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ClinSci 2 Exam 2 > Bronchopneumonia in Food Animals > Flashcards

Bronchopneumonia in Food Animals Flashcards

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1
Q

what are the 2 mechanisms of colonization resistance?

A
  1. direct microbe-microbe inhibition: bacteria themselves interact with other pathogens and resist colonization
  2. indirect microbe-stimulated host immunity: innate system maintains host defense: leukocytes, epithelial cells active, etc
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2
Q

mucociliary apparatus

A

glands produce mucin and peptides as part of immune defense. host epithelium maintains the mucociliary defense

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2
Q

what maintains the mucociliary apparatus?

A

host epithelium

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3
Q

central hypothesis with BRD pathogenesis

A

immunocompromised host with risk factors, virus infects and causes damage to the resp epithelium and immune suppression. this allows commensals to overgrow

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4
Q

expanded hypothesis with BRD pathogenesis

A

immunocompromised host but also environmental factors: air quality, smoke, etc, that impacts airways, viral infx
- pathobionts: commensal bacteria that live in the resp microbiome that have a good beneficial relationship with host to not allow other pathogens to colonize RT, but in situations where they overgrow, can express pathogenic virulent factors. have a dual virulent factor
- get a dysbiosis in the URT and LRT, and the pathobionts start to dominate and express virulence factors

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5
Q

pathobionts

A

pathobionts: commensal bacteria that live in teh resp microbiome that have a good beneficial relationship with host to not allow other pathogens to colonize RT, but in situations where they overgrow, can express pathogenic virulent factors. have a dual virulent factor

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6
Q

how does BRD present?

A

complex and many clinical presentations
- clinical vs subclinical
- localization: URT, lng
- duration: acute vs chronic
- also depends on what part of the production cycle these animals are in
beef animals may just have decreased appetite/rumen fill and no nasal discharge
calves can show nothing at all and have no outward signs of disease

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7
Q

what are major risk factors for BRD?

A
  • FPI: failure of passive immunity
  • stress!! impacts the immune system substantially
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8
Q

risk factors for BRD

A

FPI and stress!!
genetics, viral infx,, group housing, air quality, dehydration, weaning, weather, transport, co mingling, nutritional deficiencies, surgical procedures

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9
Q

T/F: we have made significant advancements in BRD thanks to prevention and therapeutics over the last 50 years

A

false. we have not made significant changes despite advancements in prevention and therapeutics
- colostrum quality super important
- stress and nutriton
- vaccination
all of these affect disease susceptibility

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10
Q

when are calves typically weaned?

A

<56 days

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11
Q

what do you have to differentiate BRD from with preweaned calves?

A

aspiration!! contamination, improper feeding, etc

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12
Q

enzootic calf pneumonia

A
  • weaned calves (2-5 months)
  • viral exposure, stress (mixing groups)
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13
Q

weaned calf BRD

A
  • weaned calves (most common 2-5 months)
  • viral exposure, stress (mixing groups)
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14
Q

replacement heifers and cows BRD

A

more commonly sporadic, metastatic

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15
Q

cow-calf beef BRD

A
  • up to 10% pre-weaned calves (3-5 months)
  • nadir if IgG: cows relying on own adaptive immunity
  • a shorter calving interval will make the herd immunity low
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16
Q

weaned calves beef BRD

A
  • shipping fever: transported to facility or stock area before feedlot
  • highest morbidity during 1st 21 days post arrival!!** EXAM
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17
Q

when do we see the highest morbidity in the beef industry with BRD?

A

in weaned calves: shipping fever
- highest morbidity during the 1st 21 days (3 weeks) post arrival!!! ***

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18
Q

finishers (feedlot) beef BRD

A
  • sporadic outbreaks, interstitial pneumonia
  • rule out altitude induced pulmonary hypertension
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19
Q

pathophysiology of BRD in lungs

A
  • depends on dominant pathobiont and/or infectious agent and passive transfer status
  • innate immune system stimulated thru pattern recognition receptors to increases chemotaxis of neutrophils and macrophages to cause inflammation = oxidative host damage
  • pro inflammatory cascade
  • secondary invaders, opportunists cause consolidation of airways or pulmonary abscesses, pleuropneumonia
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20
Q

mannheimia hemolytic

A
  • Pasteurellae, Gram neg, aerobic rod
  • normally in animals in their nasopharynx
  • opportunistic in lungs: dysbiosis allows it to take over
  • viral infx increase severity!
  • pathology: lobar pneumonia –> necrotizing fibrinous pleuropneumonia
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21
Q

virulence factors with mannheimia hemolytic

A
  • leukotoxin: cytolysis of ruminant leukocytes
  • endotoxin/LPS: proinflammatory (neutrophil chemotaxis)
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22
Q

pathology of mannheimia hemolytic

A

lobar pneumonia –> necrotizing fibrinous pleuropneumonia
peracute rapidly consolidating syndrome

