Tuberculosis

Tuberculosis (TB) has become a threat. It is second only to HIV as the prominent infectious killer of adults throughout the world. It is an infectious disease caused by bacteria known as Mycobacterium tuberculosis. According to the estimation of WHO, nearly 2 billion people, i.e. one third of world’s population are infected with these bacteria and new infections crop up- at the rate of one per second. Tuberculosis generally affects the lungs but can also involve other parts of the body. It spreads through the air as people having the disease cough, sneeze, or spit. This infectious disease has plagued humans since the Neolithic age.

Physicians in ancient Greece called this illness \”phthisis\” to reflect its fatal character. During the 17th and 18th centuries, TB brought about up to 25% of all deaths in Europe. Recently, tuberculosis has been termed \”consumption”. Robert Koch secluded the tubercle bacillus in 1882 and proved TB as a transmittable disease and got Noble Prize. In the 19th century, patients were kept isolated in sanatoria and offered treatments that include injecting air into the chest cavity. Doctors also attempted to reduce lung size by surgery called thoracoplasty. During the first half of the 20th century, there was no effective treatment available. Streptomycin, the first antibiotic to combat TB, was introduced in 1946, and isoniazid (Laniazid, Nydrazid) became accessible in 1952. The number of people who become sick with tuberculosis each year is stable or falling worldwide but, because of the rise of population, the absolute number of new cases is still mounting. In 2007 there were evident of an estimated 3.7 million chronic active cases, 9.3 million new cases, and 1.8 million deaths, most of them in developing countries.

There are two types of TB:

TB infection: In this kind of infection bacteria remain present but do not make you sick or contagious; you are not able to spread the disease. TB infection is also termed as latent TB or inactive one.

Active TB: In this type the bacteria remain present causing symptoms. This makes you able to transmit the disease.

How does a person get infected?

A person can become infected with tuberculosis bacteria on inhaling microscopic particles of infected sputum from the air. The bacteria get into the air as person with tuberculosis lung infection coughs, sneezes, shouts, or spits (which is common in some cultures). People close to the infected person can then possibly breathe the bacteria into their lungs. You don\’t get TB only by touching the clothes or shaking the hands of an infected person. Tuberculosis is transmitted mainly from person to person by breathing contaminated air during close contact.

There is a form of uncommon tuberculosis, transmitted by drinking unpasteurized milk. Related bacteria, called Mycobacterium bovis, cause this type of TB. Earlier, this type of bacteria was a key cause of TB in children, but now it rarely causes TB as most milk is now pasteurized that means milk undergoes a heating process in order to dstroy the bacteria.

What are the symptoms of tuberculosis?

The symptoms of active TB infection comprise:

Cough that lasting for 3 weeks or longer, that can bring up blood
Chest pain
Fever
Fatigue
Unintentional weight loss
Loss of appetite
Chills and night sweats

Although most preliminary infections show no symptoms and people overcome them, they may have fever, dry cough, and abnormalities detected on a chest X-ray. This is called primary pulmonary tuberculosis which often goes away by itself, but in 50%-60% of cases, the disease may recur.

Tuberculous pleuritis may occur in 10% of people suffering from the lung disease owing to tuberculosis. The pleural disease comes out of the rupture of a diseased area into the pleural space (the space between the lung and the lining of the abdominal cavity). These people experience a nonproductive cough, chest pain, and fever. The disease may go away and then come back afterwards.

In marginal people with weak immune systems, TB bacteria may spread through their blood to various parts of the body causing military tuberculosis and generates fever, weakness, loss of appetite, and weight loss.

Generally, return of dormant tuberculosis infection affects the upper lungs showing similar symptoms as before.

About 15% of people may suffer from tuberculosis in an organ rather than their lungs. About 25% of these people usually had known TB with poor treatment. The most common sites include the following:

Lymph nodes
Genitourinary tract
Bone and joint sites
Meninges
The lining covering the outside of the gastrointestinal tract

Exam & Test

The most commonly used method to diagnose tuberculosis is the PPD skin test. A PPD skin test is also known as Montaux test. A positive PPD indicates that you have been exposed to a tuberculosis patient and you have been infected with the bacteria that develop the disease.

If your PPD skin test is positive, you will recommended to have a chest X-ray and a physical exam to find out if you have active TB and are presently contagious and able to transmit the disease to other people.

It usually requires only a few days to determine whether you\’re contagious. Most of the time people with a positive skin test are not contagious.

QuantiFERON-TB Gold test:
This is a blood test that helps the diagnosis of TB. This test can help identify active and suppressed tuberculosis. The body responds to the presence of the tuberculosis bacteria in this test. Following special techniques, the patient\’s blood is incubated with proteins from TB bacteria. If the bacteria remain in the patient, the immune cells present in the blood sample react to these proteins and produces a substance called interferon-gamma (IFN-gamma).

Sputum testing:
Sputum testing for acid-fast bacilli is the only test to confirm a TB diagnosis. If sputum (the mucus you cough up) is available, or can be induced, a lab test may provide a positive result in up to 30% of people with active disease.

Sputum or other bodily secretions such as from your stomach or lung fluid can be cultured to detect growth of mycobacterium to confirm the diagnosis.

It may require one to three weeks in order to detect growth in a culture, but eight to twelve weeks needs to be certain of the diagnosis.

If I have a positive PPD test, do I have tuberculosis?

A person can get infected with the bacteria causing tuberculosis but not necessarily have active tuberculosis. Many people get infected with the bacteria that develop tuberculosis, but only a few of these people (about 10%) go on to have active TB.

Healthy people infected with the tuberculosis bacteria often succeed to defend the infection and do not develop active TB. The bacteria are actually inactive in their lungs. If the body is not able to fight the infection and the bacteria continue to grow, active tuberculosis grows.

Treatment

Doctors will prescribe few special medications that you must consume for 6 to 9 months. The 2 antibiotics that are most commonly used include rifampicin and isoniazid. The DOTS or Directly Observed Treatment Short-course strategy of tuberculosis treatment recommended by WHO was dependant on clinical trials done in the 1970s by Tuberculosis Research Centre, Chennai, India. Drug-resistant TB is a public health issue in many developing countries, as treatment takes much time and needs more expensive drugs.

Immunizations

Bacille Calmette Guérin, also known as BCG, is a vaccine given in many parts of the world to give protection against TB. It is a derivative of an atypical Mycobacterium but offers protection from budding active tuberculosis, especially in infants and children. This vaccination is believed to be imperative in parts of the world where TB is quite prevalent.

Presently several new vaccines are being developed to prevent TB infection. The first recombinant tuberculosis vaccine rBCG30, went for clinical trials in the United States in 2004, sponsored by the National Institute of Allergy and Infectious Diseases. A very promising TB vaccine, MVA85A, is at present in phase II trials in South Africa by a group conducted by Oxford University. It is based on a genetically modified vaccine virus.

Before disposing off the sputum, it should be boiled.Don’t spit here and there.
Immediately consult a physician and get yourself examined thoroughly.

Take medicines as prescribed.Don’t get scared or hide your disease if you observe any of the symptoms of TB.

DOs	DON’Ts
Cover your face while coughing or sneezing.	Don’t cough or sneeze without covering your face.