Disease Information (8) (Provided by Emerging Exotic Diseases Lab, Foreign Animal Diseases Division) ( 07/05/11 ) | |||||
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Part | Charger | leeyh | date | 07/05/11 | |
□ Contagious bovine pleuropneumonia
1. Definition
- Contagious bacterial disease for bovine affecting the lungs and pleura of cattle
2. Aetiology
- Mycoplasma mycoides subsp. mycoides SC (bovine biotype)
- Mycoplasmas are microorganisms deprived of cell walls and are, therefore, a) pleomorphic and b) resistant to antibiotics of the beta-lactamine group, such as penicillin
- Growth of the mycoplasma is relatively fastidious and requires special media rich in cholesterol (addition of serum).
- There is only one antigenic type
3. Host range
- Cattle (Bos taurus), zebu (Bos indicus) and water buffalo (Bubalus bubalis). Wild bovids and camels are resistant
4. Geographical distribution
- CBPP is widespread in Africa and it is also present in other regions of the world, including southern Europe, the Middle East and parts of Asia. In Africa, its economic importance is particularly high in Sahelian and Sahelo-Sudanese countries
- For detailed information on occurrence, see recent issues of World Animal Health and the OIE Bulletin
5. Transmission
- Aerial, mostly by direct contact: droplets emitted by coughing animals, saliva, and urine. Transmission up to several kilometres has been suspected under favourable climatic conditions
- Transplacental infection can occur
- Inapparent carriers are a major source of infection
- Cattle movement is important in the spread of the disease
6. Incubation period
- Incubation period is 1-3 months (sometimes longer)
7. Gross lesions
- Important amount of yellow or turbid exudate in the pleural cavity (up to 30 litres) that coagulates to form large fibrinous clots
- Fibrinous pleurisy: thickening and inflammation of the pleura with fibrous deposits
- Interlobular oedema, marbled appearance due to hepatisation and consolidation at different stages of evolution usually confined to one lung
- Sequestrae with fibrous capsule surrounding grey necrotic tissue in recovered animals
8. Diagnosis
- During an outbreak of natural disease, only 33% of animals present symptoms (hyperacute or acute forms), 46% are infected but have no symptoms (subclinical forms) and 21% seem to be resistant
- Clinical diagnosis
In adults
Moderate fever with respiratory, pulmonary and pleuretic symptoms: polypnoea, characteristic attitude (elbows turned out, arched back, head extended), cough (at first dry, slight, and not fitful, becoming moist)
When the animal gets up or after exercise, breathing becomes laboured and grunting can be heard
At percussion, dull sounds can be noticed in the low areas of the thorax
In calves
Pulmonary tropism is not the general rule, and infected calves present arthritis with swelling of the joints
Co-existence of pulmonary symptoms in adults and arthritis in young animals should alert the clinician to a diagnosis of CBPP
- Laboratory diagnosis
Identification of the agent
Isolation of pathogen and identification by metabolic and growth inhibition tests
MF-dot
Polymerase chain reaction
Serological tests
Complement fixation (prescribed test in the Manual). This test should be used only at herd level and never for individual diagnosis
Competitive ELISA (under validation by International Atomic Energy Agency and several reference laboratories), and haemagglutination
Agglutination test can be used as penside test in active outbreaks at the herd level
Samples
Lung lesions, pleural fluids, lymph nodes, lung tissue exudate - frozen for isolation of the organism
Acute and convalescent sera
9. Control and eradication
- In disease-free areas: quarantine, serological tests (complement fixation) and slaughtering of all animals of the herd in which positive animals have been found
- control of cattle movements is the most efficient way of limiting the spread of CBPP
10. Public health aspects
- There is no risk to human health
11. Further infomation : http://www.oie.int/eng/maladies/en_fiches.htm?e1d7
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