Molecular epidemiology of hepatitis C in Australia.

The aim of this study was to determine the distribution of hepatitis C virus (HCV) genotypes in Australian patients with hepatitis C and to identify factors associated with particular genotypes. Serum isolates of HCV-RNA were genotyped using a commercial oligonucleotide hybridization (line probe) assay. Relationships between demographic factors, mode of HCV transmission and HCV genotype were assessed by logistic regression analysis. Among 463 patients with hepatitis C, 425 tested positive for HCV-RNA and a single HCV genotype was identified in 420 cases. The patients' places of birth were Australia or New Zealand (62%), Asia (13%), Europe (12%), Mediterranean (6%), Middle East (6%) and other countries (< 1%). The most common genotypes were type 1 (52%) or type 3 (32%); type 2 (9.3%), type 4 (5.5%) and type 6 (1.7%) were less common. Patients with genotype 1b were older (48 +/- 13 years, P< 0.001) and patients with genotype 3 were younger than the remaining patients (37 +/- 11 years vs 42 +/- 12 years, P< 0.001). Among type 1 isolates, 1b was more common for patients born outside Australia compared with those born in Australia (50% vs 13%, P< 0.001) whereas non-1b subtypes were more common among Australian-born patients. Likewise, 21 of 23 (91%) patients with type 4 were from Egypt and six of seven (86%) with type 6 were from Vietnam. The relative importance of parenteral risk factors for HCV also varied according to geographic origin. Thus, a definite risk factor for HCV acquisition was identified in > 95% of Australian-born patients, but in only 33% of Asian or Mediterranean-born patients. Logistic regression analysis indicated that region of birth and risk factor (intravenous drug use or not) would allow 98% of type 4 cases and 76% of type 1b cases to be identified correctly. In summary, region of birth, patterns of migration over time and risk factors for transmission of HCV interact to determine the distribution of HCV genotypes in a multi-racial community like Australia.

Coinfection with hepatitis B and C or B, C and delta viruses results in severe chronic liver disease and responds poorly to interferon-alpha treatment.

Chronic coinfection with the hepatitis B (HBV) and hepatitis delta (HDV) viruses is known to cause severe liver disease, but the importance of coinfection with hepatitis C virus (HCV) and HBV has not been well documented. In the present study, the clinical and pathological severity of liver disease among patients with hepatitis resulting from multiple viruses was examined and an open trial of the efficacy of interferon-alpha 2b (IFN-alpha) treatment was conducted. Nineteen patients with chronic HBV and HCV infection and 17 with HBV, HCV and HDV infection were studied; 12 in each group underwent liver biopsy. For each coinfected patient, two patients infected with HCV alone were selected as controls, and these were matched for age and risk factor and were estimated to have been infected for a similar duration. Coinfection with HBV and HCV or HBV, HCV and HDV was associated with more severe liver disease than HCV alone (P < 0.01); total Scheuer score, portal and lobular inflammation and fibrosis were all worse in coinfected subjects. Eight patients with chronic HBV and HCV were treated with recombinant IFN-alpha 2b [3 million units (MU), thrice weekly for 6 months]. Liver function tests normalized in two patients and one lost hepatitis B surface antigen (HBsAg). Seven patients with hepatitis B, C and delta coinfection were treated with the same regimen and only one normalized serum alanine aminotransferase (ALT) during (and after) treatment. It is concluded that coinfection with multiple hepatitis viruses is associated with histologically more severe liver disease than HCV alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Seroprevalence of hepatitis A antibodies among residents of a centre for people with developmental disabilities.

BACKGROUND: In February 1993, 11 cases of hepatitis A virus (HAV) were identified in permanent residents of a centre for young people with developmental disabilities. AIMS: To define the extent of the outbreak in the centre, to determine the seroprevalence of hepatitis A antibodies (anti-HAV) in permanent residents, and to ascertain risk factors for serological evidence of HAV infection. METHODS: A cross-sectional serological survey of 270 permanent residents, aged eight to 40 years, in a centre for people with developmental disabilities, was conducted in western Sydney. Using a radioimmunoassay technique, sera were tested for anti-HAV (IgM and total antibody). We used logistic regression to determine risk factors for presence of anti-HAV. RESULTS: Blood samples were collected from 259 permanent residents (96%). Serological testing revealed anti-HAV in 128 residents tested (49%). Presence of anti-HAV was associated with living in specific residential units, and with residents' age and length of stay at the centre, but was not associated with reported behavioural factors. CONCLUSIONS: More than half of the residents of the centre were susceptible to HAV infection. Behavioural characteristics of the residents and their close contact with each other make HAV transmission difficult to control. HAV vaccine should be promoted in communities at risk, such as those with developmental disabilities.

Does hepatitis C virus play a role in "non-viral" chronic liver disease?

