| Abstract|| |
Hepatitis C virus (HCV) infection is widely prevalent world-wide particularly in high-risk individuals including patients on hemodialysis (HD). Parenteral route seems to be the main route of transmission of this infection though other routes also exist. The high prevalence of HCV infection in patients on HD who have never received blood transfusions points to the dialysis machine as one of the likely sources of transmission of infection. The reported prevalence of antiHCV in patients on HD in Saudi Arabia is about 68%. The natural history of HCV shows a tendency to progress to chronic liver disease including chronic active hepatitis, cirrhosis and hepatocellular carcinoma. The prevalence of anti-HCV in the general population varies from 0.5 to 3% and thus vigorous screening should be applied to all potential blood donors. A policy of public health education should be designed and implemented on the general public and health workers to reduce the non-parenteral spread of HCV. Separate HD machines should be considered for patients who are anti-HCV positive. Such preventive measures are vital because treatment of HCV with interferon has met with mixed success so far.
Keywords: Hepatitis C virus infection, An update, Saudi Arabia.
|How to cite this article:|
Al-Faleh FZ. Hepatitis C Virus Infection: An Update. Saudi J Kidney Dis Transpl 1995;6:118-21
| Introduction|| |
Viral hepatitis could be caused by five etiological agents namely hepatitis A, B, C, D and E. Viral hepatitis B and C are now seen as the most common cause of chronic liver disease throughout the world. Due to the availability of sensitive and specific tests for these viruses considerable progress has been made in our understanding of viral hepatitis. In this article, I intend to update the information on certain aspects of hepatitis C virus (HCV) infection. This update will cover the possible modes of transmission, epidemiology, prevention and treatment including our experience in Saudi Arabia.
| Transmission|| |
A. Parenteral blood and blood products
The high prevalence of antibody of HCV (anti-HCV) among frequently blood transfused patients (e.g. thalassemics), those who receive blood products (e.g. hemophiliacs), and among intravenous drug abusers confirmed the parenteral route as the major route of HCV infection. Those at risk for acquiring the infection by the parenteral route also include patients on hemodialysis (HD). However, only 40% of HCV infection could be explained by parenteral transmission and the remaining are usually referred to as community-acquired infection. In a recent study in Gizan, Saudi Arabia, only 25% of anti-HCV positive persons had a past history of blood transfusion  .
B. Sexual transmission
Heterosexual transmission of HCV is uncommon. In some of the studies where partners of anti-HCV positive cases were investigated, the evidence for sexual transmission of HCV was minimal  .
C. Perinatal transmission
Perinatal transmission of hepatitis B virus infection is well established. In case of HCV infection, most of the studies have failed to demonstrate mother-to-infant transmission (vertical transmission). Infants born to antiHCV positive mothers may become transiently anti-HCV positive but this antibody is of maternal origin  . The application of polymerase chain reaction (PCR) in testing infants born to anti-HCV positive mothers has also confirmed the uncommon incidence of mother-to-infant transmission of HCV , .
D. Intrafamilial transmission
Intrafamilial transmission does not seem to be an efficient route for spread of HCV  . Family members and contacts of 20 Saudi patients with chronic HCV infection are currently under investigation for possible contraction of HCV infection. Our preliminary data support earlier reports that intrafamilial transmission of HCV is uncommon.
E. Arthropod-borne vectors
So far, there is no evidence to support such routes of transmission except for the high prevalence of community acquired HCV that has been noted in areas where the presence of arthropods is common.
F. Other routes of transmission ?
The association between high HCV infection rate and the frequent use of machines or syringes that are not properly sterilized is strong. Sherlock emphasizes this association to explain the difference in the prevalence of HCV infection between North Europe and South Europe (European Association for the Study of the Liver (EASL) meeting in Greece, 1994). Also, the high prevalence of HCV infection in patients on HD who did not receive blood transfusion points to the dialysis machines as the likely source of infection  .
