Temporal Association Between Dengue Outbreaks and Neurologic Autoimmune Diseases in French Guiana.

BACKGROUND AND OBJECTIVES: Recent decades have witnessed the emergence of arbovirus infections, such as dengue, chikungunya, and Zika viruses, which are responsible for neurologic complications such as Guillain-Barré syndrome (GBS). To date, it has mainly been demonstrated that these neurologic complications occur concomitantly with infectious processes. We hypothesized that arbovirus infections may also influence the incidence of autoimmune diseases of the central or peripheral nervous system. METHODS: This was a retrospective, observational, single-center study conducted between January 2002 and January 2024 at the Cayenne Hospital in French Guiana including patients with autoimmune encephalitis, neuromyelitis optica spectrum disorders (NMOSDs), GBS, chronic inflammatory demyelinating polyneuropathy, and myasthenia gravis (MG). This series was compared with the incidence of arbovirus infections recorded by the French Public Health Agency during the same period. RESULTS: We observed a significant correlation between dengue infection and the incidence of NMOSD (Spearman rho = 0.88 [p = 0.03]) and MG (Spearman rho = 0.82 [p = 0.048]). GBS was significantly associated with chikungunya (Spearman rho = 0.97 [p = 0.01]), but not with other arbovirus infections. In addition, the mean estimated incidence of NMOSD was high at 5.08 (95% CI 3.03-7.13) per million person-year, approaching the world's highest incidence observed in the French West Indies. DISCUSSION: This study reports the epidemiology of neurologic autoimmune diseases in French Guiana. We found a high incidence of NMOSD, like that reported in the French West Indies. Multicenter studies involving countries in the tropical zone are needed to better elucidate the relationship between dengue outbreak and NMOSD and MG.