E A Follett

Detection of three types of hepatitis C virus in blood donors : investigation of type-specific differences in serologic reactivity and rate of alanine aminotransferase abnormalities

The serologic reactivity and epidemiology associated with different hepatitis C virus (HCV) variants were investigated in a cohort of 113 anti‐HCV‐positive donors. In Scotland, HCV type 1 accounted for one‐ half of all infections; 40 percent of subjects were infected with HCV type 3, and the remainder were infected with type 2. Reactivity with the NS‐4‐encoded antigens in the first‐generation anti‐c100 assay was absent in 68 percent of donors infected with types 2 and 3, as compared with 10 percent for those infected with type 1. Even when combined with surrogate marker testing, first‐generation tests would have failed to detect 12 percent of HCV‐infected blood donors. The age distribution, incidence of past infection with hepatitis B virus, and reported risk factors were similar in donors infected with types 1 and 3 (mean ages were 31.9 and 29.9; 18 and 17.5% were positive for antibody to hepatitis B core antigen; and 47 and 48% had past intravenous drug abuse). However, the distributions of alanine aminotransferase levels were significantly different in those infected with type 3 (abnormally raised in 83%) and those infected with type 1 (55% abnormal alanine aminotransferase; p < 0.05) or type 2 (60%; p < 0.01) and those who were nonviremic (8%; p < 0.0001). These data suggest that HCV type 1 is the most common HCV infection in blood donors and that infection with HCV type 3 may be associated with more severe liver disease, because of more recent infection or because of a greater inherent pathogenicity of type 3 variants.

A cumulative review of studies on travellers, their experience of illness and the implications of these findings

A cumulative review of illness experienced by 13,816 travellers returning to Scotland since 1977, shows an overall attack rate of 36%. Alimentary complaints predominated; 18% of travellers had these alone and a further 10% had other symptoms as well as their gastro-intestinal disorder. Higher attack rates were noted in those taking package holidays. Inexperience of travel, smoking, more southerly travel and younger age (particularly those between 20- and 29-years-old) were other contributing factors. A similar pattern emerged from a I year study of hospital in-patients with travel related admissions. Serological studies of 470 travellers showed that 20% had incomplete immunity to poliomyelitis; 25% of those tested (312 travellers) had serological evidence of typhoid immunisation, I.9% (of 760 travellers) had antibodies to Legionella pneumophila, 64% (5II travellers tested) had antibodies to hepatitis A, 87% (288 tested) had adequate levels of tetanus antitoxin but only 40% of the 225 travellers tested had adequate levels of diphtheria antitoxin. Amongst a subgroup of 645 travellers the travel agent was the most frequently consulted source of pre-travel health advice. This carries particular significance for the dissemination of relevant advice in view of the inadequacies found from study of the health information in travel brochures. These findings, viewed against the perspective of the continuing growth in international travel, means that travellers, the medical profession, the travel trade, health educators, global health agencies and health authorities in those countries accepting and encouraging tourists, will be required to recognise the health implications of further tourism development if this problem of illness associated with travel is to be brought under control.

Influence of smoking on immunological responses to hepatitis B vaccine

When 115 health-care workers participated in a study that monitored their serological responses to hepatitis B vaccine at regular intervals, it was found that smoking significantly affected their antibody titre responses adversely. The study group was randomly allocated into two comparable groups that received hepatitis B vaccine either in a rapid schedule (vaccination at 0, 1, 2 and 12 months) or a standard schedule-most commonly used worldwide-(vaccination at 0, 1, and 6 months). A significantly higher proportion of smokers, in both schedules, failed to seroconvert and to achieve higher antibody levels at month 3 (p = 0.01) and at month 13 (p = 0.0003). At month 7 a similar pattern was noted in smokers following the standard vaccination schedule (p < or = 0.05), but not in those following the rapid schedule.

