After 1989 paratuberculosis has been often diagnosed in imported ruminants. In December 1992, 19 highly pregnant heifers of the breed Charolais were purchased from Hungary (original import from France to Hungary). In January 1993 one heifer was born who left the herd in November 1993 and until May 1994 (ie. 7 months) moved freely in the nature in the range of 15 - 20 km. After having been caught, the clinical signs of paratuberculosis (emaciation and diarrhoea) were evident. Consequently, 4 other cases of animals infected with the same strain of DNA type B-C1 were revealed. Therefore in the period 1995-1996 sampling of the small intestine and corresponding lymph nodes from 83 shoot red deer (Cervus elaphus) and roe deer (Capreolus capreolus) from 43 different locations in the same district were examined. 6 strains of Mycobacterium avium subsp. paratuberculosis were totally isolated: one strain of DNA type B-C1 from a stag; four strains of DNA type B-C1 and one strain of DNA type B-C9 from roe deer. Regarding the fact that the five wild ruminants (one stag and four roe deer) infected with the strains of the DNA type B-C1 were located in the same area as the infected heifer, the infection source could be the infected heifer. In one roe deer infected with the strain of DNA type B-C9 the infection source was different: the stags who ran away from a farm were purchased from an area infected with this DNA type. In the following survey carried out during 1997 -1998 in the whole Czech Republic, divided into 74 districts, more than 400 heads of hoofed game were examined from more than 70 % of the districts. M.a.paratuberculosis has been found so far in 8 animals (stag, fallow deer, moufflon) kept in farms and game parks. In wild the infection has been so far found in two stags and a moufflon in the districts where infected cattle herds occurred. All the isolated strains are at present identified using DNA fingerprinting to assess all epizootiological relations. Our research was partially supported by the Ministry of Agriculture (grant no. EP0960006087) and the Ministry of Health of the Czech Republic (grant no. 4211-3/97). Permanent address of Robin du Maine - Hogeschool van Utrecht, Netherlands.