Tuberculosis: Causes, Types, Signs & Symptoms, Risk Factors, Diagnose, Treatment and Prevent

What is Tuberculosis?

Tuberculosis (TB) is a chronic infectious disease, caused by bacteria-Mycobacterium tuberculosis. Tuberculosis generally affects lungs; however it may involve any organ in the human body. Earlier due to lack of proper treatment, patient used to waste away, therefore tuberculosis was known as “consumption”.

It can affect almost anybody irrespective of age or sex, but the high-risk group includes:

  • Homeless and poor people
  • Immigrants
  • People living with active TB patients

Today the complete treatment of the disease is possible with the use of antibiotics.

What are the Types of Tuberculosis?

Broadly speaking tuberculosis can be of two types – active and inactive tuberculosis. It can also be classified depending upon the organ involved, like intestinal TB, spine TB, TB of uterus, etc.  

There are two main types of tuberculosis:

Active Tuberculosis

In this type of tuberculosis the bacteria are active in the body. Illness occurs due to the inability of the immune system to cope with the invading organisms. Patients’ sneezing or coughing transmits the disease.

Inactive Tuberculosis

It is also known as latent tuberculosis. An individual is said to have latent TB, when the invading bacteria are destroyed by the immune system of the person. Such individuals neither have any symptoms of tuberculosis nor spread the infection to other healthy people.

Other important types of TB are:

  • Intestinal Tuberculosis: TB of the intestines
  • TB of Spine: Tuberculosis of spinal cord
  • TB of Uterus: Tuberculosis of uterus is an important cause of infertility
  • Bone Marrow TB:  Tuberculosis of bone marrow of long bones

What are the Causes of Tuberculosis?

Tuberculosis is caused by inhaling the bacteria and not by shaking hands with the affected person.  The bacterium is released in the surroundings by coughing, sneezing, shouting or spitting, etc.  

What are the Signs and Symptoms of Tuberculosis?

An individual may be infected by tuberculosis if he/she comes in contact with the bacterium released via coughing, sneezing or spitting by a person affected with lung tuberculosis.

Some of the common symptoms are chest pain, coughing, fatigue, loss of weight, etc.

  • Cough for more than 2-3 weeks
  • Chills
  • Chest pain
  • Loss of appetite
  • Fatigue
  • Night sweating
  • Difficulty and pain in breathing
  • Breath shortness
  • Mild fever
  • Weight loss
  • Tiredness

What are the Risk Factors of Tuberculosis?

Tuberculosis is a serious health disorder. The susceptible individuals are alcoholics, diabetics, HIV infected people, etc.  

Important Risk Factors of Tuberculosis are as under:

  • Alcoholism
  • Aging
  • Over-crowded places
  • HIV infection
  • Homelessness
  • Health care workers
  • Weakened immunity
  • Use of drugs for curing arthritis
  • Low socio-economic status
  • Migration from one country to another
  • Nursing homes

Screening Tests for Tuberculosis

The screening of Tuberculosis is quite important. Mainly tuberculin skin test and Interferon-Release Assays do it. A major health problem in the developing nations is Tuberculosis.

With surmounting cases of HIV and resistance to anti Tuberculosis drugs, Tuberculosis has become a major health concern.

According to WHO, about 9,400,000 fresh cases of Tuberculosis were diagnosed across the world in 2010. 30% of the diagnosed cases belonged to Africa and 35% in South East Asia.  Tuberculosis led to a death toll of 1,300,000 in 2010. People with weak immunity especially those infected with HIV are more vulnerable to the ailment.

Who should undergo screening for Tuberculosis?

The susceptible individuals are advised to go for the screening test of Tuberculosis. These involve:

  • Individuals who work with Tuberculosis patients
  • HIV patients and other individuals with lowered immunity
  • People dwelling in areas where Tuberculosis is prevalent like Africa, Asia, and Latin America.
  • People dwelling in conditions where the disease spreads easily like Prisons
  • Drug addicts injecting drugs

Which tests are used for screening for Tuberculosis?

The commonly employed tests for screening of Tuberculosis are the tuberculin skin test and Interferon-Release Assays.

Tuberculin Skin Test (TST)

It is also commonly called Mantoux test, Pirquet test or the PPD test. This test involves injecting a small dose of the antigen (tuberculin) in between the layers of skin (intradermally) followed by marking of the area. The area is checked for any swelling or induration after 48-72 hours.

