Low Seroprevalence of Torque Teno Virus in HCV positive patients and phylogenetic analysis from Pakistani isolates.

The torque teno virus (TTV) has a heterogeneous genome and its role in hepatitis C (HCV) infection is still controversial, therefore the purpose of the present study was to determine if there is any association between Hepatitis C and TTV co-infection and to determine the phylogenetic relationship between existing types in the Pakistani population. A total of 500 individuals (250 HCV positive patients and 250 healthy controls) were selected. DNA was extracted from serum samples and polymerase chain reaction (PCR) of the open reading frame 1 (ORF1) region of TTV was performed. Out of 500 samples 9 HCV positive index cases (3.6%) and 8 healthy samples (3.2%) were found to be positive for TTV. A comparison was made between TTV sequences reported from all over the world with the ones obtained in the present study by sequencing of TTV positive samples followed by phylogenetic analysis using maximum parsimony (MP) method. Our results indicated that the virus was undergoing divergent evolution as very high sequence diversity was found in the ORF1 gene. The study also shows that association between HCV and TTV was not found. Because the virus was found to be affecting both healthy individuals and HCV infected population with almost same frequency. Therefore a thorough screening of TTV virus at the population level is required in order to draw a comprehensive inference.