Respiratory Pathogens Flashcards
Where are ciliated epithelium found? What is its function?
- Ciliated epithelium in nasal turbinate/trachea/bronchi/bronchioli
o Remove mucus and debris
What 3 bacteria have tropism for respiratory tract (ciliated epithelium)
Bacteria with tropism for respiratory tract (ciliated epithelium)
* Bordatella
* Mycoplasma
* Chlamydia
List 3 routes of pathogen exposure to respiratory tract
- Aerosol
- Particle/droplet
- Conjunctival
List 4 common respiratory bacteria that affect cattle
Cattle
Mannheimia haemolytica
Histophilus somni
Mycoplasma bovis
Mycobacterium bovis
List 3 types of virulence factors that impact adhesion
o Pili/fimbriae
o Adhesions
o Biofilm
List 3 types of virulence factors that impact invasion
- Invasion
o Adhesion type invasins
o Interaction with cytoskeleton
o M protein (staphylococcus)
List 2 types of virulence factors that impact cell survival
- Survival in cells
o Compete for Fe
o Survive in phagosome
List 2 types of virulence factors that impact host damage
- Disease production/damage host
o Super antigens
o Cell wall components
What causes BRD
Cattle; BRD (shipping fever)
* Primary + secondary pathogens (bacteria and/or viruses) + environmental stress
What are the bacaterial characteristics of Mannheimia haemolytica
Mannheimia haemolytica
* Gram (-) pleomorphic, rod/coccobacilli
* Fastidious
* Related to Pasturella with many different serotypes – based on capsule antigens
* Commensal in the oropharynx
What disease manifestations does Mannheimia haemolytica cause?
- Cause bronchopneumonia and septicemia
- Predispose to pneumonic pasturellosis
What are the 3 main virulence factors does Mannheimia haemolytica use
- Virulence factors
o Leukotoxin: lyse leukocytes/platelet
o Capsular polysaccharide: prevent phagocytosis
o LPS: cytokine release and microvascular necrosis
What is the pathogenesis of Mannheimia haemolytica
- Pathogenesis:
o Viral infection + stress = shift mucosal microbiome
o Transmit via inhalation/infective droplets
o Bacteria deposit in mucociliary apparatus
o Mucociliary dysfunction
o Pneumonia
o Colonize animal and spread
What is the lesions of Mannheimia haemolytica
- Lesions
o Hemorrhagic fibrinonecrotic bronchopneumonia
o Septicemia = fibrinous pleuritis/pericarditis/peritonitis
What are the bacaterial characteristics of Histophilus somni
- Gram (-), pleomorphic rod
- Fastidious – need CO2 (capnophilic)
- Colonize mucosal surfaces
What is the pathogenesis of Histophilus somni
- Pathogenesis
o Adhere to endothelial cells
o Cytotoxic change – vasculitis – form fibrinoid thrombi
o Intracellular survival and replication in neutrophils/macrophages/monocytes
o LPS phase can change over time = enable immune evasion
What are the clinical signs/manifestations of Histophilus somni
- Clinically: >1 organ system
o Septicemia
o Resp: pleuritis +/- bronchopneumonia
o Myocarditis and sudden death
o Thrombotic meningoencephalitis
o Arthritis
What are the gross lesions of Histophilus somni
- Lesions
o Fibrinous pleuritis
o Pericarditis
o Bronchopneumonia
o Focal myocardial lesions
o Polyarthritis
o Fibrinous laryngitis
What are the bacaterial characteristics of Mycobacterium bovis
- Weak gram (+), rod
- Very slow growing
- Use acid fast stain
- Facultative intracellular pathogen
What are the virulence factors of Mycobacterium bovis
o Mycosides/phospholipids/sulfolipids: protect from phagocytosis
o Glycolipid: cause granuloma = protect from phagocytosis
o Wax/tuberculoproteins: induce delayed hypersensitivity
How is Mycobacterium bovis transmittted
- Transmit: resp secretions and aerosol
o Also contaminated milk/feces/vaginal secretions/urine/semen
What are the clinical signs of Mycobacterium bovis
- Clinically
o Emaciation
o Fluctuating fever
o Intermittent cough
o Enlarged LN (mediastinal and retropharyngeal)
o Lethargy/anorexia
Describe the pathogenesis of Mycobacterium bovis
o Inhale aerosol
o Engulfed by alveolar macrophages
o Migrate into lung interstitial – bacteria are expelled out and infect other (neutrophil/monocyte/dendritic cells)
Innate immune system may be able to clear but most not
o Dendritic cells will prime T cells for cell mediated response = IFNy release = macrophage and neutrophil activation
o Granuloma production = become ‘stable granuloma’ = latent
