The molecular epidemiology of type 2a hepatitis C virus (HCV) infections in
patients undergoing haemodialysis in the same unit in a Turkish hospital w
as investigated. Of nine HCV-infected patients four were infected with type
2a, four with type Ib and one with type la viruses. Since type 2 HCV infec
tions in the Turkish population are rare, the possibility of nosocomial inf
ection was investigated by means of phylogenetic analysis of viral sequence
s amplified by the polymerase chain reaction in the NS5b region. One of the
samples failed to show amplification and therefore could not be sequenced.
The sequences of the remaining three virus samples were grouped closely in
a cluster within the type 2a group. The results thus showed that three pat
ients were infected with the same HCV type 2a strain. Seroconversion and cl
inical data suggested that these patients may have been infected on differe
nt occasions, there being possibly more than one mode of transmission. Brea
ches in infection control procedures and lack of environmental decontaminat
ion between two haemodialysis sessions were probably the causes of HCV infe
ctions in these patients.