Pathology and microbiology of respiratory disease 1, 2 and 3 Flashcards
1
Q
List some bacteria that are normally present in the URT
A
Step - alpha haemolytic and non-haem and beta Pasteurella Staphylococci E.coli Actinobacillus Proteus Bordatella Pseudomonas Neisseria Lactobacillus Clostridium Bacillus Mycoplasmas Chlamydophila
2
Q
T/F: all viruses that cause infections of the URT or LRT can predispose to bacterial infections
A
True
3
Q
Outline features of bacterial infections of the LRT
A
primary/secondary
pure/mixed
4
Q
Are primary or secondary bacterial infections of the LRT more clinically important?
A
secondary infections
5
Q
Outline bacteria that can cause respiratory disease in small animals
A
Bordatella Pasteurella (B-haem strep) Actinomyces and Nocardia Chlamydophila (Mycoplasmas)
6
Q
What are the 4 species of Bordatella?
A
B.bronchisceptica
B. pertussis (whooping cough)
B. parapertussis (humans, sheep)
B. avium
7
Q
Describe B. bronchiseptica
A
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
8
Q
Outline B. bronchiseptica in the cat
A
Resp. disease common (unclear bacteria involvement)
Serological evidence - early exposure in kittens
Cultured in 11% cats (not household)
Vaccine = NobivacBb
9
Q
Pathogenesis and pathology - B. bronchiseptica
A
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)
10
Q
What are the B. bronchiseptica pathogenicity factors? 2
A
ADHERENCE TO RESP. CILIATED EPITHELIUM - FHA, fimbriae and OMP
TOXINS - leucocyte toxin, tracheal cytotoxin (inhibits DNA synthesis), dermonecrotic toxin (ADP-ribosylation)
11
Q
Properties - Pasteurella multocida
A
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)
12
Q
Pathology - Pasteurella multocida - cats/dogs
A
severe suppurative pneumonia and pleuritis (pyothorax/empyaema)
Cat bites and wounds
Often mixed infections
13
Q
What is another name for rabbit snuffles?
A
enzootic pasteurellosis
14
Q
Describe rabbit snuffles clinical signs
A
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.
15
Q
Control - rabbit snuffles
A
Bacterin vaccines - fail
Long-term AM therapy (enrofloxacin) - to control and eliminate
16
Q
T/F: rabbits don’t have neutrophils
A
True - they have heterophils instead.
17
Q
Describe Actinomyces viscosus as a bacteria
A
Gram positive, filamentous, branching
aerobic growth
commensal - canine oral cavity
–> granulomatous thoracic infection (dogs)
localised granulomatous abscesses of skin (chronic and progressive)
18
Q
Outline Nocardia asteroides
A
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
19
Q
Treatment - Nocardia asteroides
A
Resistant to penicillin and some other AMs
Prolonged use of TMPS, TCs, Ampicillin
20
Q
Pathology - nocardiosis
A
Copious red-brown exudate in pleural cavity
May become chronic with adhesion formation
Exudate contains ‘sulphur granules’
21
Q
What are sulphur granules on the pleural surface typical of?
A
filamentous bacteria (very hard for ABs to reach these bacteria here).
22
Q
Outline Chlamydophila felis as a bacteria
A
intracellular
gram-negative rods
no growth on laboratory media
23
Q
Clinical signs - Chlamydophila felis?
A
Conjunctivitis (cats, most commonly)
Progress to interstitial bronchopneumonia (rare, only really if immunosuppression present too)
24
Q
Diagnosis - Chlamydophila felis?
A
PCR - increasingly commonly
ELISA - Ag
Kosters stain (modified ZN) or fluorescein-labelled Ab.
25
Prevention - Chlamydophila felis?
Fel-O-Vax 4 or 5
| No disease in the dog.
26
What causes canine nasal aspergillosis?
