Tb is a disease which in humans is usually caused by bacteria called mycobacterium tuberculosis (m. Tuberculosis). Tb is an abbreviation of the word tuberculosis and is how people often refer to the disease.
Bovine tb is a disease caused by similar bacteria called mycobacterium bovis (m. Bovis). Bovine tb mainly affects cattle but can also affect humans.
Just a few years ago it was believed that tb was an old disease, and that it was no longer a problem in humans. But now because of such issues as drug resistance and hiv, it has become a major problem again.
Globally, more than 1 in 3 individuals is infected with tb. According to the who, there were 8.8 million incident cases of tb worldwide in 2010, with 1.1 million deaths from tb among hiv-negative persons and an additional 0.35 million deaths from hiv-associated tb. In 2009, almost 10 million children were orphaned as a result of parental deaths caused by tb.
Overall, the who noted the following:
1. Active tb
Active tb is an illness in which the tb bacteria are rapidly multiplying and invading different organs of the body. The typical symptoms of active tb variably include cough, phlegm, chest pain, weakness, weight loss, fever, chills and sweating at night. A person with active pulmonary tb disease may spread tb to others by airborne transmission of infectious particles coughed into the air.
If you are diagnosed with an active tb disease, be prepared to give a careful, detailed history of every person with whom you have had contact. Since the active form may be contagious, these people will need to be tested, as well.
Multi-drug treatment is employed to treat active tb disease. Depending on state or local public health regulations, you may be asked to take your antibiotics under the supervision of your physician or other healthcare professional. This program is called “directly observed therapy” and is designed to prevent abandonment or erratic treatment, which may result in “failure” with continued risk of transmission or acquired resistance of the bacteria to the medications, including the infamous multi-drug resistant tb (mdr-tb).
2. Miliary tb
Miliary tb is a rare form of active disease that occurs when tb bacteria find their way into the bloodstream. In this form, the bacteria quickly spread all over the body in tiny nodules and affect multiple organs at once. This form of tb can be rapidly fatal.
￼Types of tb
1. Cavitary tb
Cavitary tb involves the upper lobes of the lung. The bacteria cause progressive lung destruction by forming cavities, or enlarged air spaces. This type of tb occurs in reactivation disease. The upper lobes of the lung are affected because they are highly oxygenated (an environment in which m. Tuberculosis thrives). Cavitary tb can, rarely, occur soon after primary infection.
Symptoms include productive cough, night sweats, fever, weight loss, and weakness. There may be hemoptysis (coughing up blood). Patients with cavitary tb are highly contagious. Occasionally, disease spreads into the pleural space and causes tb empyema (pus in the pleural fluid).
2. Latent tb infection
Latent tb occurs when a person has the tb bacteria within their body, but the bacteria are present in very small numbers. They are kept under control by the body’s immune system and do not cause any symptoms.
People with latent tb do not feel sick and are not infectious. They cannot pass the bacteria on to other people. In addition they will usually have a normal chest x-ray and a negative sputum test. It is often only known that someone has latent tb because they have had a test, such as the tb skin test.
You are at risk of tb infection if you are around people with active tb disease who are coughing, which releases bacteria into the air. The risk of infection increases for intravenous drug users, healthcare workers, and people who live or work in a homeless shelter, migrant farm camp, prison or jail, or nursing home.
Most people who are infected with the bacteria that cause tb do not develop active disease. The following factors increase the risk that latent disease will develop into active disease:
The mycobacterium tuberculosis bacterium causes tb. It is spread through the air when a person with tb (whose lungs are affected) coughs, sneezes, spits, laughs, or talks.
￼Causes of tuberculosis
Although tuberculosis (tb) is most frequently associated with symptoms involving the lungs—because the disease most often affects the lungs—it can affect any organ of the body. The disease can cause a variety of symptoms. If you have symptoms, your doctor will want to know when they began.
People with latent tb infection (an infection without active disease) have no symptoms.
The usual symptoms of tb include:
The symptoms may be mild and may not seem particularly worrisome to the patient. In other people, the symptoms become chronic and severe.
Other symptoms of active tb disease depend on where in the body the bacteria are growing. If active tb disease is in the lungs (pulmonary tb), the symptoms may include a bad cough, pain in the chest, and coughing up blood. If active tb is outside the lungs (for example, the kidney, spine, brain, or lymph nodes), it is called extrapulmonary tb and has other symptoms, depending on which organs are affected. For example, tuberculosis in the spine may cause back pain or stiffness.
Diagnosis and test
Types of tb test
There are a range of tests to show if you have tb, such as a sputum test, a culture test and x-rays.
A chest x-ray can show damage in your lungs, but you might need further tests to prove you have tb, such as sputum and culture tests or scans.
A lab will use a microscope to look at any sputum (phlegm) that you cough up. If there are tb germs in your sputum, you have tuberculosis of the lungs or throat (pulmonary tb). This test also helps doctors to understand how infectious you may be.
If it is thought that you have tb, but not in your lungs or throat, the doctor may take a biopsy to test for tb. This is a small sample of tissue or fluid taken from the area where the tb is thought to be.
This test uses your sputum or tissue sample to grow any tb bacteria that may be there. It tells doctors how infectious you are and also whether your tb is resistant to any antibiotics. This helps ensure they put you on a combination of drugs that will cure you. As tb culture grows slowly, it may take up to eight weeks to get some of the results.
Treatment and medications
Treatment for active tb
If you have this form of the disease, you’ll need to take a number of antibiotics for 6 to 9 months. These four medications are most commonly used to treat it:
Your doctor may order a test that shows which antibiotics will kill the tb strain. Based on the results, you’ll take three or four medications for 2 months. Afterward, you’ll take two medications for 4 to 7 months.
You’ll probably start to feel better after a few weeks of treatment. But only a doctor can tell you if you’re still contagious. If you’re not, you may be able to go back to your daily routine.
Treatment of latent tb
The treatment of latent tb is considered by many people to be an important part of tb prevention.
It is not recommended that everyone with latent tb infection (ltbi) should have tb treatment. Rather it is recommended that certain “target” groups should receive treatment. The main “target” groups considered by the world health organisation (who) to be most at risk from progressing from latent to active tb include people in low tb burden countries:
Who have certain clinical conditions, or conditions which compromise their immune system, such as people with diabetes, and people with chronic renal failure.
In high tb burden countries the populations that are most strongly recommended for the treatment of latent tb infection are people living with hiv, and children under five who are household contacts of pulmonary tb cases.
Treatment for miliary tb
If you test positive for latent tb infection, your doctor may advise you to take medications to reduce your risk of developing active tuberculosis. The only type of tuberculosis that is contagious is the active variety, when it affects the lungs. So if you can prevent your latent tuberculosis from becoming active, you won’t transmit tuberculosis to anyone else.
Protect your family and friends
In countries where tuberculosis is more common, infants often are vaccinated with bacillus calmette-guerin (bcg) vaccine because it can prevent severe tuberculosis in children. The bcg vaccine isn’t recommended for general use in the united states because it isn’t very effective in adults. Dozens of new tb vaccines are in various stages of development and testing.