Hepatitis C Virus (HCV)
Sample for Hepatitis C Virus (HCV)
- 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 for Hepatitis C Virus (HCV)
- Separate serum or plasma immediately to avoid virus degradation by the white blood cells.
Indications for Hepatitis C Virus (HCV)
- To diagnose the patient with HCV infection.
- For screening of the blood donor.
- Should be done to healthcare workers.
- Advised 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 with hemophilia were treated before 1987.
Definition of Hepatitis C Virus (HCV)
- This was formally called non-A, non-B viral infection (NANB) because no tests were available. This was suspected by the exclusion of HBV and HAV.
- Later on, the Hepatitis D virus was discovered, and this virus was separated from NANB.
- In 1991 virus identified was named Hepatitis C Virus (HCV).
- The second-generation test for HCV was available in 1993.
- A third-generation test for HCV was available in 1994.
- First and second-generation tests diagnose only HCV-IgG.
Biology and structure of Hepatitis C Virus (HCV)
- Hepatitis C virus (HCV) is a hepatotropic virus. It belongs to the Flavivirus family.
- HCV is a small enveloped virus measuring 55 to 65 nm.
- HCV is a small positive-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 exists in 4 genotypes or strains:
- Core antigen.
- NS3 gene.
- NS4 antigen.
- NS5 antigen
- 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.
Characteristic features of Hepatitis C Virus (HCV)
Parameters | Characteristic features |
Family | Flaviviridae |
Genus | Not named |
Genome | ssRNA |
Genome size | 9.5 kb |
Size of virus | Virion = 30 to 60 nm, spherical |
Envelope | It is present |
Incubation period | 40 to 120 days |
Commonage group | Adults |
Any seasonal incidence | It is present throughout the year |
Its presence in urine | Probably absent |
Fever | It is less common |
Liver function test (LFT) | Abnormal 1 to >6 months |
Transmission | Parenteral |
Prevalence | Moderate |
Fulminant disease | It is rare |
Chronicity | It is common (>50%) |
Stability |
|
As an oncogenic virus | It can form liver cell carcinoma |
Genetic variation of Hepatitis C Virus (HCV)
- Genotypes of HCV are detected because of their response to treatment.
- There are 6 genotypes with several sub-types.
- Type 1 genotype progress to chronicity and cirrhosis. It is less responsive to treatment.
- Type 2 and 3 genotypes are very responsive to antiviral treatment.
- 75% of Americans have genotype 1, and it has subtypes 1a and 1b.
- 20 to 25% have genotypes 2 and 3.
- The smaller percentage has genotypes 4, 5, and 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.
Hepatitis C Virus (HCV) genome structure:
- It consists of N- a terminal and C-terminal.
- There are core proteins, envelope proteins, and non-structural proteins.
Hepatitis C Virus (HCV) is found in:
- Blood (Serum).
- Saliva.
- Semen.
- Major risk groups are:
- Blood transfusion.
- I/V drug abusers.
- Blood products.
Mode of the spread of Hepatitis C Virus (HCV):
- The mode of spread is like HBV, with some differences.
- In 50%, the source of the cases is not known.
- One of the modes is blood transfusion or blood products (Now, it is rare because of screening tests available since 1987).
- HCV hepatitis (post-transfusion hepatitis) is quite common in volunteer blood donors who are HBV-negative.
- Vertical transmission from mothers to newborns is not as common as HBV infection.
- This can spread through sexual contact, but some believe that sexual transmission is uncommon.
- This is seen in sex with multiple partners and unprotected.
- Male homosexuals are less likely to be infected as compared to HBV.
- It is also seen less in number in heterosexual groups.
- This is seen in organ transplantation (before 1992).
- This is common in I/V drug users.
- Tattooing in an unhygienic atmosphere.
- This may be seen in HIV patients.
- Sharing personal items like toothbrushes or shavers that may have blood contamination.
- It is believed that 50% of the case’s transmission mode is unknown.
