Molecular evidence for transmission of human T-lymphotropic virus type II infection by a human bite.

Investigation of a human T-lymphotropic virus type II (HTLV-II) infection in a female Australian blood donor identified a human bite as the likely mode of transmission, confirmed by nucleotide sequencing of the proviral tax/rex from both donor and contact. We believe this to be the first report of the transmission of an HTLV by a human bite.

Post-transfusion hepatitis revisited.

OBJECTIVE: To evaluate the risk of post-transfusion and postoperative non-A non-B hepatitis in Australia immediately before the introduction of screening for hepatitis C. DESIGN: Retrospective testing of blood samples from a prospective study of cardiac surgery patients. Samples were taken from transfusion recipients and non-transfused controls at regular intervals for 12 months after surgery during 1987-1989. For all donor, recipient and control samples, alanine aminotransferase (ALT) levels were measured and tests for antibody to hepatitis B (anti-HBc, anti-HBs) and, when available, to hepatitis C (anti-HCV) were performed. SETTING: Cardiac surgery units. PARTICIPANTS: Participants were included if they lived in the metropolitan area, and had not had a transfusion in the past year. MAIN OUTCOME MEASURES: Post-transfusion hepatitis (two consecutive samples showing raised ALT levels, > 90 IU/L with no other known cause); hepatitis C infection and carriage (antibody to hepatitis C). RESULTS: Post-transfusion hepatitis occurred in 1.1% of 736 recipients of blood not screened for hepatitis C (i.e., two cases per 1000 unscreened units given). No hepatitis occurred in 514 controls. Seven of the eight patients with post-transfusion hepatitis seroconverted to hepatitis C virus infection. Seven of the 26 anti-HCV-positive donations transmitted hepatitis C, six of these were positive by recombinant immunoblot assay (RIBA) (one by second generation testing only) and one was RIBA indeterminate. Nineteen were RIBA non-reactive; one transmitted hepatitis but the recipient did not develop anti-HCV, although hepatitis C RNA was detected in the donation. Serum ALT was raised in four of the six infective donations. CONCLUSIONS: Hepatitis C virus infection accounted for almost all cases of non-A non-B post-transfusion hepatitis. First generation anti-HCV tests detected about 85% of infective donations. Surrogate testing of donations by ALT or anti-HBc offers no additional advantage.

Hepatitis B in urban Australian schoolchildren. No evidence of horizontal transmission between high-risk and low-risk groups.

OBJECTIVE: To document the prevalence of hepatitis B virus (HBV) infection in urban Australian primary schoolchildren, and to look for evidence of horizontal transmission of HBV in schools between children at high risk of infection and those at low risk. We compared the prevalence of infection in a group of low-risk children attending control schools (less than 5% of students from high-risk groups) with the prevalence in low-risk children attending test schools (more than 20% of students from high-risk groups). METHODS AND RESULTS: Venous blood was collected and tested for hepatitis B markers by radioimmunoassay; 2883 children (1431 boys) of mean age 11.3 years (SD, 0.7) from 50 schools were tested. Evidence of past or current infection was present in 169 children (5.9%). This number comprised three of the 1347 low-risk children (0.2%), 10 of the 602 medium-risk children (1.7%), 154 of the 731 high-risk children (21.1%) and two of the 203 other children (1%). Fifty-four of the 169 infected children were hepatitis B surface antigen (HBsAg) positive, 36 of the 54 were also positive for hepatitis B e antigen (HBeAg). There was no difference between children in the low-risk group in test and control schools for markers of hepatitis B virus infection. CONCLUSIONS: A low prevalence of HBV infection was found in low-risk school-children irrespective of the proportion of high-risk children in their classes. Targeting vaccination to infants and children with known risk factors is the most important strategy in low endemicity countries; vaccination of children without risk factors could be delayed till early adolescence.

Prevalence of hepatitis C virus antibodies in Sydney blood donors.

OBJECTIVE: To determine the prevalence of hepatitis C virus (HCV) antibodies in the Sydney blood donor population. DESIGN: All blood donations collected from Red Cross blood donors in Sydney from February 1990 until April 1991 were tested for HCV antibodies. For those samples found reactive in an anti-HCV screening test, a confirmatory test was carried out for the presence of HCV antibodies and the alanine aminotransferase level was measured. RESULTS: The prevalence of repeated reactivity to the screening test was 0.45% among blood donations overall, and 1.02% in donors giving blood for the first time in the study period. The confirmatory test result was positive for 30.8% of donations found to be repeatedly reactive in the screening test. There was little change over the study period in the HCV antibody prevalence of donors giving blood for the first time, but there was a clear decrease in the prevalence among all donations. Prevalence in males was nearly twice the prevalence in females--a difference which was consistent across age groups. The highest prevalence in both sexes was in the age group 30-34 years. Among samples for which the screening test results was positive, there was a strong correlation between the reactivity recorded for the screening test and both the proportion found positive by the confirmatory test and the proportion with an elevated alanine aminotransferase level. CONCLUSION: The small proportion of blood donations found to be repeatedly reactive by anti-HCV screening and the relatively good correlation with the confirmatory test and liver function assay indicate that a policy of discarding these donations will decrease the risk of transfusion-transmitted HCV infection without materially affecting the supply of blood.

