The origin of the HM175 strain of hepatitis A virus.
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Adolescent↗
Biomedical subjects
N I Lehmann
Publications and source records attributed to N I Lehmann.
Aetiology of fatal viral hepatitis in Melbourne. A retrospective study.
In the period from January 1971 to June 1983, 46 of 5477 patients (0.84%) admitted to Fairfield Hospital, Melbourne, with acute viral hepatitis died of fulminant hepatic failure. The case-fatality rate for patients with hepatitis A was 0.14%; for patients with hepatitis B, 0.84%; and for patients with non-A non-B (NANB) hepatitis, 2.29%. The highest case-fatality rates were observed in patients with post-transfusion hepatitis B (18.8%), and in patients with NANB hepatitis aged less than 5 years (50%) and 40 years and over (10%).
Adolescent↗
Monoclonal antibodies against hepatitis A virus.
Three monoclonal antibodies (K2-4F2, K3-2F2, and K3-4C8) of the immunoglobulin G2a class were raised against hepatitis A virus. The specificity of these antibodies was confirmed by immune electron microscopy, solid-phase radioimmunoassay, and in vitro neutralization in cell culture. Binding studies suggested that they all recognize closely related antigenic determinants. These monoclonal antibodies should prove to be of great value as diagnostic and research reagents.
Animals↗
Viral hepatitis: a four-year hospital and general-practice study in Sydney. 2. Transmission of viral hepatitis among residential contacts in Sydney.
Clinical and serological study of household contacts of index patients suffering from acute viral hepatitis showed the high infectivity of hepatitis A viral (HAV) for susceptible contacts. The anti-HAV specific IgM developed in sera of 67% of susceptible children and 31% of susceptible adult contacts. Of 81 susceptible contacts whose sera became anti-HAV positive, 28.4% developed clinically overt hepatitis. Administration of human immunoglobulin reduced the rate of clinical expression of hepatitis A among susceptible contacts; it also appeared to reduce the actual infection rate. The infection rate among susceptible adult contacts of adult index cases suffering from hepatitis B was 24%. Of 25 susceptible contacts whose sera became HBV-marker positive, 24% developed clinical illness. Transmission occurred probably both by parenteral and non-parenteral means. It is currently not possible to determine susceptibility or seroconversion to hepatitis non-A non-B agents.
Adolescent↗
Viral hepatitis: a four-year hospital and general-practice study in Sydney 1. Epidemiological features, natural history, and laboratory findings.
We studied 761 patients admitted to hospital with viral hepatitis between 1971 and 1974, and 53 patients with viral hepatitis seen in general practice in Sydney, following up some of them for one to two years. We evaluated factors contributing to each type of hepatitis. We noted differences in the patterns in hepatitis A, B and non-A non-B between Anglo-Saxon and non-Anglo-Saxon sectors of the community. All patients with hepatitis A regained normal liver function within 20 months of the acute illness. Of 115 hepatitis B patients seen at 12 months, 6% had chronic hepatitis Bs antigenaemia, 60% had developed anti-HBs antibodies, and 7.3% still had abnormal liver function. Of 20 non-A non-B patients followed for 12 months, liver function was still abnormal in three, but one of these had developed hepatitis B. The case fatality rate for the whole series was 0.66%.
Adolescent↗
A longitudinal study of hepatitis infection in an institution for the mentally retarded.
The natural history of hepatitis A and B infections in a large institution for the mentally retarded were studied over an eight year period. Serum samples were obtained from most subjects on three occasions and tested for anti-HAV, HBsAg, anti-HBs and occasionally anti-HBc, by solid-phase radioimmunoassay. Hepatitis A was found to have been a common infection was 74.8% of subjects having detectable levels of antibody. The virus does not appear to be endemic, as the prevalence of antibody in children admitted since the last outbreak was no higher than amongst non-institutionalised children. The infection rate amongst subjects with Down's syndrome (DS) was higher than amongst subjects with other forms of mental retardation (OMR), and more than 95% of infections in both groups were unrecognised. By contrast with hepatitis A, hepatitis B virus was endemic in the institution with 81.2% of residents showing serological evidence of current or past infection. Of these, 40.8% of subjects with DS and 9.2% of those with OMR were found to be chronic carriers. The carrier rate was higher in males than females and tended to be more prolonged in subjects with DS. During the study period, the predominant subtype of HBsAg detected in the institution changed from adw to ayw.
