Raising Awareness about Tuberculosis – World TB Day, 24 March 2012 Pt. 2

Why We Should Care About TB

Image source: WHO

Many people in the West have never thought about tuberculosis as a risk to their health.  Tuberculosis is often considered to be a disease of the past.  In 2011 in Canada the incidence of any form of tuberculosis was only 5 per 100,000, according to the World Health Organization (WHO).  But, within Canada certain communities, such as Aboriginal and Inuit populations, have borne an unequal share of the disease.  And, in other locations around the world tuberculosis is a dangerous epidemic that affects thousands of people and their communities.

Raising Awareness about Tuberculosis – World TB Day, 24 March 2012 Pt. 1

What is TB?

Culture of tuberculosis bacteria

Tuberculosis is caused by an infection with Mycobacterium tuberculosis, rod-shaped bacteria that are spread mostly through air-born droplets or dust micro-particles of dried sputum.  Once inhaled, the body’s immune system typically reacts by engulfing the bacteria, forming a tubercle that contains the bacteria to help keep it from spreading.  In most cases, the bacteria will die; in others, however, the bacteria can survive, become dormant, and the infected individual may develop active disease at a later date, sometimes soon after infection, sometimes years later. 

History of Health Care: Quarantine and Isolation

Before the nineteenth century, quarantine and isolation had been practiced in an effort to protect the community from contagious diseases such as plague and smallpox in the absence of specific treatment. Such diseases were considered contagious even though the cause and method of transmission were not known.

Two important developments occurred during the last half of the nineteenth century. An understanding of the cause and transmission of contagious disease occurred due to research leading to the germ theory. Government assumed increasing responsibility for the protection of the community from contagious diseases with legislation that established provincial and municipal Boards of Health.

Image from National Library of Medicine, http://www.nlm.nih.gov/exhibition/smallpox/sp_threat.html

History of Health Care: Vaccination

Why will Jane and John Jones born in 2010 and 2011 respectively live four score years or longer?

Vaccination as a deliberate attempt to protect humans against disease has a short history.

In spite of this, vaccination has had a major effect on the reduction of mortality and length of life

Figure 1. Edward Jenner

Since the time of Edward Jenner (Figure 1), vaccination has eliminated smallpox. Smallpox was greatly feared as the leading cause of death in the western world in the 18^th century. Because of the high mortality with smallpox (25%), the practice of variolation with the smallpox virus had been practiced in eastern societies and was introduced in Britain in 1721. However the subsequent infection was occasionally severe with a mortality of 1 to 2%.

In 1798, Jenner introduced vaccination with cowpox vaccine as protection against smallpox which rapidly replaced variolation. Although many were anxious regarding vaccination (Figure 2) and in spite of an anti-vaccination campaign, vaccination was rapidly accepted. During the 19^th and first half of the 20^thcenturies the methods of vaccination continued to be refined (Figure 3) and the quality of the vaccine improved. A worldwide vaccination campaign eliminated this disease as of 1979.

Figure 2. Vaccination scene by Louis Leopold Boilly, 1807. Credit: Wellcome Library, London

 

A Brief History of Isolation and Infectious Disease

Drawing about the Cholera in Le Petit Journal, c. 1912

Contagious disease has challenged society throughout human history. Quarantine and isolation was practiced in response to the pandemics of bubonic plague and cholera, beginning in the Middle Ages. In the 18th and 19th centuries, smallpox led to smallpox hospitals in some large urban communities. At the same time, citizens lived with the fear of outbreaks of typhus, typhoid fever, diphtheria, scarlet fever and influenza. The effectiveness of isolation was often limited due to the lack of knowledge of the cause and transmission of these infectious diseases.

The germ theory of infectious disease was formulated during the second half of the 19th century. In the absence of specific treatment, isolation became the principle strategy to prevent the transmission of contagious disease. The Ontario Public Health Act in 1884 provided for the expropriation of land for isolation hospitals and required separate facilities for smallpox. Kingston established a Board of Health and created high standards of quarantine with a freestanding isolation hospital and the isolation of contagious disease in the home.