Use of DNA fingerprinting for epidemiological studies of paratuberculosis in Sweden and the Czech Republic

Due to liberalisation of trade in farm animals, paratuberculosis is rapidly spreading among ruminants in many European countries. Two countries with different situations concerning Johne's disease are Sweden and the Czech Republic. Sweden has a very low disease prevalence and imports few cattle. The Czech Republic has imported massive numbers of cattle since 1992. Isolates of Mycobacterium avium subsp. paratuberculosis from the two countries were examined using RFLP (Restriction Fragment Length Polymorphisms) with restriction endonucleases PstI and BstEII. Twenty Swedish isolates of M. a. paratuberculosis from cattle herds were investigated. Five isolates from animals imported from Denmark (four Blonde d'Aquitaine, one Limousine) and one isolate from a cow imported from Finland (Aberdeen Angus). Six isolates came from herds within a domestic chain of infection in the Limousine breed, originating from cattle importation from France via Denmark in 1975. One isolate came from a Swedish Friesian cow apparently without any contact with imported animals. All Swedish isolates were of one RFLP type: B-C1. This finding supports the notion that the infection was spread from imported animals to cattle reared in Sweden. Isolations made from 24 cattle herds originally reared in the Czech Republic were RFLP types A-C10, B-C1, B-C9, C-S1 and D-C12. In all 44 infected cattle herds (Blonde d'Aquitaine, Charolais, Holstein, Hereford, Jersey, Limousine, Mont Belliarde, Sarers) imported From Denmark, France, Germany and Hungary, RFLP type B-C1 was the most prevalent. In ten of these herds, animals were infected with other RFLP types (A-C10, B-C5, B-C9, D-C12, E-C1, H-C1, I-C13 and M-C16). Among other ruminants with paratuberculosis, domestically reared sheep were infected with RFLP types A-C8, A-C10, B-Ci, B-C2, and E-C1, goats B-C1, B-C9 and C-S1 and wild ruminants RFLP types A-C10, B-C1, B-C9 and M-C16. In imported wild goats from Estonia RFLP type B-C1, in imported goats from Denmark RFLP type B-C1, in imported sheep from Poland and France RFLP type A-C1 and in red deer imported from Scotland RFLP type M-C26 were found.