STOP TUBERCULOSIS!

Tuberculosis, or TB, is an infectious disease caused by Mycobacterium tuberculosis.  Usually the bacteria attack the lungs; however it can affect any part of the body: brain, spine, and kidney. Without the proper treatment, TB disease can be fatal.

Statictics

World Health Organization (WHO) repots that nearly two million deaths from TB and about nine million new cases occur world-wide every year. Among curable infectious diseases TB takes the first place as the cause of death. In 1993 WHO declared tuberculosis a global emergency and world pandemic. Globally TB is one of the three deadliest diseases, along with Aids and malaria.

Every second at least one person in the world is infected by TB. Almost one third of the world’s population has latent or active tuberculosis.

In the USA 10 to 15 million people have latent tuberculosis.

Every year the Centers for Disease Control and Prevention (CDC) reports 12-15 thousands cases of active tuberculosis.

In 2006 there were 644 deaths from TB in the USA (the most recent data available).

Every 10th of infected individuals will get sick with active tuberculosis.

Diabetes and AIDS increase the risk of latent TB infection progressing to active TB disease.

Although the TB rate is declining in the United States, last years the decrease has slowed because of immigration, according to CDC.

In 2008 were registered 12,904 cases of active TB.

TB disease per region of the world (WHS, 2009

1 2 3 4
Africa 2,529 29% 74.0
The Americas 352 4% 5.5
Eastern Mediterranean 565 6% 21.0
Europe 445 5% 7.4
South East Asia 2,993 34% 31.0
Western Pacific 1,927 22% 17.0
Global 8,811 100% 24.0

1 – World region

2 – Number Thousands

3 – % Of Global Total

4 – TB Mortality Per 100,000 Of Population

 

 

 

Overview of the disease

The Father of Medicine Hippocrates described the “phthisis” illness 2000 years ago. Over the centuries tuberculosis has been known as a major scourge of the human species. At the beginning of 20th century TB was called “consumption”, “king’s evil” and “white plague”.  In Europe improvements in public health helped to reduce TB level to the middle of 20th century, when the antibiotic streptomycin was discovered. From this time scientists hoped to exterminate TB globally.

Causative agent of TB is the species of bacteria that is called Mycobacterium tuberculosis complex.

When the mycobacteria reach the lung, it invades to pulmonary alveoli and replicate within the endosomes of alveolar macrophages, creating the primary site of infection.  Dendritic cells (immune cells) pick bacteria to stop the replication, but DCs can transport the bacteria to lymph nodes, then to the bloodstream and spread the infection. All parts of the body are vulnerable to secondary TB, though kidneys, brain, bones and lymph nodes affected by the disease more often then it happened to be with muscles, heart, pancreas, and thyroid.

Immune cells surround the infected macrophages and forms granuloma to prevent dissemination of the mycobacteria. In the center of tubercles the cells death, or necrosis, and tissue destruction develop.

Symptoms and early signs

TB-infected people don’t know about their infection because they don’t have any symptoms and don’t feel sick. The only way to diagnose latent TB infection is special blood and skin tests. People with latent infection do not spread bacteria to others, though as was stated above, every tenth of them will be sick with active TB disease.

Symptoms and early signs of active TB-disease can be the following: chills, fever, and loss of appetite. Symptoms of further TB development are pain in chest and cough as well as sweating at night, weight loss, and total weakness. The speed of TB development depends on the immune system of infected person. Those, whose immune systems are weak, develop TB disease within weeks. Other people may develop the disease later. For example, diabetes increase the risk of TB disease in three times, AIDS increases the disease probability in hundred times. Another risk factors are severe kidney disease, overweight or too low weight, silicosis, some types of cancer and others.

Diagnosis of TB disease

Medical workers use two types of tests that help to detect TB infection – PDD test, or TB skin test, and a QuantiFERON®-TB Gold, or TB blood test.  Positive test result reflects that a patient has been infected with TB bacteria. It does not reveal active from of TB disease. Thus, to see if the patient has TB disease other tests are used: chest radiograph and a sample of phlegm or sputum.

