Etiology and Serological Diagnosis of Swine Enzootic Pneumonia

Swine enzootic pneumonia (SEP) is probably the most prevalent and important disease of pigs in the world today. Economic loss due to growth retardation and low feed efficiency in the infected pigs is a serious problem for pig producers. The occurrence of this disease has been known since the 1930's in European countries. At present this disease probably occurs everywhere swine are raised as domestic animals. In Japan this disease was first reported by Konno et al. (1963). However, it is not known whether the disease had existed in Japan before that time. Swine enzootic pneumonia is a chronic pneumonia characterized by a non-productive cough, loss of condition, growth retardation, high morbidity and low mortality. The disease is spread by aerosol transmission. Our modern system of swine management in which a large number of pigs are confined in close contact may provide, therefore, an ideal environment for the rapid spread of this disease. Clinical signs usually appear 2 to 3 weeks after exposure. At necropsy, gross pneumonic lesions are found predominantly in the apical, cardiac and intermediate lobes, as well as on the anterior parts of the diaphragmatic lobes. They are usually well-demarcated, plumcolored or grayish lesions. Histological examination of the lesion reveals pronounced peribronchiolar and perivascular lymphoid hyperplasia, thickening of the alveolar wa lls, septal cell proli feration, and a moderate neutrophil infi ltration. Etiology of SEP