Relevance of RIBA-3 supplementary test to HCV PCR positivity and genotypes for HCV confirmation of blood donors

HCV antibody screening of 624,910 blood donations resulted in 3,832 samples being referred for confirmation. All were tested by RIBA‐3 with 2,710 negative, 945 indeterminate and 177 positive results. HCV RNA was detected by PCR in an average of 69.5% of RIBA‐3 positives (4 bands 84.1%; 3 bands 74.1%; 2 bands 34.1%) and only 0.53% of RIBA‐3 indeterminates. Eighty‐four percent of samples with a total RIBA‐3 band intensity score (maximum 16) of ≥8 were PCR positive compared with only 22% of those with a score of <8. Total mean band intensities for HCV genotype 1 samples (n = 65) were 13.2, genotype 2 (n = 17) 11.4 and genotype 3 (n = 65) 11.2 with type 1 samples showing greater reactivity with c100 and c33 antibodies. No PCR positive type 1 samples were found with RIBA‐3 total band scores less than 8, no PCR positive type 2 samples less than 6, whilst PCR positive type 3 samples were found with scores as low as 2. NS5 indeterminates were the most common (40.2%) single band pattern but yielded no PCR positive samples, followed by c33 (23.3%) with one PCR positive and c100 (20.2%) with one PCR positive whilst c22 indeterminates were least common (16.3%) but included three PCR positive donors. All five RIBA‐3 indeterminate PCR positive donors were type 3.

HIV testing among injecting drug users in Glasgow

The use of saliva rather than blood for epidemiological studies of HIV prevalence, especially among injecting drug users, has several practical advantages. In a cross-sectional, behavioural and prevalence study among drug users in Glasgow during 1990, salivary samples were therefore obtained by the use of salivettes. Such samples were requested for anonymous anti-HIV testing from 498 persons in locations varying from residential rehabilitation centres to the open streets. Of this number, 35 refused to give a sample, resulting in a compliance rate of 93%. Of the 463 salivettes received by the laboratory, eight were found to be dry. Of the remaining 455 specimens, eight were found to be positive for HIV-1 antibody by means of an IgG antibody capture ELISA, so giving a prevalence rate of 1.8%. The results of testing saliva and blood spot samples collected at the same time on filter paper from 98 persons for HIV-1 antibody were 100% concordant. The study confirms the experience of others that specimens of saliva are easy to collect under variable conditions by non-medical staff and demonstrates that the salivette can provide an HIV antibody test result the same as that obtained from a blood spot. The prevalence of HIV antibody determined in this study is similar to that of other studies taking place in the city during the same period of time.

Hepatitis C virus in saliva of haemophiliac patients attending an oral surgery unit

This study determined the frequency with which hepatitis C virus (HCV) could be detected in the saliva of 21 HCV-seropositive haemophiliac patients attending an Oral Surgery Unit. All sera were positive for HCV RNA by the polymerase chain reaction (PCR). Six of the patients were also HIV antibody positive. Saliva was collected both by spitting into a Universal container (whole saliva), and by means of Salivettes. Following RNA extraction from saliva specimens and synthesis of cDNA, nested PCR was performed. Amplified DNA was detected by agarose gel electrophoresis and ethidium bromide staining. Overall, HCV was detected in saliva from 10 of the subjects (8 HIV seronegative and 2 HIV seropositive) but there was not complete concordance between the Salivette specimens and normal whole saliva. Analysis of pellet and supernate fractions from whole saliva produced similar discrepancies. Repeat runs of PCR for HCV following freezing and thawing of the initially positive saliva specimens were unsuccessful. It was concluded that HCV is present in the saliva of some haemophiliac patients. However, careful optimisation of sample handling and storage methods and of PCR technique are required before the true prevalence of HCV shedding in saliva can be determined.

Third-generation recombinant immunoblot assay: comparison of reactivities according to hepatitis C virus genotype.

