Biological and clinicopathological features associated with hepatitis C virus type 5 infections

The biological and clinicopathological features of hepatitis C virus infections of type 1 and type 2 have been well documented. However, little is known about the nature of HCV type 5 infections, which have been found to occur in South Africa but rarely elsewhere.

We investigated the HCV genotypes in 125 viremic blood donors and 125 viremic patients by restriction endonuclease analysis of amplified 5' non-coding region sequences. Donors and patients infected with type 5 were further studied. Serum HCV RNA levels were assessed by a differential-size PCR-aided transcript titration assay.

HCV type 5 infections were identified in seven (5.6%) of the blood donors and in five (4.0%) of the patients. Sera from these 12 persons reacted with the core and NS3 antigens in both RIBA-2 and RIBA-3 tests. Six (50%) and 10 (83%) sera reacted with the NS4 antigens in RIBA-2 and RIBA-3 tests, respectively. HCV type 5 was found to replicate to high titers that ranged from 10(6.0) to 10(8.0) molecules/ml. Transfusion was the most frequently observed risk factor (5 of 12) and persons infected with type 5 were generally older than those infected with other types (< 40 years vs. > or = 40 years, p = 0.01). Cirrhosis was found in two of six (33%) donors and three of four (75%) patients. The duration of infection appeared to be an important determinant for the presence of cirrhosis.

In this small group of Canadians infected with HCV type 5, a high proportion developed severe liver disease.