Tuberculosis is a lung infection caused by a bacterium called Mycobacterium tuberculosis. Tuberculosis (abbreviated as TB) mostly affects the lungs, but it can also affect other parts of the body such as the spine, brain, or kidneys.

Types of Tuberculosis

Not everyone infected with the TB bacterium becomes sick. As a result, two TB-related conditions exist: Latent TB infection and Active TB infection.

Latent TB: This means the TB bacterium is present in the body, but the immune system is fighting to keep it from spreading. Latent TB has no symptoms, and the person is not contagious. However, the infection can turn into active TB at any time, so it is important to start treatment immediately.

Active TB: A latent TB infection turns into active TB when the body’s immune system cannot stop the bacterium from multiplying. Active TB makes a person sick, and a person becomes contagious. 90% percent of active TB cases in adults come from a latent TB infection.


TB is transmitted through tiny droplets in the air. When a person with an active TB infection in the lungs or throat coughs or speaks, TB bacterium can get into the air, and can infect anyone who breathes them in.

Tuberculosis bacterium do not survive on surfaces. Therefore, you can’t get TB from shaking hands with someone, or by sharing their food or drink.


Latent tuberculosis has no symptoms

Active tuberculosis can show various symptoms. While symptoms of active TB are mainly associated with the respiratory system, there may be other symptoms depending on where the TB bacteria is growing.

Symptoms of TB in the lungs include:

• Cough lasting more than 3 weeks
• Coughing up blood or sputum
• Chest pain
• Evening rise of temperature (66% of cases)

General TB symptoms include:

• Fatigue
• Fever
• Chills
• Night sweats
• Appetite loss and weight Loss

In addition to general symptoms, when TB spreads to other organs, symptoms can include:

• Kidneys: Blood in urine and loss of kidney function
• Spine: Back pain and stiffness, muscle spasms, and irregularity of the spine
• Brain: Nausea and vomiting, confusion and loss of consciousness

Tuberculosis Testing

SCREENING TESTS: Screening is testing that looks for a problem when there are no symptoms present. For tuberculosis, screening is used to check high-risk people for latent. TB infections. A person should get screened for tuberculosis if they have experienced a contact history, for example:

• Have spent time with someone who has or is at risk of TB
• Have spent time in a country with high rates of TB
• Work in an environment where TB may be present

The two tests used for TB screening are:

Skin Test (also known as the Mantoux PPD test): A small amount of fluid is injected under the skin of the arm, and the size of the swelling is measured after 2-3 days to see whether it is positive or negative.

Blood Test (also known as IGRA TB Test): This blood test for TB, like the TB skin test, is used to screen for a latent TB infection.

Both tests can determine whether the body’s immune system has had any contact with a TB bacterium in the past. However, they cannot determine whether an infection is latent or active.

DIAGNOSTIC TESTS: If a person has a positive skin or blood test for latent TB, various diagnostic tests may be carried out to determine whether the disease is latent or active. These include:

Chest X-ray: A chest x-ray may be done by the doctor to look for specific changes in the lungs.

AFB Testing: AFB testing can be used to detect many types of acid-fast bacilli (AFB) but is mostly done to identify an active TB infection.

An AFB smear is a microscopic examination of a specimen to detect acid-fast bacilli. An AFB smear is confirmed by an AFB culture.

Spread and Prevention

If one is infected with TB they must take the necessary precautions to prevent the spread to others:

• In case of a latent infection, one must promptly start taking medication, so it doesn’t
become active and contagious
• If one has active TB, they must limit their contact with other people, and wear a
surgical mask covering the mouth when around others

Treatment for any kind of TB infection requires taking medicines for several months. It is important to finish taking all medications, even when one feels better. If not, the bacteria can become resistant to the drugs, and the person can relapse, requiring a longer recovery period

TB in Pakistan

TB is highly epidemic in Pakistan. According to the latest WHO estimations it is ranked fifth among TB high-burden countries worldwide.

In many countries, infants are vaccinated with the Bacille Calmette-Guerin (BCG) vaccine. The BCG vaccine was introduced in Pakistan as part of the EPI Program in 1978 to protect children against different childhood diseases.

Pakistan also has the fourth highest prevalence of multidrug-resistant TB globally. The reasons for emergence of drug resistant TB in Pakistan are: delays in diagnosis, unsupervised and inadequate drug regimens, poor follow-up and lack of social support programs