Chikungunya virus-associated encephalitis: A cohort study on La Réunion Island, 2005-2009

Neurology. 2016 Jan 5;86(1):94-102. doi: 10.1212/WNL.0000000000002234. Epub 2015 Nov 25.


Objective: To estimate the cumulative incidence rate (CIR) of Chikungunya virus (CHIKV)-associated CNS disease during the La Réunion outbreak, and assess the disease burden and patient outcome after 3 years.

Methods: CHIKV-associated CNS disease was characterized retrospectively in a cohort of patients with positive CHIKV reverse transcriptase PCR or anti-CHIKV immunoglobulin M antibodies in the CSF and fulfilling International Encephalitis Consortium criteria for encephalitis or encephalopathy. Neurologic sequelae were assessed after 3 years.

Results: Between September 2005 and June 2006, 57 patients were diagnosed with CHIKV-associated CNS disease, including 24 with CHIKV-associated encephalitis, the latter corresponding to a CIR of 8.6 per 100,000 persons. Patients with encephalitis were observed at both extremes of age categories. CIR per 100,000 persons were 187 and 37 in patients below 1 year and over 65 years, respectively, both far superior to those of cumulated causes of encephalitis in the United States in these age categories. The case-fatality rate of CHIKV-associated encephalitis was 16.6% and the proportion of children discharged with persistent disabilities estimated between 30% and 45%. Beyond the neonatal period, the clinical presentation and outcomes were less severe in infants than in adults.

Conclusions: In the context of a large outbreak, CHIKV is a significant cause of CNS disease. As with other etiologies, CHIKV-associated encephalitis case distribution by age follows a U-shaped parabolic curve.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Chikungunya Fever / diagnosis*
  • Chikungunya Fever / epidemiology*
  • Chikungunya virus*
  • Cohort Studies
  • Encephalitis / diagnosis*
  • Encephalitis / epidemiology*
  • Female
  • Follow-Up Studies
  • Humans
  • Infant
  • Infant, Newborn
  • Male
  • Middle Aged
  • Prospective Studies
  • Retrospective Studies
  • Reunion / epidemiology