Adolescent↗
Detection of hepatitis A virus in the feces of patients with naturally acquired infections.
A prospective study was carried out on 200 patients admitted to Fairfield Hospital, Melbourne, Australia, with acute hepatitis A to determine the frequency with which virus could be detected in their feces. Evidence of infection with hepatitis A virus (HAV) was obtained by detecting IgM specific for HAV in a single serum sample or by demonstrating a rising titer of antibody in paired sera by solid-phase radioimmunoassay. HAV was detected in the feces of 59 of the 200 patients by solid-phase radioimmunoassay and immune electron microscopy. When patients were admitted within one week of the onset of dark urine, 45% were found to be shedding HAV, whereas only 11% of specimens obtained from patients admitted during the second week contained virus. HAV was not detected in fecal specimens collected more than 14 days after the onset of dark urine. These findings suggest that patients admitted to hospital with hepatitis A may still be infectious and that appropriate precautions against fecal contamination should be maintained.
Acute Disease↗
Hepatitis A outbreak in a residential school.
Outbreaks of hepatitis A occurred sequentially in two wards for children in a residential institution for the mentally retarded in Sydney. Twenty-six of 41 children were initially susceptible to hepatitis A. In the first ward affected, 11 of 13 susceptible children (85%), and in the second ward, four of 13 susceptibles (31%), were infected. Of the 15 showing serological evidence of infection, five (33%) were clinically jaundiced.
Adolescent↗
Use of immunoglobulin M antibody to hepatitis B core antigen in diagnosis of viral hepatitis.
To determine the diagnostic value of hepatitis B core (HBc)-specific immunoglobulin M (IgM) antibody (anti-HBc IgM), the sera of six patients with known recent acute viral hepatitis B were examined for the presence of anti-HBc periodically for up to 21 months from the onset of the attack by a sensitive radioimmunoassay technique (CORAB, Abbott Laboratories). It was found that anti-HBc IgM was detectable for approximately 17 months from the onset of the illness. Hence the finding of anti-HBc IgM suggests infection by hepatitis B virus, probably within the preceding 1 to 2 years. A high level of anti-HBc IgM in the acute-phase serum of an individual with viral hepatitis is indicative of recent hepatitis B virus etiology; one patient, however, showed a low titer of anti-HBc IgM in the acute-phase serum sample, which remained virtually unchanged 15 months from onset. The diagnostic use of this serologaical marker is illustrated in 25 patients with viral hepatitis, in whose acute-phase sera anti-HBc was found.
Adolescent↗
Seroepidemiology of infection with hepatitis A and B viruses in an isolated Pacific population.
To determine the prevalence of infection with hepatitis A virus and hepatitis B virus in an isolated population, samples of serum were collected from 574 healthy subjects living on the remote Pacific Island of Funafuti. Each specimen was tested for antibody to hepatitis A virus, hepatitis B surface antigen, and antibody to hepatitis B surface antigen by solid-phase radioimmunoassay. Overall, 79.8% of the population showed evidence of previous infection with hepatitis A virus, and 72.5% with hepatitis B virus; the high prevalence of antibody to both viruses in young adults suggested that the majority of infections were acquired in the first decade of life. Although it is known that hepatitis B virus maintains itself in isolated populations through a reservoir of chronic carriers, the reason for the persistently high rate of infection with hepatitis A virus is unknown.
Adolescent↗
A seroepidemiologic study of infection with HAV and HBV in five Pacific Islands.
A batch of 1025 serum samples, obtained from healthy subjects and hospital patients from five Pacific islands (Viti Levu, Funafuti, Niue, Rarotonga and Upolu) were tested for antibody to hepatitis A virus (anti-HAV), hepatitis B surface antigen (HBsAG) and antibody to hepatitis B surface antigen (anti-HBs) by solid phase radioimmunoassay (SPRIA). High frequencies of anti-HAV were observed in each population (Funafuti, 79.9%; Upolu, 81.6%; Viti Levu, 84.3%; Rarotonga, 95.0%; and Niue, 95.2%), and the age-specific prevalence suggested that the majority of infections with this virus had occurred in the first decade of life. Hepatitis B was endemic in each population, although the total infection rates (as measured by the sum of HBsAG and anti-Hbs frequencies) were lower than for hepatitis A. While infections with each virus tended to run in parallel, peak prevalence of anti-HAV was usually reached in the second decade of life and peak prevalence of HBsAg and anti-HBs was not attained until a decade later. The pattern of infection with HBV was similar in each of the groups studied with the exception of Indians living in Viti Levu, among whom unusually low levels of antigen and antibody were demonstrated.
