One-third of the world’s burden of tuberculosis (TB), or about 4.9 million prevalent cases, is found in the World Health Organization (WHO) South-East Asia Region.
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Text from from WHO
What Is Tuberculosis?
Tuberculosis, commonly known as TB, is a bacterial infection that can spread through the lymph nodes and bloodstream to any organ in your body. It is most often found in the lungs. Most people who are exposed to TB never develop symptoms because the bacteria can live in an inactive form in the body. But if the immune system weakens, such as in people with HIV or elderly adults, TB bacteria can become active. In their active state, TB bacteria cause death of tissue in the organs they infect. Active TB disease can be fatal if left untreated.
Because the bacteria that cause tuberculosis are transmitted through the air, the disease can be contagious. Infection is most likely to occur if you are exposed to someone with TB on a day-to-day basis, such as by living or working in close quarters with someone who has the active disease. Even then, because the bacteria generally stay latent (inactive) after they invade the body, only a small number of people infected with TB will ever have the active disease. The remaining will have what’s called latent TB infection — they show no signs of infection and won’t be able to spread the disease to others, unless their disease becomes active.
Because these latent infections can eventually become active, even people without symptoms should receive medical treatment. Medication can help get rid of the inactive bacteria before they become active.
TB was once a widespread disease. It was virtually wiped out with the help of antibiotics developed in the 1950s, but the disease has resurfaced in potent new forms — multidrug-resistant TB and extensively drug-resistant TB. Today, these new and dangerous forms of the disease — resistant to some of the commonly used drug treatments — have created a public health crisis in many large cities worldwide. If you have TB — in its active or latent state — you must seek medical treatment.
All cases of TB are passed from person to person via droplets. When someone with TB infection coughs, sneezes, or talks, tiny droplets of saliva or mucus are expelled into the air, which can be inhaled by another person.
- Once infectious particles reach the alveoli (small saclike structures in the air spaces in the lungs), another cell, called the macrophage, engulfs the TB bacteria.
- Then the bacteria are transmitted to the lymphatic system and bloodstream and spread to other organs occurs.
- The bacteria further multiply in organs that have high oxygen pressures, such as the upper lobes of the lungs, the kidneys, bone marrow, and meninges — themembrane-like coverings of the brain and spinal cord.
- When the bacteria cause clinically detectable disease, you have TB.
- People who have inhaled the TB bacteria, but in whom the disease is controlled, are referred to as infected. Their immune system has walled off the organism in an inflammatory focus known as a granuloma. They have no symptoms, frequently have a positive skin test for TB, yet cannot transmit the disease to others. This is referred to as latent tuberculosis infection or LTBI.
- Risk factors for TB include the following:
- HIV infection,
- low socioeconomic status,
- crowded living conditions,
- diseases that weaken the immune system,
- migration from a country with a high number of cases,
- and health-care workers.
Tuberculosis Symptoms and Signs
You may not notice any symptoms of illness until the disease is quite advanced. Even then thesymptoms — loss of weight, loss of energy, poor appetite, fever, a productive cough, and night sweats — might easily be blamed on another disease.
- Only about 10% of people infected withM. tuberculosis ever develop tuberculosis disease. Many of those who suffer TB do so in the first few years following infection. However, the bacillus may lie dormant in the body for decades.
- Although most initial infections have no symptoms and people overcome them, they may develop fever, dry cough, and abnormalities that may be seen on achest X-ray.
- This is called primary pulmonary tuberculosis.
- Pulmonary tuberculosis frequently goes away by itself, but in more than half of cases, the disease can return.
- Tuberculous pleuritis may occur in some people who have the lung disease from tuberculosis.
- The pleural disease occurs from the rupture of a diseased area into the pleural space, the space between the lung and the lining of the chest and abdominal cavities.
- These people have a nonproductive cough, chest pain, and fever. The disease may go away and then come back at a later date.
- In a minority of people with weakened immune systems, TB bacteria may spread through their blood to various parts of the body.
- This is called miliary tuberculosis and produces fever, weakness, loss of appetite, and weight loss.
- Cough and difficulty breathing are less common.
- Generally, return of dormant tuberculosis infection occurs in the upper lungs. Symptoms include
- common cough with a progressive increase in production of mucus and
- coughing up blood.
- Other symptoms include the following:
- loss of appetite,
- weight loss, and
- night sweats.
- Some people may develop tuberculosis in an organ other than their lungs. About a quarter of these people usually had known TB with inadequate treatment. The most common sites include the following:
- lymph nodes,
- genitourinary tract,
- bone and joint sites,
- meninges, and
- the lining covering the outside of the gastrointestinal tract.
