Sera from 410 patients from the Wuhan area in the central part of China with the diagnosis of chronic liver disease were analyzed for markers of hepatitis B, C and D virus infections. All sera, plus liver biopsy specimens from 188 of the patients, were also tested for hepatitis B virus DNA by polymerase chain reaction. Sixty-eight percent were HBsAg positive in serum, whereas 29% showed markers of past hepatitis B virus infection. Hepatitis B virus DNA was detected in all HBeAg-positive sera but also in 58% of patients with HBe antibody. In the liver specimens of the corresponding patient groups, 97% and 78%, respectively, were hepatitis B virus DNA positive. However, more noteworthy was that of the HBsAg-negative/HBs-antibody positive patients 30% had detectable hepatitis B virus DNA in serum and 32% had hepatitis B virus DNA in liver tissue, whereas in a control group of healthy blood donors, of which 90% had HBs antibody, none was hepatitis B virus DNA positive. Our results demonstrate that among patients with chronic liver disease, infections with hepatitis B virus or hepatitis B virus-related virus(es) may frequently occur without being revealed by conventional serological methods. Hepatitis C and D viruses seem to be of only minor importance in the pathogenesis of chronic liver disease in this part of China.

A polymerase chain reaction (PCR)-based assay using primers against the hepatitis C core gene has been described [Okamoto et al. (1992a): Journal of General Virology 73:673-679]. Within the two major HCV genotypes 1 and 2, the Okamoto system identifies two subtypes each (1a, 1b and 2a, 2b, respectively). Typing is achieved by a primary PCR with consensus primers followed by a nested PCR with type specific primers. The original assay was modified by addition of a parallel second PCR identifying the recently described major genotype 3. The assay also identifies in duplicate subtype 1b (type II by Okamoto), suggested to respond poorly to interferon. Reaction conditions were reviewed and melting temperatures of all typing primers equalised to increase strigency. The modified system functioned well and typing results were supported by partial core sequencing. The following distribution of genotypes was found in 53 hepatitis C virus (HCV) infected Swedish blood donors: genotype 1a (57%), 3 (19%), 1b (13%), and 2b (11%). In six recipients of HCV infected blood identified in a retrospective study, the recipient HCV genotype was identical to donor HCV genotype. Furthermore, in HCV positive couples identical genotype was observed when only one partner had an external risk factor; whereas genotypes were often diverse if both sex partners had parenteral risk factors. Finally, a cluster of hepatitis C cases in a haemodialysis unit was evaluated retrospectively. Eight patients had genotype 1b, two had mixed 1a and 1b, and one had type 1a. The modified HCV genotyping assay was of value in examining different epidemiological situations and can be expanded presumably to include future genotypes.

Two different categories of hepatitis B antigen carriers have been investigated. One comprises patients treated with dialysis and known to be highly infectious. The other consists of blood donors found in routine screenings. Serum specimens have been studied with regard to Dane particles, Dane-core-associated DNA polymerase activity, and e-antigen. The two groups differed markedly in the aspects studied. The five healthy blood donors had no, or very few, detectable Dane particles and no detectable DNA polymerase activity; four of the five healthy donors had antibodies against e-antigen. The one sick donor and all six dialysis patients had many Dane particles and polymerase activity; five of the six dialysis patients had e-antigen. Thus, these results further underline the difference between the two groups, and e-antigen and DNA polymerase activity could represent possible useful parameters for judging infectivity.

One hundred and ten consecutive cases of acute sporadic hepatitis among Ethiopian patients were studied to define viral causes, identify risk factors, and analyze demographic and clinical data. IgM antibodies to hepatitis A virus were found in nine patients (8%), and hepatitis B surface antigen and IgM antibodies to hepatitis B core antigen were found in 22 (20%); these findings were considered evidence of acute hepatitis A and hepatitis B, respectively. Sera from the remaining 79 patients were tested for antibodies to hepatitis E virus by a blocking fluorescent antibody test. Thirty-six (33%) of these patients were seropositive, as compared to 4 (7%) of 59 healthy control subjects; for 43 patients (39%), the cause of the acute sporadic hepatitis was unidentified. Twenty-one (19%) of the patients had antibodies to hepatitis C virus, as determined by ELISA. Demographic, biochemical, and clinical data (except in regard to sequelae) were comparable for the different types of infections. The study subjects included 32 pregnant women, 19 (59%) of whom had hepatitis E virus infection; these infections caused death in eight of the women (mostly in the third trimester) and 10 fetal complications. Thus, hepatitis E virus is a common cause of acute sporadic viral hepatitis in Ethiopian patients, and its occurrence during pregnancy is associated with high maternal and fetal morbidity and mortality.