Aspergillus fumigatus
27
Diagnosis - canine nasal aspergellosis
```
Radiology
Endoscopy
Serology (ID presence of fungi)
Culture (ID species)
Microscopy
```
28
Pathology - nasal aspergellosis
nasal turbinates progressivley destroyed by chronic granulomatous (and eosinophilic) inflammation
yellow-green mycotic exudate in caudal nasal cavity
29
Pathology - nasal aspergellosis
numerous fungal hyphae (histopathological exam)
| Special strains = Grocott (black hyphae) and PAS (stains LPS pink)
30
Which breeds are prone to nasal aspergellosis?
```
GSDs
Doliocephalics (long head)
```
31
Treatment - nasal aspergellosis
long course of antifungals
32
Bacteria causing respiratory disease in sheep and cattle -7
```
Mannheimia
Pasteurella
Histophilus
Mycobacterium
Mycoplasma
Actinomyces
Actinobacillus
```
33
What factors lead to complex respiratory infections?
crowding, viruses, bacteria, stress, poor ventilation etc
34
What effects do viruses have on epithelial cells of the resp.T.?
cilia clumping
mucous pooling
eventual loss of cilia (increases secondary infection risk)
35
Other names of bovine respiratory disease complex (BRDC)? 2
Enzootic pneumonia
| 'Shipping Fever'
36
What viruses contribute to BRDC?
PI3
RSV
BHV/IBR
37
What other pathogens are implicated in BRDC (other than PI3, RSV and BHV/IBR)? 3
Mycoplasma bovis
Followed by:
Pasteurella multocida
Mannheimia haemolytica
38
Outline IBR infection?
causes 'red nose'
URT infections --> fibrinous laryngitis and tracheitis
```
Diagnosis - Pathology - intranuclear viral inclusions
Vaccines available (multiple pathogens)
```
39
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
```
40
PI3:
Family
Effect
Prevention
```
Family = Paramyxoviridae
Effect = URT infections
Prevention = vaccine (multivalent)
```
41
T/F: in BRDC, if you prevent the viral infection, you will stop the bacterial infection.
True
42
What disease does Mannheimia haemolytica cause in cattle?
Epizootic (endemic) pneumonia in cattle
Shipping Fever
Bovine pneumonic pasteurellosis
SHEEP - pasteurelloosis
43
T/F: M. haemolytica is a normal commensal in the nasopharynx of ruminants.
True
44
Outline M.haemolytica bacterial properties
beta-haemolytic on sheep blood agar
growth (weak) on MacConkey
Oxidase positive
45
What is the primary agent responsible for calf pneumonia (numbers and severity wise)?
Mannheimia haemolytica
46
How many biotypes of M.haemolytica are there?
2 - biotype A and T
47
What allows M.haemolytica serotype A1 to cause disease (i.e. Bovine pneumonic pasteurellosis)?
Predisposing injury
48
Outline histopathological features of Mannheimia haemolytica/pneumonic pasteurellosis
Fibrinous fluid
| Fibrin, influx of cells (neutrophils predominantly)
49
Pathology - pneumonic pasteurellosis - cattle
80% cases involve M.haemolytica and P.multocida
- Bronchopneumonia is fibrinous to necrotising (leukotoxin and LPS)
- pleuritis frequent
- implicated in meningitis, also polyarthritis (2-4 month old housed calves)
- sporadic cases of peracute fatal mastitis in cows
50
Pathology - M. haemolytica
Pasteurellosis (lambs <3 months old)
septicaemia, severe pleuritis and pericarditis
Sheep/goats - severe mastitis
51
Vaccination - M. haemolytica
CATTLE - natural protection via Ab to leukotoxin and capsular polysaccharide. (Bacterins not effections, Leukotoxin not effective. Iron-restricted OMP in combination with leukotoxin may be better). Bovipast RSP (RSV, PI3 and M. haemolytica).
