Chapter 22 Diseases Flashcards
What causes streptococcal respiratory disease?
Genus Streptococcus
Lancefield Group A – S. pyogenes
What causes tuberculosis?
Mycobacterium tuberculosis
What causes influenza?
Influenza virus types A and B
characteristics of streptococcus lance field A?
-gram positive, facultatively anaerobic cocci in chains or pairs
-streptococci differentiated by Lancefield grouping
characteristics of mycobacterium tuberculosis?
Non endospore forming, gram-positive rod with cell walls containing mycolic acid (acid fast positive)
characteristics of influenza?
Eight different ssRNA molecules as genome, pleomorphic envelope, glycoprotein spikes
reservoir for streptococcal respiratory disease?
human
reservoir for tuberculosis?
human
reservoir for influenza?
human
mode of transmission for streptococcal respiratory disease?
Respiratory droplets
mode of transmission for tuberculosis?
Inhalation of respiratory droplets
mode of transmission for influenza?
Droplet transmission, airborne transmission, and indirect contact transmission (fomites)
portal of entry for streptococcal respiratory disease?
Upper respiratory tract
portal of entry for tuberculosis?
Upper respiratory tract
portal of entry for influenza?
Eyes, nose, mouth
virulence factor for streptococcal respiratory disease?
-M protein
-Hyaluronic acid capsule
-Streptokinases
-C5a peptidase
-Pyrogenic toxins
-Streptolysins
virulence factor for tuberculosis?
Mycolic acid directly responsible for unique characteristics of pathogen
-cord factor
virulence factor for influenza?
Genomes are extremely variable.
Antigenic shift
Antigenic drift
how does streptococcal respiratory disease affect the body?
Infects the throat but the disease is temporary
how does tuberculosis affect the body?
Macrophages in alveoli phagocytize organisms but cannot digest them. Bacteria replicate freely within macrophages, gradually killing them, cycle repeats itself. T cells produce lymphokines that attract and activate more macrophages and trigger inflammation. Collagen fibers enclose granuloma
Reactivated: organism ruptures granuloma. Bacteria spread through lungs via bronchioles, macrophages carry pathogen via blood and lymph to variety of sites
how does influenza affect the body?
Infects cells in the upper and lower respiratory tract. Lytic replication cycle eliminates the lungs first line of defense.
signs and symptoms for streptococcal respiratory disease?
Back of pharynx red, swollen lymph nodes, purulent abscesses over tonsils, pain during swallowing, fever, malaise, headache, can cause laryngitis and bronchitis.
Scarlet fever, pharyngitis, acute glomerulonephritis
signs and symptoms for tuberculosis?
Not initially apparent and may be limited to minor cough and mild fever
Fatigue, malaise, chest pain, wheezing, and cough up blood
signs and symptoms for influenza?
Symptoms due to cytokines. Sudden fever, pharyngitis, congestion, dry cough, malaise, headache, myalgia
epidemiology for streptococcal respiratory disease?
A human adapted pathogen
Winter and spring among elementary and middle school children
Is sensitive to antimicrobial drugs
epidemiology for tuberculosis?
1.7 billion people were infected with TB
Responsible for the second highest number of deaths worldwide due to an infectious disease
Greatest risk of infection: low immunity people
epidemiology for influenza?
Changing antigens guarantee there will always be susceptible people
Some people are carriers
diagnosis for streptococcal respiratory disease?
Some estimate that <50% of pts. Diagnosed with strep have it. Most have viral pharyngitis
-serological testing
diagnosis for tuberculosis?
TB skin test
Cell-mediated hypersensitivity reaction
Chest x ray
Sputum sample
diagnosis for influenza?
Flu signs and symptoms during a community wide outbreak are often sufficient for diagnosis
treatment for streptococcal respiratory disease?
Oral or intramuscular penicillin G, penicillin V, or amoxicillin
treatment for tuberculosis?
Common antimicrobials have little effect
Pyrazinamide with INH, rifampin and either streptomycin or ethambutol
treatment for influenza?
Two drugs available: tamiflue and Relenza
prevention of streptococcal respiratory disease?
Antibodies against M protein
Keep sick children isolated
prevention of tuberculosis?
Antibacterial drugs used prophylactically
BCG vaccine (attenuated)
prevention of influenza?
Immunization with a multivalent vaccine, culling infected birds, good personal hygeiene
