Epidemiological basis of tuberculosis eradication. 3. Risk of pulmonary tuberculosis after human and bovine infection.

Cattle tuberculosis was eradicated in Denmark more than 10 years ago, but still a sizable proportion of Danish tuberculin reactors owe their sensitivity to tuberculous infection derived from bovine sources. This paper deals with the question whether the risk of pulmonary tuberculosis after such infection is different from that after tuberculous infection acquired from man. This problem has been studied by utilizing data from the Danish tuberculosis mass campaign, 1950-52, including eight years of follow-up, and data from the eradication programme for cattle tuberculosis. It is shown that the tuberculin reactors can be divided into two groups carrying a widely different risk of late pulmonary tuberculosis: one, infected from bovine sources, carrying a low risk; the other, infected from human sources, carrying a relatively high risk.