Tuberculosis in Various Ages and Different Races: Anachronisms

¹ The Department of Internal Medicine, School of Public Health, and Student's Health Service, University of Minnesota.

Since 1920, longitudinal observations made on persons in various ages of life have revealed that: (a) Among 1,011 infants and young children infected, 30 (2.96 per cent) developed clinical tuberculosis. The others remained free from clinical disease during the period of childhood. (b) Among 2,979 children who reacted to tuberculin between the ages of 6 and 14 years, 137 (4.6 per cent) developed clinical lesions. (c) Chronic pulmonary tuberculosis usually made its debut during adolescence and throughout the remainder of life.

Among 2,266 persons who became infected at the age of 19 years or older and were recently traced, 2,080 with 24,431 person years of follow-up had developed no demonstrable tuberculous lesion. There were 54 in whom primary pulmonary infiltrates (Ghon tubercles in the inflammatory stage) cast visible x-ray shadows about the time allergy could be elicited. Pleurisy with effusion appeared in 67, mostly about the time allergy was detectable. Clinical reinfection type of tuberculosis subsequently developed in 65, of whom 60 had pulmonary and five extrathoracic lesions.

All demonstrable lesions behaved in the same manner as those previously observed in children and among adults who had been infected in childhood.

The natural defense mechanism of the human body apparently does not differ with age of life or races of people. Mental illness per se does not influence resistance.

The defense mechanism of the human body is handicapped when reinfections occur because of allergy which has been introduced following the primary invasion. Although the defense mechanism copes at least temporarily with many reinfections, it fails often enough to account for all the illness and death from tuberculosis.