Briefing Note: West Nile virus disease Brazil - 20 September 2023

The Health Secretary of the State of Tocantins confirmed on 10 May 2023, the first case of West Nile virus disease in a resident of Caseara municipality, Tocantins State, Brazil. The case is a 16-year-old male with onset of symptoms on 1 April 2023; he resides in a rural area of the municipality of Caseara, Tocantins. The patient presented with acute viral encephalitis as well as symptoms of fever, headache, seizure, and odynophagia. The case has been discharged with severe sequelae. Serum and cerebrospinal fluid (SCF) samples were collected and tested by the Evandro Chagas Institute. The RT-PCR analysis of the collected SCF was positive for West Nile fever (WNF).