52
What does Pasteurella trehalosii cause?
acute/peracute septicaemia, older lambs (5-12months)
53
T/F: you normally vaccinate sheep against M.haemolytica and P.trehalosii
True
54
Outline Histophilus somnii infection
```
Normal commensal (genitals, transiently in URT)
Causes peracute death (young calves): acute thromboembolic meningoencephalitis, pneumonia, myocarditis
```
55
What are the 2 categories of mycobacteria
Pathogenic mycobacteria and atypical mycobacteria (environmental saprophytes)
56
Features - mycobacterium
Strict aerobes, very slow growing
Resistant - drying and chemicals
Virulent spp fully resist intracellular killing
57
Can bovine TB kill a cow?
Yes - chronic eventually fatal, pneumonia and wasting.
58
What is an open case of TB?
continuous shedding into the environment from lesions excreting to the exterior (kidney, udder)
59
Diagnosis - bTB
Comparative ID test (PPD)
New methods = gamma IFN stimulation test (take a blood sample, take lymphocytes and stimulate with PPD then see if yIFN is produced in response to PPD. Positive reaction indicates prior exposure)
60
Pathology - bovine TB
granulomatous pneumonia and lymphadenitis. Nodules have characteristic caseating ('cheesy') cut surface.
61
Why are dairy cattle most at risk of bTB?
intensive management
62
Outline Mycoplasma infections
inhabit mucosal surfaces
acquire host Ag to evade IR
infection may depress performance (90%)
involved in BRDC
63
Why aren't Mycoplasmas susceptible to B-lactam ABs?
no cell wall
64
What does Myocplasma bovis (i.e. not Mycobacterium bovis) cause?
Arthritis, mastitis (and pneumonia)
Resp.T. commensal
'Cuffing' pneumonia in calves
65
Gross pathology - Mycoplasma bovis - 'cuffing' pneumonia in calves
- Part of calf pneumonia complex
- Progressive cranioventral consolidation (bronchiectasis)
- On cut surface, exudate in the main airways of affected lobules with thickening of the surrounding CT.
66
Microscopic features - Mycoplasma bovis - 'cuffing' pneumonia in calves
- Lymphoid nodules and follicles around airways
- Follicles may compress bronchial lumina
- Mixed cellular exudate in airways
- Partial alveolar collapse
- Slight thickening of alveolar walls (lymphocytes)
- NO TOXINS
67
Define BALT
bronchiolar lymphoid tissue
68
What causes contagious bovine pleuropneumonia (CBPP)?
Mycoplasma mycoides subspecies mycoides SC (notifiable)
69
Significance of contagious bovine pleuropneumonia (CBPP)
Not so much in western world, otherwise mortality up to 50% in indigenous breeds, no specific age association, transmission (aerosol, close contact),
DIAGNOSIS - CFT
70
Pathology - CBPP - 5
- Fibrino-necrotic bronchopneumonia with fibrinous pleuritis
- Dorsocaudal areas may be affected
- Interstitial septa widened by fibrinous exudate and oedema
- Necrotic areas may be encapsulated (sequestra)
- lung involvement is usually UNILATERAL
71
Which mycoplasmas can affect sheep and goats?
M. ovipneumoniae - pneumonia
M. capricolum - pneumonia
M. mycoides sbsp. capri - pneumonia
72
List 3 respiratory viruses of sheep.
PI3 (occasionally causes lamb penumonia)
RSV
Adenoviruses (ovine and bovine)
Isolated from resp. disease sheep but roles not certain - may predispose M.haemolytica (part of enzootic pneumonia complex in sheep).
73
Control - respiratory viruses of sheep
No vaccines licensed for PI3, RSV or adenoviruses in sheep.
74
What fungi cause respiratory disease -cattle/sheep?
Aspergillus and Micropolysporum
75
Which bacteria cause respiratory disease in horses? 4
Step. equi subsp. equi
Rhodococcus
Actinobacillus
Mycoplasmas
76
Which viruses cause respiratory disease in horses? 3
Equine influenza virus
| EHV - 1 and 4
77
Describe Strep. equi as a bacteria
```
gram positive
obligate parasite of horses
Lancefield group C
1 M-protein type
strongly beta-haemolytic with mucoid colonies
HA capsule becomes matt
```
78
How can Strep. equi be differentiated from other beta-haemolytic strep?
