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Vet clinics of N. America-Food Animals > 2020.Iss2, BovineRespiratory disease > Flashcards

2020.Iss2, BovineRespiratory disease Flashcards

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1
Q

Viruses in Bovine Respiratory Disease in North America

What are the two biotypes of BVDV?

A

cytopathic
noncytopathic

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2
Q

Viruses in Bovine Respiratory Disease in North America

What are the two species of BVDV?

A

BVDV1 & 2

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3
Q

Viruses in Bovine Respiratory Disease in North America

What is the prominent BVDV sybtype?

A

BDVD1b

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4
Q

Viruses in Bovine Respiratory Disease in North America

What is the most important source of BVDV, virus exposure?

A

persistently infected calves

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5
Q

Viruses in Bovine Respiratory Disease in North America

Which strain of bovine coronavirus is included in most licensed BOCV vaccines?

A

BoCV1

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6
Q

BRD: looking back and looking forward, what do we see?

Research in the 1970s showed that respiratory viral infection followed by exposure to what pathogen, leading ot fibrinous pneumonia, hte hallmark of feed lot BRD?

A

Mannheimia haemolytica

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7
Q

Respiratory bacterial microbiota in cattle: from development to modulation to enhance respiratory health

Increased abundance of what respiratory bacteria is associated with good respiratory health?

A

Lactobacillus & lactococcus

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8
Q

Respiratory bacterial microbiota in cattle: from development to modulation to enhance respiratory health

The respiratory microbiota is inhabited predominantly by which 5 bacterial phyla?

A

proteobacteria
firmicutes
tenericutes
acitnbacteria
bacteroidetes

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9
Q

Respiratory bacterial microbiota in cattle: from development to modulation to enhance respiratory health

Probiotics promote respiratory health through what 3 main mechanisms

A
  1. direct antimicrobial action against bacterial resp pathogens by producing antimicrobial molecules
  2. probiotics can enhance the epithelial barrier (ie stim production of mucin or antimicrobial peptides)
  3. modulate host immune responses (both innate & adaptive) by interacting with host pattern recognition receptors of the mucosa
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10
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

What clinical diseases are associated with H. somni infections?

A

thrombotic meningoencephalitis
septicemia
myocarditis
arthritis
reproductive failure
pneumonia

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11
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

Coinfection with which virus is there a syngergistic effect with H. somni?

A

Bovine respiratory syncytial virus (BRSV)

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12
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

Which antibiotic response is protective against H. somni?

A

humoral immunity
IgG2

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13
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

How does H. somni acquire iron from bovine transferrin?

A

It utilizes transferrin-binding proteins

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14
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

What virulence factor for H. somni contributes to apoptosis and suspected to contribute to vasculitis?

A

lipooligosaccharides

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15
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

Which virulence factor allows H. somni evade the hosts immune response by providing a shield against recognition & inactivation by the cells of the immune system?

A

Binding of immunoglobulins

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16
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

H. somni has the ability to stimulate a severe immune response by stimulating production of which immunoglobulin?

A

IgE

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17
Q

Histophilus somni: antigenic and genomic changes relevant to BRD

Which virulence factor allows H. somni to evade host immune response– with antigenic variation?

A

outer membrane proteins– phase variation

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18
Q

Details to attend to when managing high-risk cattle

list the key biocontainment principles:

A
  1. understanding the business models of operations– unlike other segments of the cattle industry, stocker operations have developed diverse and adaptable business models, if not practical for operation, biocontainment efforts will not be adopted
  2. udnerstanding current disease status of existing cattle population– although many feeder cattle operations operate with ltd professional veterinary input, have more insight into pathogen dynamics over time and are best position to use impactful biocontainment interventions
  3. effect of pen size on disease dynamics– as pen size increases, the risk & severity of epidemic disease increases. Mitigating dz risk by reducing pen size can be powerful mgmt techique
  4. cattle flow– placement of immunologically naive cattle in pens near or adjacent to cattle in teh peak of a BRD epidemic provides opportunity for dz propagation & pathogen amplification. Strategically separating naive & susceptible populations from epidemic & endemic populations in the foundation of biocontainment efforts
  5. Mitigating pathogen spread through use of common facilities such as hospital & treatment recovery pens
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19
Q

Details to attend to when managing high-risk cattle

What are the key components to biocontainment in arrival barns as follows?

