170 likes | 475 Views
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
E N D
CLS 1113Introduction 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 • 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