Biochemical tests - trehalose (neg), sorbitol (neg), salicin (pos)
79
Does Strep. equi cause lymphadenitis?
Yes (a suppurative lymphadenitis) - enlarged, abscessed LNs in head and neck. Also GP empyaema (site of long-term carriage). These can rupture and cause formation of draining tracts to skin surface.
80
Define empyaema
a collection of pus within a naturally existing anatomical cavity. DDx = abscess which is a collection of pus BUT in a newly-formed anatomical cavity
81
How can Strangles be prevented in horses?
Strepguard vaccine - ineffective
| Equilis StrepE - live modified strain, inject in MM, now removed from market
82
T/F: Streptococcus pneumoniae is the main cause of respiratory disease in the training horse
False - Streptococcus pneumoniae is an occasional cause of respiratory disease in the training horse
83
Features - Rhodococcus equi
```
Gram positive rod (despite name)
variably acid fast
Actinomycete group
Naturally in soil and GIT (horses)
Persists in manure for a long time
```
84
Pathology - Rhodococcus equi - foals
- Important cause of suppurative bronchopneumonia - foals 2-6 months old
- Complex lipid cell wall - resists digestion
- Foci of caseous necrosis (lungs)
- Lesions often extensive before CS show
- High mortality (40-80%)
- Bronchial LNs may also contain caseating foci
- Dissemination to other organs
- Adult horses immune
85
Why does Rhodococcus equi cause granulomatous lesions in the lung?
It is a facultative intracellular pathogen --> undeveloped CMI
86
Which horses do Actinobacillus affect?
Adult thoroughbreds
87
```
Outline EIV as a respiratory disease:
subtypes
infection
CS
Secondary infections
vaccines
```
- Subtypes (H7N7 or H3N8)
- URT infection, may spread to LRT and cause bronchitis and bronchiolitis
- CS: cough, pyrexia, depression
- Secondary infections: Strep, Staph, Klebsiella
- Vaccines: required for UK competing horses, inactivated vaccines containing both subtypes but aren't protective against all strains.
88
Outline EHV as a respiratory disease:
Subtypes
Infection location
CS
Vaccines
***EHV4 - main resp disease, rarely abortion***
Also, EHV1 (resp disease, abortion, paresis), EHV5 (equine multinodular pulmonary fibrosis)
Infection - URT
CS: nasal discharge, cough, pyrexia
Vaccines: inactivated containing EHV1 and EHV4
89
What causes equine GP mycosis
Aspergillus nidulans
90
Why does equine GP mycosis cause severe nasal bleeding and dysphagia?
close associated to internal carotid artery
91
Diagnosis - equine GP mycosis
```
***Endoscopy***
Radiology
Serology
Culture
Microscopy
```
92
Treatment - equine GP mycosis - 3
Local antifungal delivery
Ligate carotid artery
Systemic azole antifungal
93
List 4 bacteria causing respiratory disease in pigs
Bordatella/Pasteurella
Actinobacillus
Haemophilus
Mycoplasmas
94
List 3 viruses causing respiratory disease in pigs
PRRSV
Swine infleunza
Porcine circovirus
95
Aetiology - atrophic rhinitis - swine
Combination of early colonisation of NP with Bordatella bronchiseptica with a dermonecrotic toxin (damages osteoblasts --> turbinate atrophy) AND Pasteurella multocida (type A or D) producing the osteolytic toxin which stimulates osteoclasts --> turbinate bone resoption and atrophic rhinitis.
96
Why is swine atrophic rhinitis uncommon?
Because it is effectively vaccinated against.
97
What causes contagious pleuropneumonia in pigs?
