Causative agent
- Mycoplasma hyopneumoniae
- Mycoplasma hyorhinis
Differential diagnosis
- Pasteurellosis
- Glasser's disease
- Atrophic rhinitis
1. History taking
- The presence of chronic pneumonia in the herd,
particularly in fattening pig, resulting in uneven
growth rate and poor feed conversion efficiency
- Transmission of M. hyopneumoniae by direct contact
with secretions from respiratory tract of infected
swine
- Some strains of M. hyorhinis may cause pneumonia,
polyserositis and arthritis in 3-10 weeks old pig,
arthritis due to M. hyosynoviae infection usually
found in 12-24 weeks of age
2. Clinical examination
- Acute form of M. hyopneumoniae: pig of all ages
may be affected and show anorexia, pyrexia,
respiratory distress and coughing
- Chronic form: young pigs of 3-10 weeks of age
develop clinical signs within 10-16 days with
transient diarrhea, dry cough and then barking
cough
- High morbidity, low mortality, death associated
with secondary bacterial infection
|
3. Necropsy
- Purple to gray areas of consolidation in cranial,
middle, accessory and cranial portion of caudal
lobes of the lung
- The bronchial and mediastinal lymph node are
enlarged
- Fibrinous pericarditis, pleurisy and peritonitis
4. Histopathological observation
- Early lesions consist of small accumulations of
neutrophils in the alveoli , some peribronchiolar
lymphocytic infiltration
- Advanced lesion, alveolar inflammation,
lymphocytic peribronchiolar hyperplasia including
obliteration of bronchioles
5. Bacterial isolation
Specimen : lung tissue emulsion, exudate from joint
cavity
Medium : Modified Friis medium or BHL medium
- Culture : incubate at 37°C until color changes,
transfer 1 drop of broth onto the same agar
medium, and incubate at 37°C under 5% CO2
condition for about 1 week, observe colonies and
identify by biochemical and serological test
Control
- Provision of an optimal environment including air
quality, ventilation, temperature and proper stock
density
- Vaccination
|