BACKGROUND: Recombinant immunoblot assay (RIBA) is widely used as a supplemental test in hepatitis C virus (HCV) confirmatory algorithms. As this assay is based on HCV type 1, its performance was examined with the common European HCV genotypes (1, 2, and 3). STUDY DESIGN AND METHODS: A study was performed to retest in third‐generation RIBA (RIBA‐ 3) all 146 second‐generation RIBA (RIBA‐2)‐positive polymerase chain reaction‐positive samples detected by second‐generation enzyme‐linked immunosorbent assays and having known HCV genotypes (74 HCV type 1, 21 type 2, 51 type 3). RIBA band intensities were examined according to HCV genotype. An additional 90 RIBA‐3‐confirmed PCR‐positive samples (47 HCV type 1, 5 type 2, 38 type 3) detected by third‐generation enzyme‐linked immunosorbent assays were also examined. RESULTS: In the first group of 146 samples, the RIBA‐3 NS4 (c100p) band showed a marked improvement in sensitivity for the detection of HCV types 2 and 3 over that of the c100 antigen of RIBA‐2, but the mean band intensities of HCV types 2 and 3 remained significantly lower than those of type 1. Improved sensitivity of the NS3 band of RIBA‐3 to HCV type 3 was also apparent, but, again, the mean band intensity measured was lower for type 3 than for either type 1 or type 2. The c22 band of RIBA‐2 and RIBA‐3 exhibited equal sensitivity for all HCV genotypes. These differences were also apparent when RIBA‐3 was used in conjunction with third‐generation enzyme‐linked immunosorbent assays. CONCLUSION: The current RIBA‐3 lacks sensitivity to the NS4 antibody for HCV types 2 and 3. The incorporation of type‐specific components to other genotypes for NS4 (and NS3) antigens should be considered by the manufacturers.

Failure of 2nd- and 3rd-generation HCV ELISA and RIBA to detect HCV polymerase chain reaction-positive donations

In the early 1980s, several countries introduced alanine aniinotransferase (ALT) testing of blood donors as a surrogate test for non-A non-B hepatitis. During the period 1980-1984, an ALT study was performed on 10,521 West of Scotland blood donors including 5,057 donors from prisons in West Scotland. A total of 54 donations, 50 from prison donors and 4 from other donors, were found to have ALT values in excess of 2.5 times the upper limit of nonnal criteria used by many to indicate hepatitis. All 54 donations were HBsAg negative by radioimmunoassay (Ausria 2: Abbott Laboratories). Thirty-two of the 54 plasma donations were stored at -20°C and aliquots were tested for the presence of anti-HCV, HCV RNA and anti-HBc in 1993. All 32 were male donors and all but 1 were prisoners, all fiilfilling the 1984 criteria for donors. Anti-HCV screening was performed using 2ndand 3rd-generation Abbott and Ortho Diagnostics HCV ELISAs. Twenty-six of the 32 donations were reactive with all 4 ELISAs whilst the remaining 6 were non-reactive with all 4 ELISAs. In the RIBA-2 assay (Chinon Corp.) 23 of the reactives were positive and 3 were indeterminate (1 c22; 2 c33 only). The 6 ELISA non-reactives were negative. All samples were retested by RIBA-3. The 3 RIBA-2 indeterminates became positive suggesting that all 26 of the donations that were reactive by 2ndand 3rd-generation Failure of 2ndand 3rd-Generation HCV ELSA and RIBA to Detect HCV Polymerase Chain ReactionPositive Donations

Estimates of HIV infection among injecting drug users in Glasgow, 1985-1990.

ObjectiveTo use research and surveillance studies in Glasgow (Scotland, UK) to estimate the number of current injectors infected with HIV, the total number of injectors infected up to the end of 1990 and the recent incidence of infection. Design(A) Prevalence of injecting drug use was estimated using log-linear modelling. (B) Prevalence of HIV infection was determined from voluntary testing of a community-wide sample of injectors

Inter-laboratory comparison of diagnosis of rotavirus infections in Scotland

Abstract Samples of 23 rotavirus positive and 17 rotavirus negative faecal specimens were distributed to 15 laboratories in Scotland which undertake rotavirus diagnosis. The results with the various techniques, electron microscopy (EM), polyacrylamide gel electrophoresis (PAGE), enzyme-linked immunoassay and latex agglutination were compared. EM and PAGE were specific and sensitive. Although the results from most commercial kits were satisfactory, there were some which were unsatisfactory. Considerable inter-laboratory variation with the same kit was also noted.