Hepatitis C virus (HCV) : Method of Transmission, Laboratory diagnosis and Management

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Hepatitis C virus

Hepatitis C virus is single stranded belonging to the flaviviridae family to which flaviviruses such as yellow fever and dengue belong. Hepatitis C virus has one serotype with at least 6 different genotype which are further divided into subtypes for instance, the HCV genotypes 1 and 3 has 2 subtypes HCV (1a, 1b and 3a and 3b). The genotypes are important for accurate treatment based on the infecting genotype. Genotype and subtypes are also important epidemiological tools.

Structure of Hepatitis C Virus
Structure of Hepatitis C Virus

Method of Transmission of Hepatitis C virus

Transmission of hepatitis C virus is through exposure to infected blood and contaminated secretions through the following means:

  • Blood and blood product transfusion.
  • Body and ear piercing, tattooing using contaminated equipment.
  • During renal dialysis especially when proper precautions are not followed.
  • From healthcare workers to patient especially during surgical treatment
  • From tissue and organ donation especially from infected donors.
  • Iatrogenic (through medical treatment) – Through reuse of needles, syringes and sharp instruments without proper sterilization for medical treatment.
  • Intravenous drug use (Sharing of contaminated equipment is the main cause)
  • Occupational hazard by healthcare workers through a sharps or needle-stick injury from an infected source patient.
  • Through sexual and from mother to child transmission.

Infectious period

About 70% of HCV patient go on to become chronically infected and are infectious for life.

Incubation period

Hepatitis C virus infections does not usually cause acute symptoms but can lead to acute hepatitis. Incubation period from exposure to development of infection is 2-6 weeks but may sometimes last up to 3 months.

Who is at risk of Hepatitis C virus infections

  • Intravenous drug users
  • Healthcare workers
  • Blood and blood products recipient
  • Hospitalized patient
  • Sexually active individuals and babies born from infected mothers
  • Individuals at risk due to their lifestyle such as body piercing, tattoo etc.

Clinical Symptoms of Hepatitis C virus infection

Most of HCV infections are asymptomatic but the most common symptoms includes;

  • Malaise
  • Nausea
  • Fatigue
  • Jaundice
  • Loss of Appetite

About 20% of patient with acute HCV infection clear the virus and 70-80% develop chronic HCV infection and those with chronic HCV do not have specific symptoms but ongoing fatigue and malaise may occur many years after infection. About 20-30% of patient with chronic HCV develop cirrhosis of the liver after 20-30 years while other develop hepatocellular carcinoma.

Laboratory diagnosis

Since most infections are asymptomatic, diagnosis of acute infection is not normally made but most common diagnosis are for chronic infection.

  • Screening for acute or chronic HCV infection is done using the rapid diagnostic hepatitis C antibody test kit where 5–10ml of clotted venous blood is obtained. Positive result indicates infection.
  • For establishing infection status of patient, 5–10ml of clotted venous blood is obtained to run a Hepatitis C PCR for HCV RNA. This is mostly a quantitative viral load assay. Positive result indicates either acute or chronic infection. Negative result indicates clearance of infection either naturally or post-treatment.
  • For the assessment of infected patient for treatment, 5–10ml of clotted venous blood is used to for Hepatitis C genotype determination. HCV genotype test guide treatment decisions including duration of treatment.
Hepatitis C Virus Rapid Diagnostic Test
Hepatitis C Virus Rapid Diagnostic Test

Management of Hepatitis C virus infection

  • Treatment is done with the combination of slow-release pegylated interferon and oral ribavirin for 6–12 months.
  • Interferon treatment is noted to have many side effects therefore, only recommended to patient who will benefit the most.
  • Patient with chronic HCV genotype 1, 4, 5, 6 should have their viral load measured at week 12 of treatment. Recommended treatment duration 48 weeks 50% with sustained viral response. Those with chronic HCV genotype 2, 3 recommended treatment duration 24 weeks 80% with sustained viral response.
  • Treatment should be discontinued in those who do not show a significant fall in HCV viral load as these patients are not likely to respond.

Effect of genotype on treatment

  • About 50% of patients infected with genotype 1 will clear infection as compare to those infected with genotype 3 and 2.
  • Patient infected with genotype 1 need longer treatment duration compared to those with genotype 3 and 2

Prophylaxis

There is no vaccination available for Hepatitis C virus

Control of Hepatitis C Virus Infection

The key to prevention of Hepatitis C virus infection lies on infection control. This depends on adequate screening and testing of blood and organ donors. The virus can be inactivated by treating   blood products such as plasma with heat. Other control measures include:

  • Proper sterilization of instrument before usage and reuse
  • Limiting infected healthcare workers from performing exposure prone procedures.
  • Application of appropriate control measures in the renal dialysis units
  • Educating people at risk

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About the Author: Labweeks

KEUMENI DEFFE Arthur luciano is a medical laboratory technologist, community health advocate and currently a master student in tropical medicine and infectious disease.

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