The Importance of Learning Your Genotype

Most of us learn about Hepatitis C as one disease, however in actuality it's really several different strains of a virus. They are all similar enough to be called hepatitis C virus, yet different enough to be classified into subgroups.

HCV GENOTYPES are broken down into sub-types, some of which include: 1a, 1b, 1c 2a, 2b, 2c 3a, 3b 4a, 4b, 4c, 4d, 4e 5a 6a 7a, 7b 8a, 8b 9a 10a 11a

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Genotype Geography Patterns:

It is believed that the hepatitis C virus has evolved over a period of several thousand years. This would explain the current general global patterns of genotypes and subtypes:

1a - mostly found in North & South America; also common in Australia

1b - mostly found in Europe and Asia.

2a - is the most common genotype 2 in Japan and China.

2b - is the most common genotype 2 in the US and Northern Europe.

2c - the most common genotype 2 in Western and Southern Europe.

3a - highly prevalent here in Australia (40% of cases) and South Asia.

4a - highly prevalent in Egypt

4c - highly prevalent in Central Africa

5a - highly prevalent only in South Africa

6a - restricted to Hong Kong, Macau and Vietnam

7a and 7b - common in Thailand

8a, 8b & 9a - prevalent in Vietnam

10a & 11a - found in Indonesia

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One way to understand the terminology of HCV like 'genotypes' and 'subtypes' is to compare them to things that we can more readily relate to.

Example:

Imagine that Viruses are like canines. Dogs have evolved into different types, just like the thousands of different viruses. Imagine that all terriers are the hepatitis C viruses, Now each type of terrier is representing different genotypes of Hepatitis C.

All terriers are still dogs, but the Australian Terrier is different from the Fox Terrier, just as the Bull Terrier is different from the Border Terrier.

You could take one major terrier type and imagine these as being one of HCV's main types (genotypes). Like the Schnauzer. There are different types of Schnauzers like the Miniature and the Standard. That represents the different subgroups within each genotype.

Now scientists predict that people who have hepatitis C, have billions of actual viruses circulating within their body. Although there may be one or two predominant sub-types, the infection as a whole is not a single entity and is composed of many different quasispecies.

It's believed that of the estimated 160,000 Australians with HCV, approx. 35% have subtype '1a', 15% have '1b', 7% have '2', 35% have '3' (mostly being 3a). The remaining people would have other genotypes.

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