Risk factors for hepatitis C virus infection in blood donors: a case-control study.

OBJECTIVE: To investigate risk factors for hepatitis C virus (HCV) infection in Sydney blood donors. DESIGN: Blood donors confirmed to be positive for HCV antibodies were compared with blood donors with a positive result of a screening assay, but whose HCV antibody status had not been confirmed. A questionnaire on sexual, parenteral and other potential risk factors was administered to both groups. SETTING: Blood Transfusion Service in Sydney. PARTICIPANTS: The study enrolled 220 donors who had confirmed HCV infection, and 210 donors who did not. RESULTS: The relative risk associated with injecting drug use was 63 (95% confidence interval, 19-260) when comparison was made with all other donors. Among donors who did not report injecting drug use, a significant, independent increase in risk was found in association with having had a tattoo. Among donors who did not give a history of parenteral exposure, there was a significantly greater risk in people with more than one life-time sexual partner than in those with at most one partner. CONCLUSION: A history of injecting drug use was elicited as the most important risk factor in Sydney blood donors with antibodies to hepatitis C. Having had a tattoo, and an increased number of lifetime sexual partners were also independently associated with HCV infection.

Prediction of hepatitis C virus infectivity in seropositive Australian blood donors by supplemental immunoassays and detection of viral RNA.

The prevalence of anti-hepatitis C virus (HCV) enzyme immunoassay (EIA)-positive in 167,511 Australian volunteer blood donors from Adelaide, Melbourne, Perth, and Sydney was 0.78%. One thousand two-hundred and eighteen EIA-positive serum samples were assessed by supplemental tests including a blocking EIA and two peptide EIAs corresponding to major epitopes of the HCV C-100-3 antigen. Seven hundred and eighteen samples (59%) were negative by supplemental testing; no evidence of reactivity with other HCV gene products or HCV RNA detected by cDNA polymerase chain reaction was found in selected samples from this group. In contrast, of 43 samples randomly selected from 400 samples (32.8%) positive by supplemental testing, 88% were reactive with HCV 33-C or core antigens and 52% contained HCV RNA, suggesting contact with HCV and infectivity of most donors in this group. Most samples equivocal by supplemental testing reacted only with C-100 and not with other HCV antigens when tested by dot immunoblot assay. Only 21% had detectable HCV RNA. The battery of assays used in this study indicated that approximately 32% of HCV EIA repeatably reactive serum samples were serologically related to HCV, corresponding to a 0.25% prevalence of potentially infectious donors.

An improved assay for human tetanus anti-toxin and its use in the accession of human plasma for the production of high-titre tetanus immunoglobulin.

A simplified passive haemagglutination (PHA) screening test, an improved quantitative PHA assay, and a stable test cell preparation are described, as well as a comprehensive testing strategy which have been used in concert at this Service over the past 10 years for the successful accession of high-titre tetanus anti-toxin (TAT) plasma for fractionation into human tetanus immunoglobulin (HTIG). The sequential deployment of the screening and quantitative assays, has permitted large numbers of donors to be screened quickly and economically, and has helped establish a significant core of regular donors with high TAT levels. The assays have proven to be highly sensitive and specific and relatively simple to perform, while the coated cells are inexpensive and easily prepared. Approximately 20% of donors screened from the Sydney metropolitan area had TAT levels of 3 IU/ml or greater.

Antibodies in the intestinal secretions of rats. Primary and secondary responses to polymeric flagellin.

The antibody responses in serum and secretions obtained from the mucosal surfaces of the small intestine of rats immunized by a parenteral and intestinal route have been compared. Though no significant differences in the mean serum titres were found, the responses of animals immunized via the latter route to large doses of antigen were far less uniform. Apart from the first few days of the primary response, antibody activity was found in three major immunoglobulin classes (IgG2, IgA and IgM), irrespective of the route of immunization. Significant antibody activity appeared in the intestinal surface secretions only after two injections of antigen. In rats immunized parenterally the activity was found only in the IgG2 component. Whilst activity was found in both IgG2 and IgA fractions of the secretions obtained from intestinally immunized rats, it was predominantly of the IgG2 class. The possible significance of this observation is discussed.

Immunoglobulins and dietary protein antibodies in childhood coeliac disease.

Twenty-four children with coeliac disease were compared with a control group, comprising 17 children with a variety of gastroenterological disorders, with respect to serum immunoglobulins and dietary protein antibodies. Elevated levels of IgA and abnormally low levels of IgM were demonstrated in one third of the coeliac patients. Antibodies to at least one of eight dietary proteins were found in 50% of coeliac children. Three children with raised levels of serum IgA and two with deficient IgM were re-examined after varying periods on a gluten-free diet. Antibodies to dietary proteins had waned and immunoglobulin levels returned to normal in all cases. The raised IgA was considered to have resulted from an extensive immunological response to antigens of dietary origin which had entered through the abnormal gut mucosa. It is suggested that IgM deficiency was due to specific inhibition of IgM synthesis by dietary components which had also entered through the mucosa.