A
  1. ensure adequate pens & space are available to keep purchase cohorts together, minimizing teh need to resort cattle after receiving
  2. avoid carry-over population. Processed calves that remain in the arrival facility as new groups of calves arrive, between purchases groups. Do not keep resident populations in the arrival barn. Incubation times can be relatively short for many respiratory pathogens. All-in/all-out mgmt methods minimize the cross- contamination of pathogens between groups over time
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20
Q

Details to attend to when managing high-risk cattle

Because many high -risk calves never previously consumed water from a tank or automatic waterer, what are way to manage watering equipment that takes up advantage of natural cattle behavior:

A

-place the waterer on the fence line, so calves are more likely to find it as they explore their pen

-allow enough waterer space, so that multiple calves can drink simultaneously

-allow water to recirculate or overflow in a way that produces the sounds of running water

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21
Q

mannheimia haemolytica & pasteurella multocida in BRD

what are Manheimia haemolytica and pasteurella multocida classified as?

A

Gram neg facultative anaerobes
**both coccobacilli

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22
Q

mannheimia haemolytica & pasteurella multocida in BRD

Which serotypes of mannheimia & pasteurella are most commonly associated with clinical disease?

A

M heamolytica serotype A1 (>75% of cses)

P. multocida serotype A3

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23
Q

mannheimia haemolytica & pasteurella multocida in BRD

What are mechanisms and virulence factors in M hameolytica & P multocida to evade the host immune response?

A

Capsule- antiphagocytic
leukotoxin- leukocyte necrosis
LPS- proinflammatory
IgA proteases- degradation of secretory IgA
Biofilm formation- evasion of protective responses
OmpP2- biofilm formation & cell adhesion

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24
Q

mannheimia haemolytica & pasteurella multocida in BRD

Which virulence factors work together synergistically?

A

endotoxin
leukotoxin

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25
Q

mannheimia haemolytica & pasteurella multocida in BRD

What are good antibiotic choices based on susceptibility against M haemolytica & pasteurella?

A

ceftiofur, enrofloxacin & florfenicol

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26
Q

mannheimia haemolytica & pasteurella multocida in BRD

How does horizontal gene transfer occur?

A
  1. acquisition of genes from so-called loose DNA in the environment via transformation
  2. transfer of genetic material by a phage via transduction
  3. via the acquisition of a mobile genetic element
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27
Q

mannheimia haemolytica & pasteurella multocida in BRD

What does integrative conjugative element (ICE) mean?

A

mobile genetic elements that integrate into the host chromosome

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28
Q

mannheimia haemolytica & pasteurella multocida in BRD

What is the primary driver for the increase in MDR strains in M haemolytica & P multocida?

A

integrative conjugative element (ICE)

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28
Q

mannheimia haemolytica & pasteurella multocida in BRD

What can be carried along with integrative conjugative elements (ICEs) be integrated into a host genome?

A

cargo genes– including antimicrobial resistance genes

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28
Q

Bovine respiratory disease vaccination

Timing of administration of different BRD antigens is critical for vaccine efficacy & efficiency, what are key times of BRD vaccine administration in beef cattle?

A

-near birth (neonates)
-during branding (nursing calves 60-120 days of age)
-at or near weaning (age of 205 days)
-arrival at subsequent production sectors (such as stocker &/or feedlot facilities)

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29
Q

BRD: What is the effect of timing

When are key times of BRD vaccine administration in beef cattle?

A
  1. near birth (neonates)
  2. at or near weaning (typical age of 205 days)
  3. ON arrival at subsequent production sectors such as stocker and/or feedlot facilities
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30
Q

BRD: What is the effect of timing

When is the best time to vaccinate cattle against BRD causative agents?

