The Saskatchewan Lung Association

The Saskatchewan Lung Association (2007) once said about tuberculosis "Over the centuries since Hippocrates, tuberculosis has been known as a major scourge of the human species." During the first half of the 20th Century, TB was called "consumption" or "white plague", and it was the number one killer of Canadians. The historic menace of the "White Plague" prevailed for so many centuries because people had a poor understanding of the disease and poor medical tools with which to fight it. But, what exactly is tuberculosis?

Definition

Tuberculosis (TB), like the common cold, is an airborne virus. Though it appears in various forms, such as in the bone, the most widely known form is pulmonary tuberculosis, which is the infectious type (Wikipedia, 2007).

Risk factors

Anyone of any age, race or nationality can contract TB, but certain factors increase one's risk of catching the disease. These factors include:

Lowered immunity: When one's immune system is healthy, macrophages can often successfully wall off TB bacteria, but one's body can't mount an effective defense if the resistance is low. A number of factors can weaken one's immune system. Having a disease that suppresses immunity, such as HIV/AIDS, diabetes and receiving treatment with corticosteroids, arthritis medications or chemotherapy drugs. Other factors include age, history of substance abuse (alcohol or drug) and malnutrition.

Close contact with someone with infectious TB: In general, one needs to spend an extended period of time with someone with untreated, active TB to become infected. One is most likely to catch the disease from a family member, roommate, friend or co-worker. When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air.

Nationality: People from regions with high rates of TB -- especially Africa, Asia and Latin America, are more likely to develop TB.

Lack of medical care: If a person who is on a low or fixed income, lives in a remote area, has recently immigrated to the United States, or is homeless, may lack access to the medical care needed to diagnose and treat TB.

Living or working in a residential care facility: People who live or work in prisons, immigration centers or nursing homes, anywhere where there is overcrowding and poor ventilation, are all at the risk of catching TB.

Living in a refugee camp or shelter: Weakened by poor nutrition and ill health and living in crowded, unsanitary conditions, refugees are at especially high risk of TB infection.

Health care work: Regular contact with people who are ill increases the chances of exposure to TB bacteria. Wearing a mask and frequent hand washing greatly reduce the risk.

International travel: As people migrate and travel widely, they may expose others or be exposed to TB bacteria.

Incidence

The World Health Organization (WHO, 2007) estimates that the largest number of new TB cases in 2005 occurred in the South-East Asia Region, which accounted for 34% of incident cases globally. However, the estimated incidence rate in sub-Saharan Africa is nearly twice that of the South-East Asia Region, at nearly 350 cases per 100 000 population.

It is estimated that 1.6 million deaths resulted from TB in 2005. Both the highest number of deaths and the highest mortality per capita are in the Africa Region. The TB epidemic in Africa grew rapidly during the 1990s, but this growth has been slowing each year, and incidence rates now appear to have stabilized or begun to fall.

In 2005, estimated per capita TB incidence was stable or falling in all six WHO regions. However, the slow decline in incidence rates per capita is offset by population growth. Consequently, the number of new cases arising each year is still increasing globally and in the WHO regions of Africa, the Eastern Mediterranean and South-East Asia.

ESTIMATED TB INCIDENCE, PREVALENCE AND MORTALITY, 2005

Incidencea Prevalencea TB Mortality

All forms Smear-positiveb

WHO region number (thousands) per 100 000 pop number (thousands) per 100 000 pop number (thousands) per 100 000 pop number (thousands) per 100 000 pop

(% of global total)

Africa 2 529 (29) 343 1 088 147 3 773 511 544 74

The Americas 352 (4) 39 157 18 448 50 49 5.5

Eastern Mediterranean 565 (6) 104 253 47 881 163 112 21

Europe 445 (5) 50 199 23 525 60 66 7.4

South-East Asia 2 993 (34) 181 1 339 81 4 809 290 512 31

Western Pacific 1 927 (22) 110 866 49 3 616 206 295 17

Global 8 811 (100) 136 3 902 60 14 052 217 1 577 24

aIncidence - new cases arising in given period; prevalence - the number of cases which exist in the population at a given point in time.

bSmear-positive cases are those confirmed by smear microscopy, the most infectious cases.

pop indicates population.

Symptoms

Adults with pulmonary TB have chest pain and severe coughs, sometimes with blood in the sputum. Exhaustion, night sweats, fever and weight loss are also symptoms of pulmonary and extra-pulmonary TB. The disease can go undetected though in children who have non-specific symptoms that could be the result of a number of childhood illnesses. They may cough, have a fever or diarrhea for more than a month, have unexplained weight loss, enlarged glands, fits and neck stiffness.

Impact of nutrition and exercise on the prognosis of the disease

Rest and properly graded exercise are important factors in the treatment of tuberculosis. So long as a tuberculosis patient is below normal weight and is running some temperature he/she is much safer at rest, even complete rest in bed, than taking exercise. During the fever stage of his disease absolute rest in bed is really necessary. After he/she gets better and no longer runs a temperature, exercise if taken within proper limits is of value, and under proper direction can be made serviceable to recovery.