Human group C rotavirus in children with diarrhea in the Federal District, Brazil

Group C rotaviruses are fastidious in their in vitro cell culture requirements. Recent serosurveys indicate that antibody to group C rotavirus is present in 3-45% of the human population in certain geographic locations, suggesting that rotavirus group C infection is more prevalent than previously believed and that the low rate of detection of these agents is probably due to the lack of sensitive diagnostic assays. From March to December 1994, 406 fecal specimens were collected from children under five years of age who were outpatients at the emergency services of nine public hospitals in Brasilia, Federal District, Brazil. In addition to the samples from children, one public outpatient unit requested virological investigation of a stool sample from an HIV-seropositive adult male with diarrhea of sudden onset. All samples were analyzed by enzyme immunoassay for group A rotavirus and adenovirus (EIARA) and by polyacrylamide gel electrophoresis (PAGE). One hundred and seven (26%) were positive for group A rotavirus. Four samples from children and the sample from the HIV-seropositive patient, although negative by EIARA, showed a group C rotavirus profile by PAGE and were positive for rotavirus by electron microscopy. Using specific VP6 and VP7 primers for group C rotavirus, a reverse transcriptase-polymerase chain reaction (RT-PCR) was performed and products were detected by agarose gel electrophoresis and ethidium bromide staining. These products were confirmed to be specific for group C rotavirus by using digoxigenin-oligonucleotide probes, Southern hybridization and chemiluminescent detection. The five positive group C rotavirus samples were detected in August (3 samples) and September (2 samples). To the best of our knowledge, this is the first report of group C rotavirus detected in the Federal District, Brazil and in an HIV-seropositive patient with acute gastroenteritis.