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Zika linked to a spectrum of neuroinflammatory diseases

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Understanding Zika-induced neurological diseases

The 2015 Zika outbreaks in the Americas were notable for the recognition that Zika virus could be associated with neurological conditions. It was found that the overall risk of congenital neurologic abnormalities in fetuses and liveborn children of mothers enrolled in the Centers for Disease Control and Prevention’s Zika Pregnancy Registry with definite laboratory evidence of Zika virus infection during pregnancy was approximately 17 times higher than the expected baseline rate in uninfected mothers. It wasn’t until later, however, that GBS became the first non–pregnancy-related neurological syndrome to be associate with Zika in adults.

It is critically important to understand both the spectrum and frequency of Zika virus–induced neurologic diseases. The article by Dr. da Silva and colleagues in this issue of JAMA Neurology represents an initial approach to this problem. During the reporting period, they found that 93% of the patients with GBS (27 of 29), 71% of the patients with encephalitis (5 of 7), 67% of the patients with transverse myelitis (2 of 3), and the single patient with chronic inflammatory demyelinating polyneuropathy showed evidence of recent Zika virus infection, indicating a link between neurological syndromes and Zika.

However, it should be noted that, because of factors including referral bias, a study such as this cannot determine exact frequencies of Zika virus infection among patients with the syndromes examined, but it may serve to help confirm that Zika can be associated with such syndromes.

Kenneth L. Tyler, MD, is the Louise Baum Endowed Professor and Chair of the department of neurology at the University of Colorado at Denver, Aurora. Karen L. Roos, MD, is the John and Nancy Professor of Neurology at the University of Indiana, Indianapolis. They published these comments in an editorial accompanying the da Silva et al. article in JAMA Neurology (2017 Aug 14. doi: 10.1001/jamaneurol.2017.1471). Neither author reported any financial disclosures.



New evidence in support of a link between Zika virus infection and an increase in the incidence of neurological syndromes in adults has come from a prospective, observational study that demonstrates the presence of the infection in both serum and cerebrospinal fluid of patients with new-onset acute neuroinflammatory disease.

In the study cohort, 29 patients were diagnosed with GBS, 7 with encephalitis, 3 with transverse myelitis, and 1 with chronic inflammatory demyelinating polyneuropathy. These numbers indicate a fourfold increase in neurological syndrome diagnoses in adults, compared with a similar time frame during 2013-2014, before the Zika outbreak in Brazil, the investigators wrote.

Overall, it appears that Zika virus is associated with the trend for the rapid increase in hospital admissions for certain neurological syndromes, Dr. da Silva and his coauthors said. In addition, “we believe that our method of matching CSF and blood serologic findings offers a substantial aid to minimize [costs and] cross-reactivity in countries with a high prevalence of other concurrent flavivirosis.”

The study cohort was enrolled at a tertiary care, academic hospital in Rio de Janeiro. The median age was 44, and 15 were women. The study was limited by selection of neurological syndromes that have previously been associated with other flaviviruses, the short study period, and the use of patients from only one hospital.

Dr. da Silva reported no financial disclosures. One author reported receiving grants from Conselho Nacional de Desenvolvimento e Pesquisa and Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro. Other study authors reported no financial disclosures.

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