Several useful animal models for both hepatitis A and E have been identified, characterized, and refined. At present, all of the best models utilize nonhuman primates: chimpanzees, tamarin species, and owl monkeys for hepatitis A; and macaque species, chimpanzees, and owl monkeys for hepatitis E. Pigs may prove useful for some studies of hepatitis E, and it is hoped that serological evidence of widespread infection of rats with an HEV-like agent may lead to the development of an animal model based on laboratory rats. As has been the case for each of the hepatitis viruses as they have been discovered, the development of useful and reproducible animal model systems has been critical for moving the field forward as expeditiously as possible. (+info)
The changing epidemiology of viral hepatitis A in Israel.
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BACKGROUND: Between 1970 and 1979, there was an increase in the incidence of viral hepatitis in Israel with a shift of peak incidence to an older age in the Jewish population, followed by a declining trend during the early 1980s. In July 1999 universal immunization of infants against hepatitis A was introduced. OBJECTIVE: To evaluate the chan-ges in the epidemiology of viral hepatitis A in Israel during the past decade. METHODS: Viral hepatitis is a notifiable disease in Israel and cases are reported to the regional health offices, which in turn provide summary reports to the Ministry of Health's Department of Epidemiology. The data in this study were derived from the summary reports and from results of seroprevalence studies. RESULTS: Following the increase in the incidence of reported viral hepatitis (mainly due to type A) between 1970 and 1979, the rates then stabilized and around 1984 began to decline until 1992. Since then there has been a slight increase. Whereas until 1987 the rates were consistently higher in the Jewish population, since then they are higher in the Arab population. The shift in the peak age-specific incidence from the 1-4 to the 5-9 year age group observed in the Jewish population around 1970 occurred 20 years later in the Arab population. The previously described seasonality is no longer evident. Recent seroprevalence studies indicate that by age 18 years only about 30-40% of the Jewish population have anti-hepatitis A antibodies. CONCLUSIONS: The decline in the incidence of hepatitis probably reflects the changing socioeconomic condition occurring at different times in the two major population groups. Since hepatitis A accounts for almost all the acute viral hepatitis in Israel, the universal vaccination of infants introduced in 1999 should substantially lower the morbidity within the next few years. (+info)
Fever in returned travelers: review of hospital admissions for a 3-year period.
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We reviewed 232 consecutive patients admitted to a tertiary-care hospital under the care of an infectious diseases unit for management of febrile illness acquired overseas. A total of 53% presented to hospital within 1 week of return and 96% within 6 months. Malaria was the most common diagnosis (27% of patients), followed by respiratory tract infection (24%), gastroenteritis (14%), dengue fever (8%), and bacterial pneumonia (6%). Pretravel vaccination may have prevented a number of admissions, including influenza (n=11), typhoid fever (n=8) and hepatitis A (n=6). Compared to those who had not traveled to Africa, those who had were 6 times more likely to present with falciparum than nonfalciparum malaria. An itinerary that included Asia was associated with a 13-fold increased risk of dengue, but a lower risk of malaria. Palpable splenomegaly was associated with an 8-fold risk of malaria and hepatomegaly with a 4-fold risk of malaria. As a cause of fever, bacterial pneumonia was > or =5 times more likely in those who were aged >40 years. (+info)
Past infection with hepatitis A virus among Vancouver street youth, injection drug users and men who have sex with men: implications for vaccination programs.
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BACKGROUND: In Canada, inactivated hepatitis A vaccines are targeted selectively at those at increased risk for infection or its complications. In order to evaluate the need for routine hepatitis A vaccination programs in Vancouver for street youth, injection drug users (IDUs) and men who have sex with men (MSM), we determined the prevalence of antibodies against hepatitis A virus (HAV) and risk factors for HAV in these groups. METHODS: The frequency of past HAV infection was measured in a sample of Vancouver street youth, IDUs and MSM attending outreach and STD clinics and needle exchange facilities by testing their saliva for anti-HAV immunoglobulin G. A self-administered, structured questionnaire was used to gather sociodemographic data. Stepwise logistic regression was used to evaluate the association between presumed risk factors and groups and past HAV infection. RESULTS: Of 494 study participants, 235 self-reported injection drug use, 51 were self-identified as MSM and 111 met street youth criteria. Positive test results for anti-HAV were found in 6.3% of street youth (95% confidence interval [CI] 2.6%-12.6%), 42.6% (95% CI 36.2%-48.9%) of IDUs and 14.7% (95% CI 10.4%-19.1%) of individuals who denied injection drug use. Among men who denied injection drug use, the prevalence was 26.3% (10/38) for MSM and 12% (21/175) for heterosexuals. Logistic regression showed that past HAV infection was associated with increased age and birth in a country with high rates of hepatitis infection. Injection drug use among young adults (25-34 years old) was a significant risk factor for a positive anti-HAV test (p = 0.009). MSM were also at higher risk for past HAV infection, although this association was nominally significant (p = 0.07). INTERPRETATION: Low rates of past HAV infection among Vancouver street youth indicate a low rate of virus circulation in this population, which is vulnerable to hepatitis A outbreaks. An increased risk for HAV infection in IDUs and MSM supports the need to develop routine vaccination programs for these groups also. (+info)
Presence of oligoclonal T cells in cerebrospinal fluid of a child with multiphasic disseminated encephalomyelitis following hepatitis A virus infection.
