A 2.5-year-old girl died suddenly during the course of rotavirus gastroenteritis. The autopsy showed encephalopathy with rotavirus systemic infection. Here, we provide evidence of rotavirus replication in multiple organs. Our findings clarify that rotavirus infection in children can extend beyond the intestinal tract through viremia. CASE REPORTA previously healthy 2.5-year-old girl presented to our hospital following two febrile seizures. She had a 2-day history of diarrhea due to rotavirus gastroenteritis, which had been diagnosed before admission by a positive rotavirus antigen test of her stool. The seizures were generalized tonic-clonic seizures lasting 1 to 5 min each and occurred within 5 h of each other.On examination, she was alert with a temperature of 39.3°C. Examination showed normal pupillary light reflexes, normal muscle tone, and normal patellar and Achilles tendon reflexes. The heart and lung sounds were also normal.Laboratory analysis of blood obtained while in the emergency room showed the following: white blood cell count, 23,800/l (97% neutrophils); hemoglobin, 11.9 g/dl; platelet count, 366,000/l; erythrocyte sedimentation rate, 11 mm/h; C-reactive protein, 0.79 mg/dl; blood sugar, 121 mg/dl; serum ammonia, 22 mg/dl; sodium, 131 meq/liter; potassium, 4.1 meq/ liter; chloride, 99 meq/liter; aspartate aminotransferase (AST), 50 IU/liter; alanine aminotransferase (ALT), 32 IU/liter; lactate dehydrogenase, 317 IU/liter; and creatinine phosphokinase, 420 IU/liter. Immune function testing revealed a low IgG level, at 384 mg/dl (normal range for age 2 years, 649 to 1,306 mg/dl) but normal IgG subclass analysis. the IgA level was 31 mg/dl, and the IgM level was 74 mg/dl. Coagulation tests were not performed. A blood culture yielded no bacterial growth.An hour after arrival at the hospital, the patient experienced two more seizures. The fourth and final seizure developed into status epilepticus and was treated with intravenous diazepam. As the seizure gradually ended, the electrocardiogram monitor showed a brief period of ventricular fibrillation followed by asystole. Immediate resuscitation attempts were unsuccessful.An autopsy was undertaken 12 h after the patient died. Cardiac tissues were submitted to the National Cardiovascular Center (Japan) for pathological analysis.Analysis of the cerebrospinal fluid (CSF) obtained at autopsy revealed a leukocyte level of 240/mm 3 and a protein level of 288 mg/dl. Rotavirus RNA was detected in the CSF by reverse transcription-PCR (RT-PCR). Serum diluted 1:16 showed a positive enzyme-linked immunosorbent assay (ELISA) reaction using an anti-VP6 mouse monoclonal antibody (YO-156) to detect antigenemia (12). The optical density at 492 nm obtained with the patient's serum was 0.932, compared with 0.035 for the negative control.The autopsy revealed brain edema but no cerebral herniation. Although there was focal inflammatory cell infiltration in parts of the subarachnoid space, this was not indicative of encephalitis or meningitis. There was concentric cardiac hyp...