Sentinel laboratory surveillance of hepatitis C antibody testing in England: understanding the epidemiology of HCV infection.

This paper describes sentinel laboratory surveillance of hepatitis C antibody testing in England. Demographic and test result data were supplemented by follow-up questionnaires sent to the requesting clinician. Between October 2002 and September 2003 almost 75000 anti-HCV tests were performed in eight sentinel centres. More males were tested than females and over half of those tested were aged 25-44 years. Overall 5.7% (3333/58144, range 2.8-7.7%) individuals tested positive. Follow-up questionnaire data showed that 82% (1043/1277) of the positives had injecting drug use reported as the main risk exposure. The majority of negative individuals were undergoing routine screening as recommended for specific patient groups. Most individuals were asymptomatic. Antibody prevalence was estimated to be 34% in current injecting drug users and 42% in former injectors. Comparing positives to routine national surveillance suggests that only 53% (1782/3333) of diagnosed cases were reported. Sentinel laboratory data can provide valuable supplementary data to national surveillance.

Risk factors, clinical features and genotype distribution of diagnosed hepatitis C virus infections: a pilot for a sentinel laboratory-based surveillance.

Hepatitis C is a global public health problem. A cross-sectional survey was undertaken to determine the frequency of reported risk factors and possible transmission routes in individuals in whom HCV antibody (anti-HCV) was newly detected. Seven public health laboratories in England and Wales reported persons with positive anti-HCV tests over a three-month period (1st November 1996-31st January 1997). A questionnaire was then sent to the clinician or general practitioner (GP) who requested the test. A total of 320 laboratory reports were received from participating laboratories and 221 (69%) questionnaires were received from clinicians and GPs. Of those patients from whom a questionnaire was received (median age 36 years; males 72.9%, females 23.1%), 86% had one or more risk factors for infection reported by the clinician/GP. Injecting drug use (68%) was the main risk factor reported. Reasons for testing included being in a known risk group (65%), liver disease (19%) and blood donation (1.4%). Of the total responders, 67% were asymptomatic, and of those that had had liver function tests 50% were abnormal. The most prevalent HCV genotypes were 3a and 1a. Risk factors for HCV infection can be identified using a simple postal questionnaire to clinicians/GPs who request patient screening.

Hepatitis C-related chronic liver disease among asymptomatic blood donors in the north west of England.

In the first 19 months of screening, the North Western Regional Transfusion Centre (RTC) tested 224,000 consecutive blood donors for antibody to hepatitis C virus (anti-HCV) by second generation enzyme immunoassay (EIA). Of these, 366 repeatedly reactive samples were referred for confirmatory testing at Manchester Public Health Laboratory (PHL). There, the initial EIA was repeated, together with two further EIAs. All the referred samples were subjected to a confirmatory line immunoblot (RIBA-II). Reverse transcription followed by the polymerase chain reaction (RT-PCR), in order to detect viral RNA, was performed on selected samples. Among the donors, 61 accepted offers for medical review and were assessed for risk factors, clinical findings and results of standard liver function tests. Of these donors, 53 proceeded to liver biopsy. The overall prevalence of confirmed positive donors was 0.04%. Main risk factors identified included intravenous drug abuse in 31 (51%) donors and prior blood transfusion in 12 (20%) but a risk factor was not apparent in 11 (18%). Viraemia, detected by RT-PCR, could be predicted with a high degree of accuracy by means of the readily available and simpler screening and confirmatory tests (EIA and RIBA-II). Established chronic hepatitis was demonstrated in 90% of the liver biopsies. A trend towards worsening histological findings accompanied increasing concentrations of serum transaminase. Even so, many donors with normal transaminase values had abnormal biopsies including those showing chronic active hepatitis (CAH). These findings indicate that a substantial proportion of previously unrecognised asymptomatic persons with established chronic liver disease exists among North Western blood donors.(ABSTRACT TRUNCATED AT 250 WORDS)

An algorithm for confirming screen reactivity in blood donors in enzyme immunoassays for antibodies to hepatitis C virus.

Three commercial second generation enzyme immunoassays (EIA) and a second generation immunoblot assay (RIBA-II) for detecting antibodies to hepatitis C virus (HCV) were evaluated in a study of confirmatory testing using sera referred by six Regional Blood Transfusion Centres (RTC). Of a total of 490 samples, 203 were negative in the same EIA as that used by the RTC and of these 162 were negative in all three EIAs. The RIBA-II immunoblot test was performed on all samples and 359 were negative, 69 were indeterminate and 62 reactive. We found a close relationship between RIBA-II reactivity, the reactivity of a sample in all three EIAs and the mean of the test/cut-off ratios of all three EIAs performed on that sample. When this was evaluated by PCR for HCV RNA, we found an association between the mean test/cut-off ratio and the probability that an immunoblot reactive or indeterminate sample was PCR positive. A mean ratio of greater than 5.0 in a RIBA-II reactive sample was associated with a 100% probability (16/16 tested) of being PCR positive. These observations should be extended by testing RIBA-II negative samples by PCR so that simplified algorithms for anti-HCV testing can be developed.

Astrovirus-associated gastroenteritis in children.

In a small astrovirus-associated outbreak of gastroenteritis in a ward of a local children's hospital two out of five children with symptoms excreted astrovirus particles. No astrovirus particles were found in faeces from the remaining asymptomatic child, and no other viral or bacterial pathogens were found in any of the children. Virus excretion persisted for only a few days. Rising antibody titres to the astrovirus particles were demonstrated in one child, and IgM was also demonstrated in this patient's serum.

Comparison of human fecal and serum parvo-like viruses.

Parvovirus-like particles found in the sera of two blood donors had the size and appearance on electron microscopy of a virus (B19) found in the serum of a blood donor by Cossart et al. (1975), and those of a virus found in the feces of a normal subject. Antibody to these viruses was detected by immune electron microscopy and immunoelectro-osmophoresis in the sera of 50 children aged 10 to 15 years. Of these, 36% had antibody to the fecal virus, 36% had antibody to B19, and 54% had antibody to the two other serum viruses. The results of these tests suggest that serologically the three serum viruses were similar to one another, but that the fecal virus was distinct. The two blood donors had nonspecific symptoms at the time of viremia. Both donors had developed immunoglobulin M antibody to the virus when tested 3.5 and 4.5 weeks later, but no viruses were detected in the feces or urine.