Inquiries on intraspousal transmission of hepatitis C virus: benefits and limitations of genome sequencing and phylogenetic analysis.

During recent years, courts had to decide in some notable cases whether or not defendants infected the plaintiffs with HIV. Lawsuits on the transmission of other viral pathogens up to now have hardly become known. We report here on the use of genome sequencing and phylogenetic analysis to investigate possible intraspousal transmission of hepatitis C virus (HCV). The high degree of genetic relatedness observed in phylogenetic analysis among the HCV strains isolated from the couple demonstrates that the man and the woman are infected with the same isolate of the virus. After other plausible routes of infection have been virtually excluded by anamnestic and conventional epidemiological evaluation we could infer that the man most probably has infected his girlfriend with HCV. This conclusion was further supported by the finding that both are also infected with closely related isolates of GB virus C (GBV-C). Thus, the results from molecular biological investigations and epidemiological evaluation are complementary pieces of evidence in inquiries on possible intraspousal transmission of HCV.

Lack of evidence for an association between TTV infection and severe liver disease.

BACKGROUND: In 1997 a new human virus, TTV, was identified. The clinical significance of the TTV infection, however, remains unknown. OBJECTIVE: Establishment of the prevalence of TTV DNA in different population groups in Germany and the assessment of the possible clinical significance of TTV infection. STUDY DESIGN: Detection of the TTV DNA by PCR in blood donors, patients with end-stage liver disease, and multiple transfused patients with haemotological disorders. RESULTS: TTV DNA was detected in 16 of 122 (13.1%) volunteer blood donors, in 34 of 77 (44.2%) patients with end-stage liver disease, and in 21 of 38 (55.3%) multiple transfused patients. There was no difference in the prevalence of the TTV DNA in end-stage liver disease patients with regard to sex, age, presence of HCV and HBV infection markers, and etiology of liver disease. Phylogenetic analysis of the amplified DNA fragments from 12 randomly selected TTV infected subjects demonstrated that in Germany at least two putative TTV genotypes and four subtypes are circulating. CONCLUSIONS: (i) TTV is widely spread in German population; (ii) one of the possible ways of its transmission is blood transfusion; (iii) TTV infection most probably does not generally lead to the development of the end-stage liver disease.

Sequence variability in the putative coding region of TT virus: evidence for two rather than several major types.

Recently a new human virus, TT virus (TTV) was identified in the serum of a patient with post-transfusion hepatitis of unknown aetiology. Comparative sequence analysis of a 222 nt fragment of ORF 1 of TTV was performed to assess the genomic variability of this virus. Phylogenetic analysis of the nucleotide sequences of 76 TTV isolates collected in 17 countries segregated them into two major groups: TTV 1 and TTV 2. The TTV 1 group comprised two distinct subgroups, which corresponded to previously described TTV subtypes 1a and 1b. The TTV 2 group was separated into four main branches, two of which included sequences previously provisionally attributed as TTV types 2 and 3. Bootstrap resampling, however, did not support the reliability of this grouping, suggesting that the isolates in the TTV 2 group should be considered as subtypes of a single type rather than different TTV types.

Genetic heterogeneity of hepatitis G virus isolates from different parts of the world.

Comparative sequence analysis of a 354 nt fragment of the NS5 region of hepatitis G virus (HGV) isolates was performed to assess two levels of HGV genomic variability: (1) heterogeneity of HGV within an infected individual, and (2) heterogeneity of different HGV isolates. Comparison of nucleotide sequences of DNA clones from two virus isolates demonstrated that in each infected individual HGV is represented by a population of virions with closely related but heterogeneous genomes (quasi-species). Phylogenetic analysis of nucleotide sequences of 42 isolates collected from 14 countries revealed less significant genome variability of HGV as compared to hepatitis C virus. Sequences of all HGV isolates fell into one group of distribution of evolutionary distances. On a phylogenetic tree all HGV sequences segregated into numerous branches. All sequences of isolates from Africa, South and South-East Asia, however, were clustered together and were separated from those of other isolates collected in Europe, North America and Central Asia.