resp 3 Flashcards
Mannheimia haemolytica
- type of pathogen, when its a problem
- serotypes, who it infects
Gram negative aerobic bacteria
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Opportunistic pathogen
◦ Follows viral infection
> BHV-1, BRSV or BcoV
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Infects cattle, sheep and goats
◦ Serotype A1- most common in cattle
◦ Serotype A2- most common in sheep and goats
◦ Serotype A6- 2nd most common in cattle
Mannheimia haemolytica
- clinical signs
◦ Dull/depressed
◦ Fever
◦ Tachypnea
◦ Inappetance
◦ Coughing
◦ Elbows abducted stance
◦ Sepsis/endotoxemia > Prolonged CRT, Dark or pale mucous membranes, Cool extremities
Mannheimia haemolytica
- prevalence
Epidemiology
◦ Isolated from 25-30% of PMs of feedlot cattle
◦ Less common in dairy calves
Mannheimia haemolytica
- pathogenesis
◦ Impaired pulmonary defenses
◦ Rapid proliferation in lungs
◦ Leukotoxin
◦ Lipopolysaccharide (endotoxin)
◦ Severe lobar necrotizing fibrinous pleuropneumonia
Mannheimia haemolytica
- diagnosis
Most reliable
◦ Culture or PCR from lungs of deceased animal
◦ MALDI-TOFMS on culture to determine serotype
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Ante-mortem
◦ Clinical signs of bacterial pneumonia
◦ Aerobic culture > Nasal swab, Guarded nasopharyngeal swab, Transtracheal aspirate
◦ Ultrasonography
Mannheimia haemolytica
- treatment and prevention
Treatment
◦ Antimicrobials
◦ NSAIDs
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Prevention
◦ Metaphylaxis > Resistance?
◦ Increasing host immunity > Adequate passive transfer, Vaccination
◦ Minimize risk factors > Mixing of animals from different locations, Long distance shipping
Pasteurella multocida
- characteristics of organism
- serogroups, diseases they cause
- bovine pneumonia type
Gram-negative aerobic bacteria
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Likely an opportunistic pathogen
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Five serogroups
◦ A- Ruminant respiratory disease
◦ B & E- Hemorrhagic septicemia
◦ D & F- regional disease in sheep
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Also cateogorized by cell wall antigen type
◦ A3- most common cause of bovine pneumonia
Pasteurella multocida
Clinical signs
vs M. haemolytica
Clinical signs
◦ Fever
◦ Increased respiratory rate
◦ +/- depression
◦ +/- mucoid-mucopurulent nasal discharge
◦ +/- coughing
◦ Endotoxemia
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- Less severe than M. haemolytica
- Shorter length of disease than M. haemolytica
Pasteurella multocida
- prevalence, significance
- pathogenesis
Epidemiology
◦ 2nd only to Mycoplasma in dairy calf pneumonia mortality
◦ In live dairy cattle most common pathogen
◦ Important contributor to respiratory disease in feedlot cattle
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Pathogenesis
◦ Not much is known
◦ LPS
◦ IROMPs
◦ May need prolonged times of respiratory immunosuppression
◦ In vitro inhibits growth of M. haemolytica
Pasteurella multocida
Diagnosis
◦ Culture of lungs at post-mortem
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◦ Antemortem:
◦ Guarded nasopharyngeal swab
◦ Tracheal wash
Pasteurella multocida
Treatment, prevention
Treatment
◦ Antimicrobials
◦ Several labelled specifically for Pasteurella multocida
◦ Associated with chronic or on-going pneumonia
◦ Therapy >3-5 days may be needed
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Prevention
◦ Decrease risk of other respiratory disease
◦ Vaccination > Unknown efficacy
> Multiple products available
> One licensed product for sheep and goats
Histophilus somni
- pathogen characteristics
- Associated disease syndromes
Gram negative aerobic bacteria
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Normal commensal of upper respiratory mucosa
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Associated disease syndromes
◦ Thrombotic meningoencephalitis (TME)
◦ Septicemia
◦ Endometritis, infertility and abortion
◦ Pneumonia/pleuritis
◦ Endocarditis/myocarditis
◦ Laryngitis, otitis and conjunctivitis
◦ Mastitis
◦ Polyarthritis
Histophilus somni
- clinical signs
◦ Fever
◦ Tachypnea
◦ Cough
◦ Nasal discharge
◦ Depression
◦ Reluctance to move
◦ Standing with elbows abducted
◦ Endotoxemia
◦ Concurrent signs in other body systems
Histophilus somni
- prevalence, epidemiology
◦ Exposure is very common
◦ Disease occurs within the first 2 months at feedlot
◦ Less prevalent in dairy calves
Histophilus somni
- pathogenesis
◦ Primary viral infection
◦ Evasion of the immune response
◦ Vasculitis and vascular thrombi
◦ Induces IgE production by host
◦ Directly produces histamine