A
  1. state of immunologic homeostasis
  2. free of acute infection
  3. at least several weeks before natural BRD challenge is expected
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31
Q

How does housing influence BRD in confinement cow-calf operations?

What disease in calves is sites as an increased risk factor for later development of respiratory disease in calves?

A

diarrhea
(calf scours)

32
Q

BRD influences on nutrition & nutrient metabolism

What is the effect of BRD on beef cattle producers & feedlot managers?

A

BRD results in:
-decreased in take, daily gain & feed efficiency in feedlot calves
-decreasing growth rates & increased required day son feed
-morbidity associated with decreased hot carcass weight & poor carcass characteristics

33
Q

BRD influences on nutrition & nutrient metabolism

What are the major viruses involved in BRD?

A

-infectious bovine rhinotracheitis virus
-bovine viral diarrhea viruses (BVDV)
-parainfluenza type-3 virus
-bovine respiratory syncytial virus (BRSV)

34
Q

BRD influences on nutrition & nutrient metabolism

Viruses weaken the immune defenses & allow secondary bacteria infection, what bacteria are most commonly isolated from lungs of calves infected with BRD?

A

Mannheimia hemolytica
Pasteurella multocida
Histophilus somni
Mycoplasma bovis

35
Q

BRD influences on nutrition & nutrient metabolism

The acute phase response can be activated by systemic increases in which hormone?

A

cortisol

36
Q

BRD influences on nutrition & nutrient metabolism

What is a consistent response in stressed calves that show clinical signs of BRD?

A

decrease in dry matter intake

37
Q

BRD influences on nutrition & nutrient metabolism

What is the recommendation for nutrition for stressed calves?

A

Nutrients should be concentrated early in the receiving period to account for low dry matter intake

38
Q

BRD what progress has been made in clinical diagnosis?

Explain what is spectrum bias?

A

concerns that selection of affected animals or nonaffected animals is not representative fo the full spectrum of disease

39
Q

BRD what progress has been made in clinical diagnosis?

Explain what is classification bias?

A

teh reference standard that serves as a comparator for establishing index test accuracy is not 100% accurate

40
Q

BRD what progress has been made in clinical diagnosis?

Explain what is Diagnostic review & incorporation bias?

A

situations where the index test & reference standard test are not independent

41
Q

BRD what progress has been made in clinical diagnosis?

Explain what is clinical review bias?

A

type of bias that occurs when clinical information for the animals reviewing the tests, as it would be in practice is missing

42
Q

BRD what progress has been made in clinical diagnosis?

Explain what is partial verification bias

A

the index test result has an impact on the probability of performing the reference standard

43
Q

BRD what progress has been made in clinical diagnosis?

Explain what is Differential verification bias

A

this type of bias occurs when different reference standard tests are applied to the animals

44
Q

BRD what progress has been made in clinical diagnosis?

Explain what is inconclusive results/withdrawal bias

A

some animals are withdrawn from a study b/c of either impossibility to perform or interpret the index test or the reference standard test

45
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

In which cattle management system is antimicrobial resistance in respiratory tract bacteria from cattle highest?

A

veal operations
& high in feedlots

-lower in closed dairy & beef herds

46
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

Which sampling techniques in cattle have the lowest risk of contamination from the nasal passage?

A

-transtracheal wash/aspirate (absent)

-endoscopic BAL (low–protective sleeve or agar plug possible)

-nonednoscopic BAL (moderate)

47
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

Which sampling technique in cattle has the highest the contamination risk from the nasal passage?

A

nasopharyngeal swab

48
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are possible complications of nasopharyngeal swab?

A

-nasal hemorrhage
-fracture of the swab shaft

49
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are possible complications of TTW/TTA?

