Hepatitis C Virus :- Part 1 – Hepatitis C Virus, HCV Profile
Sample
- The best sample is the serums of the patient.
- The serum is stable for 7 days at room temperature for anti-HCV.
- This test can be done on the plasma as well.
- This test can be performed on a random sample.
Precaution
- Separate serum or plasma immediately to avoid degradation of the virus by the white blood cells.
Indications
- To diagnose the patient with HCV infection.
- For screening of the blood donor.
- Should be done on healthcare workers.
- Advised in the drug users.
- In a person who has sex with HCV positive partner.
- The patients with HIV positive.
- In abnormal liver function tests.
- Blood transfusion or organ transplantation before July 1992.
- The patients of hemophilia treated before 1987.
Pathophysiology
- This was formally called non-A, non-B viral infection because no test was available. This was suspected by the exclusion of HBV and HAV.
- Hepatitis C virus (HCV) is a hepatotropic virus.
- HCV is a small enveloped virus measuring 55 to 65 nm.
- HCV is a single-stranded RNA virus of the Flaviviridae family.
- This was formally called non-A, non-B viral infection because no test was available. This was suspected by the exclusion of HBV and HAV.
- HCV infection is unlike HBV because this gives rise to more than 60 % as a chronic disease.
- 20 % of the patient develop cirrhosis and hepatocellular cancer.
- The incubation period is 2 to 12 weeks after the exposure. (other references give 2 to 52 weeks and the average period being 7 or 8 weeks).
- HCV-Ab (IgG) appears 3 to 4 months. and disappears in 2 years.
- The anti-HCV can be detected in acute hepatitis-C during the initial phase of elevated aminotransferases activity. This antibody may never be detected in 5 to 10% of the patient with acute Hepatitis-C and anti-HCV may become undetectable after the recovery from acute hepatitis.
- HCV-Ab (IgG) appears 3 to 4 months. and disappears in 2 years.
- The current screening test detects antibodies against HCV.
- An anti-HCV screening test is available for less than 10 years.
- This is the unique virus in which in acute infection you can find an Anti-HCV antibody and also the antigen HCV-RNA.
- The presence of Anti-HCV remain for many years, therefore anti-HCV test positive indicate infection or carrier state but not infectivity or immunity.
Signs and Symptoms
- HCV infection also called a silent disease.
- Only 15% develop acute infection rest goes into a chronic disease.
- Chronicity of the infection is seen in the 50 to 80% of the cases (another reference says 70 to 80%).
- Fulminant hepatitis is seen in 1 to 2% of the patient.
- HCV infection symptoms may not appear or very mild for years.
- Chronic infection is often asymptomatic.
- The silent disease still causes damage to the liver.
- The patient with the silent disease may come with chronic liver disease and may develop cirrhosis and liver cell carcinoma.
- Common symptoms of HCV are :
- Tiredness
- Loss of appetite
- Nausea and vomiting
- Abdominal pain
- Joints pain
- Fever
- dark urine and gray-colored stool
- Ultimately patient develops jaundice
- This virus chronic infection can lead to liver cell carcinoma.
Mode of spread
- The mode of spread is like HBV with some differences.
- One of the modes is blood transfusion or blood products (Now it is rare because of screening tests available since 1987).
- Vertical transmission from mothers to a newborn is not as common as HBV infection.
- This can spread through sexual contacts, but some believe that sexual transmission is uncommon.
- This is seen in sex doing with multiple partners and unprotected.
- This is seen in organ transplantation (before 1992).
- This is common in the I/V drug users.
- Tattooing in the unhygienic atmosphere.
- This may be seen in HIV patients.
- Sharing personal items like toothbrushes, or shaver which may have blood contamination.
- Now it is believed that 50% of the cases mode of transmission is not known.
Hepatitis C profile
- An anti-HCV screening test is available for less than 10 years.
- Anti-HCV antibodies are IgM and IgG type.
