Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. These bacteria usually attack on lungs, but TB bacteria can also attack other body organs such as spine, kidney and brain.


By Wajeeha Rafaqat, Dr. Sohail Sajid, Dr. Urfa Bin Tahir, Dr. Aisha Khatoon, Mahvish Rajpot

Tuberculosis (TB) was called “phthisis” in ancient Greece, “tabes” in ancient Rome, and “schachepheth” in ancient Hebrew. In the 1700s, TB was called “the white plague” due to the paleness of the patients. TB was commonly called “consumption” in the 1800s even after Schonlein named it tuberculosis. One important thing thay everyone infection with TB show sign and symptoms or become sick. According to this finding, two conditions exist about TB: latent TB infection and TB disease.


  • Persons with latent TB infection do not feel sick and do not have any symptoms. They are infected with M. tuberculosis, but do not have TB disease. The only sign of TB infection is a positive reaction to the tuberculin skin test or TB blood test. Persons with latent TB infection are not infectious and cannot spread TB infection to others.
  • In some people, TB bacteria overcome the defenses of the immune system and begin to multiply, resulting in the progression from latent TB infection to TB disease. Some people develop TB disease soon after infection, while others develop TB disease later when their immune system becomes weak.

Spread of TB:

This bacteria transmit through the air from one individual to another. Mycobacterium can get into air when a infected person cough, sneez,  or sings. Nearby people in the environment may breath in these infected bacteria and become infected. TB is not transmitted by shaking hands, touching bed clothing or toilet seats, kissing, sharing drink, food and tooth brushes. When an individual breaths in air infected with TB bacteria, the bacteria settle in lungs and begin to grow. From lungs, they can transmit through blood to other body parts such as brain, spine and kidney. After incubation period (3-9 weeks) sign and symptom of TB include fever, fatigue, night sweats, chills, coughing up blood or mucus, chest pain, or pain with breathing or coughing, unintentional weight loss.

Risk factors for TB:

Some individuals develop TB (within weeks) soon after becoming infected before their immunity status can be able to fight TB bacteria. Soem other people may become sick years later on weak or destroyed immune system. Overall, about 5 to 15% of infected people who do not have access to proper medication for latent TB will develop TB disease with severe sign and symptoms at some time in their lives. People with weak immune status especially HIV infected persons are at higher risk of getting TB disease. Generally, people at higher risk for getting TB fall into two categories:

  • People who have been recently infected with TB bacteria (close contacts of a person with infectious TB disease, children less than 5 years of age who have a positive TB test, persons who have immigrated from areas of the world with high rates of TB)
  • People with some medical conditions that weaken their immunity (HIV infection, substance abuse, diabetes, silicosis, mellitus, severe kidney disease, neck and head cancer, low body weight, organ transplants)

TB in Pakistan (national prospect):

National TB control program (NTP) is working for TB free Pakistan by reducing 50% prevalence of TB in overall population by 2025 and achieving Zero TB death. Pakistan ranks 5th amongst the high burden countries in the world. The incidence, prevalence,  and mortality per 100,000 people per year from TB in Pakistan are 276, 348,  and 34 respectively. NTP is revived under Ministry of Health subsequent to declaration of TB as national emergency in Pakistan in 2001 and is currently strives along with National Institutes of Health, Pakistan. National TB Control is parallel program of National Institutes of Health and stands out as one of the public health programs on track towards achievement of MDG targets in 2015. It acts as a collaborating center at the central level for development of strategies and uniform policies facilitating the donor liaison at national and international levels. NTP at this point is implementing Global Fund supported grant through Single Stream Funding (SSF).

Objectives of NTP:

  • To increase the number of notified TB cases from 298,981 in 2013 to at least 420,000 by 2020 while maintaining the treatment success rate at 91%.
  • To reduce, by at least 5% per year by 2020. the prevalence of MDR-TB among TB patients who have never received any TB treatment.
  • To strengthen programmatic and operational management capacity of the TB Control Program while enhancing public sector support for TB control by 2020.

TB in the world (international prospect):

Most of the people who get infected with TB live in low- and middle-income countries, but TB is present all over the world. About half of all people with TB can be found in 8 countries: Bangladesh, India, Indonesia, China, Nigeria, Philippines, Pakistan and South Africa. About one-quarter population of the world’s  is estimated to be infected by TB bacteria. Only 5-10% of these people will fall ill with active TB disease. The rest people have TB infection but are not ill and cannot spread the disease. Both TB infection and disease are curable using proper treatment or antibiotics.

By wajeeha Rafaqat

Microbiologist Epidemiologist