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Sequencing analysis of hepatitis C virus mixed genotype in a hemodialysis patients
1Division of Pathology, National Institute of Preventive Medicine, Taipei, Taiwan, R.O.C.
Insights
Hepatitis C virus (HCV) genotype distribution in Taiwan revealed mixed-type infections in 3.3% of samples. Further analysis confirmed a hemodialysis patient had a dual HCV infection, not a new variant.
Area of Science:
- Hepatology
- Virology
- Molecular Biology
Background:
- Hepatitis C virus (HCV) genotypes exhibit variations in pathogenicity, infectivity, and treatment response.
- Understanding HCV genotype distribution is crucial for effective public health strategies and therapeutic interventions.
Purpose of the Study:
- To investigate the prevalence and distribution of HCV genotypes in Taiwan.
- To clarify the nature of mixed-type HCV infections detected in serum samples.
Main Methods:
- HCV typing was performed using type-specific DNA primers targeting the HCV core region.
- Nucleotide sequencing of recombinant plasmid DNA and PCR products was conducted using an autosequencer.
- DNA sequences in the NS5 region were analyzed using a primer system designed by Chayama et al. to confirm results.
Main Results:
- Among 280 serum samples, 3.3% (4/122) showed evidence of mixed-type HCV infection.
- Sequence analysis of a hemodialysis patient's samples indicated a dual infection with two distinct HCV strains.
- Results ruled out the possibility of a single infection with a novel HCV variant.
Conclusions:
- Mixed-type HCV infections are present in Taiwan, necessitating further investigation into their clinical implications.
- Dual HCV infections, rather than novel variants, can explain some mixed-type findings.
- Accurate genotyping methods are essential for understanding HCV epidemiology and guiding patient management.
Abstract:
It has become clear that the genotypes of HCV vary with respect to pathogenicity, infectivity, response to antiviral therapy and geographic clustering. The prevalence of genotype distribution of HCV infection in Taiwan was investigated by typing with type-specific DNA primers in HCV core region. Using a design by Okamoto et al., it was found that in 280 serum samples examined, 3.3% (4/122) of the virus detected were mixed type. The implication of mixed type infection remains to be clarified: whether it is a single infection with a new variant, or infection with two HCV virions at different times or confusion with type-specific DNA primers themselves. The nucleotide sequences of the recombinant plasmid DNAs and the PCR products recovered from gel electrophoresis were analyzed by autosequencer. Gene sequences of HCV cDNAs of the two blood donors were used as control. To double check the results, we have also analyzed the DNA sequences of the cloned plasmids in the NS5 region with the primer system designed by Chayama et al. Results indicated that the hemodialysis patient was doubly infected with HCV, rather than by a HCV variant.