Japanese Encephalitis Presenting Without Cerebrospinal Fluid Pleocytosis

Etiological identification of viral agents in acute encephalitis in Guadalajara, México, 2011-2015

Introduction: Viral encephalitis is a well-known inflammatory process associated with neurological dysfunction that might derive into severe brain damage or a fatal outcome. In México there is no epidemiological data that describes the prevalence of viral agents responsible for acute encephalitis. Objective: To identify the main viral agents by real time PCR involved in acute encephalitis in Mexico. Materials and methods: We obtained cerebral spinal fluid (CSF) samples from all patients with suspected viral encephalitis admitted to the emergency service of the Hospital Civil de Guadalajara “Fray Antonio Alcalde”. To identify pathogens, we performed nucleic acid extraction using real-time PCR and RT-PCR. Results: Sixty-six patients were diagnosed with acute encephalitis from 2011 to 2014. A definitive viral etiological diagnosis was established in 16 patients (24%); the main causative agents were enteroviruses in 50% of the 16 positive samples, followed by herpes simplex virus (37%) and cytomegaloviruses (12.5%). Patients with encephalitis were predominantly male (63.3%) and a seasonal predominance was observed during autumn (37.5%). The main clinical characteristics in the acute encephalitis phase were fever (48.45) and cephalea (36.3), followed by seizures, disorientation, and muscular weakness (30.3%). Kerning sign was present in two cases (3%) and other two cases presented Brudzinski’s sign (3%). Conclusions: CSF PCR is a suitable diagnostic technique for the identification of viral encephalitis caused by viral infections that allows an appropriate antiviral therapeutic treatment.