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)
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
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)
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
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
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
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
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
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
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