The Condition
General
Atrophic rhinitis is a multifactorial disease affecting the turbinate bones of the snout, causing inflammation and deformity (Cowart, 1995). In the progressive form, the disease continues to affect stock as they grow, significantly reducing growth rates and increasing susceptibility to other diseases. Up to 26% of UK herds are affected, and 10% severely affected (Taylor, 1995).
There is very little published information available on the prevalence of the disease in outdoor units. It is, however, suggested that the disease is likely to be less prevalent in outdoor units than in indoor systems, along with other respiratory diseases.
Two types of atrophic rhinitis are distinguished:
Non-progressive atrophic rhinitis, caused by Bordetella bronchiseptica, is widespread but has little impact on productivity and the health status of the animal (de Jong, 1999).
Progressive atrophic rhinitis, caused by Pasteurella multocida, is of far greater economic significance, leading to reduced growth rates in affected stock (de Jong, 1999). The disease affects other species, including small and large ruminants, poultry, rabbits and humans, and is therefore a zoonotic disease. Poultry, sheep, cattle, dogs, rats and cats are all considered to be potential carriers of the disease (de Jong, 1999), but pig-to-pig transmission is most significant (Cowart, 1995). This section mainly discusses progressive atrophic rhinitis.
Causes
Atrophic rhinitis is caused by the P. multocida bacterium, but other viral and bacterial agents present in the snout may also complicate the disease (Taylor, 1995).
Signs
Young piglets on the sow may be clinically affected most by the disease, and will sneeze and snort, and show respiratory discomfort or nasal discharge (Cowart, 1995). Early signs may be difficult to distinguish from those of swine influenza or PRRS (de Jong, 1999). Chronic signs are easier to detect and are usually seen in fattening pigs. They include distortion of the snout, particularly with a relative shortening of the upper jaw bone, and reduced growth rates (Cowart, 1995).
Links to other respiratory diseases: