Genetic variability of hepatitis A virus strain HAF-203 isolated in Brazil and expression of the VP1 gene in Escherichia coli

The hepatitis A virus (HAV) HAF-203 strain was isolated from an acute case of HAV infection. The primary isolation of HAF-203 in Brazil and its adaptation to the FRhK-4 cell lineage allowed the production of large amounts of viral particles enabling molecular characterization of the first HAV isolate in Brazil. The aim of our study was to determine the nucleotide sequence of the HAF-203 strain genome, compare it to other HAV genomes and highlight its genetic variability. The complete nucleotide sequence of the HAF-203 strain (7472 nucleotides) was compared to those obtained earlier by others for other HAV isolates. These analyses revealed 19 HAF-specific nucleotide sequence differences with 10 amino acid substitutions. Most of the non-conservative changes were located at VP1, 2C, and 3D genes, but the 3B region was the most variable. The availability of HAF-203 complementary DNA was useful for the production of the recombinant VP1 protein, which is a major determinant of viral infectivity. This recombinant protein was shown by enzyme-linked immunoassay and blotting, to be immunogenic and resemble the native protein, therefore suggesting its value as a reagent for incorporation into diagnostic tests.

Early infection and asymptomatic spread of hepatitis A virus in a public child care center in Rio de Janeiro, Brazil: should attending children under two years of age be vaccinated?

A cross-sectional study was conducted in order to identify hepatitis A virus (HAV) serological markers in 418 individuals (mean age, 16.4 years; range, 1 month-80 years) at a public child care center in Rio de Janeiro, Brazil, as well as to analyze risk factors and determine circulating genotypes. Serum samples were tested using an enzyme immunoassay. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect and characterize HAV RNA, and sequencing was performed. Anti-HAV antibodies and IgM anti-HAV antibodies were detected, respectively, in 89.5 percent (374/418) and 10.5 percent (44/418) of the individuals tested. Acute HAV infection in children was independently correlated with crawling (p < 0.05). In 56.8 percent (25/44) of the IgM anti-HAV-positive individuals and in 33.3 percent (5/15) of the IgM anti-HAV-negative individuals presenting clinical symptoms, HAV RNA was detected. Phylogenetic analysis revealed co-circulation of subgenotypes IA and IB in 93.3 percent (28/30) of the amplified samples. In present study, we verify that 79 percent (30/38) of children IgM anti-HAV-positive were asymptomatic. In child care centers, this asymptomatic spread is a more serious problem, promoting the infection of young children, who rarely show signs of infection. Therefore, vaccinating children below the age of two might prevent the asymptomatic spread of hepatitis A.

Epidemiological pattern and mortality rates for hepatitis A in Brazil, 1980-2002: a review

The prevalence of hepatitis A virus (HAV) infection is high in developing countries, in which low standards of sanitation promote the transmission of the virus. In Latin America, which is considered an area of high HAV endemicity, most HAV-positive individuals are infected in early childhood. However, recent studies have shown that prevalence rates are decreasing. Herein, we review the data on HAV prevalence and outbreaks available in scientific databases. We also use official government data in order to evaluate mortality rates in Brazil over the last two decades. Studies conducted in the northernmost regions of Brazil have indicated that, although improved hygiene has led to a reduction in childhood exposure to HAV, the greatest exposure still occurs early in life. In the Southeastern region, the persistence of circulating HAV has generated outbreaks among individuals of low socioeconomic status, despite adequate sanitation. Nationwide, hepatitis A mortality rates declined progressively from 1980 to 2002. During that period, mortality rates in the Northern region consistently exceeded the mean national rate and those for other regions. Excluding the North, the rates in all regions were comparable. Nevertheless, the trend toward decline observed in the South was paralleled by a similar trend in the North.

Detection of hepatitis A, B, and C virus-specific antibodies using oral fluid for epidemiological studies

In this report, we examine the adaptability of commercially available serological kits to detect antibodies markers for viral hepatitis in oral fluid samples. We also assessed the prevalence of hepatitis A, B, and C virus-specific antibodies, and related risk factors for these infectious diseases through sensitivity of the tests in saliva samples to evaluate if oral fluid can be an alternative tool to substitute serum in diagnosis of acute viral hepatitis and in epidemiological studies. One hundred and ten paired serum and saliva specimens from suspect patients of having acute hepatitis were collected to detect antibodies to hepatitis A (total and IgM), hepatitis B (anti-HBs, total anti-HBc and IgM anti-HBc), and hepatitis C (anti-HCV) using commercially available enzyme-linked immunossorbent assay (EIA). In relation to serum samples, oral fluid assay sensitivity and specificity were as follows: 87 and 100 percent for total anti-HAV, 79 and 100 percent for anti-HAV IgM, 6 and 95 percent for anti-HBs, 13 and 100 percent for total anti-HBc, 100 and 100 percent for anti-HBc IgM, and 75 and 100 percent for anti-HCV. The consistency observed between antibodies tests in saliva and expected risk factors for hepatitis A and C suggests that the saliva method could replace serum in epidemiological studies for hepatitis A and C.

