|
 Zika has already been linked with the autoimmune disorder
Guillain-Barre 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 new discovery now shows Zika may provoke an immune attack on the
central nervous system as well.
The findings add to the growing list of neurological damage
associated with Zika.
According to the World Health Organization, there is a strong
scientific consensus that, in addition to Guillain-Barre, Zika can
cause the birth defect microcephaly, though conclusive proof may
take months or years. Microcephaly is defined by unusually small
heads that can result in developmental problems.
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.
In addition to autoimmune disease, some researchers also have
reported patients with Zika infections developing encephalitis and
myelitis - nerve disorders typically caused by direct infections in
nerve cells.
"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.
ADEM typically occurs in the aftermath of an infection, causing
intense swelling in the brain and spinal cord that damages myelin,
the white protective coating surrounding nerve fibers. It results in
weakness, numbness and loss of balance and vision, symptoms similar
to multiple sclerosis.
Brito presented her findings on Sunday at the American Academy of
Neurology meeting in Vancouver. 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.
Six of these patients developed symptoms consistent with autoimmune
disorders. Of these six, four had Guillain-Barre and two had ADEM.
In both ADEM cases, brain scans showed damage to white matter. ADEM
symptoms typically last about six months.
[to top of second column] |
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.
At least 13 countries have reported cases of Guillain-Barre linked
with outbreaks of Zika, according to the World Health Organization,
and WHO believes that Zika likely is the cause.
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-Barre, but said doctors should be on the lookout for
ADEM and other central nervous system illnesses.
"Of course, the remaining question is 'Why?'" Sejvar said. "Why does
Zika virus appear to have the strong association with GBS and
potential other immune/inflammatory diseases of the nervous system?"
Sejvar, who has studied Guillain-Barre Syndrome (GBS) in Brazil and
is involved in a major clinical trial of Guillain-Barre in Puerto
Rico, said he hopes future studies will shed more light on such
questions.
(Reporting by Julie Steenhuysen; Editing by Jonathan Oatis)
[© 2016 Thomson Reuters. All rights
reserved.] Copyright 2016 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
 |
