Patient Information
A 37-year-old man presented to a health center in N’Djamena, Chad, with acute onset of occipital headaches, vomiting, and generalized asthenia. The patient had recently traveled from France to Chad and spent approximately three months in the country, primarily in the N’Djamena area with brief stays in Ouaddaï (Abéché) and Borkou (Faya-Largeau) regions. Initial clinical examination revealed fever and photophobia without evidence of neck stiffness. No prior relevant medical history was reported.
Diagnosis
The patient was initially evaluated in Chad, but was repatriated to France for further management 5 days after symptom onset and admitted to a neurology ward. Over the next two days, he developed confusion and convulsions necessitating transfer to the intensive care unit (ICU).
Metatranscriptomic sequencing of cerebrospinal fluid (CSF) obtained on day 9 post-symptom onset identified viral sequences closely related to Lassa virus (genus Mammarenavirus). The sequences covered the entire small (S) segment and nearly all (98%) of the large (L) segment of the viral genome, showing 77.3% homology with Lassa virus S segment and 75.0% with L segment sequences. Reverse-transcriptase polymerase chain reaction (RT-PCR) targeting Old World mammarenavirus consensus sequences confirmed viral RNA presence in CSF obtained on days 6 and 8, but no viral RNA was detected in plasma or urine samples at later time points.
