The Zika virus may be associated with a high risk for neurologic complications in affected adults, according to results published in JAMA Neurology.

Investigators conducted an observational cohort analysis consisting of 40 patients who were admitted to a tertiary referral center in Brazil and evaluated for 3-month neurological outcomes. Specifically, the researchers sought to compare pre-outbreak incidences of Guillain-Barré syndrome (GBS), meningoencephalitis, and transversemyelitis to post-outbreak rates.

Of the cohort, 35 patients (88%) had serologic and/or molecular evidence of a recently acquired Zika virus infection, of which 27 had GBS, 5 were diagnosed with encephalitis, 1 had chronic inflammatory demyelinating polyneuropathy, and 2 developed transversemyleitis.

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Overall, 9 patents with a recent Zika virus infection required intensive care, and 5 needed mechanical ventilation. There was a mean increase in GBS admissions of 1.0 to 5.6 per month compared with the time period prior to the Zika outbreak in Brazil.

In addition, encephalitis admissions increased from a pre-outbreak rate of 0.4 per month to 1.4 per month post-outbreak. More than half of patients with Zika virus infection had chronic pain at 3 months (51%).

The 5-month study duration represented one of the potential limitations of the meta-analysis. The researchers commented that if they were to factor in the winter months, annual Zika virus-associated neurologic complications rates may be lower than described in this study. An additional limitation was the use of a single, tertiary neurologic referral center in one geographic location.

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The investigators advised that combined use of “serum and cerebrospinal fluid ZIKV and dengue testing may constitute a practical algorithm for ZIKV diagnosis in territories with a high prevalence” of the Zika virus.


da Silva IRF, Frontera JA, Bispo de Filippis AM, Nascimento OJMD; RIO-GBS-ZIKV Research Group. Neurologic complications associated with the Zika virus in Brazilian adults [published online August 14, 2017]. JAMA Neurol. doi:10.1001/jamaneurol.2017.1703