SEROLOGICAL DIAGNOSIS OF INFECTIOUS DISEASES (Viral infections) Flashcards
memorization
Other name of Hepatitis A:
Infectious Hepatitis
MOT of Hepatitis A:
Fecal oral
Ingestion of contaminated food/water
what family does Hepatitis A (HAV) belong?
Picornaviridae (RNA)
Incubation of HAV:
15-45 days (short incubation hepatitis)
Other name of Hepatitis B:
Serum Hepatitis
MOT of HBV:
Sex
Blood transfusion
Transplacental
Sharing of needles
What family does HBV belong to?
Hepadnaviridae (DNA virus/the only DNA virus)
Incubation of HBV:
45-160 days (Long incubation hepatitis)
Other name of Hepatitis C
Post transfusion hepatitis
Non-A, Non-B Hepatitis
MOT of Hepatitis C
same as HBV
What family does HCV belong to?
Flaviviridae
What family does Hepatitis E belong to?
Calciviridae
HAV antibodies:
- IgM Anti-HAV
- marker of acute hepatitis
- indicates recent infection - IgG Anti-HAV
- indicates immunity to HAV, results from infection or immunization
Serologic marker of Hepa B; represents the outer lipoprotein coat (envelope) of hepatitis B virus; indicates ACUTE INFECTION AND INFECTIVITY; First marker to appear, indicates active infection either acute or chronic
HbsAg
HbsAg is also known as:
Australia Ag
Indicates past infection with immunity or immune response to HBV vaccine; it is a marker of immunity and recovery
Anti-HBs
Antibody produced against the core of HBV; Important marker during the window period (only serological marker detected in window period)
Anti-HBc
Hepatitis B related antigen; associated to the core of HBV (circulating form of the core); a marker for ACTIVE VIRAL REPLICATION AND HIGH INFECTIVITY OF SERUM
HbeAg
Suggests lower titer of HBV; first serologic evidence of convalescence phase (first marker for recovery)
Anti-Hbe
Most sensitive test for the detection of HBV; detected by PCR (molecular)
HBV-DNA
Third-generation tests for HBV:
- RIA (Radioimmunoassay) (most sensitive serological test)
- Reverse passive hemagglutination
- ELISA (second most sensitive)
- Reverse passive latex agglutination
Second-generation tests for HBV:
- Counterelectrophoresis
- Complement fixation
First-generation test for HBV:
Ouchterlony double diffusion
Interpret:
HBsAg - negative
Anti-HBc - negative
Anti-HBs - negative
Susceptible to infection
Interpret:
HBsAg - negative
Anti-HBc - positive
Anti-HBs - positive
Immune because of natural infection
Interpret:
HBsAg - negative
Anti-HBc - negative
Anti-HBs - positive
- Immune because of natural vaccination
- Acutely infected
Interpret:
HBsAg - positive
Anti-HBc - positive
IgM anti-HBc - negative
Anti-HBs - negative
Chronically infected
Interpret:
HBsAg - negative
Anti-HBc - positive
Anti-HBs - negative
Four interpretations possible
Serologic marker for Hepatitis C virus that is generally used to diagnose Hepatitis C infections:
Anti-HCV
Serologic marker for Hepatitis C used in monitoring response to antiviral therapy; AKA viral load
HCV-RNA
An RNA virus, almost identical to a viral agent called GB virus type C (GBV-C)
Hepatitis G virus
Prevalence patterns of GBV-C/HGV suggest that the virus is transmitted sexually.
true or false
true
MOT of HGV:
Bloodborne (transfusion, IV abusers)
Epstein-Barr virus is characterized by the presence of _____ cells in the PBS:
Downey cells (reactive T-lymphocytes)
MOT of EBV:
- Most common through saliva (kissing disease)
- Blood transfusion
- Transplacental
EBV causes what diseases?
- INFECTIOUS MONONUCLEOSIS (IM)
- Kissing disease - acute infectious disease of the mononuclear phagocyte system
Other diseases associated with EBV:
1. Burkitt’s lymphoma
2. Nasopharyngeal Ca
3. Neoplasm of thymus
An EBV antigen produced by the infected B cells and can be found in the cytoplasm
Viral Capsid Antigen (VCA)
EBV antibody that is usually detectable early in the course of infection, disappears within 2-4 months
a. Anti-VCA IgM
b. Anti-VCA IgG
c. Anti-VCA IgA
d. Anti-VCA IgE
a. Anti-VCA IgM
EBV antibody that is usually detectable within 4-7 days after the onset of signs and symptoms and persists for an extended period perhaps lifelong
a. Anti-VCA IgM
b. Anti-VCA IgG
c. Anti-VCA IgA
d. Anti-VCA IgE
b. Anti-VCA IgG
EBV antigen that is found in the nucleus and cytoplasm of the B cells; disappears in about 3 months:
Early Antigen-Diffuse (EA-D)
Anti-EA-D of the IgG type is highly indicative of _____ infection
a. Acute
b. Chronic
Acute infection (Not IgM)
EBV antigen that is found as a mass only in the cytoplasm:
Early Antigen-Restricted (EA-R)
Anti-EA-R IgG appears transiently in the later, _______ phase
convalescent phase (recovery phase)
EBV antigen found in the nucleus of all EBV-infected cells.
