Calf Pneumonia Flashcards

1
Q

what is pneumonia

A

acute or chronic disease marked by inflammation of the lungs and caused by viruses, bacteria, other microorganisms and sometimes physical and chemical irritants

in cattle is usually a result of interactions between a complex mixture of pathogens and environmental stressors

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2
Q

what is bovine resp disease complex

A

non-infectious predisposing factors

infectious predisposing factors –> viruses, mycoplasma, bacteria, lungworm

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3
Q

what are the general principles of resp infections

A
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4
Q

how is BRD multifactorial

A
  • may start with a viral infection
  • viruses damage cells lining the resp tract
  • damaged cells normally involved in bacterial removal
  • bacteria invade –> tracheitis, bronchitis, pneumonia
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5
Q

what are common causes of young calf pneumonia

A

RSV: bovine respiratory syncytial virus

PI3: parainfluenza virus 3

BVD: bovine viral diarrhea

IBR: infectious bovine rhinotracheitis

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6
Q

what are common causes of BRD in calves housed in autumn

A

RSV

PI3

BVD

IBR

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7
Q

what are common causes of BRD in calves bought at market

A

IBR

RSV

PI3

BVD

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8
Q

what is RSV

A

respiratory syncytial virus

primary cause of serious calf pneumonia

epidemiology not understood, peak times of disease in winter months

no evidence of how virus is maintained in populations (persistently infected animals, overwinering in buildings)

vaccination has variable success but is essential for autumn house cattle

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9
Q

what does RSV cause

A

creates substances which damage lung remote from the areas of viral multiplication

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10
Q

what are the symptoms of RSV

A

clear watery discharge (nasal)

coughing

fast laboured breathing, frothy saliva

bouts of coughing

may die if severe

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11
Q

what is PI3

A

primary cause of calf pneumonia but usually less severe than RSV –> may predispose to bacteria

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12
Q

is there a vaccine for PI3

A

vaccination has variable success

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13
Q

what is the epidemiology of PI3

A

transit fever –> moving animals and big groups in feedlot

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14
Q

where does PI3 replicate

A

in epithelial cells

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15
Q

where does damage occur in PI3

A

primarily in the lower resp tract

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16
Q

what does PI3 cause

A

causes bronchitis, bronchiolitis, alveolitis

in acute stage proliferation and necrosis of bronchiolar epithelial cells

widespread descruction of cilia and of ciliated cells in small bronchi and bronchioli

infects alveolar macrophages

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17
Q

what is bovine herpesvirus type 1 - IBR virus

A

primary pathogen

usually tracheitis but can progress to pneumonia

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18
Q

what does IBR cause

A

occasionally causes fatal neonatal disease

reduced appetite, watery eye, nose, coughing, fever, purulent discharge, coughing (may be thick blood stained material coughed up)

may be secondary bacteria and death

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19
Q

what is the epidemiology of IBR

A

crucial in the persistence of disease is the latently infected carrier

sheds virus at times of stress (moving, housing, calving)

all unvaccinated, seropositive animals should be considered latently infected

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20
Q

what is the IBR vaccine

A

deletion mutant vaccines exist to differentiated vaccinated animals from wild type infected animals

vaccination good at controlling

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21
Q

what are other viruses that cause BRD

A
  1. adenovirus type 3
  2. orthomyxovirus
  3. coronavirus
  4. BVDV
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22
Q

how can viral infections be diagnosed

A

taking ocular and nasal swabs, lung fluid

for control –> collection of blood samples 2 weeks apart

post mortem

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23
Q

what are bacterial species involved in BRD

A
  1. manheimia haemolytica
  2. pasteurella multocida
  3. histophilus somni
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24
Q

what are the features of the bacteria that cause BRD (6)

A
  1. gram negative
  2. non-motile
  3. pleomorphic cocco-bacilli
  4. aerobic/facultatively anaerobic
  5. most species are pathogenic
  6. optimal growth at 37 degrees
25
Q

what are the virulence factors in pasteurellaceae

A

the LPS and lipooligosaccharide (LOS)

26
Q

what are the toxic effects of LPS

A

initiation of complement and coagulation cascades –> increased vascular permeability and coagulation –> accumulation of inflammatory cells, edema and fibrin deposition in the lung

27
Q

what are the characterisitcs of H. somni

A
  1. small to med sized, gram negative, coccobacilli
  2. non-motile and capable of fermenting sugars
  3. fastidious nature, will not grow on some laboratory media, CO2 sometimes required
  4. found on mucosal surfaces of cattle and are extremely host specific
28
Q

what are the virulence factors of H.somni

A

capsule –> form protective coat around the bacterium and allows it to evade host defenses

antibodies to somatic antigens (membrane proteins and LPS) may also distinguish distinct serotypes

29
Q

what are the exotoxins that H.somni produce

A

weak hemolysin

30
Q

what other virulence factors does haemophilus

A
  1. proteases: destroy mucosal IgA
  2. outer membrane proteins that bind to the Fc receptor of normal IgG and block binding of specific IgG
  3. binding nucleotides on the cell surface to enhance survival in or killing of phagocytic cells
  4. antigenic phase variation of its lipooligosaccharide
31
Q

what is the host specificity of haemophilus

A

due to the ability of a species to obtain iron only from a single host

under iron-limiting conditions the bacteria produce outer membrane proteins that are able to obtain from the host transferrin molecules

iron regulated outer membrane proteins (IROMPS)