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23
Q

T/F: mannheimia hemolytic is commonly associated with shipping fever

24
most of the bacteria in livestock resp diseases are
gram -
25
pasteurella multocida
- pasteurella, gram -, aerobic, coccobacilli - normal nasopharyngeal inhabitant - with high levels of ammonia, the chemicals will damage the host epithelium and allow Pasteurella to grow and populate!
26
pathology of pasteurella multocida
purulent lobar bronchopneumonia, less likely fibrin and necrosis often dark red cranioventral lung consolidation
27
clinical signs of pasteurella multocida
- acute: fever, depression, nasal dc, moist cough - endemic dz in housed calves group "enzootic pneumonia" - thoracic auscultation may be unremarkable
28
histophilus somni
- normal nasopharyngeal inhabitant - opportunist in lung and extrapulmonary sites - important secondary invader from primary viral infx - virulence factors dictate severity VASCULITIS AND THROMBOSIS from apoptosis of endothelial cells!!
29
what is unique about histophilus somni?
virulence factor LOS: lipooligosacchardie induces inflammatory cascade, which causes VASCULITIS AND THROMBOSIS bc it induces apoptosis of endothelial cells similar bronchopneumonia signs to other pathogens, but the extra pulmonary signs are thrombotic meningoencephalitis (TEME): vesicles in meninges see vasculitis and thrombosis
30
what are *extrapulmonary signs* of histophilus somni?
thrombotic meningoencephalitis (TEME): vesicles in meninges see vasculitis and thrombosis also otitis, mastitis, polyarthritis, myocarditis, abortion, etc
31
how is mycoplasma primarily transmitted?
milk, colostrum
32
trueperella pyogenes
- opportunistic pathogen - secondary or tertiary invader - pulmonary abscess: chronic invader - has a virulence factor pyolysin that has a capsule: you can't penetrate that with antibiotics
33
bovine herpes virus type 1
- causes IBR: infectious bovine rhinotracheitis - surface glycoproteins allow for host attachment - direct contact or aerosol - 1st target is epithelial cells. immunosuppression facilitates binding of leukotoxin - LATENCY RELATED TRANSCRIPT**: allows survival of infected cells beyond message of apoptosis latency is important for spread!
34
what virus has an LRT? (latency related transcript)?***
bovine herpesvirus 1! IBR allows survival of infected cells beyond message of apoptosis latency is important for spread! can survive and recrudesce in ganglia (goes dormant) if there is a stressor event. difficult to completely remove from herd and why it is in vaccines
35
clinical presentation of BHV 1
many: resp, conjunctiva, infx vulvovaginitis, abortions, muzzle hyperemia, focal plaque necrosis primary respiratory disease: high morbidity, low mortality unless co infected with Mannheimia hemolytica
36
BRSV: bovine respiratory syncytial virus
- direct contact, aerosol - atypical interstitial pneumonia: emphysema, bullae - BRSV- SPECIFIC IGE PRODUCTION!!*** mast cell degranulation, eosinophil influx almost like a type 1 hypersensitivity rxn - lymph node infection may allow for persistence
37
what effect does BRSV have on the immune system?***
stimulates IgE production!! if vaccinated animal can cause a severe allergic response
38
what antibody does BRSV stimulate?
BRSV specific IgE: produces histamine and get inflammatory response
39
what is the big clinical consequence of BRSV?***
PNEUMOTHORAX!! ruptured bullae peracute presentation, severe dyspnea hypersensitivity
40
what virus causes pneumothorax/ruptured bullae?
BRSV
41
bovine viral diarrhea virus pathogenesis
- impairs host immunity! - co infections with mannheimia hemolytica, mycoplasma bovis, BRSV! - diverse clinical presentations: mucosal erosions, diarrhea, abortions, infertility, persistent infections of fetuses infected between 40-120 days
42
what are the most important ways to prevent BRD?
- colostrum management! quality and quantity - reduce stress!! almost impossible but need to mitigate - avoid mixing different age groups that are vulnerable - herd surveillance, treatment approach
43
what is an important viral target of vaccine protocols for BRD prevention?
BVDV
44
why can mycoplasma not be targeted with a vaccine?
VSP: variable surface proteins: can switch these around so that vaccines are not effective
45
what are clinical signs of mycoplasma bovis, dispar?
pneumonia, otitis in preweaned calves, arthritis, tenosynovitis in weaned calves other signs: mastitis, conjunctivitis, myocarditis, pericarditis, abortion transmitted by milk, colostrum
46
BHV 1 primary respiratory disease has high morbidity and low mortality unless co-infected with
Mannheimia hemolytica
47
BHV1 is most common in
feedlots in weaned steers
48
influenza in cows
- PI-3: RNA virus - direct contact, aerosol - disease often mild/subclinical unless secondary bacterial infection - direct injury to ciliated epithelial cells, mucus, mucociliary apparatus
49
when do PIs occur with BVDV?
PI of fetuses infected between 40-120 days
50
vaccines for BRD prevention?
- inconsistent efficacy for reducing risk in beef and dairy - MLV have low quality evidence - timing most important. stress, maternal effects, preconditioning. - vaccines given at arrival period have suboptimal response
51
multivalent MLV vaccines for BRD induce what type of immunity?
humoral and cell mediated immunity (CMI)
52
what is the downside of killed/inactivated RBD vaccines compared to MLV?
less robust CMI
53
MLV vaccines that include what virus have the most evidence for reducing BRD in weaned beef cattle?
BVDV 1,2
54
what are superior vaccines for BRD: MLV or killed?
multivalent MLV
55
when should calves receive intranasal MLV BRD vaccine?
PRIOR to colostrum dairy: booster 3 weeks, 3-6 months beef: booster after weaning. high risk (booster 2 weeks later)
56
when should dairy and beef calves receive intranasal MLV BRD vaccine?
dairy: booster 3 weeks, 3-6 months beef: booster after weaning. high risk (booster 2 weeks later) prior to colostrum!!
57
when should heifers receive the MLV BRD vaccine?
parenteral MLV 45 days prior to breeding
58
when should adult cows receive the MLV BRD vaccine?
annual booster if not previously vaccinated with MLV, KV may be required

ClinSci 2 Exam 2 (22 decks)

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