Tuberculosis Among Nurses

¹ Professor of Medicine and Public Health, Medical and Graduate Schools, University of Minnesota.
² Professor of Public Health and Director, Students' Health Service, University of Minnesota.
³ Professor of Public Health and Dean, Medical Sciences, University of Minnesota.

1. This study, undertaken in schools of nursing in 1920, at first consisted of examining and treating students who presented symptoms. In 1927, an attack was begun on the tubercle bacillus rather than just the damage it had caused. This consisted of testing students with tuberculin, thus dividing them into two groups: (a) Reactors who were harboring tubercle bacilli, and (b) those who were uninfected.

2. Reactors on entrance were examined semiannually while in school. Students uninfected on entrance were retested semiannually and converters were examined every six months.

3. Periodic examinations of tuberculin reactors usually revealed clinical lesions while in the silent stage, before they were contagious and when treatment was successful.

4. Periodic testing of the uninfected on entrance provided the earliest possible diagnosis of tuberculosis. Moreover, it served as an excellent epidemiological agent.

5. Sources of infections of converters were sought. This led to affiliated hospitals, sanatoriums, departments within the home schools, etc. Finding such offenders was reason to discontinue or correct them.

6. In one school, patient admission and personnel examinations were conducted as a demonstration in 1933. In 1936 and in 1938 this was made routine in two other schools and in the remaining institutions in 1952 and 1953.

7. Investigation of all methods of protecting students that have been proposed revealed only one that seemed sound, namely, management of tuberculosis as a contagious disease.

8. Contagious disease technique was instituted in one school in the early 1930's and proved so adequate that it is now employed in most general hospitals of this area. Periodic testing with tuberculin is the best criterion as to whether technique is being rigidly enforced.

9. Infection with tubercle bacilli may cause not only early illness such as pleural effusion but also and more often serious tuberculosis years and decades later. A tuberculin reaction is an ill omen as it is the first manifestation of the presence of tuberculosis. Student and graduate nurses are justified in demanding adequate protection whenever and wherever they are in contact with contagious cases of tuberculosis.

10. In the four original study schools, 5,304 students graduated in the classes from 1930 to 1954 inclusive, of whom 807 (15.2 per cent) had been infected before admission. Among the remaining 4,497, infections were acquired by 1,020 (22.7 per cent) students. In the classes from 1930 to 1942, of the 1,619 who entered uninfected, 575 (35.5 per cent) converted. In the classes from 1943 to 1949, of the 1,876 uninfected on entrance, 324 (17.3 per cent) converted. After 1949 there were 1,002 nonreactors, of whom 121 (12.1 per cent) converted. Obviously, the tuberculin conversion problem has not been completely solved, but it appears the methods now in use are capable of doing so.

11. All persons who react characteristically to tuberculin have at least multiple primary lesions. Therefore, in the classes of 1930 to 1954, the 807 students who reacted on entrance had such lesions. Among the 758 in the classes from 1930 to 1951, reinfection type clinical lesions evolved in 26 (3.4 per cent), seven while they were in school and 19 after graduation. Five died.

12. Among the 950 (classes of 1930 to 1951) who converted while in school, all of whom had primary lesions, clinical tuberculosis appeared in 31 (3.3 per cent), two in students and 29 since graduation. One died.

13. Among the 2,441 uninfected on graduation who were contacted, 414 have converted. Of this number, 15 (3.6 per cent) have had clinical tuberculosis. One died.

14. To avoid erroneous deductions, tuberculous lesions must be classified. Demonstrable allergic manifestations, including erythema nodosum, primary pulmonary infiltrates and pleurisy with effusion, which appear about the time allergy is established, belong to the same category as other lesions which are too small or are not so situated as to be detectable but are present in all tuberculin reactors. The only difference is consistency, position and size. They are in no way comparable to reinfection clinical type lesions which later evolve.

15. With decreased incidence of infection there has been a corresponding reduced number of clinical lesions. In the classes of 1947 through 1951, only seven are known to have developed clinical disease, five of whom were in classes of 1947. In the Fairview School, where 12 to 19 per cent developed demonstrable lesions before protective measures were well under way, there have since been only four students, who, while in school, developed clinical pulmonary tuberculosis. All four were infected before admission to school.

16. Many nurses who finished training uninfected with tubercle bacilli have traveled and worked in various other parts of this country and abroad, including military service, where contagious tuberculosis is rife, but we have seen no evidence to substantiate the theory that those who acquired infections later in life tolerated them differently than those infected in childhood or as students.

17. Treatment of tuberculosis among student and graduate nurses included in this study has been that in vogue at the time demonstrable lesions evolved. With antimicrobial drugs, it may be possible to effect a cure if administered promptly after invasions with tubercle bacilli occur. The lesions are then small and vascular and drugs may be expected to reach all bacilli. If present or future drugs prove to be germicidal, one may hope to destroy all organisms at that time. More observation is necessary before final conclusions can be drawn concerning efficacy of such treatment.

18. In this study, the tuberculin test has been the master key. It detects presence of tuberculosis earlier than any other procedure, is our best epidemiological agent, best determines magnitude of problem, provides best evidence of effectiveness of control measures and now may determine not only when to begin but also when to stop treatment.