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  Diagnosis of TB

 Mass Surveys

Students of the Saskatchewan Normal School line up to be given the tuberculin skin test for TB (ca. 1938).

In Canada, Ferguson and Connell of Saskatchewan, and in the U.S.A., Potter and others, working along parallel lines, helped popularize this public health facility during the late 1930s and early 1940s. Mass chest x-ray for large groups of apparently healthy people was the best way to find hidden cases of TB among the general population. It was the only way to find tuberculosis infection in people who felt and acted healthy. Increased efficiency of x-ray devices and the increased use of miniaturized machines allowed scanning of whole populations by means of mobile equipment.

 Skin Test
 Mass Surveys
 Sputum Test
 Gastric Washing
 Laboratory Tests

Trucks housing mobile x-ray machines for use in mass surveys in Spring, 1943. Although photofluorography was done by the British Navy in 1939, and machines were produced by Siemens of Germany even before that, these two Saskatchewan trucks ran what may have been the first survey of this type in North America in 1941.

Advances in the use of miniature film included faster fluoroscopic screens, improved lenses for the recording camera, standardization of effective film types and sizes, and the invention of a photoelectric timing device that eliminates guesswork and guarantees uniformity of results the automatic control of current and time factors. Matching these have been a steady reduction in the size, weight, and relative cost of equipment, and the production of portable and mobile units that bring x-ray to people who would not or could not otherwise go seeking it. Listed last, but perhaps of prime importance, both as to regular x-ray apparatus and photofluorographic machines, has been the development of rotating anode tubes that focus sharply and can stand up under the almost constant bombardment of hundreds of exposures made in rapid succession.

Prime Minister Louis Stephen St. Laurent watches as PC leader George Drew is x-rayed at the kick-off of a TB mass survey of the city of Ottawa in 1953.

For many years, sanatorium admissions had shown that two out of every three enter in a moderately or far-advanced stage. In mass x-ray surveys, more than one half of the cases found were still minimal.

As their name implies, the mass surveys were a major effort, and required an intense workforce to carry out. Without the help of many different groups, the surveys would never have been possible and we would not have seen the same decline in TB as we did. However, Canadians quickly caught on and both individuals and community groups came out both to help run the surveys and to be surveyed themselves. A 1953 article in the New Glasgow News (Nova Scotia) reported the assistance of more than 20 community organizations in the local TB survey. Representatives were included from the Red Cross, Trenton Home and School, the Silver Cross Club, the IODE (International Order of the Daughters of the Empire), the Local Council of Women, the Catholic Women’s League and many other church organizations, several business clubs, and even the local branches of several banks.

This mobile x-ray unit was the first to operate in the province of Nova Scotia. It was purchased by the province in 1948 for $25,000, of which the TB Association donated $10,000 from their sale of Christmas Seals.

Mass surveys continued in some form from their inception in the 1930s until the early 1980s. As the incidence of TB fell in Canada, the surveys found less and less infected people, but the surveys were still costing as much or more to execute. Thus, the cost of finding each case of infective TB was skyrocketing while the benefits decreased. Today, TB surveys still exist, but are carried out on targeted groups where prevalence is expected to be much higher than average; areas such as inner-city slums and reservations where living conditions are much poorer.