The hepatitis c virus is an rna containing flavivirus which cannot yet be grown but which can infect primates.humans seem to be the sole source of infection and inoculation with blood or blood products isthe best recognised mode of transmission.
Hcv caused over 90% of post transusion hepatitis before serological tests allowed the screening of blood donors and accounted for the high incidence of chronic hepatitis in patients with haemophilia.screening of blood donors and heat treatment of coagulation factor concentrates should prevent infection in future.parentral drug users continue to be a high risk of hcv infection.sexual and vertical spread may occur but are less common than in hbv infection.
Chronic infection occur in about 70-80% of patient and this is usually life long.patient with chronic infection are often asymptomatic or complain of mild fatigue.other manifestations are vasculitis,arthritis and glomerulonephritis.
Hcv contain several antigens giving rise to antibodies in infected person and this used in diagnosis.current laboratory diagnosis depend on identifying antibodies to several viral anitgens.this test generally identify chronic hcvinfection,as the diagnostic antibodies appear irregularlyin the blood during the first three month of illness.
Approximately 50% of patient will respond to interferon but relapse is common and only 20% show long term response.
The treatment of choice for chronic hapatitis c infection is now a combination of interferon and ribavirin.the later is a synthetic nucleoside analogue whic resemble guanosine.ribavirin’s maintoxicity is haemolytic anaemia and the drug should be avoided in patients with pre existing anaemia or cardiopulmonary disease.it also cause abortion when given to women.