- Fetal and neonatal transmission is uncommon.
- Passive transfer of anti-HCV antibodies is quite common.
The incubation period for Hepatitis C Virus (HCV):
- It is 2 to 12 weeks after exposure. (other references give 2 to 52 weeks) and the average period being 7 or 8 weeks).
- Incubation of 2 weeks to one year is also reported.
Type of antigens and antibodies of Hepatitis C Virus (HCV):
- HCV-Ab (IgG) appears in 3 to 4 months. and disappears in 2 years.
- Most cases develop HCV-IgG antibodies by 6 weeks, and the range is 5 to 30 weeks after the onset of the symptoms.
- 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.
- The current screening test detects antibodies against HCV.
- An anti-HCV screening test has been available for less than 10 years.
- This is a unique virus in which, in acute infection, you can find an Anti-HCV antibody and also the antigen HCV-RNA.
- Anti-HCV remains for many years. Therefore, an anti-HCV test positive indicates infection or carrier state but not infectivity or immunity.
Signs and Symptoms of Hepatitis C Virus (HCV)
- HCV infection is also called a silent disease.
- The clinical S/S are like HBV infection, but these are less severe.
- It is in 12% to 25% of cases of sporadic hepatitis that is not related to parenteral inoculation or sexual transmission.
- Only 15% develop acute infection rest goes into a chronic disease.
- Chronicity of the infection is seen in 50% to 80% of the cases (another reference says 70 to 80%).
- Chronicity is more common than HBV infection.
- It is seen in 60% of post-transfusion cases and may take 10 years.
- 30% of cases may develop cirrhosis in around 10 years.
- HCV infection may lead to chronic active hepatitis and cirrhosis.
- In one of the studies, chronic active hepatitis was seen in <20%, and 3% had cirrhosis.
- Fulminant hepatitis is seen in 1 to 2% of the patient.
- HCV infection symptoms may not appear or are 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.
- It is considered a major etiology for liver cell carcinoma.
Common symptoms of Hepatitis C Virus (HCV) are :
- Jaundice is seen in only 25% of acute hepatitis.
- Tiredness
- Loss of appetite
- Nausea and vomiting
- Abdominal pain
- Joints pain
- Fever
- dark urine and gray-colored stool
- Ultimately patient develops jaundice
- This chronic virus infection can lead to liver cell carcinoma.
Hepatitis C Virus (HCV) serological profile:
- An anti-HCV screening test has been available for less than 10 years.
- Anti-HCV Ab (IgG) indicates:
- Convalescent stage.
- Old HCV infection.
- Anti-HCV Ab (IgG) indicates:
- Anti-HCV antibodies are IgM and IgG types.
- 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.
Lab diagnosis of Hepatitis C Virus (HCV)
- 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 show the virus’s presence in the blood.
- PCR is the confirmatory test for HCV infection.
- PCR is done in patients to start the treatment.
- Acute infection = Anti-HCV antibody will be positive.
- Chronic infection = Almost 85 % shows Anti-HCV antibody.
- Positive HCV-Ab indicates present or past infection.
- Table showing HCV markers in various conditions:
Test Normal Early infection Acute Chronic Carrier Recovery Anti-HCV Negative Negative + + + + PCR Negative + + + + Negative
The complication of Hepatitis C Virus (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 say chronicity is from 50% to 80%)
Treatment Options for Hepatitis C Virus (HCV):
- 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 combination therapy, with the addition of Ribavirin.
- Alfa-interferon with Ribavirin as combination therapy.
- The latest therapy can cure 95% of patients.
- To label, that patient is cured when for three months PCR HCV is negative after the completion of the treatment.
Preventions of Hepatitis C Virus (HCV):
- There is no vaccination available for HCV.
- Proper testing of the blood donors for transfusion for HCV has decreased the incidence.
Questions and answers:
Question 1: What is the chronicity in HCV infection as compared to HBV?
Question 2: Is there any possibility of vaccine for HCV?
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/