Spread of tuberculosis through tainted food

By Zsofia Balla Monjezi

The tubercle bacilli is an airborne pathogen, that spreads through airborne contact.  According to the Centers for Disease Control and Prevention, when someone infected with pulmonary TB coughs, TB bacteria in tiny water droplets issue from the infected person’s mouth and stay in the air for several hours. Another person can easily inhale these tiny infected water droplets containing tubercle bacilli, the bacterium responsible for causing the disease. Inhaled TB bacteria travel down the trachea of the respiratory system and collect in the alveolar sacs of the lungs when they start to multiply. The body’s immune system can initially counteract the harmful effects of the bacterium by forming granuloma around bacteria. At this stage, one would test positive for TB and would be diagnosed with latent tuberculosis but would not be infectious nor would show any symptoms of tuberculosis yet. Once, the granuloma breaks open, the bacteria can cause its lethal effects on the lungs or can travel to other parts of the body through the blood stream, infecting different organ systems.

René-Théophile-Hyacinthe Laennec (1781-1826) De l’auscultation médiate… (1819)
Lungs affected by tuberculosis. Wikimedia Commons.

TB infecting the lungs are called pulmonary tuberculosis and TB infecting other body systems are called extra-pulmonary disease. The World Health Organization reports that, people with active tuberculosis can infect 5-15 non-infected people per year. 45% of non-HIV TB positive patients die because of tuberculosis and nearly all TB patients who also have HIV die because of tuberculosis. Knowing about all the statistics regarding death rates and how easily TB spreads, it is not surprising to see so many jobs and schools requiring TB tests before admission.

In the 20th century London, tuberculosis was a fairly common illness, due to low practices of self-hygiene and poor living conditions. In 1949 the airborne spread of tuberculosis was clear for the London population but was not preventable. Tuberculosis was known to infect the air passages of both the healthy carriers and the infected ill. In order to prevent the spread of the disease, MOH advised the public to cover their mouth when sneezing and coughing, and to dump and sweep whenever possible.  The technology was able for TB diagnosis through laboratory practices, and medical officers were ready for tuberculosis confirmed patients’ hospital admission.

Tuberculosis was a very serious and easily spreadable disease in the 1900s in London. To decrease such a rapid spread of this deadly disease, government officials have taken actions in order to protect citizens. Tuberculosis dispensaries were responsible for educating the public about how to prevent infection, and local government board officials ensured shelters and sanatoriums for tuberculosis patients so they would not transmit the disease.

The Medical Officers of Health with the assistance of School Medical Inspectors reported the most vulnerable population to the spread of tuberculosis was elementary school children of poor families. Most of these minors were diagnosed with early pulmonary tuberculosis and their families were not able to provide the conditions and nourishment for their children to start recovery.

At the end of the 19th century, bovine tuberculosis was strikingly spreading to farm animals which was also a major contributor for London to be later called the tuberculosis capital of Europe.

At that time, medical professionals were not sure if the bacteria are transmissible to humans. Despite the discovery of the same bacterium causing tuberculosis in both animals and in humans, experiments done in 1900 by Dr. Robert Koch seemed to prove that bovine tuberculosis is not transmissable to humans, nor is human tuberculosis infectious to animals. Dr. Koch reasoned his findings by saying that those exposed to tuberculosis infected meat were not showing signs of intestinal tuberculosis.

Finally, in 1909 experiments run by the Royal Commission confirmed that animal tuberculosis is able to spread to humans, therefore actions were necessary to be taken to alleviate such cases.

Charles Flint, Milch cows and dairy farming (1864)

There were several measures taken to prevent the spread of bovine tuberculosis:

 In the 1950s dairy products were routinely tested for the tubercle bacillus. Medical Officer of Health for Wandsworth, Metropolitan Borough were testing milk, synthetic cream, ice-cream, cake-fillings and fresh-cream.

According to another report, food agencies were also investigating several animal products such as sausages, beef brisket, and pork ribs to avoid the spread of extra-pulmonary disease caused by the meat industry.

To eliminate bovine spread tuberculosis, under the Diseases of Animals Acts and Orders, veterinarians frequently visited cattle farms to test for tuberculosis. Doctors microscopically examined cow milk to see if the mycobacterium tuberculosis was present. When they found the bacteria, under the Provision of Tuberculosis Act the cows were slaughtered.

Because of all these preventative steps taken by the government 11,259 lbs of animals were slaughtered , which decreased the spread of animal caused extra-pulmonary disease by 40%.