New research is revealing that infection from the Zika virus can produce serious neurological conditions in adults beyond the rare cases of Guillain-Barre syndrome.
Research in the journal JAMA Neurology reveals that aside from being a health risk for pregnant women, for whom Zika infection brings a risk of devastating neurological birth defects such as microcephaly, the virus can also produce neurological damage in adults —and not solely in the form of rare cases of Guillain-Barre syndrome, as previously thought, but also encephalitis and inflammation of the brain and spinal cord.
Transmitted mainly by mosquitoes, the Zika virus was in the past restricted to Africa but in recent years has spread through southeast Asia and, starting in 2015, North and South America. In only about 18 per cent of cases does Zika infection present with symptoms, usually involving fever and a rash. Yet, the virus has also been linked to both microcephaly in newborns and, in rare cases in adults, Guillain-Barre syndrome (GBS), a disorder which causes weakness and tingling in the extremities.
Now, researchers have broadened the scope of Zika’s potential effects to “post-infectious syndromes,” resulting from the body’s response to the infection, which triggers other autoimmune impacts on the central nervous system.
Researchers followed 40 adult patients referred to a tertiary care academic hospital for neurological diseases in Rio de Janeiro, Brazil, between December, 2015 and May, 2016. Of the 40 patients, 35 were found to have had a recent Zika infection in their cerebrospinal fluid or serum. Of those testing positive for Zika, 27 had GBS, five had encephalitis, two had transverse myelitis and one had chronic inflammatory demyelinating polyneuropathy, an immune-related inflammatory disorder.
“In this single-center Brazilian cohort, ZIKV infection was associated with an increase in the incidence of a diverse spectrum of serious neurologic syndromes,” say the study’s authors.
Another recently released study in the Journal of Critical Care drew similar results, this time through a case comparison across 16 different intensive care units in eight countries, including Canada. The study included 49 critically ill patients who were enrolled with diagnoses of Zika infection. GBS was identified in all patients, two of which had symptoms evolve into encephalitis.
"Now we're realizing that adults may be impacted,” said Michael Osterholm, director of the University of Minnesota's Center for Infectious Disease Research and Policy in Minneapolis, who was not involved in the studies, to the Chicago Tribune. "There are clinical implications."
Although transmission of the virus is commonly through mosquitoes, the virus can be spread human-to- human, as well. Health officials in Florida recently confirmed the first case of sexually transmitted Zika virus in 2017 in the state, whereby a Florida resident contracted the virus through sexual contact with the resident’s partner who had recently traveled to Cuba and contracted Zika.
As of February of this year, the Public Health Agency of Canada reported 473 travel-acquired cases of Zika in Canada and three acquired through sexual transmission. 27 of the reported cases were in pregnant women, with two of those cases showing signs of Zika-related abnormalities and two of them not showing signs of abnormalities.