Folk medicine could also contribute to the transmission of HCV infection if the instruments used are not properly sterilized. Cautery, circumcision and venesection are some examples of folk medicine which could be incriminated in transmitting HCV in some countries including Saudi Arabia and other Middle Eastern countries. In an area of Japan, which is hyperendemic for HCV (anti-HCV prevalence rate: 20.5%), it was shown that the primary cause of this high rate of infection was the use of unsterilized needles in the practice of folk medicine  .
| Epidemiology|| |
Hepatitis C infection is widely distributed throughout the world. In Japan, it has been reported that 1-3% of blood donors are antiHCV positive  . In Western countries, the prevalence of HCV infection in the general population ranges from 0.5-3%. In Saudi Arabia, we reported the prevalence of anti-HCV among children 1-10 years old to be 0.7%  . Published data on blood donors showed the prevalence of anti-HCV to range from 0.3-3% , and in a recent nationwide screening program of blood donors, a prevalence of 1.1% was found (Al-Momen AK, personal communication). In a community-based study in Gizan, we showed that the prevalence of anti-HCV could reach 5% in people over 50 years of age  .
Among the high-risk groups for acquiring HCV infection are patients with end-stage renal disease maintained on HD. Huraib, et al  , in a multi-center study, reported a prevalence of anti-HCV of 68% among Saudi patients on HD. Also, Saudis with liver disease were found to have high prevalence of anti-HCV (25-50%) , . The natural course of HCV shows a tendency to progress to chronic liver disease in more than 50% of cases. The time interval between chronic hepatitis and the development of cirrhosis ranges from 3 to 10 years. About 20% of patients with chronic active hepatitis (CAH) go on to develop cirrhosis and later hepato-cellular carcinoma.
| Prevention|| |
After introducing sensitive and specific tests (second generation ELISA assay) for screening blood donors, one would expect a rapid decrease in post-transfusion-related hepatitis. The optimal goal would be to achieve zero hepatitis risk following blood transfusion. With regard to other possible routes of transmission of HCV infection like medical, dental, and folk medicine practices, a policy of public health education should be designed and implemented on the general public as well as health workers. Strict sterilization procedures of instruments and machines is essential. Furthermore, in HD centers, a separate machine for HCV positive persons should be considered along with increased precautionary measures among the HD staff. Preparation of a vaccine against HCV infection is in progress. The Chiron group in USA has announced the development of such a vaccine at the International Symposium on Viral Hepatitis and Liver Diseases in Tokyo in 1993. However, it will not be easy to develop protective vaccine against all types of HCV due to the heterogeneity of the HCV genome  .
| Treatment|| |
Inferferon α and β were introduced for the treatment of chronic hepatitis since 1985 and are now the standard treatment of chronic HCV. Among Western patients, the initial response was reported to be between 40-70% but sustained response was noted in only 10-25% of the treated patients  . Various regimens for treatment of chronic hepatitis C have been tested and the most commonly accepted one is 5 mU three times a week for 6 months. Gender, presence or absence of cirrhosis on liver histology, virus load and genotype are among the factors which might influence the final outcome of treatment. In a pilot study, Al-Karawi, et al reported a 23% initial response rate in Saudi patients with chronic hepatitis C treated with interferon  . In another study from Saudi Arabia, a sustained response rate of 53% was reported in 13 patients with chronic hepatitis C and end-stage renal disease treated with inteferon  . We have just completed a multi-center study of interferon treatment of chronic hepatitis C among Saudi patients (manuscript is under preparation) and the intitial response in the 66 patients studied was 32%.
Ribavirin has also been used in the treatment of chronic hepatitis C  and results have shown a return of alanine transaminase levels to the pre-treatment value after discontinuing the drug  . Studies using combination therapy of interferon and ribavirin are now in progress in many clinical centers.
| Conclusion|| |
Hepatitis C virus infection is widely prevalent world-wide, particularly in some high-risk groups like patients receiving frequent blood transfusions and patients on maintenance HD. Though the parenteral route is the commonest route of transmission of the virus, there may be some as yet unidentified routes. Strict attention should be paid to prevent the transmission of the virus since preliminary results with therapy are not satisfactory.
