Experiments were conducted on guinea pigs. A study was made of the pathogenicity of brucellae culture isolated from various wild and Game animals of the extreme North of the USSR (wolf, polar fox, ermine, glutton). The majority of the cultures under study proved to be highly pathogenic. Observations carried out led to the conclusion that brucella cultures circulating between the wild and domestic reindeers and migrating to other species of animals presented definite danger to the health of man.