Detection of caliciviruses associated with acute infantile gastroenteritis in Salvador, an urban center in Northeast Brazil

Acute gastroenteritis caused by viruses is one of the leading causes of infantile morbidity. The aim of the present study was to investigate the presence of human caliciviruses of the genera norovirus and sapovirus in children up to 3 years of age with acute gastroenteritis from low-income communities in the city of Salvador, Brazil. This study is an extension of previous work carried out to establish the profile of the most prevalent enteric pathogens present in these communities. In this report, 139 fecal samples, collected from July 2001 to January 2002 were analyzed by RT-PCR and 13 (9 percent) were positive for human caliciviruses. By sequencing, seven isolates were characterized as norovirus genogroup GII and one as sapovirus genotype GII/1. Sequencing of the previously detected group-A rotaviruses and human astroviruses was also performed and revealed the circulation of rotavirus group A genotypes G1P[8] and G9P[8], and human astrovirus genotypes 6, 7, and 8. No mixed infection was observed. Community-based studies provide geographically representative information on disease burden. However, there are only a few reports in developing countries concerning the genotypes of the most important gastroenteric viruses detected in such communities. The present findings demonstrate the wide diversity of genotypes of the most important viruses responsible for acute gastroenteritis circulating in low-income communities.

Reverse transcription-polymerase chain reaction assay for rabies virus detection

Este estudo teve por objetivo implantar um protocolo de amplificação genômica, precedida de transcrição reversa (RT-PCR) para o gene da nucleoproteína do vírus da raiva, para a utilização dessa metodologia em laboratórios onde são realizadas investigações para a detecção do vírus rábico. Foram utilizadas 50 amostras de tecido encefálico de animais (44 bovinos, 5 eqüinos e 1 quiróptero) oriundos do Estado do Rio de Janeiro, positivos por imunofluorescência direta e/ou prova biológica para o vírus rábico. A extração do RNA foi feita a partir da suspensão a 10 por cento em PBS pH7,2 do tecido encefálico utilizando-se a metodologia de TRIzolTM (Life Technologies) e o protocolo de RT-PCR descrito por Heaton et al. (1997), incluindo algumas modificações. Dentre as 50 amostras analisadas, 50 foram positivas pela prova biológica e pela RT-PCR e destas, 49 foram positivas pela imunofluorescência direta. Estes resultados demonstram ser este protocolo de RT-PCR uma metodologia sensível, específica, rápida e extremamente valiosa, podendo ser utilizada como rotina em laboratórios que trabalham no diagnóstico de vírus rábico.

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 per cent 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 Brasília, 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 per cent) 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.