The low specificity of screening ELISAs for antibodies to hepatitis C virus in blood donors has called for confirmatory tests. Two types of supplementary antibody assays are available, recombinant immunoblot assays (RIBA-1 and RIBA-2) and an antibody consumption test referred to as a neutralization assay. Amplification of viral nucleic acid by the polymerase chain reaction (PCR) provides an antibody independent mode of detecting viral infection. We applied reverse transcription-double PCR to detect an HCV 5'-noncoding viral RNA sequence in serum specimens and compared PCR findings with confirmatory antibody tests. This study includes sera from 37 blood donors found positive by the Ortho anti-HCV (C100-3) ELISA out of 14,591 donations. Of the 37 positive sera, 8 were positive by RIBA-1 and 1 further by RIBA-2. Seven of the RIBA positive sera contained HCV RNA by PCR. Among the 8 indeterminate and the 21 negative donor sera by RIBA-1, no PCR positive serum was found. The 37 anti-HCV positive donor sera identified by Ortho ELISA were also tested by Abbott anti-HCV (C100-3) ELISA whereby 22 were positive. Of these 22 sera plus 1 further with ELISA OD just below cutoff, 8 were positive by the "neutralization assay," (Abbott Laboratories, North Chicago, IL, USA) and 6 of these, including the borderline serum, were PCR positive. One of the two neutralizable but PCR negative sera was RIBA positive and the other was indeterminate. However, one ELISA (Abbott Laboratories) positive (OD 1.99) serum was not neutralizable but nevertheless contained HCV RNA by PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

An outbreak of acute hepatitis E virus (HEV) infection occurred from October 1988 to March 1989 in military camps in northern Ethiopia. The epidemic was waterborne and entirely confined to military men, of whom 423 hospitalized, icteric patients were studied. The clinical course was mild and short, without any fulminant hepatitis or death. All sera tested for anti-HAV-IgM were negative and among 54 (13%) patients who were positive for HBsAg, 7 (2%) were positive for anti-HBc IgM. On the other hand, 28 of 30 (93%) patients had antibodies against hepatitis E virus (anti-HEV) in contrast to 1 of 29 (3%) asymptomatic controls (P less than .01). The need for an easily available, inexpensive serologic test for HEV infection, protection of water supplies from fecal contamination, adequate chlorination and/or boiling of drinking water, and health education about personal and environmental hygiene, especially in communities at high risk, is emphasized.

To investigate the epidemiology of infection with delta (delta) agent in a Swedish city, 181 chronic carriers of hepatitis B surface antigen (HBsAg) and 599 patients with acute, self-limited hepatitis B were analyzed for delta antigen and antibody to delta antigen (anti-delta). The study covered the period from 1970 to 1981. The delta agent was found to have been introduced to this population in 1973. Markers of infection with delta agent were almost exclusively found in intravenous drug addicts and their close contacts. The proportion of drug addicts who were chronic HBsAg carriers with anti-delta increased with time and reached 72% in 1979-1981. An episode of acute hepatitis was frequently seen in connection with seroconversion to anti-delta. Among the domestic cases of acute, self-limited hepatitis, no simultaneous infections with hepatitis B virus and delta agent were found before 1975. From 1975 to 1980, between 18% and 44% of the drug addicts with acute hepatitis B were also infected with delta agent.

A search for the simultaneous presence of two hepatitis C virus (HCV) types in sera of a group of chronically infected intravenous drug users, hemodialysis patients and hemophiliacs from Sweden and Russia was performed with two genotyping methods based on the use of type-specific primers from core and NS4 regions of the viral genome. An important feature of NS4 based assay is that type-specific primers are used in both rounds of nested PCR, thus providing the possibility of the identification not only of the abundant type, but also of the minor HCV type present in a particular serum. The experiments, however, did not reveal the simultaneous presence of two or more HCV types in any of the 40 samples. These results suggest that the frequency of mixed infections in serum with different HCV types is very low even in high-risk groups, at least in the geographic region studied.