32
Q

how is haemophilus diagnosed

A

isolation of the bacteria from normally sterile sites or in pure culture from infected area is necessary to confirm the isolate is present as a pathogen and not as normal flora

most isolate from animals require only NAD, and therefore will grow either on commercial chocolate agar or on blood agar with a streak of staphylococcus to provide NAD

33
Q

what are the specific diseases of H.somni

A

spectrum of diseases in cattle

  1. thromboembolic meningoencephalitis (TEME): weakness, fever, staggering, somnolence, dyspnea, paralysis, sudden death–> lesions of fibrinous meningitis with thrombosis and necrosis
  2. pneumonia with pleuritis and arthritis
  3. repro failure –> endometritis, metritis or late abortion, mastitis, vaginitis
34
Q

what are the general characteristics of pasteurella and manheimia

A
  1. gram negative, short to medium sized coccobacilli, bipolar staining
  2. facultatively anaerobic
  3. ferment glucose, gas is not produced
  4. M. haemolytica is B-hemolytic on blood agar will grow to some extent on MacConkey agar
  5. pasteurella species are normal commensals of mucosal membranes of resp tract
35
Q

what are the types of pasteurella multocida

A

A, B, D, E

36
Q

what is the most common serotype of pasteurella multocida isolated from BRD

A

A3

37
Q

what does type D pasteurella multocida produce

A

dermonecrotoxin

38
Q

how many serotypes of manheimia are there and what are the main ones

A

13

a1 and 16 are the main ones in resp disease in cattle

39
Q

when does disease from manheimia occur

A

results following stress, such as transport, inclement weather or predisposing infections

40
Q

which bacteria are encapsulated

A

p. multocida and p. haemolytica

41
Q

what role does LPS play in virulence factors

A
  1. protect the organism from host defenses through the carbohydrate moeity
  2. induce inflammation through the lipid A component
42
Q

what are the exotoxins in pasteurella

A

a dermonecrotoxin produced by type D and some type A strains of P. multocida and is considered an important virulence factor in the pathogenesis of atrophic rhinitis

m. haemolytica produces a labile leukotoxin (RTX toxin) important in the pathogenesis of shipping fever and resp disease

43
Q

how is pasteurella diagnosed

A

isolation

gram or giemsa stain: bipolar organisms

grow on blood agar

isolation from nasal tract is of little significance because they are part of the normal flora

44
Q

what are the risk factors for bronchopneumonia

A
  1. poor ventilation
  2. low space per calf
  3. management procedures
  4. animals of different in ages in the same airspace
  5. pooling calves from many sources
  6. poor colostrium management
  7. dam minerals/vitamin deficiency
  8. insufficient energy/protein
45
Q

what is the pathogenesis of bovine pneumonia

A
  1. commensal colonization
  2. predisposing factors: stress transport, virus, mycoplasmas
  3. decreased mucociliary clearance impaired alveolar macrophages function
  4. proliferation and inhalation of nasopharyngeal M. haemolytica A1 colonization of lung
  5. release of leukotoxin, endotoxin, and other virulence factors
  6. mast cell degranulation, complement activation, cytokine release, infilatration and lysis of neutrophils, macrophages
  7. fibrinous pneumonia
46
Q

how is resp disease controlled

A
  1. management –> grazing systems, reduced sotcking density, segregation of ages, minimize stress, environment
  2. vaccination –> managed health problems
  3. antimicrobial metaphylaxis
47
Q

how can the environment be improved to reduce BRD

A
  1. reduce moisture
  2. improve ventilation –> intro of clean air, removal of used air, dry comfortable, well distributed inlets, no draughts
48
Q

how can cattle pneumonia be treated

A

wide range of antibiotics are effective againts bacterial pneumonias (penicillins, tetracylcines, fluroquinolones, sulphonamides, macrolides)

49
Q

what are the vaccine types

A
  1. live
  2. killed
  3. marker (live/killed)
  4. nasal (live)
  5. injected
50
Q

what are the advantages of live vaccines (3)

A
  1. more rapid onset of immunity
  2. single dose
  3. used in young calves in presence of maternally derived antibodies
51
Q

what are the advantages of killed vaccines

A

safety: will not cause disease

can often be used in pregnancy

52
Q

what are the advantages of marker vaccines

A

can differentiate vaccinated and infected

53
Q

what are the advantages of nasal vaccines

A

can get rapid immunity

good for outbreaks

can be used in young calves in presence of MDA

54
Q

what are the advantages of injected vaccines

A

security of dosing

55
Q

what are the disadvantages of injected vaccines

A

local reaction

56
Q

what are the disadvantages of live vaccines

A

can cause mild version of disease

some cannot be used in preg

57
Q

what are the disadvantages of killed vaccines

A

may not get as good immunity

adjuvant many –> local reaction

58
Q

what are the disadvantages of nasal vaccines

A

can cause mild version of disease

can shed vaccine strain

59
Q

what is the ideal vaccine

A

IBR, PI3, BRSV, BVD

some combo of these viruses

probably modified live attenuated MLA to enhance mucosal immunity