Re-activate in times of immunosuppression = shedding
Describe the lesions of Mycobacterium bovis
- Lesions: granulomatous lesions in lungs and mediastinal LN
List 3 types of diagnostic testing to ID Mycobacterium bovis
o Tuberculin test: cell mediated immune response test via intradermal inoculation of M. bovis = inflammation 72hrs after
o In vitro cell mediated immune test: collect blood and incubate with M bovis antigens – measure IFNy response
o Culture and PCR: ID mycobacterium species
List 2 types of specific tuberculin testing to ID Mycobacterium bovis
Caudal fold tuberculin: intradermal, examine after 72h
* If animal is ‘reactor’ = positive response = contact CFIA and quarantine animal
Comparative Cervical Tuberculin = 2 intradermal inoculations of M. bovis or M. avium
* CFIA worker only
* Negative/suspect (retest in 60d)/reactor (euthanize aand necropsy)
* If positive = cull herd
What are the bacaterial characteristics of Mycoplasma bovis
Mycoplasma bovis
* No cell wall, small and pleomorphic
o No gram staining
* Fastidious (need special media = PCR > culture)
* Slow growing
* Obligate pathogen
* Host specific
What is the tropism of Mycoplasma bovis
- Tropism: respiratory and urogenital
What is the the mechanism of damage of Mycoplasma bovis
- Mechanism of disease: attach to ciliated epithelium in trachea/bronchi/bronchioles
o loss of cilia
o change mucus
o reduce mucociliary clearance
o cause chronic low grade infection
o carrier state
o enable other organisms to infect
What are the virulence factors of Mycoplasma bovis
o Biofilm
o Adhesins: attachment
o H2O2/ROS: affect ciliary movement
What is the pathogenesis of Mycoplasma bovis
- Pathogenesis
o Adhere to host
o Direct damage to ciliated epithelium
o Increased neutrophil and mononuclear response
o Ciliostasis
o Pneumonia
What are the common lesions of Mycoplasma bovis
- Lesion
o Bronchitis/bronchiolitis/pneumonia
Ventral part of apical and cardiac lung lobe
o Pleuropneumonia
Fibrinonecrotic pneumonia
Serofibrinous pleuritis
Serosanguinous fluid in thorax
Fibrous capsule with viable bacteria
What are 2 common sheep and goat pathogens
Bibierstinia trehalosi
Mycoplasma ovipneumoniae
What are the bacaterial characteristics of Bibierstinia trehalosi
- Gram (-), pleomorphic, rod/coccobacilli
- Facultative anaerobe
- Related to pasturella
- Commensal of tonsil and nasopharynx
- Opportunistic
What disease manifestations does Bibierstinia trehalosi cause
- Causes bronchopneumonia and septicemia
What are the virulence factors of Bibierstinia trehalosi
o Leukotoxin
o Capsular polysaccharide
o LPS
What is the pathogenesis of Bibierstinia trehalosi
- Pathogenesis
o Stress
o Susceptible to resp infections and predisposes to bacterial infection
o Pneumonia
o Systemic spread to kidney/heart/spleen/joint/meninges
What are the common lesions of Bibierstinia trehalosi
o Fibrinous and ulcerative lesions in esophagus/larynx
o Suppurative bronchopneumonia
o Septicemia
What is the most important pathogen causing resp disease in sheep
Mycoplasma ovipneumoniae
What are the risk factors for Mycoplasma ovipneumoniae
- Risk factors
o Other bacterial pneumoniae (pasturellosis) and viral infections
o Stress
What are the clinical signs of Mycoplasma ovipneumoniae
- Clinically
o Tachypnea
o Cough
o Nasal discharge
o Fever
What is the main pathologic lesion of Mycoplasma ovipneumoniae
- Pathology: suppurative bronchopneumoniae
What are the 2 main respiratory pathogens affecting pigs
Actinobacillus pleuropneumoniae (APP)
Bordatella bronchiseptica (atrophic rhinitis)
What causes Porcine Resp Disease Complex
Porcine Resp Disease Complex
* Primary or secondary bacteria
o Mycoplasma hyopneumoniae
o Pasturella multocida
o Strep suis
o Actinobacillus suis
o Glaesserella parasuis
* Primary or secondary virus
o PRRS
o Swine influenza
o Porcine respiratory coronavirus
o Porcine circovirus type 2
* Stress
How is Actinobacillus pleuropneumoniae (APP)
transmitted
- Transmit: aerosol droplet between pigs (close contact)
What are the virulence factors of Actinobacillus pleuropneumoniae (APP)
- Disease: depends on age/herd health/environmental conditions
o Can see similar disease with Actinobacillus suis (except A. suis is systemic!) - Virulence
o Fimbriae: adhesion and attachment
o Toxins: APX toxin that hasa affinity for alveolar/endothelial/RBC/neutrophils/macrophage cells
