Clinical features in children hospitalized during the 2005 epidemic of Japanese encephalitis in Uttar Pradesh, India.

Background: Japanese encephalitis is a disease that affects the rural poor in Asia. In August-September 2005, a severe epidemic of Japanese encephalitis occurred in Uttar Pradesh, one of India's poorest states.
Methods: Children admitted to the King George Medical University hospital (Lucknow, Uttar Pradesh, India) with acute febrile encephalopathy (defined as fever plus encephalopathy of <or=2 weeks' duration) from July to October 2005 underwent ELISA for Japanese encephalitis virus immunoglobulin M in cerebrospinal fluid or serum on hospital admission. Clinicolaboratory features of patients with positive test results were recorded.Results. Of the 223 children tested, 77 had positive results for Japanese encephalitis immunoglobulin M. Patients were from 18 districts of Uttar Pradesh. All but 1 were from rural areas, and none were <2 years of age. The prodromal period was very short (mean+/-standard deviation, 2.61+/-2.23 days). Convulsions were present in 76 patients (98.7%). The mean (+/- standard deviation) Glasgow Coma Scale score was 7.4+/-2.7. Generalized hypertonia was found in 39 patients (50.6%), and focal deficits were found in 35 patients (45.4%), including 19 cases of monoparesis and 16 cases of hemiparesis. Gastric hemorrhage was found in 42 patients (54.5%). Extrapyramidal features were found in 24 (31.1%), a hyperepneic breathing pattern was found in 20 (26%), and thrombocytopenia was found in 5 (15.6%) of 32 patients. The mean cerebrospinal fluid cell count was 48.3 cells/mm(3). The serum bilirubin level was normal in all patients, but the aspartate aminotransferase level was elevated in all 21 patients (100%) tested and the alanine aminotranferase level was elevated in 25 (47.2%) of 53 patients. In-hospital mortality was 34%.
Conclusions: Clinical features of Japanese encephalitis were severe. Derangements in liver function and thrombocytopenia were found in a significant proportion of patients. These findings were not highlighted during earlier epidemics of the illness and could suggest a possible mutation of the virus towards other flaviviruses.