6- Antigen Antibody Reaction

Hepatitis B and C VirusWhat is Hepatitis..?

Medical condition defined by the inflammation of the liver. The condition can progress to fibrosis (scarring) and cirrhosis.

Hepatitis may occur with limited or no symptoms, but often leads to jaundice, anorexia (poor appetite) and malaise.

Hepatitis is acute when it lasts less than six months and chronic when it persists longer.

Source ofvirusfecesblood/blood-derivedbody fluidsblood/blood-derivedbody fluidsblood/blood-derivedbody fluidsfecesRoute oftransmissionfecal-oralpercutaneouspermucosalpercutaneouspermucosalpercutaneouspermucosalfecal-oralChronicinfectionnoyesyesyesnoPreventionActive immunizationPassive immunizationNo vaccineblood donorscreening;risk behaviormodificationPrevention of HBV infectionsensure safedrinkingwaterTypes of HepatitisABCDEBlood donor screeningActive immunization3

Hepatitis B Virus

Characteristics of the virusDNA virus from Hepadna virus family Sexual - Sex workers and homosexuals are particular at risk.

Parenteral Intra venous drug abuse (IVDA), Health Workers are at increased risk.

Perinatal - Mothers who are HBeAg positive are much more likely to transmit to their offspring than those who are not. Perinatal transmission is the main means of transmission in high prevalence populations. Hepatitis B Virus Modes of Transmission222 HighModerateLow/NotDetectablebloodsemenurineserumvaginal fluidfeceswound exudatessalivasweattearsbreastmilkConcentration of Hepatitis B Virus in Various Body Fluids111

1- Clinical Features of acute hepatitis B:The incubation period: Between 45 and 120 days, with an average of 60 to 90 days. Common clinical features are :Chronic Persistent Hepatitis asymptomatic.Chronic Active Hepatitis - symptomatic exacerbations of hepatitis.Cirrhosis of Liver.Hepatocellular Carcinoma.29Markers for DiagnosisVarious serological tests are used for the diagnosis of acute and chronic hepatitis B infection.HBsAg - used as a general marker of infection.HBsAb - used to document of immunity to HBV infection. anti-HBc IgM - marker of acute infection.anti-HBcIgG indicates past or chronic infection.HBeAg - indicates active replication of virus.HBV-DNA Also indicates active replication of virus. Used mainly for monitoring response to therapy.Laboratory Diagnosis (Techniques)Several serological Test are available for detection of above mention markers as:

ELISAImmunochromatographyRIA

Also DNA of the virus can be detected using PCR Technique.

HBsAg Rapid TestThe HBsAg rapid test device: Is a chromatographic immunoassay for the qualitative detection of HBsAg in whole blood, serum or plasma. The membrane is pre-coated with anti-HBsAg antibodies on the test line region of the device. Specimen + Anti-HBsAg antibodies conjugated particles

Generates a colored line which indicates a positive result. Allow the test device, specimen, buffer and/ or control to equilibrate to room Temperature prior to testing.For serum or plasma specimen: Hold the dropper vertically, transfer 3 drops of serum or plasma to the specimen well (S) of test device and then start the timer.For Whole Blood specimen: Hold the dropper vertically, transfer 3 drops of venipuncture or 75 ul of fingerstick whole blood to the specimen well (S) of test device, then add 1 drop of buffer and start the timer.Wait for the colored line(s) to appear. The result should be read at 15 minutes. Method:7

Interpretation of Results

Positive: Two distinct colored lines appear. One line should be in the control region(C) and another in the test region(T).

Negative: one colored line appears in the control region(C).

Invalid: Control line fails to appear.

HEPATITIS C VIRUS (HCV)

Characteristics of the virusSingle -stranded RNA virus of family: FlaviviridaeTransfusion or transplant from infected donor.Intravenous drug abuse (IVDA).Hemodialysis (years on treatment).Accidental injuries with needles/sharps.Sexual/household exposure to HCV-positive contact.Multiple sex partners.Birth to HCV-infected mother.

Mode of Transmission of HCV 111111 Incubation period: Average (6-7 wks) - Range (2-26 wks).

Chronic Hepatitis C Infection:

The spectrum of chronic hepatitis C infection is essentially the same as chronic hepatitis B infection.

All the manifestations of chronic hepatitis B infection may be seen, although with a lower frequency i.e. chronic persistent hepatitis, chronic active hepatitis, cirrhosis, and hepatocellular carcinoma.

