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Geographical distribution of hepatitis C virus genotypes in blood donors: an international collaborative survey
1Edinburgh and South East Scotland Blood Transfusion Service, Royal Infirmary of Edinburgh, United Kingdom.
Insights
Hepatitis C virus (HCV) genotype distribution varies globally. Type 1 is common in Europe and Asia, while type 4 dominates in Egypt, suggesting region-specific vaccine needs.
Area of Science:
- Hepatology
- Virology
- Epidemiology
Background:
- Hepatitis C virus (HCV) is a significant global health concern.
- Understanding the geographical distribution of major HCV genotypes is crucial for effective treatment and vaccine development.
- Previous studies have indicated variations in HCV genotype prevalence across different regions.
Purpose of the Study:
- To investigate the frequency of six major hepatitis C virus (HCV) genotypes in blood donors across nine countries.
- To analyze the geographical distribution of HCV genotypes and their serological reactivity.
- To inform the development of effective, potentially region-specific, HCV vaccines.
Main Methods:
- Collected plasma samples from 447 HCV-infected blood donors across Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan.
- Amplified viral RNA from the 5'-noncoding region.
- Typed HCV genotypes using restriction fragment length polymorphism (RFLP) analysis with specific enzymes (HaeIII-RsaI, ScrFI-HinfI, MvaI-HinfI).
- Assessed serological reactivity using the Chiron RIBA-2 assay.
Main Results:
- HCV genotypes 1, 2, and 3 were predominant in Western Europe and Australia.
- HCV genotype 1 was prevalent in Hungary, with types 2 and 3 absent.
- Japan and Taiwan showed infections with types 1 and 2, while Hong Kong had types 1, 2, and 6.
- HCV genotype 4 was almost exclusively found in Egyptian donors.
- Type 1 infection elicited broad serological reactivity; divergent genotypes primarily reacted with specific antigens (c22-3, c33c).
Conclusions:
- Significant geographical variations in HCV genotype distribution were observed.
- HCV genotype 1 exhibits broad serological reactivity, while other genotypes show more specific reactivity patterns.
- The high variability in HCV envelope regions suggests a need for multivalent and geographically adapted vaccines.
Abstract:
The frequency of infection with the six classified major genotypes of hepatitis C virus (HCV) was investigated in 447 infected volunteer blood donors from the following nine countries: Scotland, Finland, The Netherlands, Hungary, Australia, Egypt, Japan, Hong Kong, and Taiwan. Viral sequences in plasma from blood donors infected with HCV were amplified in the 5'-noncoding region and were typed by restriction fragment length polymorphism analysis. Electrophoresis of DNA fragments produced by cleavage with HaeIII-RsaI and ScrFI-HinfI allowed HCV types 1 (or 5), 2, 3, 4, and 6 to be identified. Further analysis with MvaI-HinfI allowed sequences of the type 5 genotype to be distinguished from sequences of the type 1 genotype. Types 1, 2, and 3 accounted for almost all infections in donors from Scotland, Finland, The Netherlands, and Australia. Types 2 and 3 were not found in the eastern European country (Hungary), where all but one of the donors were infected with type 1. Donors from Japan and Taiwan were infected only with type 1 or 2, while types 1, 2, and 6 were found in those from Hong Kong. HCV infection among Egyptians was almost always by type 4. Donors infected with HCV type 1 showed broad serological reactivity with all four antigens of the second generation Chiron RIBA-2 assay (Chiron Corporation, Emeryville, Calif.), while infection with divergent HCV genotypes elicited antibodies mainly reactive to c22-3 and c33c. Reactivities with antibodies 5-1-1 and c100-3 were infrequent and were generally weak, irrespective of the geographical origin of the donor. Because the envelope region of HCV is even more variable than the NS-4 region, it is likely that vaccines based on these proteins need to be multivalent and perhaps specifically adapted for different geographical regions.