CLS 1113 Introduction to Clinical Laboratory Practices

							             CLS 1113
Introduction to Clinical
  Laboratory Practices
       Unit 7
       Streptococcus,
       Herpes Viruses
Detection of Group A
Streptococcus
   Streptococus Pyogenes (Group A)
   Other Groups
       Group B
       Group D
   Group A strep: Two major sites


   Symptoms: Pharyngitis
       sore throat, headache, exudative tonsils, and
        lymphadenopathy
Rheumatic Fever
   Cross-reactive antibodies to strains
    of Group A strep
       React with Heart valve antigens

 Sequel to pharyngitis
 Symptoms
     Usually begin several weeks
     Joint pain & cardiac abnormalities
Testing
   Culture
Testing

   Rapid detection of Group A antigen
       Acute pharyngitis
       High specificity but a low sensitivity
   Rheumatic Fever/Acute Glomerulonephritis
       Bacterial antigens?
       More than 20 exotoxins
       Most important antibodies are anti-
        streptolysin, anti-DNase B, anti-NADase, and
        antihyaluronidase.
Herpes Viruses
 Cytomegalovirus
 Epstein-Barr Virus
 Herpes Simplex Virus
 Varicella-Zoster Virus
       DNA viruses


   Chapter 17, page 268
Epstein-Barr Virus

   Oral transmission
       Infectious Mononucleosis
       Burkitt’s lymphoma
       Nasopharyngeal carcinoma
       Etc.
   Infect
       B Cells
       Endothelial cells of the oropharynx and
        uterine cervix
Epstein-Barr Virus
   The most common test for EBV is for the
    detection of “heterophile antibodies”
       Antigen that stimulates production
   There are other types of heterophile
    antibodies that look and act like IM
       “Forssman Antibodies” (formed in response to
        certain bacteria and animal tissue)
       Heterophile antibodies: Serum sickness
 EBV

 Heterophile    Guinea Pig        Beef
 Antibodies      Kidney       Erythrocytes
Forssman
                Absorbed      Not Absorbed
Antibodies
Serum
                Absorbed       Absorbed
sickness
Infectious
               Not Absorbed    Absorbed
Mono
EBV
   Direct detection methods
       EBV specific antibodies: VCA-IgM, VCA-
        IgG, EA-IgG, and EBNA-IgG



   Enzyme Immunoassay and Indirect
    Immunofluorescence
Cytomegalovirus (CMV)
   Transmission
       saliva, sexual contact, blood
        transfusions, organ transplant, and
        perinatally
 Lymphocytes and monocytes
 50-75% of individuals in developed
  countries are infected with CMV
  (100% in developing countries)
Cytomegalovirus (CMV)
   Individuals infected by CMV
       Asymptomatic


   Life-threatening
       Newborns

       Immunodeficient patients
Cytomegalovirus (CMV)
   Testing
       Latex

       Culture

       Fluorescence

       ELISA
Rubella Virus
 RNA Virus
 Transmission
       Acquired: “German Measles”
        • Spread through direct or droplet contact
          from nasopharyngeal secretions
       Congenital
        • Perinatally
        • Pregnant women are routinely screened
   99% decrease due to immunizations
    (MMR)
Rubella
 Table 17-4, page 272
 Testing
     Why?
     Who?

   Latex agglutination

   ELISA