Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides (Mmm), is a highly contagious bacterial infectious disease of the respiratory tract in cattle.

Bovine pulmonary disease is now predominantly found in sub-Saharan Africa

Domestic and zebu cattle as well as yak and water buffalo are susceptible. There are isolated reports of occurrence in sheep, goats, and American bison. However, these do not play an epidemiological role

Bovine pulmonary disease is transmitted primarily by direct animal-to-animal contact. The transmission is aerogenic (droplet infection)

3 weeks to 6 months

Clinical symptoms include respiratory symptoms (dyspnea, cough, nasal discharge), anorexia, and fever

In countries free from bovine pulmonary plague, no treatment is administered. 

Live vaccines are used in endemic areas. Vaccination is not recommended for countries with low prevalence or for CBPP-free areas.

Bovine pulmonary disease does not currently occur in Austria or Europe. The last outbreak in Europe took place in Portugal in 1999.

Mmm belongs to the Mycoplasma genus, a group of cell-wall-less bacteria in the class ‘Mollicutes’. It is part of the Mycoplasma mycoides cluster, which comprises five different Mycoplasma strains that cause disease in cattle and goats and are closely related to one another both phenotypically and genotypically (Mycoplasma mycoides subsp. mycoides, Mycoplasma mycoides subsp. capri, Mycoplasma capricolum subsp. capricolum, Mycoplasma capricolum subsp. capripneumoniae, Mycoplasma leachii).

CBPP has been known since the 18th century and spread worldwide in the second half of the 19th century as a result of livestock trade. It was eradicated in many countries at the beginning of the 20th century through culling strategies (UK, USA) or a combination of vaccination campaigns and culling (Australia). Today, the disease is endemic in sub-Saharan Africa and causes significant economic damage. Little is known about the current situation in Asia. In Europe, the last case occurred in Portugal in 1999.

Symptoms

Bovine pleuropneumonia can take an acute, subacute or chronic course.

The acute form is characterised by high fever (up to 42 °C) and pronounced respiratory symptoms (coughing, chest pain, polypnoea, dyspnoea, nasal discharge). In endemic areas, subacute and chronic forms predominate. These animals show few or non-specific symptoms such as coughing and progressive weight loss, leading to cachexia. In calves, CBPP tends to manifest as arthritis (joint swelling) rather than respiratory symptoms.

The clinical presentation of the disease is strongly influenced by the virulence of the strain in question and the susceptibility of the host (breed, age, immune status). In the event of a new infection in a herd, mortality can be very high (up to 90%), whereas in endemic areas it is low (<10%).

Pathological changes in the thoracic cavity are considered characteristic. CBPP is characterised by fibrinous bronchopneumonia and pleuritis. In the acute phase, pleural effusions of several litres may form, whilst in the chronic phase, fibrotic adhesions develop between the lung and the chest wall. Changes in the lung are usually unilateral, with the caudal lobe being the most commonly affected. In the early phase of the disease, a typical marbled lung surface is observed, resulting from the juxtaposition of healthy and diseased tissue, separated by thickened interlobular septa. Encapsulated necrotic areas, known as sequestra, are also typical. In calves, fibrinous polyarthritis is predominantly observed.

Transmission

CBPP is a highly contagious infectious disease that can spread rapidly. It is mainly transmitted via the air. The pathogens have also been detected in saliva, urine, foetal membranes, uterine discharge and semen. Transplacental transmission is possible. The main source of infection are silent carriers of a chronic infection, whereby live pathogens can persist in encapsulated lung lesions (sequestra) for up to two years and can be reactivated by immunosuppression.

CBPP is spread mainly through the movement of livestock. Countries where CBPP is present are therefore excluded from international trade in livestock. It is listed as a notifiable animal disease in Annex II to Regulation (EU) 2016/429.

Clinical diagnostics are unreliable, since chronic carriers in particular often show little or no clinical symptoms. A suspected case must always be clarified by microbiological, molecular biological, pathological or serological methods. Since the pathomorphological changes are very characteristic, the slaughterhouse examination is suitable as a monitoring method.

Sampling of the living animal:

• Nasal swab
• Bronchoalveolar lavage (BAL)
• Pleural effusion (by puncture)
• Serum

Sampling on dead animal:

• Lung lesions
• Lung or mediastinal lymph nodes
• Pleural fluid
• Synovial fluid

Detection method:

• Direct pathogen detection by culture on selective culture media.
• Molecular detection: PCR
• Serological detection: Complement Binding Reaction (CFT), Antibody ELISA, (Immunoblot)