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We have investigated the clonality of beta-chain T-cell receptor (TCR) transcripts from the cerebrospinal fluid (CSF) and peripheral blood from a 7-year old child who developed a multiphasic disseminated encephalomyelitis following an infection with hepatitis A virus. We amplified beta-chain TCR transcripts by nonpalindromic adaptor (NPA)-PCR-Vbeta-specific PCR. TCR transcripts from only five Vbeta families (Vbeta13, Vbeta3, Vbeta17, Vbeta8, and Vbeta20) were detected in CSF. The amplified products were combined, cloned, and sequenced. Sequence analysis revealed in the CSF substantial proportions of identical beta-chain of TCR transcripts, demonstrating oligoclonal populations of T cells. Seventeen of 35 (48%) transcripts were 100% identical, demonstrating a major Vbeta13.3 Dbeta2.1 Jbeta1.3 clonal expansion. Six of 35 (17%) transcripts were also 100% identical, revealing a second Vbeta13 clonal expansion (Vbeta13.1 Dbeta2.1 Jbeta1.2). Clonal expansions were also found within the Vbeta3 family (transcript Vbeta3.1 Dbeta2.1 Jbeta1.5 accounted for 5 of 35 transcripts [14%]) and within the Vbeta20 family (transcript Vbeta20.1 Dbeta1.1 Jbeta2.4 accounted for 3 of 35 transcripts [8%]). These results demonstrate the presence of T-cell oligoclonal expansions in the CSF of this patient following infection with hepatitis A virus. Analysis of the CDR3 motifs revealed that two of the clonally expanded T-cell clones exhibited substantial homology to myelin basic protein-reactive T-cell clones. In contrast, all Vbeta TCR families were expressed in peripheral blood lymphocytes. Oligoclonal expansions of T cells were not detected in the peripheral blood of this patient. It remains to be determined whether these clonally expanded T cells are specific for hepatitis A viral antigen(s) or host central nervous system antigen(s) and whether molecular mimicry between hepatitis A viral protein and a host protein is responsible for demyelinating disease in this patient. (+info)
Posttravel hepatitis A: probable acquisition from an asymptomatic adopted child.
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We report a case of acute hepatitis A in an adoptive parent that was probably acquired from a recently adopted child with asymptomatic, active infection. Prospective adoptive parents should be protected against hepatitis A because of potential exposure during travel and the risk of unrecognized active infection in adopted children. (+info)
Genetic variability of hepatitis A virus in South America reveals heterogeneity and co-circulation during epidemic outbreaks.
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Genetic analysis of selected genome regions of hepatitis A virus (HAV) suggested that distinct genotypes of HAV could be found in different geographical regions. In order to gain insight into the genetic variability and mode of evolution of HAV in South America, an analysis was performed of sequence data obtained from the VP1 amino terminus and the VP1/2A region of HAV strains isolated over a short period of time in Uruguay, Argentina and Chile. Sequences obtained from 22 distinct HAV isolates were compared with published sequences from 21 different strains isolated all over the world. Phylogenetic analysis revealed that all strains isolated belong to a unique sub-genotype (IA). Strains isolated during an outbreak period showed a higher degree of heterogeneity than anticipated previously and the co-circulation of different isolates. The genetic variability among strains isolated in this region seems to be higher in comparison with strains isolated in other regions of the world. (+info)
The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors.
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A serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log-log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2-3 members per room (RR = 1.4; 95% CI = 1.04-1.8) or more than three per room (RR = 1.5; 95% CI = 1.2-2.0). People living on hilltops (RR = 1.5; 95% CI = 1.02-2.2), near to open sewers (RR = 1.2; 95% CI = 1.03-1.5) or lacking a kitchen (RR = 1.4; 95% CI = 1.08-1.9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR = 0.9 for each tap; 95% CI = 0.9-0.98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains. (+info)