Case Report: A Fatal Neuroinvasive West Nile Virus Infection in a Traveler Returning from Madagascar

Abstract :

A 58-year-old woman living in Reunion Island and returning from Madagascar was hospitalized forneuroinvasive encephalitis and died 1 month later. West Nile virus (WNV) infection was biologically confirmed by detection of immunoglobulin M (IgM) reactive with WNV antigens in both cerebrospinal fluid and serum, and weakneutralizing activity was also detected. A veterinary survey performed in her traveling area showed a seroprevalence ofWNV of 28.7% (95% confidence interval [CI] = 21.1–36.3) in adult poultry, confirming an active circulation of the virus.Development of a severe form could be related to a weak antibody response, because the patient presented low IgM andIgG titers. This case report underlines the constant risk of emergence of West Nile in Indian Ocean territories, includingReunion Island where competent vectors are widely present during the whole year.

A 58-year-old woman living in Reunion Island and returning from Madagascar was hospitalized forneuroinvasive encephalitis and died 1 month later. West Nile virus (WNV) infection was biologically confirmed bydetection of immunoglobulin M (IgM) reactive with WNV antigens in both cerebrospinal fluid and serum, and weakneutralizing activity was also detected. A veterinary survey performed in her traveling area showed a seroprevalence ofWNV of 28.7% (95% confidence interval [CI] = 21.1–36.3) in adult poultry, confirming an active circulation of the virus.Development of a severe form could be related to a weak antibody response, because the patient presented low IgM andIgG titers. This case report underlines the constant risk of emergence of West Nile in Indian Ocean territories, includingReunion Island where competent vectors are widely present during the whole year.