Risk factors and prevalence of antibodies against hepatitis A virus (HAV) in children from day-care centers, in Goiania, Brazil

A seroepidemiologic survey about hepatitis A virus (HAV) infection was carried out in a group comprising 310 children, ranging in age from 3 months to 9 years, from day-care centers, in Goiania, a middle sized city in the central region of Brazil. The biomarkers employed in the investigation of previous infection include total IgG and IgM anti-HAV antibodies, and for the detection of more recent infection, IgM anti-HAV antibodies were analyzed. The study was performed in 1991 and 1992. According to the results, 69.7% of the children presented total IgG/IgM anti-HAV antibodies, with 60% of the group in the age range of 1 to 3 years. Among 10 day-care centers analyzed, the prevalence of the biomarker IgM anti-HAV was 3.2%, with an uniform distribution of the cases in the group of children ranging in age from 1 to 4 years. Multi-variate analysis was performed to investigate the sociodemographic factors that could influence the results. It was verified that the risk for the infection increased with the length of the attendance in the day-care centers, i.e., the risk for children with attendance of one year or more was 4.7 times higher, when compared with children with one month attendance (CI 95% 2.3-9.9). According to the results, hepatitis A is an endemic infection in day-care centers in the study area. The length of attendance in the day-care settings was demonstrated to be a risk factor for the HAV infection. Such findings suggest that if hepatits A vaccination becomes available as a routine policy in our region, the target group should be children under one year. Moreover, those children should receive the vaccine before they start to attend the day-care centers.

Hepatitis A antibodies in two socioeconomically distinct populations of São Paulo, Brazil

To evaluate the prevalence of antibody against hepatitis A in two socioeconomically distinct populations of a developing country, 540 serum specimens from children and adults living in São Paulo, Brazil, were tested for IgG anti HAV by a commercial radioimunoassay (Havab, Abbott Laboratories). The prevalence of anti-HAV in low socioeconomic level subjects was 75.0% in children 2-11 years old and 100.0% in adults, whereas in middle socioeconomic level significantly lower prevalences were observed (40.3% in chidren 2-11 years old and 91.9% in adults). Voluntary blood donors of middle socioeconomic level showed a prevalence of 90.4%. These data suggest that hepatitis A infection remains a highly endemic disease in São Paulo, Brazil.

The presence of antibodies for hepatitis a virus in amazonia Didelphis marsupialis (Vertebrata, Marsupialia)

Anti-HAV was detected by enzyme - immunoassay in sera collected from 6 (18,75%) of 32 Didelphis marsupialis trapped in the Amazon region. No anti-HAV were found in the sera from 136 other wild animals, including small rodents, reptiles and other marsupials.

Seroepidemiology of hepatitis a and b in two urban communities of Rio de Janeiro, Brazil

Hepatitis B markers were determined in 397 individuals from Niterói and 680 from Nova Iguaçu and prevalences of 9.1% (1.0% of HBsAg and 8.1% of anti HBs) and 11.1% (1.8% of HBsAg and 9.3% of antiHBs) were found, respectively. The comparative prevalence of both markers in relation to age showed a higher prevalence of HBsAg in the group 21-50 years old. Considering the antiHBs antibody, it was demostrated a gradual increase with age, reaching 14.9% in Niterói and 29.1% in Nova Iguaçu in individuals over 51 years old. For hepatitis A, in 259 samples from Niterói, equally distributed by age groups, an overall prevalence of 74.5% of anti-HAV antibodies was found. This prevalence increases gradually reaching 90.0% at age over thirty. In 254 samples from Nova Iguaçu analysed, a prevalence of 90.5% of antibodies was encountered when the same criteria of distribution of samples were used. This level of prevalence reached 90.0% already in the age over ten years old. The tests were performed by enzyme immunoassay with reagents prepared in our laboratory.

Duality of patterns in hepatitis a epidemiology: A study involving two socioeconomically distinct populations in Campinas, São Paulo state, Brazil

To evaluate the prevalence of antibodies against hepatitis A in two socioeconomically distinct populations, 101 and 82 serum samples from high and low socioeconomic groups, respectively, were analysed for the presence of IgG anti-HAV using a commercial ELISA. The prevalence in low socioeconomic level subjects was 95.0%, whereas in high socioeconomic subjects was only 19.6% (p<0.001). These data show a duality in Brazil: anti-HAV prevalence in low socioeconomic subjects is similar to that of developing countries, while in high socioeconomic subjects, a pattern typical of developed countries is found. The control of this infection in our country is primarily related to the improvement of sanitation, but especially for high socioeconomic level populations, the use of vaccination against hepatitis A is strongly advisable to avoid the occasional appearance of this disease in adults.