When to Seek Medical Care
If someone among your family or close associates is found to be sick with active TB, you should see your doctor and be tested for tuberculosis.
- The dangerous contact time is before treatment. However, once treatment with drugs starts, the sick person is noncontagious within a few weeks.
- If you develop any side effects from medications prescribed to treat tuberculosis — such as itching, change in color of skin, tiredness, visual changes, or excessive fatigue — call your doctor immediately.
The doctor will complete the following tests to diagnose tuberculosis. You may not be hospitalized for either the initial tests or the beginning of treatment.
- Chest X-ray: The most common diagnostic test that leads to the suspicion of infection is a chest X-ray.
- In primary TB, an X-ray will show an abnormality in the mid and lower lung fields, and lymph nodes may be enlarged.
- Reactivated TB bacteria usually infiltrate the upper lobes of the lungs.
- Miliary tuberculosis exhibits diffuse nodules at different locations in the body.
- The Mantoux skin test also known as a tuberculin skin test (TST or PPD test): This test helps identify people infected with M. tuberculosis but who have no symptoms. A doctor must read the test.
- The doctor will inject 5 units of purified protein derivative (PPD) into your skin. If a raised bump of more than 5 mm (0.2 in) appears at the site 48 hours later, the test may be positive.
- This test can often indicate disease when there is none (false positive). Also, it can show no disease when you may in fact have TB (false negative).
- QuantiFERON-TB Gold test: This is a blood test that is an aid in the diagnosis of TB. This test can help detect active and latent tuberculosis. The body responds to the presence of the tuberculosis bacteria. By special techniques, the patient’s blood is incubated with proteins from TB bacteria. If the bacteria is in the patient, the immune cells in the blood sample respond to these proteins with the production of a substance called interferon-gamma (IFN-gamma). This substance is detected by the test. If someone had a prior BCG vaccination (a vaccine against TB given in some countries but not the U.S.) and a positive skin test due to this, the QuantiFERON-TB Gold test will not detect any IFN-gamma.
- Sputum testing: Sputum testing for acid-fast bacilli is the only test that confirms a TB diagnosis. If sputum (the mucus you cough up) is available, or can be induced, a lab test may give 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 for growth of mycobacteria to confirm the diagnosis.
- It may take one to three weeks to detect growth in a culture, but eight to 12 weeks to be certain of the diagnosis.
Tuberculosis (TB) Treatment
Today, doctors treat most people with TB outside the hospital. Gone are the days of going to the mountains for long periods of bed rest. Doctors seldom use surgery.
- Doctors will prescribe several special medications that you must take for six to nine months.
- Standard therapy for active TB consists of a six-month regimen:
- two months with Rifater (isoniazid,rifampin, and pyrazinamide);
- four months of isoniazid and rifampin(Rifamate, Rimactane);
- and ethambutol (Myambutol) or streptomycin added until your drug sensitivity is known (from the results of bacterial cultures).
- Treatment takes that long because the disease organisms grow very slowly and, unfortunately, also die very slowly. (Mycobacterium tuberculosis is a very slow-growing organism and may take up to six weeks to grow in a culture media.)
- Doctors use multiple drugs to reduce the likelihood of resistant organisms emerging.
- Often the drugs will be changed or chosen based on the laboratory results.
- If doctors doubt that you are taking your medicine, they may have you come to the office for doses. Prescribing doses twice a week helps assure compliance.
- The most common cause of treatment failure is people’s failure to comply with the medical regimen. This may lead to the emergence of drug-resistant organisms. You must take your medications as directed, even if you are feeling better.
- Another important aspect of tuberculosis treatment is public health. This is an area of community health for which mandated treatment can occur. In some cases, the local health department will supervise administration of the medication for the entire course of therapy.
- Doctors likely will contact or trace your relatives and friends.
- Your relatives and friends may need to undergo appropriate skin tests and chest X-rays
- Treatment to prevent active TB from developing in a person with a latent tuberculosis infection (LTBI) aims to kill walled-up germs that are doing no damage right now but could break out (activate) years from now.
- If you should be treated to prevent sickness, your doctor usually prescribes a daily dose of isoniazid (also called INH), an inexpensive TB medicine.
- You will take INH for up to a year, with periodic checkups to make sure you are taking it as prescribed and that it is not causing undesirable side effects. In some cases, intolerance or allergic response can mandate an alternative treatment that may go on for 18 months.
