To evaluate the prevalence of enteric viruses and their possible association with diarrhea, 244 stool samples were collected from HIV-infected and uninfected patients with or without diarrhea (subgroups I-a, Ib, II-a, and II-b, respectively). Subjects were screened by polyacrylamide gel electrophoresis, latex agglutination, and enzyme immunoassays for rotaviruses, adenoviruses, picobirnaviruses, and astroviruses. Enteric viruses were found significantly more often in specimens from HIV patients (20%) than in specimens from uninfected HIV patients (0%) (p < 0.05). Picobirnavirus was detected in 14.63% of 82 HIV-infected patients with diarrhea, but it was detected neither in those without diarrhea (0%) (p < 0.05) nor in the groups of uninfected HIV subjects (0%) (p < 0.05). Nor could astrovirus (subgroups I-a [4.00%] versus subgroup I-b [5.26%],p > 0.05) or enteric adenovirus (subgroup I-a [1.22%] versus subgroup I-b [0%], p > 0.05) be linked to the diarrhea disorder in HIV-infected patients. Rotaviruses were not detected in any of the clinical subgroups studied. Enteric viruses were detected in 15 of 93 (16.13%) of the HIV-infected patients with CD4+ T cell count <200/microl and 3 of 19 (15.79%) of those HIV-infected individuals with a CD4+ T cell count 200-499/microl, showing no significant difference (p > 0.05). According to our data, unusual enteric viruses such as picobirnavirus, astrovirus, and enteric adenovirus occur in HIV-infected population in Córdoba, Argentina. However, only picobirnaviruses could be significantly associated with diarrhea in these patients.

Objectives: This study was carried out in order to evaluate the efficacy of the recently developed picobirnavirus (PBV) sets of primers and to establish the phylogenetic relationships of Argentine strains with PBV strains isolated in China and the USA. Methods: Thirteen fecal specimens tested as positive for PBV by polyacrylamide gel electrophoresis were analyzed by reverse transcription-polymerase chain reaction assays using primers target to the genomic segments 2 of PBV strains isolated in China and the USA. The amplicons were sequenced and analyzed. Results: Primers derived from the China strain produced amplicons in only 4 of the 13 specimens (30.76%). No sample was revealed as positive with the primers derived from the US strain. DNA sequencing of polymerase chain reaction products differed in nucleic acid and amino acid sequences by 13.9–42.28% and 18.1–51.1%, respectively. Despite this strain diversity, three domains of conserved nucleotide sequences as well as the amino acid motif D-S-D typical of RNA-dependent RNA polymerase gene of double-strand RNA viruses were identified. Comparatively, these conserved regions were also identified in homologous PBV strains from the USA and China. Phylogenetic analysis showed no time or geographic clustering. Conclusions: These findings provide evidence that PBV may represent an emerging heterogeneous group of viruses.

Diarrhea due to enteric pathogens is an important complication of advanced HIV infection. Picobirnaviruses are agents recently linked with human enteritis. In total, 197 fecal samples collected from HIV-infected and noninfected patients with and without diarrhea were investigated for the presence of rotavirus and picobirnavirus by polyacrylamide gel electrophoresis. Picobirnavirus was detected in 8.8% of 57 HIV-infected patients with diarrhea, but it was detected in neither those without diarrhea (p<.018) nor in the group of subjects uninfected with HIV (p<.022). All genomic electropherotypes of picobirnavirus strains had a wide pattern. Picobirnavirus genome segments varied in size between 2.4 and 2.7 and 1.6 and 1.9 kbp for the slow and fast migrating bands, respectively. Rotaviruses were not detected in any of the clinical groups studied. Two methods for the extraction of nucleic acid-phenol/chloroform and guanidinium thiocynate (GTC)/silica-were compared. Detection of picobirnavirus by polyacrylamide gel electrophoresis was 2.5 times more sensitive following guanidinium thiocynate RNA extraction. This investigation offers preliminary results about the circulation of picobirnavirus in HIV-infected patients in Córdoba, Argentina.

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