A

-subcutaneous emphysema
-wound infection
-local hemorrhage
-accidental tearing of the catheter by retraction over the needle & intratracheal loss of remaining part
-respiratory distress caused by insufficient aspiration of instilled fluid

50
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are possible complications of nonendoscopic bronchoalveolar lavage?

A

-nasal hemorrhage
-intrapulmonary hemorrhage
-airway perforation (rigid catheter only)
-respiratory distress caused by insufficient aspiration of instilled fluid

51
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are possible complications of endoscopic BAL?

A

-nasal hemorrhage
-respiratory distress caused by insufficient aspiration of instilled fluid

52
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the advantages of microbial culture?

A

-cheap
-evidence of live pathogen
-quantification possible
-antibiogram possible

53
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the disadvantages of microbial culture?

A

-live organisms needed
-more time consuming
-lower sensitivity
-fastidious growers (eg histophilus somni) more easily overgrown (false-negatives)
-specific media needed for certain pathogens (eg mycoplasmata)

54
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the advantages of PCR?

A

-very high sensitivity
-no live organisms required
-limited effects of contaminated samples
-pooling of samples possible
-quantification possible (qPCR)

55
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the disadvantages of PCR?

A

-possible detection of insignificant of quantities or dead bacteria (high sensitivity)
-possible detection of vaccine antigen (false-pos)
-more expensive

56
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the advantages of serology (antibody ELISA)?

A

-longer time frame for pathogen detection
-both infection & vaccination status

57
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are disadvantages of serology (antibody ELISA)?

A

-indirect evidence of infection
-variable, but generally lower sensitivity & specificity
-results require 3 wks (paired sera)
-no differentiation vaccine induced antibodies form natural infections

58
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the advantages of culture-enriched Direct MALDI-TOF?

A

-cheap (cost comparable with culture)
-rapid
-antibiogram possibel with MBT-ASTRA

59
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

What are the disadvantages of culture enriched direct MALDI-TOF?

A

-MALDI-TOF required
-lower diagnostic accuracy in polymicrobial or mixed culture samples

60
Q

BRD diagnosis, what progress has been made in infectious diagnosis?

Interpret the following cultures

A
61
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Vaccination of beef calves around the time of weaning with which vaccines, reduces bovine respiratory disease complex morbidity and mortality after weaning?

A

multivalent MLV vaccines alone or in combination with Mannheimia haemolytica/Pasteurella multocida bacterins

62
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Is it beneficial to vaccinate young beef calves before weaning age?

A

uncertain if vaccination reduces BRD morbidity & mortality before weaning

63
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Economic losses associated with BRD occur most commonly in which calf populations?

A
  1. beef calves around time of weaning, between 5-8 months old
  2. Preweaning beef calves younger than 5 months old
  3. Dairy calves younger than 3 months old
64
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

As far as revaccination– what is the timing in MLV vaccines vs killed vaccines?

A

MLV– fewer doses

Killed vaccines– at least 2 doses 21 days apart to provide protection

65
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

What evidence exists that vaccination of beef calves with MLV/killed vaccines reduce BRD associated morbidity and mortality after experimental challenge with BVDV, BHV-1 or BRSV?

A

strong, high-quality evidence that vaccinaitn of beef calves with vaccines containing MLV alone or in combinatino with M ahemolytica/P multocida bacterins is superior to Killed vaccine for reducing BRD-assoc morbidity/mortality after experimental challenge with BVDV, BHV-1 or BRSV

66
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Does killed BRSV vaccination reduce naturally occuring BRD morbidity and mortality of young beef calves?

A

there is very limited evidence of moderate quality indicating deleterious or no effect of killed BRSV vaccination in reducing naturally occurring bRD morbidity & mortality of young beef calves

67
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

What is the effect of vaccination on BRD associated morbidity and mortality after experimental challenge/exposure to BVDV?

A

limited evidence of moderate quality
–no effect of MLV vaccination or positive effects of KV vaccination for reducing BRD-assoc morbidity & mortality after experimental challenge with BVDV of young beef calves

68
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Are MLV virus vaccines similarily effective for providing clinical protection against bovine respiratory disease in young dairy calves?

