167. Contagious bovine pleuropneumonia.

Question 1

Occurrence and aetiology?

Answer 1

Occurrence:

• Africa, Asia; Hungary free (1902), sometimes appeared in Europe (Italy, Spain, France till 1999)

Aetiology

• M. mycoides subsp. mycoides (SC)
• Host range (narrow)
• Cattle, buffalo, bison, other
• Sheep, goat: can carry without clinical signs (only colonisation, can maintain & shed infection)
• Wild living ruminants are not susceptible
• Virulence variants (2 clones found in Africa, 1 found in Europe)
• African (South African & continental African clones):
• More virulent
• Shorter incubation, faster course
• European clone:
• Genetic difference, Less virulent
• Longer incubation, milder, slower course

Question 2

Epidemiology?

Answer 2

Epidemiology

• Agent present only in infected animals!
• Maintaining the infection
• Bacterium carrier animals
• Long carriage and shedding
• Highly contagious
• Slow spreading within the herd, close contact needed to infect others
• Infection: aerogenic, shared pasture, drinking well, market (nomad animal breeding), no indirect infection, cannot be
• carried with meat
• Morbidity ~100%, mortality ~50%

Question 3

Pathogenesis?

Answer 3

Pathogenesis

• Aerogenic infection
• Lung, replication in bronchioli
• Lobular fibrinous pneumonia, pleuritis
• Slow intra canalicular spreading (inflammation of the different lobules are in a different phase ʹ
• marble-like lesions of the lungs)
• Thrombus formation in blood vessels
• Localised lesions (necrosis, sequesters)
• Cough: bacteria get out of sequesters
• Intermittent shedding
• Bacteriaemia: extra pulmonary lesions (young animals)
• Immunity in recovered animals but bacterium carriage
• Immune suppression

Question 4

Clinical signs?

Answer 4

Clinical signs

• Acute: susceptible animals
• Chronic: more resistant animals ʹ arthritis, edema
• Incubation: 1-4 months
• Fever: 41-41.5oC,
• severe dyspnoea (strange stance, extended neck),
• increased heart rate, increased breath rate,
• dry cough, drop milk production

Question 5

Diagnosis?

Answer 5

Diagnosis

• Epidemiology ʹclinical signs ʹPM lesions
• Notifiable disease ʹ need lab confirmation!
• Detection of the agent: isolation of bacteria, IF, PCR
• Detection of antibodies: CFT, ELISA (screening only), immune blot (confirmation)
• Limited value

Question 6

Treatment?

Answer 6

Treatment

• Only in endemic areas
• Anti-mycoplasma antibiotics: tiamulin, tylosine, tetracyclines, fluoroquinolons
• Eliminate clinical signs only!!
• Bacterium carriers remain

Question 7

Prevention?

Answer 7

Prevention

• Notifiable disease!!
• Disease free countries
• Closed herds, stamping out
• Protection and surveillance zone: observation, serological tests
• Infected countries
• Closed herds, movement restrictions on susceptible animals
• Vaccination of susceptible animals (continuous) ʹ live attenuated:
• T1/44 strain: some virulence retained, 12 months protection
• T1sr: strain - 6 months protection
• T1/44 (LppQ): lipoprotein deficient mutant - DIVA
• Formerly: KH3J (Karthoum) strain