Hepatitis C is an infectious disease affecting primarily the liver, caused by the hepatitis C virus (HCV). The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years. In some cases, those with cirrhosis will go on to develop liver failure, liver cancer or life- threatening esophageal and gastric varices. The present project was carried out to study the prevalence of laboratory based confirmed patients of Hepatitis-C in various public, private hospitals and in high risk groups among the population of Lahore metropolitan and its distribution and pattern with respect to person, time and place. Second part of the project was designed to study the risk factors of Hepatitis-C patients from out patient departments of various public and private hospitals of Lahore. Individuals at high risk from different organizations and occupations across the city population of Lahore metropolitan were also included in the study. The third part of the project was designed to investigate the distribution of genotypes of Hepatitis-C virus among patients through RT-PCR and theireffect on viral load, various haematological and biochemical parameters. Project-I Study-1: To estimate the prevalence of hepatitis C in various public and private hospitals of Lahore Metropolitan among different groups a total of 1399 individuals were tested to estimate the hospital based prevalence of HCV. Out of these 233 individuals produced positive result for Hepatitis-C virus infection. The overall hospital based prevalence was estimated to be 16.66% during the year 2009. The current study revealed that the highest prevalence was estimated in Dialysis patients and Organ recipients (41.17%) followed by General Patients of age > 12 years (14.60%) and pregnant women (10.84%). It was further observed that the least affected group was the Children of age ≤ 12 years (3.85%). Study-2: The results of estimated prevalence of Hepatitis C virus infection in high risk groups from the population in and around Lahore revealed that the highest prevalence was estimated in patients with HIV/AIDS (36.36%) followed by injecting drug users (36.09%), blood donors (17.78%), long rout truck drivers (14.70%), house hold and direct contact personal (14.6%) and prisoners (14.28%). It was also find out that the less affected groups were police department (10.66%), staff nurses and other health care workers (9.87%) and barbers and beauticians (6.97%) while doctors and dental surgeons were least affected (1.32%) among the high risk groups. Study-3: To find out the pattern and distribution of HCV patients with respect to person place and time a total of 924 patients were selected from the registry of Provincial Hepatitis Control Cell Lahore through systematic random sampling. Out of these, 154 fulfilled the inclusion criteria. Among these, 90 were male and 64 were females. Average age of male and female patients was 35.88±10.49 and 37.78±9.12 years, respectively. The age difference between male and female patients was statistically non-significant (P-value>0.05). It was further observed that 147 patients were Punjabi and 7 were from other provinces. Moreover, It was found that the highest number of patients was observed during the month of December (n=18) followed by November, 2008 (n=15), March (n=15) and July, 2009 (n=14) while the least number of patients were observed during the months of September, 2008 and May, 2009 (n=10). Project-II To study the risk factors associated with HCV infection an analytical cross sectional study was conducted. Study-1: Lower socio economic class, place of birth (hospital), delivery assisted by whom and breast feeding were significantly associated with HCV infection in children of age ≤ 12 years. The mean age of reactive and non-reactive general patients was significantly associated (P=0.012) with anti-HCV status. Marital status (OR=2.042), socioeconomic status, blood donation (OR=2.15), prescription by doctor or non-doctor (OR=2.664), route of drug administration, relative having hepatitis and towel sharing (OR=1.987) were also significantly associated (P<0.05) risk factors for HCV infection. The mean age of reactive and non-reactive pregnant women was 27.55±3.43 and 25.37±4.24 years, respectively. Educational level (OR=3.093) and occupational status (OR=2.228) were the important risk factors associated with HCV infection. Tattoo on the body (OR=11.833), comb sharing (OR=20.86) and razor sharing (OR=4.786) were significantly associated (P<0.05) with HCV infection. Pregnant women who gave the history of dental procedures and tooth brush sharing were 3.15 and 4.12 times more prone to get HCV infection, respectively. In 205 patients having dialysis and organ recipients 41.17% patients were reactive for Anti-HCV. Blood transfusion, glass sharing and qualification of the patients were significant factors in this group. Study-2: In case of doctors/dental surgeons a significant association was observed with history of blood transfusion and duties in medical and surgical wards. The nurses who worked in surgical wards, visited beauty salons were significantly associated (P<0.05) with HCV infection. Among health care workers age, gender and other factors did not have any significant influence on the reaction of HCV. Among blood donors female to male ratio was 1:16.5. It was found that the occupational status (p=0.002), place of surgical treatment (p=0.035), history of blood transfusion (p=0.000), ever pricked by sharps (p=0.045), habit of injecting drugs (p=0.04) and glass sharing (p=0.017) were significantly associated with occurrence of hepatitis C in blood donors. In long route truck drivers geographical status, surgical procedure, dental treatment and family history were significantly associated (P<0.05). Among the injecting drug users, demographic factors like marital (P=0.007) and educational status (P=0.000) were found to be significantly associated with HCV infection. Furthermore, the behavioral factors; use of injectable drugs with reused syringes (P=0.003), sharing of syringes in groups (P=0.004), place of shaving (P=0.000), use of disinfected ustra (razor) (P=0.003) and razor sharing (P=0.000) were significantly associated with anti-HCV status for IDUs. Among HIV/Aids patients a statistically significant (P<0.05) difference was present among the ages of reactive and non reactive patients. Comb sharing has also a positive effect of HCV but all other factors were not contributing in this group. In Police personals odds ratio for married persons was higher (9.57) but statistically insignificant. The mean age for reactive persons was 39.75±8.24 years. A non- sexual contact with HCV patient and spoon sharing were significantly associated. In prison inmates skin infection and sexual involvement were significantly associated (P<0.000) with HCV infection. In the group of 43 barbers/beauticians age, working shift, tattoo on body (OR=19.5), injecting drugs (OR=19.5) and pre-testing for HCV (OR=19.5) were significantly associated with HCV infection. In house hold and direct contact group previous history of accidents and family history of HCV (OR=18.36) were significantly associated with HCV infection. Project-III A molecular epidemiological study was conducted in which the HCV reactive patients as tested by ELISA test were subjected to viral load and genotyping through RT-PCR. The positive cases of Project-I were included in this project. In the present study 558 patients were reactive for Anti-HCV. Out of these, 34 (6.09%) patients had Type-1 genotype, 67 (12%) patients were accounted for Type-2 and 410 (73.47%) patients were positive for Type-3. Multiple genotypes were seen in 19 (3.4%) patients, 9 (1.61%) patients had un-type able genotype whereas in 19 (3.4%) patients genotype could not be detected. According to the distribution of genotype-1, 1a was present in 30 (88.23%) while 1b was seen in 4 (11.76%) patients. In patients of Type-2 genotype, 2a and 2b were present in 54 (80.59%) and 13 (19.40%) patients, respectively. In patients having Type-3, 3a and 3b were identified in 353 (86.09%) and 57 (13.90%) patients, respectively. Furthermore, Bilirubin, ALT, AST, ALPT, viral load, Hb, TLC, DLC, Platelet and ESR were statistically same in all genotype. Key Words: HCV; Prevalence; Risk Factors; Genotypes; Haematology" xml:lang="en_US