Hepatitis C

Hepatitis C

Causative agents

The hepatitis C virus is a hepacivirus of the Flaviviridae family of viruses that causes Hepatitis C in humans. It is a small, enveloped, single-stranded RNA virus divided among six main genotypes with more than one hundred different subtypes. [1]

Epidemiology

It is estimated that HCV has a worldwide prevalence of 3% affecting around 180 million people with between 3 to 4 million new infections each year. The vast majority of infected people (70-90%) develop chronic infection.  Though chronic infection may be asymptomatic, it is a leading cause of chronic liver diseases, including cirrhosis in between 20 to 50% of patients. Treatments may be effective in 10-50% of patients depending on the applied therapy. [2]

Modes of Transmission

Hepatitis C is believed to be spread through contact with infected blood. However, unlike many other blood borne viruses, HCV may be transmitted even through indirect sources like a used razor. That makes HCV more transmissible than other blood borne viruses –including HIV. Common routes of transmission include transfusion of blood products, intravenous and percutaneous drug and needle use, work accidents among healthcare workers and any other blood to blood contacts, such as sexual practices and from mother to newborn (maternal-infant transmission). Statistical studies have revealed no risk factors for HCV transmission in the activities of daily living (sneezing, coughing, hugging, etc.). [2], [3]

Diagnosis

Enzyme-linked Immunosorbent Assay (ELISA ) based on the detection of specific antibodies against HCV in human serum, Recombinant immunoblot assay (RIBA) based on identifying the antibodies against HCV antigens through Western  and dot blotting techniques, determination of the alanine transferase level in serum  are the common conventional methods used to detect and monitor HCV infections. However ELISA may tend to give false negative results in the early stage of the infection (before the antibodies become detectable). RIBA used to confirm the ELISA may not be applied in routine since it requires a liver biopsy and the determination of the ALT level is not enough sensitive.
The molecular tests based on the measurement of the HCV-RNA level in serum overcome these drawbacks of the conventional methods.  It is more sensitive than the conventional methods and may be useful to monitor the patient’s virologic response to treatment at a certain time. [4], [5]

Annotated Bibliography

  1. 1-K. E. Nelson, C. Williams, and N. Graham., Infectious Disease Epidemiology: Theory and Practice, July 15, 2000 , p :923-926
  2. 2-Theodore Sy and M. Mazen Jamal, Epidemiology of Hepatitis C Virus (HCV) Infection, Int J Med Sci. 2006; 3(2), p:41–46.
  3. 3-Anonymous, Hepatitis C Fact Sheet No. 164. 2000, World Health Organization.
  4. 4-Ghany MG, Strader DB, Thomas DL, Seeff LB; Diagnosis, management, and treatment of hepatitis C: an update , Hepatology. 2009 Apr;49(4):1335-74.
  5. 5-Isa K. Mushahwar, Viral Hepatitis Molecular Biology Diagnosis and Control, 10, NOV-2003, P: 143-151

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