172. Diseases of pigs and sheep caused by haemotropic mycoplasmae. Flashcards

1
Q

Swine M.suis occurence ethiology and epidemiology?

A

Icteroanaemia of swine caused by M. suis

Occurrence:

  • sporadic,
  • worldwide

Etiology:

  • Mycoplasma suis (Eperythrozoon suis),
  • species specific,
  • cannot be cultured,
  • replication on red blood cells

Epidemiology:

  • Transmission:
  • blood sucking parasites (mechanical vectors - lice), surgery (iatrogenic),
  • cannibalism
  • (fresh blood in contact), intrauterine infection can occur,
  • discharges
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2
Q

Epidemiology of swine M.suis?

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 of life)
  • 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 of M.suis?

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 proliferation -> peribronchial infiltration(immune response)-> epithelial 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 of M.suis?

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 of M.suis?

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 of M.suis?

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 of M.suis?

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
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8
Q

Prevention of M.suis?

A

Prevention: general epidemiological rules

  • ͞”all in or all out” isolation of different age groups
  • Optimal nutrition and management
  • Vaccines: inactivated vaccines, subunit vaccines - will prevent the severe form of disease
  • 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 of M .suis ?

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: reach joints
  • Clinical signs:
  • 3-10 week old piglets (around weaning),
  • slight fever, polyserositis, arthritis, restricted movement
  • 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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