Hepatitis E virus antibodies in swine herds of Mato Grosso state, Central Brazil

A infeccão pelo vírus da hepatite E (VHE) ainda não foi detectada entre suínos na região central do Brasil. Com o intuito de avaliar se o VHE circula entre suínos no estado de Mato Grosso, um estudo de soroprevalência foi realizado em suínos de 17 propriedades rurais, correspondentes a 13 municípios. Os animais foram escolhidos aleatoriamente em lotes no momento da chegada para abate em dois frigoríficos entre dezembro de 2002 e fevereiro de 2003. Amostras de soro foram coletadas e testadas para a presenca de anticorpos de classe IgG contra o VHE (anti-VHE) por ensaio imuno-enzimático (EIE). Este EIE foi executado utilizando-se duas proteínas recombinantes como antígenos. Uma proteína mosaico (MP-II) e outra proteína contendo a região dos aminoácidos 452 a 617 da ORF2 da cepa Burma do VHE. 211 dos 260 animais examinados eram anti-VHE reativos. A soropositividade não variou com gênero e idade, mas variou entre 15% a 100% de uma propriedade para outra. Nossos resultados apontaram que o VHE parece circular entre suínos do estado de Mato Grosso, sugerindo que o vírus encontra-se disseminado na região, como verificado em outros países ao redor do mundo.

Serological evidence of hepatitis E virus infection in different animal species from the Southeast of Brazil

Serological evidence of hepatitis E virus infection (HEV) has been observed in both humans and different animal species living in non-endemic areas, suggesting that animals could be important reservoir for virus transmission to man. Antibodies to HEV have been detected in some Brazilian population groups. Nevertheless, sporadic cases of acute HEV infection have never been reported. We collected 271 serum samples from several domestic animals and also from pig handlers from Southeast of Brazil in order to investigate the seroprevalence of HEV infection. Anti-HEV IgG was detected in cows (1.42 percent), dogs (6.97 percent), chickens (20 percent), swines (24.3 percent), and rodents (50 percent), as well as in pig handlers (6.3 percent). The recognition of swine HEV infections in pigs in many countries of the world led us to investigate a larger sample of pigs (n = 357) from the same Brazilian region with ages ranging from 1 to > 25 weeks. IgG anti-HEV was detected in 100 percent of 7-day old pigs. Following a gradual decline between weeks 2 and 8 (probably due to loss of maternal IgG), the prevalence then steady increased until it reached 97.3 percent of animals older than 25 weeks. Besides the detection of anti-HEV antibodies in different animal species, the results showed that swine HEV infection seems to be almost universal within this Brazilian pig population. This is the first report that shows evidences of HEV circulation in Brazilian animal species and pig handlers.

Ocorrência de hepatites näo-A näo-B em unidade de hemodiálise / Occurrence of non-A non-B hepatitis in hemodyalisis unit

A monitorizaçäo mensal de alanina aminotransferase (ALT) sérica de pacientes em hemodiálise e os testes sorológicos para exclusöes de infecçöes por vírus da hepatite A (HAV), vírus da hepatie B (HBV), citomegalovirus (CMV) e vírus Epstein-Barr (EBV), permitiu-nos identificar 11 casos de hepatites näo-B em 111 indivíduos avaliados durante o período de 12 meses e acompanhados por 2 anos. Foram observados 3 padröes de atividade de ALT: elevaçäo em pico monofásico em 2, bifásico ou polifásico em 6 e em platô em 3 pacientes. Individuos com padräo monofásico exibiram os níveis amis elevados de ALT. Cinco pacientes apresentaram normalizaçäo bioquímica persistente 4,8 meses em média após o início da elevaçäo aguda e seis evoluíram com ascensäo crônica de ALT durante o período de estudo. A hepatite näo-A, näo-B foi, predominantemente, assintomática e anictérica, sempre antecedida por transfusöes sangüíneas e com maior incidência nos seis primeiros meses de terapia dialítica dos pacientes