Two cases of bovine JD were detected by post-mortem examination in 4-6 years old Holstein cows of a 170 head dairy herd in the State of Pernambuco, Northeast-Brazil. During 2006, three more cases were diagnosed by post-mortem examination in a 130 head Girolanda dairy herd in the State of Rio de Janeiro. The histopathological findings were granulomatous enteritis, lymphadenitis and lymphangitis. The inflammatory infiltrate was composed of macrophages, epithelioid and Langhans cells. Samples of intestine tissue and feces were inoculated in HEYM with/without mycobactin for Map isolation. Cultures on HEYM supplemented with mycobactin yielded colonies identified as Map according to their phenotypic properties and PCR reaction. From intestinal tissues and feces from cows with JD and from asymptomatic cows of the Pernambuco herd, five Map strains, and of the Rio de Janeiro herd, two strains were isolated in HEYM. The prevalence of Map infection was estimated by whole herd testing in the two dairy herds by absorbed ELISA using PPA-3 commercial antigen. The ELISA test identified 55 positive cows (32.3%) among the 170 animals from Pernambuco and 57 positive cows (43.8%) among the 130 from Rio de Janeiro. The Map infection was disseminated in bovine dairy herds in Pernambuco and Rio de Janeiro States showing the necessity for adoption of control measures for the protection of Brazilian dairy herds.