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
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
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)
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
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
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
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
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
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
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