  • Positive test consist of swelling have more than 10 mm. It is seen in patients who are exposed to the Tuberculosis bacteria.
  • A swelling of more than 5 mm is regarded as positive in HIV patients and those with low immunity.
  • False negative reactions may appear in individuals with low immunity and in severe infections.
  • False positive reactions may be seen in individuals with previous BCG vaccination and also with infections occurring due to non-tubercular mycobacteria.

Interferon – Release Assays

They are haematological test used to detect Tuberculosis. By injecting blood of patients incubated with specific proteins of the TB bacteria, interferon is released by the immune cells of the patient. Detection of the interferon forms the basis of this test. Commonly available tests include QuantiFERON-TB Dold, QuantiFERON-TB Gold In-Tube test (QFT-GIT) and T-SPOT.TB test.

In these test false positive reactions due to BCG vaccination or other infections are less liable to be seen. Less frequent visits are needed for these tests and results are obtained within 24 hours.

No skin induration is needed. Skin swellings are quite subjective and may vary with the observer. So, there are fewer chances of errors.

These tests are specific for Tuberculosis and are expensive. However they may not be preferred in children under 5 years.

How to Prevent Tuberculosis?

The preventive measures of tuberculosis include improving immunity, having adequate sleep, etc. If the situation worsens active treatment can be taken.


Strict parameters of ventilation and air filtration are required for effective prevention against tuberculosis.

  • Following are the important preventive measures:
  • Have adequate sleep
  • Boost and strengthen immunity
  • Have adequate diet
  • Use a mask to cover your mouth to prevent inhaling the bacteria
  • BCG vaccine is available, and has proven efficacy in preventing TB
  • INH (Isoniazid) is helpful in preventive the occurrence of TB in people at risk.
  • Try to avoid nutritional imbalance and deficiencies as it weakens immunity. 

Treatment for Tuberculosis

Treatment of Tuberculosis involves administration of following drugs:

  • Antibiotics can be used for treating active TB.
  • Streptomycin injections can be given effective in treating tuberculosis.
  • Application of DOTS approach (Directly Observed Treatment Short Course) involves administration of medicine in the presence of a trained healthcare worker.
  • On failure of medication, surgery of the lungs may be done.

Tuberculosis: Important Facts

  • The mode of transmission of the disease is from person to person. Droplet infection is also responsible for the disease.
  • An individual may have dormant or inactive tuberculosis for years and may not reflect any symptoms.
  • When the individual’s immune system weakens, the dormant or inactive tuberculosis may become evident or reactive.
  • People with diabetes, cancer, HIV or occupations like health care people are the most susceptible individuals.
  • Drug-resistant tuberculosis- It is serious and unsolved health concern particularly in Russia, Africa, Southeast Asia and in prison captivity.
  • The frequency of occurrence of tuberculosis has been increased manifold by the presence of HIV infection.
  • Tuberculosis affects when a person inhales the bacteria from infected sputum. By droplets released in the atmosphere by coughing, sneezing or spitting.
  • Shaking hands do not transmit tuberculosis with an infected person.

Tuberculosis (TB) – FAQs

Some frequently asked questions about tuberculosis screening.

1. When should I see a doctor?

In case you get abnormal result of the above-mentioned tests, you should consult a qualified physician. 

2. What a false negative or a false positive test should infer?

A False positive test implies that the patient is not suffering from the disease but due to any other reason the test is positive. Similarly a false negative test means that the individual is a sufferer of the disease but due to any other reason the test is negative. 

3. Which of the above mentioned test is best?

The haematological or the blood test should be preferred as they are precise and accurate. However they should not be conducted in children less than 5 years of age.

4. What if my tuberculin test reflects a red area with no induration? Should I consider it positive?

No, swelling or induration is essential for tuberculin test to be positive.

Tuberculosis: Glossary

AIDS– It stands for Acquired Immune Deficiency Syndrome. It is the final stage in the development of HIV disease in which profound immunosuppression predisposes to certain aids-defining infections and other disease of which commonest across the world ion TB. 

BCG– It stands for Bacillus Calmette- Guerin. It is the only vaccine available to prevent the occurrence of tuberculosis. It was developed by French scientist Albert Calmette and Camille Guerin at Institus Pasteur, Lille It is a live attenuated variant of bovine tubercle bacillus.

– It is a process where bacteriological specimens are grown in an incubator.

DOTS– It is the brand name of the WHO’s strategy for control of tuberculosis. Its components are government commitment, diagnosis chiefly by sputum microscopy, availability of efficient drugs, directly administration of drugs to the patient and monitoring of the efficacy of the control activities.


  • Tuberculosis
  • Basic TB Facts (