**4. Epidemiology of TB**

TB infection is one of the most common infections in the world. It is estimated that 30-60% of adults in developing countries have TB infection. Annually about 8-10 million people develop TB disease and 2-3 million people die of the disease. TB disease is the leading cause of death due to infectious disease around the world 24, 25. When the health department learns about a new case of TB, it should take steps to ensure that the person receives appropriate treatment. Is very important that the health authorities should also start a contact investigation, this means interviewing a person who has TB disease to determinate

Infection for *Mycobacterium tuberculosis* and

**5. Diagnosis of tuberculosis** 

well as in countries with increasing prevalence of HIV/AIDS 32-34 .

diagnostic for TB disease. Tuberculin skin testing useful for 29:

To examine person who has symptoms of TB.

**5.1 Chest radiography**  The chest radiography is for:

superior segments of lower lobe.

Nontuberculous Mycobacteria in the HIV/AIDS Patients 7

*tuberculosis* strain that is resistant to at least rifampicin and isoniazid among the first-line antitubercular drugs (MDR-TB) in addition to resistance to any fluroquinolones and at least one of three second-line drugs, namely amikacin, kanamycin and/or capreomycin. Current studies have described XDR-TB strains from all continents. Worldwide prevalence of XDR-TB is estimated in 6.6% in all the studied countries among MDR-TB strains. The emergence of XDR-TB strains is a reflection of poor tuberculosis management, and controlling its emergence constitutes an urgent global health reality and a challenge to tuberculosis control activities in all parts of the world, especially in developing countries and those lacking resources and as

The systemic symptom of Tuberculosis include fever, chills, night sweats, appetite loss, weigh loss, and easy fatigability, the symptoms of pulmonary TB are productive and prolonged cough (>14-21 week) , chest pain and in some case the patient present hemoptysis. It is important to ask persons suspected of having tuberculosis about their history of TB exposure, infection, or disease. The clinicians may also contact the local health department for information about whether a patient has received tuberculosis treatment in the past, if the drug regimen was inadequate or if the patient may did not adhere to therapy, this disease may recur and may be drug resistant. Also is important to consider demographic factors; country of origin, age, ethnic or racial group and occupation, this factors may increase the patient's risk for exposure to TB or drug-resistant TB disease. Clinicians should determinate whether the patient has medical conditions, especially HIV infection, because this infection increases the risk for TB disease. All patients who do not know their current HIV status should be referred for HIV counseling and testing 26, 27. The tuberculin skin test and the chest radiography, are two probes that help in the

 To examine a person who is not ill but may be infected with *Mycobacterium tuberculosis,*  such as a person who has been exposed to someone who has TB. This test is the only way to diagnose tuberculosis infection before it has progressed to tuberculosis disease. To determine how many people in group are infected with *Mycobacterium tuberculosis.*

A negative reaction to the tuberculin skin test does not exclude the diagnosis of TB, especially for patients with severe TB illness or infection with HIV. Some persons may not react to the tuberculin skin test if they are tested too soon after being exposed to the infection. Generally it takes 2-10 week after infection for a person to develop an immune response to tuberculin. In children younger than 6 months of age may not react to the

To detect abnormalities often seen in apical or posterior segments of upper lobe or

 To detect atypical images in immunosuppressed persons an in HIV-positive persons. In HIV-infected persons, pulmonary TB may appear in the chets radiograph. For example; TB disease may cause infiltrates without cavities in any lung zone, or it may cause

tuberculin skin test because their immune systems are not yet fully developed 32.

who may have been exposed to TB, this person are screened for TB infection and disease 8, 26- 28.

In order to the decrease in the number of TB cases reported annually is very important to comply three factors 29:


In the control of TB disease is also important to know the Groups at High Risk for TB 29, 30: People at Higher Risk for Exposure or Infection:


People at Higher Risk for TB disease:


Infection with HIV makes people susceptible to rapidly progressive tuberculosis; over 10 millions peoples are infected with both HIV and *Mycobacterium tuberculosis* <sup>8</sup>*.* 

TB in Children:

The occurrence of TB infection and disease in children provide important information about the spread of TB in homes and communities. When a child has TB infection or disease is important to learn if 29-31 :


#### **4.1 Drug-resistant tuberculosis**

Drug-resistant TB is transmitted in the same way as drug-susceptible TB. The earlier outbreaks of multidrugs-resistant (MDR) TB support the findings that drug-resistant TB is no less infectious than drug-susceptible TB, although prolonged periods of infectiousness that often occur in the patients with drug-resistant TB may facililate transmission. Drug resistance was divided in two types; primary resistance and secondary or acquired resistance. Primary resistance develops in persons who are initially infected, with resistant organisms. Second resistance, or acquired resistance develops during TB therapy, either because the patient was treated with an inadequate regimen or because the patient did not take the prescribed regimen appropriately 27, 29, 32. The MDR-TB are resistant to rifampicin and isoniazid drugs. Recently drug-resistant tuberculosis (XDR-TB) is defined as tuberculosis caused by a *Mycobacterium*  *tuberculosis* strain that is resistant to at least rifampicin and isoniazid among the first-line antitubercular drugs (MDR-TB) in addition to resistance to any fluroquinolones and at least one of three second-line drugs, namely amikacin, kanamycin and/or capreomycin. Current studies have described XDR-TB strains from all continents. Worldwide prevalence of XDR-TB is estimated in 6.6% in all the studied countries among MDR-TB strains. The emergence of XDR-TB strains is a reflection of poor tuberculosis management, and controlling its emergence constitutes an urgent global health reality and a challenge to tuberculosis control activities in all parts of the world, especially in developing countries and those lacking resources and as well as in countries with increasing prevalence of HIV/AIDS 32-34 .