Mantoux tuberculin skin test

Mantoux tuberculin skin test is performed by injecting a small amount of tuberculin into the skin on the underside of the forearm.  After i48 to 72 hours patient has to return, let a trained health care worker measure the swelling and know if the reaction is positive or negative. To make sure that patient has no latent TB infection, he has to repeat skin test 8 to 10 weeks later.

Special TB blood tests

The QuantiFERON®-TB Gold test measures how the immune system responds to the bacteria that cause TB when they are mixed with a small amount of blood.  If the test result is positive, patient has to be tested for active tuberculosis.

Tests for active TB

These tests usually include a chest x-ray and a test of the phlegm. Chest radiograph helps to rule out the possibility of pulmonary TB in a person who has had a positive reaction to a TST or special TB blood test. The test of the phlegm for the presence of tuberculosis bacteria culture confirms the diagnosis of TB disease.

Treatment

First the isolate of mycobacterium tuberculosis should be tested for drug resistance. Drug resistant patterns of bacteria cannot be killed with usual medicine. It is important to identify drug resistance as early as possible. In most cases TB can be treated with the correct medicines for the right amount of time.

Usually the treatment of TB takes the half of a year or more. Combination of different antibiotics can better kill bacteria and prevent them to become drug-resistant. Moreover, TB-infected patient needs regime, fresh air and food rich for vitamins.  Treatment for Latent TB Infection (LTBI)

TB-infected people have non-active TB germs in their bodies, but they do not have symptoms of disease, and they cannot spread the germs to others. To prevent the future development of disease, they are often treated with one of the usual drugs, especially isoniazid. The treatment lasts for near nine months. During this time INH kills the TB bacteria in the body. Some categories of patients need longer treatment, for example, children.

Treatment for TB Disease

Active disease produces a great quantity of bacteria in the body. That is why treatment can take no less then six months and up to one year. It is very important to finish the treatment though the patient can feel better long before the end of the treatment. If the medicament treatment is not finished, a person can be sick again because the germs are still alive in his body. Moreover, such germs can become drug-resistant and thus disease will demand more long and expensive further treatment.

Secondary or tertiary health promotion strategies

Preventing Tuberculosis: An Overview

In the United States try to use early diagnose to identify the infected people before latent infection progress into active tuberculosis.  Infected people can be cured before they become contagious. Anyone who contacted with TB-infected person should be tested for latent tuberculosis.

TB is especially dangerous for people with HIV infection, children, and aged people.  In the case of TB infection these categories of patients need medicine right away to keep from developing an active case.

Hospitals and clinics use ultraviolet light to sterilize the air, special filters, respirators, and masks to prevent TB transmission.

The BCG Vaccine as Part of Tuberculosis Prevention

To prevent the spread of TB in some parts of the world (especially some Asian countries and Russian Federation), infants should receive a Bacille Calmette Guerin vaccine.  This vaccine is made from a live, but weakened bacterium similar to tuberculosis bacteria (Mycobacterium tuberculosis). Vaccination prevents the spread of TB bacteria within the body and prevents the disease development. However, this vaccine has some drawback. Bacille Calmette Guerin does not take effect for adults and can be used for infants only. In addition, the skit TB test can show positive result after vaccination. That why U.S. health experts do not recommend BCG vaccination for general use in this country.

 

Prevention program of WHO

“Primary prevention through public health action can be enormously effective in reducing the burden of human suffering and the cost of treating disease. From 1900 to 1940, the nation’s public health efforts achieved a 97% reduction in the death rate for typhoid fever; 97% for diphtheria; 92% for infectious diarrhea; 91% for measles, scarlet fever, and whooping cough; and 77% for tuberculosis.” (Winslow, 1944)

Globally, WHO has developed a new six point Stop TB Strategy.

“1. Pursue high-quality DOTS expansion and enhancement

2. Address TB-HIV, MDR-TB, and the needs of poor and vulnerable populations

3. Contribute to health system strengthening based on primary health care

4. Engage all care providers

5. Empower people with TB, and communities through partnership

6. Enable and promote research.” (WHO, 2009)

 

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