Zika Virus Associated With High Risk for Neurologic Complications in Adults

Viral encephalitis illustration
Viral encephalitis illustration
Rates of neurologic complications increased in the months after the Zika virus outbreak in Brazil.

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.

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.

Related Articles

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