- Anti-HCV antibodies:
- Anti-HCV Ab seen against:
- Core antigen.
- NS3 gene.
- NS4 antigen.
- NS5 antigen.
- Anti-HCV Ab seen against:
- Anti-HCV antibodies:
-
- HCV by PCR which detects HCV-RNA is used to confirm the diagnosis.
- Viral load advises quantitative PCR.
- Usually, SGPT (ALT) is raised in this infection and chronic cases.
- A negative Anti-HCV antibody does not exclude the HCV infection because seroconversion may not occur up to 6 months after exposure.
- HCV by PCR which detects HCV-RNA is used to confirm the diagnosis.
- Usually, SGPT ( ALT ) is raised in infection and chronic cases.
- A negative Anti-HCV antibody does not exclude the HCV infection because seroconversion may not occur up to 6 months after exposure.
Genetic variation of HCV
- Genotypes of HCV are detected because of its response to treatment.
- There are 6 genotypes with several sub-types.
- Type 1 genotype progress to chronicity and to cirrhosis. It is less responsive to treatment.
- Type 2 and 3 genotypes are very responsive to antiviral treatment.
- 75% of the Americans have genotype 1 and it has subtype 1a and 1b.
- 20 to 25% have genotype 2 and 3.
- The smaller percentage has genotype 4, 5, 6.
- Genotype 4 is more common in African countries.
- Genotype 5 is more common in South Africa and Asia.
- Genotype 6 is more common in Southeast Asia.
- HCV genome structure consists of N- terminal and C-terminal.
- There are core proteins, envelope proteins, and non-structural proteins.
Lab diagnosis
- Interpretation of HCV profile:
- Acute infection = Anti-HCV antibody will be positive.
- Anti-HCV by ELIZA is confirmatory.
- PCR can confirm the diagnosis.
- Qualitative PCR for HCV genome.
- Quantitative HCV RNA PCR.
- PCR (polymerase chain reaction) will tell the presence of the virus in the blood.
- PCR is the confirmatory test for HCV infection.
- PCR is done in patients to start the treatment.
- Chronic infection = Almost 85 % shows Anti-HCV antibody.
- Positive HCV-Ab indicates present or past infection.
- Table showing HCV markers in various conditions:
Test Acute Chronic Carrier Recovery Anti-HCV + + + None PCR + + + +
- Acute infection = Anti-HCV antibody will be positive.
The complication of HCV infection
- There are chances for:
- Fulminant hepatitis is seen in 1 to 2% of the patients.
- Cirrhosis is seen in 5% of the cases.
- Liver failure.
- Liver cancer risk is 15%.
- HCV infection is unlike HBV because this gives rise to more than 60% as a chronic disease.
- (some references says chronicity is from 50 to 80%)
Treatment Options
- Alfa-interferon alone. It gives benefits to <50% of the cases. Relapse is common at the stop of the treatment.
- Interferon (IFN-α2, 3,000,000U) 3 doses per week is subcutaneously given for one year.
- It prevents the development of liver cell carcinoma.
- Monitor with SGPT, SGOT, and PCR for HCV.
- Retreatment can be given in 50 to 80% of the relapse cases.
- Type 2 and 3 genotypes positive patients are three times more sensitive to antiviral treatment like alpha-interferon or with combination therapy, with the addition of Ribavirin.
- Alfa-interferon with Ribavirin as combination therapy.
- The latest therapy can cure 95% of the patients.
- To label, that patient is cured when for three months PCR HCV is negative after the completion of the treatment.
Prevention
- There is no vaccination available for HCV.
- Proper testing of the blood donors for transfusion for HCV has decreased the incidence.
Here you say anti hcv last 2 years then you write many years. What is true?
Thanks for the question. I have elaborated on the statement in the text. Please see the link.
https://www.labpedia.net/hepatitis-c-virus-part-1-hcv-profile/