Pathology and microbiology of respiratory disease 1, 2 and 3 Flashcards
List some bacteria that are normally present in the URT
Step - alpha haemolytic and non-haem and beta Pasteurella Staphylococci E.coli Actinobacillus Proteus Bordatella Pseudomonas Neisseria Lactobacillus Clostridium Bacillus Mycoplasmas Chlamydophila
T/F: all viruses that cause infections of the URT or LRT can predispose to bacterial infections
True
Outline features of bacterial infections of the LRT
primary/secondary
pure/mixed
Are primary or secondary bacterial infections of the LRT more clinically important?
secondary infections
Outline bacteria that can cause respiratory disease in small animals
Bordatella Pasteurella (B-haem strep) Actinomyces and Nocardia Chlamydophila (Mycoplasmas)
What are the 4 species of Bordatella?
B.bronchisceptica
B. pertussis (whooping cough)
B. parapertussis (humans, sheep)
B. avium
Describe B. bronchiseptica
Strict aerobe, Gram negative rod No different serotypes Slow growing Normal URT inhabitant Exogenous or endogenous infection --> tracheobronchitis (KC) and bronchopneumonia (following distemper) 2 vaccines - live avirulent IN
Outline B. bronchiseptica in the cat
Resp. disease common (unclear bacteria involvement)
Serological evidence - early exposure in kittens
Cultured in 11% cats (not household)
Vaccine = NobivacBb
Pathogenesis and pathology - B. bronchiseptica
Initial trauma –> viral infection
Adherence (tracheal cilia)
Proliferation (airway)
Toxins released –> irritation and coughing
PATHOLOGY: Epithelial necrosis, peribronchial inflammation and interstitial pneumonia, severe pneumonia due to secondary invaders (e.g. b-haem strep)
What are the B. bronchiseptica pathogenicity factors? 2
ADHERENCE TO RESP. CILIATED EPITHELIUM - FHA, fimbriae and OMP
TOXINS - leucocyte toxin, tracheal cytotoxin (inhibits DNA synthesis), dermonecrotic toxin (ADP-ribosylation)
Properties - Pasteurella multocida
gram negative rod oxidase positive no growth on MacConkey strong catarrhal smell
Normal oral bacteria (dog and others) Secondary infection - URT infections Common after bite wounds Capsular serotypes - A and D Vaccines (inappropriate currently)
Pathology - Pasteurella multocida - cats/dogs
severe suppurative pneumonia and pleuritis (pyothorax/empyaema)
Cat bites and wounds
Often mixed infections
What is another name for rabbit snuffles?
enzootic pasteurellosis
Describe rabbit snuffles clinical signs
Pasteurella multocida/ennzootic pasteurellosis
chronic nasal discharge and sneezing, purulent material filling sinuses, multifocal pulmonary abscesses
sometimes fatal
colonisation - respT (URT), middle ear, genitalia, occasionally lungs (ciliotropic)
Enzootic amongst rabbit colonies
difficult to eradicate
easy transmitted to uninfected rabbits.
Control - rabbit snuffles
Bacterin vaccines - fail
Long-term AM therapy (enrofloxacin) - to control and eliminate
T/F: rabbits don’t have neutrophils
True - they have heterophils instead.
Describe Actinomyces viscosus as a bacteria
Gram positive, filamentous, branching
aerobic growth
commensal - canine oral cavity
–> granulomatous thoracic infection (dogs)
localised granulomatous abscesses of skin (chronic and progressive)
Outline Nocardia asteroides
soil bacteria
gram ppositive rods
thin, short filaments
partially acid-fast (wax-like mycolic acid)
grow within and destroy macrophage
chronic, progressive, suppurative thoracic granulomas
Treatment - Nocardia asteroides
Resistant to penicillin and some other AMs
Prolonged use of TMPS, TCs, Ampicillin
Pathology - nocardiosis
Copious red-brown exudate in pleural cavity
May become chronic with adhesion formation
Exudate contains ‘sulphur granules’
What are sulphur granules on the pleural surface typical of?
filamentous bacteria (very hard for ABs to reach these bacteria here).
Outline Chlamydophila felis as a bacteria
intracellular
gram-negative rods
no growth on laboratory media
Clinical signs - Chlamydophila felis?
Conjunctivitis (cats, most commonly)
Progress to interstitial bronchopneumonia (rare, only really if immunosuppression present too)
Diagnosis - Chlamydophila felis?
PCR - increasingly commonly
ELISA - Ag
Kosters stain (modified ZN) or fluorescein-labelled Ab.
Prevention - Chlamydophila felis?
Fel-O-Vax 4 or 5
No disease in the dog.
What causes canine nasal aspergillosis?
Aspergillus fumigatus
Diagnosis - canine nasal aspergellosis
Radiology Endoscopy Serology (ID presence of fungi) Culture (ID species) Microscopy
Pathology - nasal aspergellosis
nasal turbinates progressivley destroyed by chronic granulomatous (and eosinophilic) inflammation
yellow-green mycotic exudate in caudal nasal cavity
Pathology - nasal aspergellosis
numerous fungal hyphae (histopathological exam)
Special strains = Grocott (black hyphae) and PAS (stains LPS pink)
Which breeds are prone to nasal aspergellosis?
GSDs Doliocephalics (long head)
Treatment - nasal aspergellosis
long course of antifungals
Bacteria causing respiratory disease in sheep and cattle -7
Mannheimia Pasteurella Histophilus Mycobacterium Mycoplasma Actinomyces Actinobacillus
What factors lead to complex respiratory infections?
crowding, viruses, bacteria, stress, poor ventilation etc
What effects do viruses have on epithelial cells of the resp.T.?
cilia clumping
mucous pooling
eventual loss of cilia (increases secondary infection risk)
Other names of bovine respiratory disease complex (BRDC)? 2
Enzootic pneumonia
‘Shipping Fever’
What viruses contribute to BRDC?
PI3
RSV
BHV/IBR
What other pathogens are implicated in BRDC (other than PI3, RSV and BHV/IBR)? 3
Mycoplasma bovis
Followed by:
Pasteurella multocida
Mannheimia haemolytica
Outline IBR infection?
causes ‘red nose’
URT infections –> fibrinous laryngitis and tracheitis
Diagnosis - Pathology - intranuclear viral inclusions Vaccines available (multiple pathogens)
Bovine Respiratory Syncytial Virus (BRSV):
Family
Effect
Prevention
Family = Paramyxoviridae Effect = URT infections, bronchitis and bronchiolitis. Cytopathic effect is syncytia formation due to fusion protein which is produced. {revention = Vaccines available
PI3:
Family
Effect
Prevention
Family = Paramyxoviridae Effect = URT infections Prevention = vaccine (multivalent)
T/F: in BRDC, if you prevent the viral infection, you will stop the bacterial infection.
True
What disease does Mannheimia haemolytica cause in cattle?
Epizootic (endemic) pneumonia in cattle
Shipping Fever
Bovine pneumonic pasteurellosis
SHEEP - pasteurelloosis
T/F: M. haemolytica is a normal commensal in the nasopharynx of ruminants.
True
Outline M.haemolytica bacterial properties
beta-haemolytic on sheep blood agar
growth (weak) on MacConkey
Oxidase positive
What is the primary agent responsible for calf pneumonia (numbers and severity wise)?
Mannheimia haemolytica
How many biotypes of M.haemolytica are there?
2 - biotype A and T