o Protease: breakdown host cell proteins
What is the pathogenesis of Actinobacillus pleuropneumoniae (APP)
- Path:
o Close contact
o Colonize tonsils and alveolar epithelium
o Phagocytosed by macrophages
o Toxin production
o Tissue damage
o Severe necrotizing vasculitis
o Septic shock/peracute death +/- lung lesions
What are the lesions of Actinobacillus pleuropneumoniae (APP)
o Hemorrhagic/fibrinous/necrotizing bronchopneumonia
o Abscess/pleuritis
What are the bacaterial characteristics of Bordatella bronchiseptica
Bordatella bronchiseptica (atrophic rhinitis)
* Gram (-), coccobacailli
* Obligate aerobe
* Obligate pathogen
* contagious
* Commensal in upper resp
What disease can Bordatella bronchiseptica cause in pigs
- Cause: atrophic rhinits when in combination with P. multocida (typee A or D) aand B. bronchiseptica
What are the virulence factors of Bordatella bronchiseptica
- Virulence factors
o Fimbriae
o Adenylate cyclase hemolysin
o LPS: cause diphtheric membrane formation
o Tracheal cytotoxin: damage and paralyze ciliated tracheal epithelium
o Dermonecrotic toxin: inhibit osteoblasts
What is the pathogenesis of Bordatella bronchiseptica in pigs
- Path
o Pre-existing infection with B. bronchiseptica
o Colonize and proliferate of P. multocida
Many toxins produced (P. multocida = PM toxin = epithelial hypoplasia/atrophy of mucus glands/osteolysis) + dermonecrotic toxin
o Atrophy of nasal turbinates’
o Shrinking of snout
What are the lesions of Bordatella bronchiseptica in pigs
o Mild = non progressive lesions
o Severe = turbinate atrophy and deviation of the nasal septum
What are 2 common resp pathogens of poultry
Poultry
Pasturella multocida (fowl cholera)
Avibacterium paragallinarum (infectious coryza)
What are the common clinical signs of resp disease in birds
Signs of Resp disease
* Cough
* Rales (crackles)
* Gasping
* Cyanosis on face/comb/wattle
* Also sneeze/discharge/facial swelling/conjunctivitis/head shaking
What are the bacaterial characteristics of Pasturella multocida
- Gram (-), non motile rods/coccobacilli
- Fastidious
- Facultative anaerobe
- Commensal in oropharynx/GI in MM
- Low survival in environment but large host rrange
What are the virulence factors of Pasturella multocida
- Virulence factors
o PM toxin = cytotoxin
o Polysaccharide capsule
What animals are most affected by Fowl cholera? When is it most common
o Turkeys (most severe) / duck/geese/chicken
o Very contagious
o Physiological stress and cooler seasons
o Can be complicated by secondary infection
Compare acute and chronic fowl cholera
Acute: sudden onset with high morbidity and mortality
* Ruffled feathers/depression/tachypnea/dyspnea/rales/cyanosis
Chronic: survive acute form
* Subclinical
* Localized exudative infection and inflammation
What are the lesions of Pasturella multocida in birds?
o Lesions
Acute: hemorrhage/hepatomegaly with focal necrosis/pharyngitis/air saccultitis/pneumonia
Chronic: exudative infection (conjunctivitis/sinusitis/otits media/meningitis)/ facial edema)
What are the bacaterial characteristics of Avibacterium paragallinarum
- Gram (-), non motile, pleomorphic, coccobacilli
- Fastidious: capnophilic (CO2)
- 3 serogroups (AA/B/C)
- Very contagious
What disease does Avibacterium paragallinarum cause in birds
- Upper resp disease in chickens: high morbidity and low mortality
o Worsened by Mycoplasma or viral coinfection
What are the virulence factors of Avibacterium paragallinarum
- Virulence:
o Capsular polysaccharide
o Hyaluronic acid: part of capsule (prevent phagocytosis)
o LPS
How is Avibacterium paragallinarum transmitted
- Transmit: direct contact/airborne droplets/contaminated drinking water
Compare the 2 forms of Avibacterium paragallinarum
- Mild: young chicken
o Depression/serous nasal discharge/mild facial swelling - Severe: young adult/older
o Depression/d/reduced feed and water consumption/low growth/sneeze/mucoid or suppurative nasal or ocular discharge/facial swelling/rales
What are the lesions associated with Avibacterium paragallinarum
- Lesions
o Severe swelling of infraorbital sinus with edema
o Sinusitis/conjunctivitis/tracheitis/bronchitis/air saccultits
What is another top differential (along wiith Avibacterium paragallinarum) for resp infection in birds
- Differential: P. multocida
