The Twentieth Global Report on Tuberculosis (TB), published by the World Health Organization, is the latest addition of an annual series that began in 1997. The report provides a comprehensive and current estimation of the epidemic, and progress being made in implementing TB prevention, control, care and research at national, regional, and global levels. It uses data reported by more than 200 countries that constitute over 99% of the global TB cases.
Defining Tuberculosis as a Major Global Health Concern
Mycobacterium tuberculosis is the pathogenic bacterium that leaves infected individuals susceptible to developing TB, a condition characterized by respiratory illness and fever which, along with infections of other body systems that TB can leave sufferers prone to, can ultimately lead to death. Approximately one-third of the global population was infected with M. tuberculosis in 2015, and new infections are occurring at a rate of one person per second. However, not all such infections result in the tuberculosis disease, and most infections are not severely symptomatic. In 2007, there were approximately 13.7 million active chronic cases, and in the year 2010 there were around 8.8 million new cases. Approximately 1.45 million deaths from TB were reported, mostly in developing countries, and 350 thousand of those deaths occurred in those individuals who were also infected with Human Immunodeficiency Virus (HIV).
Tuberculosis on the African Continent
In 2007, the country with the highest number of TB incidences relative to populations was Swaziland. It recorded 1,200 cases per every 100,000 people. TB is especially problematic in Africa, with Swaziland, Lesotho, South Africa, Namibia, Djibouti, Mozambique, and Zimbabwe being the only nations on the globe to have rates higher 500 incidences per 100,000 people.
Massive Death Tolls on the Indian Subcontinent
In 2014, India recorded the highest absolute counts, with around 2.2 million new infections. India consequently recorded over 300 thousand deaths from TB complications over 5 years, and economic losses of over $23 billion within the year. TB was the second deadliest disease in India, claiming approximately 63,265 casualties in the year 2011, 61,887 in the year 2012, and around 57,095 in 2013.
Tuberculosis Among Developed Nations
In developed countries, TB is not common, and is mostly seen in specific sectors of urban populations. In the UK, for example, the TB incidence rate was just 15 per 100,000 people in 2007, while the highest incidence rates of tuberculosis (per 100,000 people) in Western Europe were seen in Spain and Portugal, at around 30 cases per 100,000 people in each nation. The rates in China stood at 98 infections per 100,000 people, while they stood at 48 per 100,000 in Brazil. In the US, the overall TB infection rate was even lower still, with four incidences per 100,000 people in 2007, while some Mid-Atlantic and Caribbean island nations have incidences of virtually zero. Unfortunately for Canada, TB is still endemic in many rural areas there, especially in comparison to other developed nations.
The Effect of Age and Season on Susceptibility
It has been reported that the incidence of tuberculosis varies significantly with age. In Africa, TB mostly affects adolescents and youths. But in countries where the disease has moved from high to low, like the United States, TB is primarily an illness of elderly populations or those with otherwise compromised immune systems, such as those suffering from HIV/AIDS. TB infection is typically seasonal, with peaks occurring during summer. The causes of these seasonal patterns remain unclear, but there is a common association with vitamin D deficiencies during winters and subsequent infections during summers.
Building on Past Successes
Efforts to curb this disease are yielding fruits in Europe and other parts of the world. In 2015, TB incidences were still dropping, but most of the biggest strides were actually made during the coming of age of the Industrial Revolution. In fact, deaths significantly dropped from 500 out of 100,000 patients in 1850 to just 50 out of 100,000 patients by the year 1950. During this time, public health improvements were curbing tuberculosis even before the discovery of antibiotics. A large part of this was due to increase public awareness of health and sanitation, which is still an integral component in the prevention of tuberculosis and other communicable diseases today.