Detection of hepatitis A antibodies by ELISA using saliva as clinical samples

The possibility of detecting acute infection and immunity using body fluids that are easier to collect than blood, mainly in children, would facilitate the investigation and follow-up of outbreaks of hepatitis A (HAV). Our study was carried out to evaluate the detection of anti-HAV IgM, IgA and total antibodies in saliva using serum samples as reference. Forty three paired serum and saliva samples were analyzed. From this total, 24 samples were obtained from children and 1 from one adult during the course of acute hepatitis A; an additional 18 samples were obtained from health professionals from Adolfo Lutz Institute. The sensitivity to detect anti-HAV IgM was 100% (95%CI: 79.1 to 100.0%), employing saliva as clinical samples. In detecting anti-HAV IgA, the sensitivity was 80.8% (95%CI: 60.0 to 92.7%) and for the total antibodies was 82.1% (95%CI: 62.4 to 93.2%). The specificity was 100% for each. The rate of agreement was high comparing the results of serum and saliva samples for detecting HAV antibodies. We conclude that saliva is an acceptable alternative specimen for diagnosing acute hepatitis A infection, and for screening individuals to receive hepatitis A vaccine or immunoglobulin.

Seasonal variation of hepatitis A virus infection in the city of Rio de Janeiro, Brazil

Hepatitis A virus (HAV) infection constitutes a major public health problem in Brazil. The transmission of HAV is primarily by fecal-oral route so the water is an important vehicle of HAV dissemination. There is a great incidence of acute cases of hepatitis A in some areas of Brazil however the seasonal variation of these cases was not documented. The aim of this study was to determine the seasonality of HAV infection in Rio de Janeiro. From January 1999 to December 2001, 1731 blood samples were collected at the National Reference Center for Hepatitis Viruses in Brazil (NRCHV). These samples were tested by a commercial enzyme-immunoassay to detect anti-HAV IgM antibodies. Yearly positive rates were 33.74% in 1999, 32.19% in 2000, and 30.63% in 2001. A seasonal variation was recognized with the highest incidence in spring and summer. Furthermore a seasonal increase in incidence of HAV infection was found during the rainy season (December to March) because the index of rains is very high. It is concluded that HAV infections occur all year round with a peak during hot seasons with great number of rains.

Anti-hepatitis A virus frequency in adolescents at an outpatient clinic in São Paulo, Brazil

The prevalence of hepatitis A virus (HAV) antibodies was assessed in adolescents (age ranging from 10.4 to 19.9 years) at an Adolescent Outpatient Clinic in São Paulo, Brazil. Anti-HAV was detected in 137 (54.2%) out of 253 individuals. When separated into two age groups, anti-HAV frequency was higher in the 15 to 19 year-old group (64%) in comparison to the 10 to 14 year-old group (46%) (Chi-square test: p = 0.004). These results suggest that adolescents in São Paulo are at risk of hepatitis A infection and are probably contracting HAV infection during this age period.

Seroprevalence for hepatitis E virus (HEV) infection among volunteer blood donors of the Regional Blood Bank of Londrina, State of Paraná , Brazil

A cross-sectional study was carried out among 996 volunteer blood donors enrolled from May 1999 to December 1999 to determine the seroprevalence of hepatitis E virus (HEV) infection among volunteer blood donors of the Regional Blood Bank of Londrina, State of Paraná, Brazil, and to evaluate whether the rate of seroprevalence of IgG anti-HEV antibodies is associated with sociodemographic variables and with seropositivity for hepatitis A virus (HAV) infection. All participants answered the questionnaire regarding the sociodemographic characterisitcs. Serum samples were tested for IgG antibodies to HEV (anti-HEV) by an enzyme linked immunoassay (ELISA). All serum samples positive for anti-HEV IgG and 237 serum samples negative for anti-HEV were also assayed for IgG anti-HAV antibodies by ELISA. Anti-HEV IgG was confirmed in 23/996 samples, resulting in a seroprevalence of 2.3% for HEV infection, similar to previous results obtained in developed countries. No significant association was found between the presence of anti-HEV IgG antibodies and the sociodemographic variables including gender, age, educational level, rural or urban areas, source of water, and sewer system (p > 0.05). Also, no association with seropositivity for anti-HAV IgG antibodies was observed (p > 0.05). Although this study revealed a low seroprevalence of HEV infection in the population evaluated, the results showed that this virus is circulating among the population from Londrina, South Brazil, and point out the need of further studies to define the clinical and epidemiological importance of HEV infection and to identify additional risk factors involved in the epidemiology and pathogenesis of this infection in this population.

SEROLOGICAL DETECTION OF HEPATITIS A VIRUS IN FREE-RANGING NEOTROPICAL PRIMATES (Sapajus spp., Alouatta caraya) FROM THE PARANÁ RIVER BASIN, BRAZIL

Nonhuman primates are considered as the natural hosts of Hepatitis A virus (HAV), as well as other pathogens, and can serve as natural sentinels to investigate epizootics and endemic diseases that are of public health importance. During this study, blood samples were collected from 112 Neotropical primates (NTPs) (Sapajus nigritus and S. cay, n = 75; Alouatta caraya, n = 37) trap-captured at the Paraná River basin, Brazil, located between the States of Paraná and Mato Grosso do Sul. Anti-HAV IgG antibodies were detected in 4.5% (5/112) of NTPs, specifically in 6.7% (5/75) of Sapajus spp. and 0% (0/37) of A. caraya. In addition, all samples were negative for the presence of IgM anti-HAV antibodies. These results suggest that free-ranging NTPs were exposed to HAV within the geographical regions evaluated.