- Treatment also can stop the spread of TB in large populations.
- The tuberculosis vaccine, known as bacille Calmette-Guérin (BCG) may prevent the spread of tuberculosis and tuberculous meningitis in children, but the vaccine does not necessarily protect against pulmonary tuberculosis. It can, however, result in a false-positive tuberculin skin test that in many cases can be differentiated by the use of the QuantiFERON-TB Gold test mentioned above.
- Health officials generally recommend the vaccine in countries or communities where the rate of new infection is greater than 1% per year. BCG is not generally recommended for use in the United States because there is a very low risk of tuberculosis infection. It may be considered for very select patients at high risk for tuberculosis and who meet special criteria.
You can expect to keep your job, to stay with your family, and to lead a normal life if you contract tuberculosis. However, you must take your medicine regularly to be sure of a cure and to prevent others from being infected.
- With treatment, your chance of full recovery is very good.
- Without treatment, the disease will progress and lead to disability and death.
A 48-year-old foreign-born woman developed cough, sputum production, and blood-tinged sputum. Sputum staining showed tubercle bacilli. Her chest X-ray showed a cavity-like lesion in right upper lobe of her lung. Click to view larger image.
Doctors treated the same woman with three medications for TB. One month later, she showed significant improvement, as seen by this repeat chest X-ray. Click to view larger image.
Mantoux test is done to identify patients who are infected with the tuberculous infection; they may or may not have the disease. This test is also used as a public-health measure to detect infection in patient’s family and friends. Click to view larger image.
Erythema nodosum is skin condition sometimes seen in tuberculosis when there are spots on the shins, which are painful and red and disappear within a few weeks. Click to view larger image.
Prior to the 1950s, medications were not available for treating tuberculosis. One of the treatments was placing paraffin wax sheets in the chest cavity to stop the infection. This patient had this treatment performed on her. This is of pure historical interest because this treatment is no longer performed.
Countries in Asia continue to suffer from the damaging impacts of infectious disease, including HIV/AIDS, avian influenza, malaria and tuberculosis (TB), which cross national boundaries. Southeast Asia in particular is susceptible to new diseases and drug resistant strains of tuberculosis and malaria. Hunger and vulnerability to hunger also persist in Asia, which is home to nearly two-thirds of the world’s poor. For example, there are approximately 536 million undernourished individuals in Asia, including close to 20% of children under age 5 in Southeast Asia and 40% in South Asia.
USAID helps countries stop the spread of HIV/AIDS by implementing replicable prevention, care and treatment model programs that target most-at-risk populations in Burma, Laos and Thailand. USAID helps Asia-Pacific countries address the spread of TB and multi-drug resistant (MDR) TB by scaling up new diagnostic tools; providing technical assistance for lab systems strengthening; training national and non-governmental staff in MDR-TB and TB case management; and advancing operational research on the implementation of new approaches and tools, especially in border areas. Through the President’s Malaria Initiative (PMI), USAID implements programs to control the development and spread of drug-resistant malaria, through personal protection, rapid and high quality case management, drug quality control and disease surveillance. USAID and the Thai Government have also launched their first ‘trilateral aid’ effort, combining expertise and other resources to reduce multidrug resistant malaria along the Thai/Burma border. Through PMI, six countries in the region have an established surveillance network to monitor anti-malarial drug resistance. USAID builds on accomplishments in the effort to combat avian influenza by strengthening the ability of countries to detect and contain emerging infectious disease—at their source in animal reservoirs—before such pathogens threaten global public health. USAID has also partnered with the Australian Agency for International Development (AusAID) to identify and mitigate emerging infectious disease risk throughout the Mekong region
The Bill & Melinda Gates Foundation has revised its TB vaccines strategy, calling for a “shift to the left” in TB vaccine research and development (R&D). Accordingly, resources will transfer from a limited number of expensive, late-stage phase IIb/III trials to basic discovery, pre-clinical development, and phase I studies to explore a broader range of vaccine concepts. Missing from this shift, however, are plans for ensuring that new vaccines under development will be equitably available to the communities hit hardest by TB.
As the largest funder of TB vaccine R&D globally, any move by the Gates Foundation will ripple across the field. Its new strategy recognizes that only candidates with a high probability of success should enter phase II and III trials, which depend on a rational selection process based on rigorous immunology work on a wider field of candidates in phase I. Focusing resources on earlier stages of R&D will enable the investigation of many vaccine concepts with less financial risk attached to any particular failure.