| References|| |
|1.||Al-Faleh FZ, Ramia S, Arif M, et al. Profile of hepatitis C virus (HCV) and the possible modes of transmission of the virus in Gizan area, Kingdom of Saudi Arabia: a community based study. Am Trop Med Parasitol 1995 (In press). |
|2.||Alter HJ. Transmission patterns in hepatitis C virus infection. In Nishioka K, et al. (eds). Viral hepatitis and liver disease. Springer Verlag, 1993;445-9. |
|3.||Gitnick G. Hepatitis C: what progress ? Scand J Gastroenterol Suppl 1992;192:50-4. [PUBMED] |
|4.||Reinus JF, Leikin EL, Alter HJ, et al. Failure to detect vertical transmission of hepatitis C virus. Ann Intern Med 1992;117:881-6. [PUBMED] |
|5.||Wfejstal R, Widell A, Mansson AS, Hermodsson S, Norkrans G. Mother-toinfant transmission of hepatitis C virus. Ann Intern Med 1992;117:887-90. |
|6.||Pipan C, Amici S, Colle R, Botta GA. Intrafamilial transmission of hepatitis C virus. J Infect 1994;29:353-61. [PUBMED] [FULLTEXT]|
|7.||Michieletto L, Pipan C, Tempasta D, et al. HCV infection in hemodialysis patients. Proceedings of the International Symposium of Viral Hepatitis and Liver Disease held in Tokyo, Japan, 1993;579:10-14. |
|8.||Alter H. Transmission patterns in hepatitis C virus infection. In: Nishioka K, et al. (eds). Hepatitis and liver disease. Springer Verlag. 1993;445-8. |
|9.||Nagata I, Iizuka T, Harada Y, et al. Prospec tive study of mother-to-infant transmission of hepatitis C virus. In: Nishioka K, et al (eds). Viral hepatitis and liver disease. Springer Verlag, 1994;468-70. |
|10.||Al-Faleh FZ, Ayoola EA, Al-JeffryM et al. Prevalence of antibody to hepatitis C virus among Saudi Arabian children: a community based study. Hepatology 1991;14:215-8. |
|11.||Al-Mofarreh M, Fakunle YM, ElKaramany WM, et al. Prevalence of antibodies to hepatitis C virus in blood donors in Riyadh. Ann Saudi Med 1991;11:501-3. [PUBMED] |
|12.||Bernvil SS, Andrews VJ, Kariem AA. Hepatitis C antibody prevalence in Saudi Arabian blood donor population. Ann Saudi Med 1991;ll:563-7. |
|13.||Huraib SO, Al-Rasheed R, Al Dress A, Al-Jefrey, Arif M, Faleh FA. High prevalence and risk factors for hepatitis C in Saudi Arabia: a need for new strategies in dialysis practice (Abstract). Saudi Kidney Dis Transplant Bull 1993;4(S1):73. |
|14.||Ayoola EA, Al-Mofleh IA, Al-Faleh FZ, et al. Prevalence of antibodies to hepatitis C virus among Saudi patients with chronic liver diseases. Hepatogastroenterology 1992;39:337-9. [PUBMED] |
|15.||Fakunle YM, Al-Mofarreh M, AlGhreimil MS, et al. Prevalence of antibodies to hepatitic C virus in Saudi and expatriate women in Riyadh, Saudi Arabia. Ann Saudi Med 1991;11:494-6. [PUBMED] |
|16.||Shikata T. Strategies for the development of hepatitis C and E vaccine. In: Nishioka K, et al, (eds). Viral Hepatitis and Liver Disease. SpringerVerlag, 1993;501-2. |
|17.||Hoofnagle JH, Di-Bisceglie AM, Shindo M. Antiviral therapy of hepatitis C - present and future. J Hepatol 1993;17(Suppl 3): 130-6. |
|18.||Al-Karawi MA, Ahmed AM, Yousuf M, Shariq S, Mohamed AE, Al-Jumah A. Alpha interferon in treatment of chronic hepatitis C viral infection (CHCV): pilot study of 18 patients. Ann Saudi Med 1994;14:464-6. |
|19.||Ellis ME, Alfurayh O, Halim MA, et al. Chronic non-A, non-B -hepatitis complicated by end-stage renal failure treated with recombinant interferon alpha. J Hepatol 1993;18:210-6. [PUBMED] |
|20.||Reichard O, Andersson J, Schvarcz R, Weiland O. Ribavirin treatment for chronic hepatitis C. Lancet 1991;337:1058-61. [PUBMED] [FULLTEXT]|
Faleh Zaid Al-Faleh
Department of Medicine, College of Medicine King Saud University, P.O. Box 2925, Riyadh 11461