169. Mycoplasma diseases of swine Flashcards

1
Q

Occurence and aetiology?

A

Enzootic pneumonia of Swine/Mycoplasma pneumonia of Swine

Occurrence: widespread, worldwide

  • Mainly large scale farms
  • great economic impact
  • Poor growth rate,
  • decr feed conversion (higher feed cost),
  • predispose to 2dary

Aetiology: M. hyopneumoniae

  • ONLY swine is susceptible (domestic and wild boars)
  • virulence variants, surface proteins (adhesion, cytotoxic effect - damage respiratory epithelial)
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2
Q

Epidemiology?

A

Epidemiology:

  • Infection via aerogen (need close contact, especially in high density of animal),
  • direct contact, tracheal discharge: respiratory infection
  • Slow spread within the herd, frequently see consequences (poor weight gain) and not the direct CS
  • High morbidity, low mortality
  • Most frequent in growers between 3 and 6 months (maternal immunity in first 2 months oflife)
  • Predisposing factors:
  • Management:
  • nutrition, overcrowding, stable, temperature, autumn, winter, humidity, NH3, mixing of
  • animals, transporting to feeding unit
  • infective agents: PRRS, circovirus, A. pleuropneumoniae, P. multocida, H. parasuis, B. bronchiseptica, Porcine respiratory disease complex (CRDC)
  • losses are influenced by management
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3
Q

Pathogenesis?

A

Pathogenesis:

  • Aerosol infection Bacteria attach to the respiratory epithelium, alveoli (cytotoxic effect) damage of the epithelial cells( block cilia movement and then damage cilia)
  • damage the alveolar macrophages, release of cytokines peribronchial infiltration(immune response) epithelial proliferation
  • proliferation
  • Immune suppression:
  • secondary infections (A. pleuropneumoniae, H. parasuis, P. multocida, B. bronchiseptica, pyogenic bacteria)
  • delayed immune response which help secondary infection
  • Limited to the lungs (cannot enter blood, NO septicemia)
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4
Q

Clinical signs?

A

Clinical signs:

  • incubation 10-16 days
  • Atypical, fever, anorexia, 1st sign - dry cough (increasing intensity)
  • interstitial pneumonia (increasing, spontaneous), poor development, low weight gain
  • secondary infections can complicate and modify clinical signs
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5
Q

Pathology?

A

Pathology:

  • Frequently seen in slaughterhouse
  • Atelectasia in the anterior lobes (liver-like), interstitial pneumonia, peribronchial infiltration, pleuritis is absent (if see, then secondary infection),
  • enlarged lymph nodes
  • Histology: peribronchial, perivascular, interalveolar cell growth, lymphoid cells, histiocytes
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6
Q

Diagnosis?

A

Diagnosis:

  • Epidemiology - clinical signs - PM lesions
  • Detection of agent: isolation (difficult, very slow, often overgrowth by other bacteria in respiratory tract), PCR, IF,
  • ELISA (antigen detection)
  • Detection of antibodies: ELISA, immunoblot, CFT, not usually used, wide infection at herd level, not reliable
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7
Q

Treatment?

A

Treatment:

  • Antibiotics (tiamulin, macrolides, lincomycin, fluoroquinolons, tetracyclines)
  • Mass treatment in feed, water - regular treatment for 10-14 days (will not be allowed in the future)
  • Remain carriers
  • Improving management
  • Prevention: general epidemiological rules
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8
Q

Prevention?

A

Prevention: General epidemiological rules

  • “all in all out” isolation of the different age groups
  • Optimal nutrition and management
  • Vaccines: inactivated vaccines, subunit vaccines - will prevent the severe form ofdisease
  • Vaccination of piglets: from 1 week of age then 4 weeks later (in endemic), better at 6-8 weeks of age
  • (after maternal immunity)
  • Vaccination of pregnant sows: higher maternal protection
  • Cannot prevent colonisation, only prevent clinical signs, efficacy can be diminished by
  • immunosuppressive infection
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9
Q

Eradication?

A

Eradication:

  • 1) SPF (most reliable), retaining old sows in breeding, herd replacement
  • 2) Generation shift (using antibiotics)
  • Sows: treatment of sows before farrowing till weaning
  • or sero-negative sows keep in breeding
  • Early weaning
  • Isolation of the piglets
  • Control: bacteriological and serological examination, laboratory diagnostics of pneumonic diseases,
  • slaughter house control
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10
Q

Diseases caused by M. hyorhinis and M. hyosynoviae?

A

Diseases caused by M. hyorhinis and M. hyosynoviae

M. hyorhinis : lower economic impact than a)

  • Widespread, present on the mucous membranes of healthy animals
  • Mainly asymptomatic infection, sometimes bacteriaemia ʹ reach joints
  • Clinical signs: 3-10 week old piglets (around weaning), slight fever, polyserositis, arthritis, restrictedmovement
  • Pathology: inflammation of serous membrane (pericarditis, perihepatitis, etc)

M. hyosynoviae

  • Carried in the upper respiratory tract
  • 30-40 kg growers (fattening pigs, 3-4 months old)
  • Septicaemia (slight fever), inflammation of joints - arthritis, bursitis, restricted movement
  • Treatment
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