A

limited moderate quality evidence
MLV vaccines is ineffective for reducing naturally occurring BRD morbidity & mortality

69
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Is there evidence to support MLV vaccines over Killed vaccines for reducing BRD associated morbidity and mortality , in young dairy calves, after experimental challenge with respiratory viruses?

A

moderate-quality evidence
**clinical protection may depend on level of colostrum-derived immunity
-homology between vaccine & experimental challenge strains
-time between vaccination & challenge

70
Q

BRD, MLV vs inactivated antigen vaccines, intranasal vs parenteral, what is the evidence?

Are MLV intranasal & parenteral vaccines similarly effective for providing clinical protection against bovine respiratory disease in young dairy calves?

A

-strong, high-quality evidence
-both intranasal & parenteral vaccination of young dairy calves with MLV vaccines result in similar reduction of BRD-assoc morbidity & mortality after experimental challenge with resp viruses

71
Q

Are MLV intranasal & parenteral vaccines similarly effective for providing clinical protection against bovine resp disease in dairy calves (naturally occurring BRD)?

A

-strong, high quality evidence
-parenteral vaccination of beef calves before or shortly after weaning with MLV vaccines is superior to intranasal for reducing naturally occurring BRD-assoc morbidity & mortality after arrival to stocker/feedlot operations

72
Q

The effect of market forces on BRD

What are the impacts of BRD on feedlot/stocker market?

A

mortality (value of death loss)
reduced weight gain
reduced feed efficiency
reduced salvage value of chronic animals
treatment costs
vaccination costs
metaphylaxis costs

73
Q

The effect of market forces on BRD

What are the impacts on the cow-calf (beef & dairy) industry?

A

-mortality (value of death loss, cows & preweaning calves)
-dec weanign weights
-treatment costs (cows & calves)
-reduced productivity (milk production)
-reduced pregancy percentage (failure to breed or early emryonic death caused by BVDV)
-reduced calving percentage (abortion, stillborn or perinatal mortality caused by BVDV)
-vaccination costs

74
Q

Pathogenesis & Virulence of Mycoplasma bovis

What is the primary pathogen of North American bison?

A

Mycoplasma bovis

75
Q

Pathogenesis & Virulence of Mycoplasma bovis

How does Mycoplasma bovis modulate the immune system of the host?

A

-altering the expression of cytokines
-inhibiting peripheral blood mononuclear cell proliferation
-reducing apoptosis of peripheral blood mononuclear cells, monocytes & alveolar macrophages

76
Q

Pathogenesis & Virulence of Mycoplasma bovis

Transmission of M bovis primarily occurs through which route?

A

aerosol
–> dairy cows– contaminated milk & close contact (aerosol)

77
Q

Pathogenesis & Virulence of Mycoplasma bovis

What are virulence factors of M bovis?

A

-variable surface proteins (VSPs)
-nuclease (degrade neutrophil traps)
-H2O2 production
-Biofilms

78
Q

Pathogenesis & Virulence of Mycoplasma bovis

M bovis mechanisms to evade the immune system

A

-antigenic variation
-inhibition of peripheral blood mononuclear (PBMC) proliferation
-resistance to monocyte & macrophage phagocytosis
-invasion of erythrocytes, PBMC, epithelial cells
-modoluation of cytokine production
-modulation of apoptosis
interference with programmed death

79
Q

Host tolerance to infection with bacteria that cause BRD

which bacteria causing BRD can form a biofilm?

A

M haemolytica
pasteruella multocida
histophilus somni
M bovis

80
Q

Host tolerance to infection with bacteria that cause BRD

In BRD the bacteria themselves do not cause illness, but cause disease by triggering the host response, such as what that leads to lung changes?

A

within the bronchiolar & alveolar airspaces
-filled with edema, neutrophils & fibrin

**impede ventilation & gas exchange

Vet clinics of N. America-Food Animals (11 decks)

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