Pathology and microbiology of respiratory disease 1, 2 and 3 Flashcards Preview

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Flashcards in Pathology and microbiology of respiratory disease 1, 2 and 3 Deck (115):
1

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

2

T/F: all viruses that cause infections of the URT or LRT can predispose to bacterial infections

True

3

Outline features of bacterial infections of the LRT

primary/secondary
pure/mixed

4

Are primary or secondary bacterial infections of the LRT more clinically important?

secondary infections

5

Outline bacteria that can cause respiratory disease in small animals

Bordatella
Pasteurella
(B-haem strep)
Actinomyces and Nocardia
Chlamydophila
(Mycoplasmas)

6

What are the 4 species of Bordatella?

***B.bronchisceptica***
B. pertussis (whooping cough)
B. parapertussis (humans, sheep)
B. avium

7

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

8

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

9

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)

10

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)

11

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)

12

Pathology - Pasteurella multocida - cats/dogs

severe suppurative pneumonia and pleuritis (pyothorax/empyaema)
Cat bites and wounds
Often mixed infections

13

What is another name for rabbit snuffles?

enzootic pasteurellosis

14

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.

15

Control - rabbit snuffles

Bacterin vaccines - fail
Long-term AM therapy (enrofloxacin) - to control and eliminate

16

T/F: rabbits don't have neutrophils

True - they have heterophils instead.

17

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)

18

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

19

Treatment - Nocardia asteroides

Resistant to penicillin and some other AMs
Prolonged use of TMPS, TCs, Ampicillin

20

Pathology - nocardiosis

Copious red-brown exudate in pleural cavity
May become chronic with adhesion formation
Exudate contains 'sulphur granules'

21

What are sulphur granules on the pleural surface typical of?

filamentous bacteria (very hard for ABs to reach these bacteria here).

22

Outline Chlamydophila felis as a bacteria

intracellular
gram-negative rods
no growth on laboratory media

23

Clinical signs - Chlamydophila felis?

Conjunctivitis (cats, most commonly)
Progress to interstitial bronchopneumonia (rare, only really if immunosuppression present too)

24

Diagnosis - Chlamydophila felis?

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