During the study period, 2,609 patients met the clinical case definition of acute encephalitis, had indication for lumbar puncture, and were included on the line list (). Among the line listed cases, 808 (31%) were from Dhaka, 878 (34%) were from Mymensingh, 768 (29%) were from Rajshahi, and 155 (6%) were from Sylhet.
A total of 1,112 patients from the line listing were assessed for pleocytosis. Of these, 492 (44%) patients had pleocytosis, were enrolled, and had samples tested for JEV (). Twenty (4%) of the 492 patients evaluated had laboratory evidence of recent JEV infection.
Cases of JE were identified in 3 (2%) of 131 of study patients in Dhaka, 4 (3%) of 156 study patients in Mymensingh, 11 (6%) of 173 study patients in Rajshahi, and 2 (6%) of 32 study patients in Sylhet.
Overall, the median age of JE cases was 18 years (range = 1.5 months–55 years). Cases were identified among all age groups with 11 (55%) cases greater than 15 years of age (). Eleven (55%) cases were males. All cases lived in rural areas and 12 (61%) resided in the northwestern part of the country (). None of the cases traveled outside Bangladesh within the month before illness. Eighteen (90%) of the cases occurred during May–October, and no cases were identified during January–April (). Fourteen (70%) JE cases were identified in the first year, and six (30%) JE cases were identified in the second year (). In the first year, 14 (5%) of 285 encephalitis patients were diagnosed with JE. In the second year, 6 (3%) of 207 encephalitis patients were positive for JEV.
Demographic characteristics of 20 cases of Japanese encephalitis, Bangladesh
Number of Japanese encephalitis cases, by month of symptom onset, Bangladesh, June 2003–July 2005.
Patients with JE had fever (100%), altered consciousness (100%), convulsion (85%), headache (79%), severe weakness or lethargy (57%), stiff neck (55%), and vomiting (35%) (). The median (range) of their Glasgow coma scores was 8 (4–15), and 11 (55%) patients had a Glasgow coma score ≤ 7 during clinical evaluation at the time of recruitment. Six (30%) patients left the hospital with neurological sequelae that included focal weakness (n = 4) and paralysis (n = 1).
Clinical features of 20 cases of Japanese encephalitis, Bangladesh
Fifteen patients, including five of the six patients who had residual neurological findings upon hospital discharge, were evaluated 4–6 weeks after recruitment. At that time, five (33%) patients had residual neurological problems (e.g., dysarthria, limb weakness, hearing impairment, and urinary incontinence). Seven (47%) reported difficulties with thinking/reasoning skills (). Two patients died; one at the hospital and one at home.
Follow-up of 15 cases of Japanese encephalitis 4–6 weeks after enrollment in the study, Bangladesh
The mean CSF leukocyte count 109 cells/mm3 (range = 7–980 cells/mm3) with a predominance of lymphocytes (mean = 75%, range = 30–100%). The CSF glucose concentrations ranged from 46 to 191 mg/dL (mean = 66 mg/dL); CSF protein levels were generally mildly elevated (mean = 58 mg/dL, range = 24–102 mg/dL).