Hepatitis C - Clinical Features888Laboratory DiagnosisHCV antibody: Generally used to diagnose hepatitis C infection. Not useful in the acute phase as it takes at least 4 weeks after infection before antibody appears.

HCV-RNA: Various techniques are available e.g. PCR may be used to diagnose HCV infection in the acute phase. However, its main use is in monitoring the response to antiviral therapy.

HCV-antigen: ELISA is used for detection. It is used in the same capacity as HCV-RNA tests but is much easier to carry out.HCV Rapid Test DeviceHCV Rapid Test Device (Serum/plasma): Is a qualitative, membrane based immunoassay for the detection of antibody to HCV in serum or plasma.

The serum or plasma The recombinant HCV antigens coated particles. Colored line.reacts with MethodAllow the test device, specimen, buffer and/ or control to equilibrate to room Temperature prior to testing.

Using Disposable Specimen Dropper : Hold the dropper vertically, draw the specimen up to the fill line and transfer to the specimen well (S) of test device, then add 2 drops of buffer and start the timer.

Wait for the colored line(s) to appear. The result should be read at 10 minutes

151515

Interpretation of Results

Positive: Two distinct colored lines appear. One line should be in the control region(C) and another in the test region(T).

Negative: one colored line appears in the control region(C).

Invalid: Control line fails to appear.

Human Immunodeficiency Virus (HIV)IntroductionIt causes Acquired Immunodeficiency Syndrome (AIDS).

Discovered during 1983-1984.

HIV-2 discovered in 1986, antigenically distinct virus and endemic in West Africa.

Characteristics of the virusIcosahedral (20 sided), enveloped virus of the lentivirus subfamily of retroviruses.Retroviruses transcribe RNA to DNA.Two viral strands of RNA found in core surrounded by protein outer coat.Outer envelope contains a lipid matrix within which specific viral glycoproteins are imbedded.These knob-like structures responsible for binding to target cell.

HIV-1 and HIV-2:HIV-1 and HIV-2 are: Transmitted through the same routes. Associated with similar opportunistic infections.HIV-1: is more common worldwide.HIV-2 : Is found in West Africa, Mozambique, and Angola.Is less easily transmitted.HIV-2 is less pathogenic.:Mode of transmissionSexual transmission, presence of sexually transmitted disease (STD) increases likelihood of transmission.Exposure to infected blood or blood products.Use of contaminated clotting factors by hemophiliacs.Sharing contaminated needles (IV drug users).Transplantation of infected tissues or organs.Mother to fetus (perinatal transmission) is variable and dependent on viral load and mothers CD-4 count.

Primary HIV SyndromeMononucleosis-like, cold or flu-like symptoms may occur 6 to 12 weeks after infection.Lymphadenopathy.Fever.Rash.Headache.Fatigue.Diarrhea.sore throat.neurologic manifestations.Some times no symptoms may be present

Symptoms are relatively nonspecific.

HIV antibody test often negative but becomes positive within 3 to 6 months, this process is known as seroconversion.

Large amount of HIV in the peripheral blood.

Primary HIV can be diagnosed using viral load titer assay or other tests.

Primary HIV syndrome resolves itself and HIV infected person remains asymptomatic for a prolonged period of time, often years.

Clinical Latency Period:HIV continues to reproduce, CD4 count gradually declines from its normal value of 500-1200.Once CD4 count drops below 500, HIV infected person at risk for opportunistic infections.The following diseases are predictive of the progression to AIDS:persistent herpes-zoster infection (shingles)oral candidiasis (thrush)oral hairy leukoplakiaKaposis sarcoma (KS)

Oral candidiasis (thrush)Herpes-zoster infection Oral hairy leukoplakiaKaposis sarcoma Spectrum of HIV Tests1- HIV diagnosis (Antibody/Antigen testing):Enzyme Immunoassays (EIAs) Rapid testsWestern blot (WB)

2- Early diagnosis in infants:P24

3- Monitoring of ART:CD4Viral Load HIV Rapid Tests:Qualitative assay to detect HIV antibodies.Most detect HIV 1 and HIV 2.As reliable as EIAs .

Body Fluids Used for HIV Rapid Testing:Serum. Plasma.Whole blood.

Immunochromatography Rapid Test:Method The test procedure and interpretation of results is same as in HCV & HBV Rapid tests.