Virology
Virology. 22-2-11. Diagnostic methods in virology. Detection of virus Detection of viral antigen Detection of viral genome Detection of serological response. Detection of viral antigens. Antisera (mono or polyclonal) are used to detect viral antigen
Virology
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Presentation Transcript
Virology 22-2-11
Diagnostic methods in virology • Detection of virus • Detection of viral antigen • Detection of viral genome • Detection of serological response
Detection of viral antigens • Antisera (mono or polyclonal) are used to detect viral antigen • These assays can be sensitive as they can detect antigens of disrupted viral particles • They are pathogen specific - separate immuno-assay must be used for each pathogen • In contrast electron microscopy and culture are catch all techniques which detect all pathogens
Methods • Antigen capture ELISA - eg rotavirus, HBsAg, HIV • Latex particle agglutination (LPA) eg rotavirus • Immunoflouresence - eg RSV, influenza,
Virus antigen detection: Latex particle agglutination for rotavirus
Virus antigen detection: Immunofluorescence of RSV-infected nasopharyngeal cells
Detection of viral genome • Genome amplification eg. PCR (polymerase chain reaction)
Detection of serological response • IgM detection • Detection of rising titre: ELISA, complement fixation test, haemagglutination inhibition
Detection of serological response: Antigen capture ELISA for HIV antibody
Case 1 • The following is a report from a lady with a 10-year history of fatigue, anorexia and elevated LFTs. Hepatitis B surface antigen: negative Hepatitis C antibody: positive Hepatitis C antibody immunoblot confirmation: positive Banding pattern: c100 c33 c22 NS5 3+ 3+ 4+ 4+
Case 1 • What additional tests would you request? • What your treatment options
Case 2 • You are given the following results on two different patients. • Are there any differences between the profiles? • What implications (if any) are there for these differences?
Case 2 Patient 1: TestsResults EIA for HBsAg Positive ***Infection Risk*** Hepatitis B e antigen Negative Hepatitis B e antibody Positive Hepatitis B core IgM antibody Negative Report comment: Hepatitis B result profile consistent with chronic hepatitis B infection.
Case 2 Patient 2: TestsResults EIA for HBsAg Positive ***Infection Risk*** Hepatitis B e antigen Positive ***High Infection Risk*** Hepatitis B e antibody Negative Hepatitis B core IgM antibody Positive: 250 IU/ml. Report comment: Hepatitis B result profile consistent with chronic hepatitis B infection.
Case 2 • Do you agree with the comments? • What additional test(s) would you request for after a discussion with the microbiologist?
Case 3 • You have vaccinated 2 patients against hepatitis B virus for the purpose of foreign travel. • What test would you request to assess the vaccination status? • Comment on the following results.
Case 3 • Patient 1: Hepatits B surface antibody: >1000 mIU/ml • Patient 2: Hepatitis B surface antibody: <10 mIU/ml
Case 4 • A patient presents with malaise, elevated LFTs and a history of intravenous drug abuse. You are given the following result: Hepatitis B surface antigen: Positive Hepatitis B surface antibody: Negative Report comment: If this is the first positive serological test on this patient, please repeat to confirm.
Case 4 • Comment on the above report. • What additional tests would you request?
Case 4 Hepatitis B surface antigen: Positive ***Infection Risk*** Hepatitis B e antigen: Positive ***High Infection Risk*** Hepatitis B e antibody: Negative Hepatitis B core IgM antibody: Negative Hepatitis B core total antibody: Positive Report comment: ……….. • What is your report comment?
Case 5 • A 23 year old female patient presents to the A/E department with malaise, lymphadenopathy, malaise and a rash. She has a history of unsafe sexual activity. • What investigations would you request?
Case 5 • Shown below is one of the patient’s laboratory results: TestsResults EIA for anti-HIV 1 (Organon) Positive EIA for anti-HIV 1+2 (Murex) Positive Report comment: ***confirmed anti-HIV 1 positive*** • What additional tests would you require? • What would you advise the patient?