Adolescent↗
Viral hepatitis and intrahepatic cholestasis of pregnancy.
Specific serological tests which are now available for the diagnosis of infection with hepatitis A and hepatitis B viruses, were used to distinguish viral hepatitis from other causes of liver disease in pregnancy. Forty-nine (51.6%) of 95 pregnant patients had viral hepatitis, 24 hepatitis A and 25 hepatitis B. The majority of patients (26 of 28) presenting before 22 weeks gestation had viral hepatitis. By contrast, 23 (34.3%) of the remaining 67 patients presenting with abnormal liver function tests at greater than or equal to 22 weeks gestation, had viral hepatitis; the majority of the remainder had features compatible with intrahepatic cholestasis of pregnancy. Although there were significant clinical and biochemical differences between the two groups, accurate diagnosis was only possible by using specific virological tests.
Adult↗
Comparison of electron microscopy, enzyme-linked immunosorbent assay, solid-phase radioimmunoassay, and indirect immunofluorescence for detection of human rotavirus antigen in faeces.
Four techniques were compared for their practicability, speed, and sensitivity for the detection of human rotavirus. Radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) were found to be the most sensitive means of identifying rotavirus, and, once processed, up to 40 specimens could be examined daily. Electron microscopy, although less sensitive than these techniques, had the advantage of being able to detect other viral agents present in faecal extracts. Indirect immunofluorescence failed to detect rotavirus as often as the other three methods. In laboratories where routine examination of faecal specimens from patients with gastroenteritis is required, ELISA and RIA are useful alternatives to electron microscopy.
Adolescent↗
Prevalence of antibody to the hepatitis A virus in a large institution for the mentally retarded.
The prevalence of antibody to hepatitis A virus (anti-HAV) was determined in 854 people living in a large institution for the mentally retarded in Melbourne. Altogether 638 (74.4%) of the subjects were found to have specific antibody detectable by solid-phase radioimmunoassay (SPRIA). No difference in antibody prevalence was observed between males and females; however, the prevalence was higher among subjects with Down syndrome (84.1%) than those of other forms of mental retardation (72.8%). In both groups there was an increase in prevalence of antibody with increasing age and duration of institutionalization. When compared with the open community, patients in this institution have a higher prevalence of antibody and appear to acquire their infections at an earlier age.
Adolescent↗
Relationship between prevalence of antibody to hepatitis A antigen and age: a cohort effect?
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Adolescent↗
Prevalence of antibody to hepatitis A and polioviruses in an unimmunized urban population.
A large group of sera collected in 1954-1955 from people living in the metropolitan area of Melbourne, Australia, was tested for neutralizing antibody to polioviruses 1,2 and 3 and for antibody to hepatitis A virus by solid phase radioimmunoassay. The age-specific prevalence of antibody to each virus was remarkable similar, being highest in the elderly and in persons of low socioeconomic status. Antibody to each virus was acquired early in life, with more than half the population showing evidence of infection by the age of 15 years.
Adolescent↗
Solid-phase enzyme-linked immunosorbent assay for detection of hepatitis A virus.
An enzyme-linked immunosorbent assay (ELISA) was developed for the detection of hepatitis A virus in human fecal specimens. Investigations with 88 fecal specimens from 77 patients with suspected viral hepatitis and 8 of their household contacts showed that ELISA was as specific and sensitive as radioimmunoassay and almost as sensitive as immune electron microscopy. The ELISA is quick and simple to perform, does not require sophisticated technical equipment, and can be read with the naked eye, making it suitable for field work and rapid diagnosis.
Antigen-Antibody Reactions↗
The polypeptides of hepatitis A virus.
Hepatitis A virus was purified from fecal specimens obtained from 3 patients with naturally acquired hepatitis A, by a process of differential centrifugation, chloroform extraction, column chromatography, and isopycnic ultracentrifugation. Analysis of purified virus by discontinuous SDS-PAGE revealed three major polypeptides with molecular weights of 34,000, 25,500, and 23,000 daltons. These polypeptides appear to be specific for hepatitis A virus and have similar molecular weights to three of the four major polypeptides reported for members of the genus Enterovirus within the family Picornaviridae.
Feces↗