Epstein-Barr Nuclear Antigen (EBNA)
Interpret
VCA IgM = (-)
VCA IgG = (-)
EA-D = (-)
EA-R = (-)
EBNA IgG = (-)
Heterophile = (-)
No previous exposure
Interpret
VCA IgM = (+)
VCA IgG = (+)
EA-D = (+/-)
EA-R = (-)
EBNA IgG = (-)
Heterophile = (+)
Recent (acute) infection
Interpret:
VCA IgM = (-)
VCA IgG = (+)
EA-D = (-)
EA-R = (-)
EBNA IgG = (+)
Heterophile = (-)
Past infection (convalescent period)
Intepret:
VCA IgM = (+/-)
VCA IgG = (+)
EA-D = (+/-)
EA-R = (+/-)
EBNA IgG = (+)
Heterophile = (+/-)
Reactivation of latent infection
Things to remember about heterophile antibodies in EBV infection:
- IgM -cold agglutinins (Anti-i)
- Also binds HORSE, SHEEP, BEEF, RBCS (heterophile)
- Does not react with EBV
Heterophile antibody tests:
- Paul-Bunnell test - Sheep RBCs agglutinate in the presence of heterophile abs
- Monospot test - Horse RBCs are use (Rapid slide agglutination method)
- DAVIDSON DIFFRENTIAL TEST
Absorption patterns (Davidson Differential test)
Forsman heterophile Ab
Absorbed by Guniea Pig Kidney cells: (yes/no)
Absorbed by beef erythrocytes: (yes/no)
Agglutination with SHEEP RBC after absorption:
GPKC: (yes/no)
Beef erythrocytes: (yes/no)
Absorption patterns (Davidson Differential test)
Forsman heterophile Ab
Absorbed by Guniea Pig Kidney cells: YES
Absorbed by beef erythrocytes: NO
Agglutination with SHEEP RBC after absorption:
GPKC: NO
Beef erythrocytes: YES
Absorption patterns (Davidson Differential test)
Infectious Mononucleosis (IM) heterophile Ab
Absorbed by Guniea Pig Kidney cells: (yes/no)
Absorbed by beef erythrocytes: (yes/no)
Agglutination with SHEEP RBC after absorption:
GPKC: (yes/no)
Beef erythrocytes: (yes/no)
Absorption patterns (Davidson Differential test)
Infectious Mononucleosis (IM) heterophile Ab
Absorbed by Guniea Pig Kidney cells: NO
Absorbed by beef erythrocytes: YES
Agglutination with SHEEP RBC after absorption:
GPKC: YES
Beef erythrocytes: NO
Absorption patterns (Davidson Differential test)
SERUM SICKNESS heterophile Ab
Absorbed by Guniea Pig Kidney cells: (yes/no)
Absorbed by beef erythrocytes: (yes/no)
Agglutination with SHEEP RBC after absorption:
GPKC: (yes/no)
Beef erythrocytes: (yes/no)
Absorption patterns (Davidson Differential test)
SERUM SICKNESS heterophile Ab
Absorbed by Guniea Pig Kidney cells: YES
Absorbed by beef erythrocytes: YES
Agglutination with SHEEP RBC after absorption:
GPKC: NO
Beef erythrocytes: NO
The most common cause of congenital infections
Cytomegalovirus (CMV)
The most important infectious agent associated with organ transplantation
Cytomegalovirus (CMV)
Laboratory diagnosis for congenital CMV infection
Virus isolation from neonatal urine or saliva within 3 weeks postpartum
Laboratory diagnosis of CMV infection through traditional methods:
Involves observing characteristic cytopathic effects (CPE) in human fibroblast cell lines inoculated with CMV-infected specimens
Laboratory diagnosis of CMV in immunocompromised patients:
Amplification of CMV DNA by PCR
Dengue virus is carried by what species of mosquitoes?
Aedes aegypti
How many serotypes does Dengue virus have?
4 (DEN-1,2,3,4)
Gold standard for diagnosing dengue infection:
Virus Isolation
How many days does it take for the virus to replicate in tissue cell culture or laboratory mosquitoes?
Takes at least 6-10 days for the virus to replicate
Molecular detection of dengue genomic RNA
RT PCR (reverse transcriptase PCR)
Rapid Dengue Immunochromatographic Test detects what immunoglobulin?
IgM
______ is a highly conserved glycoprotein, which appears essential for virus viability; non-structural protein 1 of the dengue virus
NS1 (detected by Dengue NS-1 Test)
Method of choice to detect T. gondii DNA in CSF
PCR (Polymerase chain reaction)
Method of choice in detecting antibodies since it is more sensitive and easier to perform for toxoplasma
Enzyme Immunoassay (EIA)
EIAs can detect IgM, IgG, and IgA
Elevations of these immunoglobulins are used to screen toxoplasmosis early in pregnant women:
IgM and IgA
What immunoglobulin can Immunofluorescent assay for toxoplasma?
IgG only
Considered the gold standard for diagnosing toxoplasma
Sabin-Feldman Dye Test - measures IgG primarily