Hepatitis C virus high efficacy testing in blood bank is by:
Ans.C.NS3ExplanationHepatitis C virus: Most common cause of Post-transfusion hepatitis in developing countries.Morphology: +ve sense ssRNA and proteins (3 structural proteins like core protein, El and E2 glycoproteins; 6 non-structural proteins like NS1, NS2, NS3, NS4A, NS4B, NS5A, NS5B).Genetic diversity:Higher rate of mutation seen in E2 envelope protein >NS5B.E2 is target against most neutralizing antibodies, genetic diversity of E2 results in mutant strains escaping body's immunity.HCV genotypes:Genotype 1 is most common type worldwideGenotype 4 seen in EgyptGenotype 5 seen in South AfricaGenotype 6 seen in Hong KongGenotype 1 and 3 common in India.Transmission:Parenteral (blood transfusion, blood products, organ transplantation, injection drug users, contaminated needles and sharps)Vertical (from mother to fetus < lower rate (6%) than HBV (20%)Sexual (rare)It doesn't spread by breast feeding/food/casual contacts of hugging, shaking hands.Extrahepatic: mixed cryoglobulinemia, arthritis, glomerulonephritis.Epidemiology:Worldwide infections every year 3-4 million people, are infected with HCV with more than 3.5 lakhs deaths.Prevalence rate: India (1%)Africa (10%) > South America, Asia > World (3%).Laboratory diagnosis.Serum antibody detectionAntigen detection* Anti-HCV antibodies are detected by Third- generation ELISAs using Core antigens, NS3, NS4, NS5 to detect anti-HCV antibodies* Hepatitis C virus RNA is most sensitive and gold standard test.* Acute diagnosis: Anti-HCV (C33c, C22-3, NS5) are detected.* Branched-chain DNA (bDNA) assay* Chronic diagnosis: Anti-HCV (C100-3, C33c, C22-3, NS5) are elevated.a.-Reverse transcriptase PCRb.-Real time RTPCRc.-Transcription mediated Amplification (TMA).Treatment:Combined therapy with pegylated interferon plus ribavirin.Start treatment within 2-3 months after onset of disease and continued till 24 weeks.
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Virology