Actinobacillus pleuropneumoniae
98
Outline contagious swine pleuropneumonia
Acute or chronic fibrinohaemorrhagic pneumonia with pleurisy
- intensive pig production
- worldwide
- high morbidity and mortality
- initial cases severe - progresses to chronic with sporadic cases
- subclinical carriers and recovered carriers (depends on degree of immunity)
99
Pathology - contagious pleuropneumonia - pigs
- Fibrinonecrotic bronchopneumonia with pleuritis (cranioventral but spreads rapidly)
- Pleural adhesions form in chronic cases.
100
Bacterial features of Actinobacillus pleuropneumoniae
```
NAD-dependent (growth on chocolate agar)
waxy, sticky colonies
delicate
gram negative
15 serotypes (UK serotypes are 8, 2 and 6)
```
101
Pathogenicity factors - Actinobacillus pleuropneumoniae
```
Apx toxins (these are RTX proteins. Cytolytic and haemolytic--> massive cytokine release --> pulmonary inflammation, haemorrhage and oedema)
Capsule polysaccharide
Takes iron from porcine transferrin
```
102
How can you protect against Actinobacillus pleuropneumoniae?
- Porcillis APP - subunit, Europe
| - Suvaxyn HPP - killed, UK, no longer marketed
103
What disease does Actinobacillus suis cause?
Pleuropneumonia-like disease (mild) in high health-status animals
104
What disease does Haemophilus parasuis cause?
Glasser's disease - polyserositis
| Fibrinos exudate in high health-status animals
105
Define polyserositis
= inflammation of several serous membranes (e.g. pleura, pericardium and peritoneum) at the same time
106
Pathology - Glasser's disease/Haemophilys parasuis - pigs
- suppurative bronchopneumonia
- polyserositis
- lesions may be present singly or in combination
- mortality high in young animals
- predisposing factors include stress
- multi-systemic disease
107
What causes enzootic pneumonia (EP) in the pig (esp. young growing pigs)?
```
Mycoplasma hyopneumoniae
80-90% pig herds
widespread
predisposition to other respiratory disease
aerosol transmission
```
108
Pathology - enzootic pneumonia/EP/Mycoplasma hyopneumoniae in pigs
- usually chronic, non-fatal disease unless secondary infection is present
- seen commonly at slaughter
- reduced growth rate and coughing
GROSS = cranioventral consolidation and red/grey discolouration
MICROSCOPY = similar to 'cuffing pneumonia' in calves = lymphoid nodules and follicles around airways, follicles may compress bronchial lumina, mixed cellular exudate in airways, partial alveolar collapse, slight thickening of alveolar walls with lymphocytes.
109
Define lung consolidation
becomes more solid
110
Diagnosis - M.hyopneumoniae
serological diagnosis by competition ELISA
111
What other mycoplasmas can affect the pig?
- M.hyosynoviae - arthritis
| - M.hyorhinis - commonly found in RespT, cause of polyserositis and arthritis
112
What causes PRRS?
the PRRS virus (Arteriviridae)
113
Outline PRRS:
Effects
CS
Predisposes what
Effects- infects URT, systemic spread in macrophages
CS - frequently subclinical respiratory signs and interstitial pneumonia
Predisposes or enhances effects of infection with other viruses or bacteria (influenza, M. hyopneumoniae)
Part of PRDC
114
Outline swine influenza
Subtypes (H1N1, H3N2 and H1N2)
CS - sudden outbreaks of resp. disease with barking cough and respiratory distress (naive herds)
Effects - bronchiolitis and pneumonia. If endemic in the herd, weaned pigs will develop CS as soon as MAb levels decline.
Primary pathogen but if endemic will contribute to PRDC.
No vaccines licensed in UK
Zoonotic risk
115
Outline PCV2:
effects
vaccines
- Effects: Immuno-suppressive. Predisposes pigs to other infections. Possible involvement in PRDC, PMWS and porcine dermatitis and nephropathy syndrome (PDNS). Overall this is referred to as PCAD = porcine circovirus associated disease.
- 2 vaccines licensed in UK