It has recently been suggested that the hepatitis C virus may play a significant role in chronic liver diseases, such as autoimmune chronic active hepatitis, which are usually attributed to non-viral causes. We tested for antibodies to hepatitis C virus (anti-HCV) in sera from 140 patients with well characterised "non-viral" chronic liver diseases as well as sera from 51 patients thought to have chronic non-A, non-B (NANB) hepatitis (acting as positive controls) and 25 patients with non-hepatic autoimmune disorders. As expected, 45 of 51 patients (88%) diagnosed as having chronic NANB hepatitis were anti-HCV seropositive. Among 26 patients with cryptogenic cirrhosis, 8 were anti-HCV seropositive; in 5 patients (22%) there was no apparent risk factor for parenteral transmission. In the remaining 114 patients with chronic liver disease, 10 patients (9%) were seropositive for anti-HCV. However, 5 of these patients had a significant risk factor for parenteral transmission of hepatitis C virus, leaving only 5 of 106 (4.7%) with unexplained positive anti-HCV test results. Among patients with high titres of circulating autoantibodies but no liver disease, no positive results occurred. It is concluded that hepatitis C virus infection may account for some cases of cryptogenic cirrhosis. Although anti-HCV occurs more commonly in patients with other "non-viral" chronic liver diseases than has been reported in the community (0.5%-1.2%), the low prevalence of the antibodies indicates that hepatitis C virus infection is unlikely to be important in the aetiology or pathogenesis of autoimmune chronic active hepatitis and other poorly understood chronic liver diseases.

Hepatitis C virus in intravenous drug users.

Sera from 172 intravenous drug users were tested for the presence of antibodies to hepatitis C virus (anti-HCV). The results were analysed in relation to aspects of the history of drug use and evidence of liver disease. The presence of anti-HCV was strongly associated with duration of intravenous drug use. Two-thirds of patients were anti-HCV seropositive within two years of commencing regular intravenous drug use, and there was 100% seropositivity among people injecting drugs for more than eight years. Seropositivity for hepatitis C virus closely paralleled exposure to hepatitis B virus, which was also endemic in this population. In contrast, only one patient tested positive for antibodies to the human immunodeficiency virus. The presence of anti-HCV correlated poorly with biochemical markers of hepatitis. About half the patients with anti-HCV had normal serum levels of alanine aminotransferase, whereas an abnormal liver biochemistry was frequently observed in anti-HCV seronegative subjects. Previous studies of non-A, non-B hepatitis that have used abnormal liver biochemistry as a marker have underestimated the prevalence of chronic hepatitis among intravenous drug users; the use of a specific screening test reveals that infection with hepatitis C virus is very common in this population.

Should all pregnant women be screened for hepatitis B surface antigen?

One thousand, one hundred and ninety-three pregnant women were screened for hepatitis B surface antigen (HBsAg) carriage after their histories had been reviewed to assess their risk status. In this prospective study, carrier rates were examined according to conventional risk criteria and also according to extended criteria that included the country of birth of the patient's parents. Twenty-six (2.2%) patients were found to be HBsAg seropositive, and one of these patients showed no identifiable risk factors. In four hepatitis B virus carriers, the only risk factor was that the patients' parents had been born in a country that was classified as high risk. Thus, five (19%) of 26 patients would not have been identified by means of previously-accepted screening procedures. Four hundred and forty-two (37%) patients showed at least one conventional risk factor and 558 (47%) patients showed at least one risk factor by our extended criteria. Given the high costs to the community of chronic hepatitis B virus carriage, it was concluded that the screening of all antenatal clinic patients for the presence of HBsAg is cost effective.

Hepatitis B infection among STD clinic patients in Sydney.

Evidence of current or past infection with hepatitis B has been studied in 809 patients attending clinics for sexually transmitted diseases in Sydney by assaying serological markers. Prevalence rates were 13.9% among male heterosexuals; 13.5% among female heterosexuals; 30.7% among female prostitutes; 64.3% among male homosexuals and 47.1% among male bisexuals. The prevalence was 80% for male homosexuals aged 36 years or more. Vaccination should be considered for persons at high risk of sexual transmission of hepatitis B, and it is the immunization of this group that is likely to have a major impact on this disease.

Rotavirus infections of neonates.

Faecal specimens from 628 newborn babies in the nurseries of six metropolitan hospitals were examined by electron microscopy for rotaviruses. 304 babies (49%) were found to be excreting virus. All those infected were in five nurseries; viruses were not detected in specimens from the sixth nursery. Two nurseries were studied for 9 mo and another for 11 mo and rotaviruses were found consistently in 40-50% of stools examined. There was no seasonal variation. None of the neonates under the age of one day were infected but by the age of three to four days approximately 50% were excreting virus. Most of those shedding virus were symptom-free but 84 (28%) had diarrhoea. Persisting endemic rotavirus infection is apparently common in hospital nurseries in Sydney. The virus is probably transmitted by environmental spread from neonate to neonate.