesh Adalja, a senior associate at the Center for Health Security at the University of Pittsburgh Medical Center. "With the large numbers of cases occurring and the heightened scrutiny of cases, we are beginning to see that the full spectrum of disease caused by this virus can include severe complications involving the central nervous system."
