J. Comp. Path. 2001, Vol. 124, 95–101 doi:10.1053/jcpa.2000.0433, available online at http://www.idealibrary.com on Pathological, Immunohistochemical and Bacteriological Findings in Kidneys of Cattle with Contagious Bovine Pleuropneumonia (CBPP) V. Grieco, M. Boldini*, M. Luini*, M. Finazzi, G. Mandelli and E. Scanziani Istituto di Anatomia Patologica e Patologia Aviare, Facolta ` di Medicina Veterinaria, Via Celoria 10, 20133 Milano and *Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia, Via Bianchi 1, 25100 Brescia, Italy Summary Between 1990 and 1993, 61 outbreaks of contagious bovine pleuropneumonia (CBPP) were reported in Lombardy, Northern Italy. In this study, gross pathological examination was carried out on 3129 slaughtered cattle, 716 of which (22·9%) showed typical CBPP pulmonary lesions. Single or multiple renal infarcts at different stages of development were observed in 88 (12·2%) of these 716 cattle. The kidneys of 77 cattle whose lungs showed typical CBPP lesions and were bacteriologically and immunohistochemically positive for the small colony type of Mycoplasma mycoides subspecies mycoides ( M. m. mycoides SC) were selected and submitted to histological, immunohistochemical and bacteriological examination. Histologically, in chronic CBPP cases, infarcts were characterized by fibrosis, calcification of cortical tubules and tubular atrophy, accompanied by the presence of interstitial inflammatory infiltrates composed of lymphocytes, plasma cells and histiocytes. M. m. mycoides SC antigen was detected immunohistochemically in 65 (84·4%) of the 77 kidneys examined. The antigen was detected in the lumen of blood vessels and in glomerular cells. Immunolabelled interstitial cells and tubular epithelial cells were seen in chronic cases only. M. m. mycoides SC was isolated from the kidneys of 12 animals (15·6%) and more frequently in cases with renal infarcts. This study confirms previous observations that demonstrated a renal involvement in cases of CBPP. Moreover, the immunohistochemical results indicated that M. m. mycoides SC antigen was frequently detectable in different renal structures and cells in spontaneous cases of CBPP.  2001 Harcourt Publishers Ltd and 1993, and eradication policy necessitated the slaughter of 17 245 cattle from infected herds Introduction (Belloli et al., 1994). The typical lesion of CBPP is a fibrinous pleuro- Contagious bovine pleuropneumonia (CBPP) is an pneumonia involving the basal lobes, with the fre- infectious disease caused by the small colony type quent development of necrotic areas that in chronic of Mycoplasma mycoides subspecies mycoides (M. m. cases are sequestered by a layer of fibrous tissue mycoides SC). CBPP is at present endemic in Africa (Dungworth, 1993; Jones et al., 1997). In addition, and East Asia (Nicholas and Bashiruddin, 1995) thoracic lymph nodes draining the affected areas but has been reported since 1958 in some European often appear enlarged and oedematous, and in countries such as Portugal, Spain and France some cases show necrotic foci (Buxton and Fraser, (Provost et al., 1987). In Northern Italy, 61 out- breaks of CBPP were identified between 1990 1977; Provost et al., 1987; Scanziani et al. , 1997). 0021–9975/01/020095+07 $35·00  2001 Harcourt Publishers Ltd