Ocorrência de hepatites não-anão-B em unidade de hemodiálise

A monitorização mensal de alanina aminotransferase (ALT) sérica de pacientes em hemodiálise e os testes sorológicos para exclusões de infecções por vírus da hepatite A (HAV), vírus da hepatite B (HBV), citomegalovirus (CMV) e vírus Epstein-Barr (EBV), permitiu-nos identificar 11 casos de hepatites não-A, não-B em 111 indivíduos avaliados durante o período de 12 meses e acompanhados por 2 anos. Foram observados 3 padrões de atividade de ALT: elevação em pico monofásico em 2, bifásico ou polifásico em 6 e em platô em 3 pacientes. Individíduos com padrão monofásico exibiram os níveis mais elevados de ALT. Cinco pacientes apresentaram normalização bioquímica persistente 4,8 meses em média após o início da elevação aguda e seis evoluíram com ascensão crônica de ALT durante o período de estudo. A hepatite não-A, não-B foi, predominantemente, assintomática e anictérica, sempre antecedida por transfusões sangüíneas e com maior incidência nos seis primeiros meses de terapia dialítica dos pacientes.

Two competitive enzyme immunoassays for the detection of IgG class antibodies to hepatitis a antigen

Two competitive enzyme immunoassays (EIA) techniques were developed: in the first (COMP-1), test sera were added together with HAV antigen on anti-HAV IgG-coated wells followed by an anti-HA VHRP conjugate; in the second (COMP-2), test sera and anti-HA VHRP conjugate competed for HAV epitopes previously adsorbed to anti-HA V IgG-coated wells. Both procedures used tetramethylbenzidine (TMB) as a substrate. Both competitive tests were shown to be reproducible and suitable for routine diagnosis and research purposes.

Acute liver failure in children: observations in Vitória, Espírito Santo State, Brazil

In this communication we report 46 cases of acute liver failure in children diagnosed at the Hospital Infantil Nossa Senhora da Glória in Vitória, E Santo. Serology for IgM anti-HAV, IgM anti-HBc, HbsAg, anti-HCV and biochemical tests were performed in all cases in a routine laboratory. The M/F ratio was 1.1:1 and the mean age was 4.7±3.2 years, without gender difference. Anti-HAV IgM+ in 38 (82.6%) cases, anti-HbcIgM+ in two (4.3 %) cases and 6 (13.1%) cases were negative for all viral markers investigated. Anti- HCV+ in one anti-HAV IgM+ case. HbsAg+ in two anti-HbcIgM+ and in two HAVIgM+ cases. Among the six A, B and C negative cases, four (8.6%) did not have the suspected exogenous intoxication. Mortality was 50%, without gender or age differences. These results demonstrate that HAV infection is the main etiology of acute liver failure in children in Brazil, confirming that, although it is a self limited, relatively mild illness, it can cause serious and even fatal disease. The observation of four cases without A, B and C viral markers and no history of exogenous intoxication, agree with the observation of non A-E acute sporadic hepatitis in Northeastern Brazil.

Prevalence of anti-hepatits A antibodies in children of different socioeconomic conditions in Vila Velha, ES

This report describes the prevalence of anti-HAV antibodies in children from elementary school in the Municipality of Vila Velha, ES, Brazil. Anti-HAV antibodies were investigated by ELISA method in the serum of 606 children (four to fourteen years old) from three elementary schools, located in neighborhoods with varying household monthly income levels: São José School, 200 chidren, household income higher than US$700; São Torquato School, 273 children, US$200 to 300; and Cobi School, 133 children, less than US$200. From each children data on age, gender, skin color, sanitary conditions, frequency of contact with sea or river water and family history of hepatitis were recorded. Anti-HAV antibodies were present in 38.6% of all children, 9% in São José School, 49.1% in São Torquato School and 61.7% in Cobi School. Logistic regression analysis demonstrated a positive correlation of positive anti-HAV test with age, non white color of the skin, absence of sewage treatment and domestic water filter, and a past history of hepatitis. The prevalence of anti-HAV antibodies in school children in Vila Velha, ES, was lower than that observed in the same age group in North and Northeast Brazil and was significantly higher in children from families with low socioeconomic status. In addition the results indicate a changing epidemiologic pattern of hepatitis A in our country, with an increasing number of children and adolescents with high risk for HAV infection, mainly in high socioeconomic class. A consideration must be given to the feasibility of vaccination programs for children and adolescents in our country.