Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (MTb). Almost all infection in humans is caused by inhalation of droplet nuclei - infectious particles of aerosolized respiratory secretions coughed up by a person with pulmonary tuberculosis. It may either result in a lifelong silent (latent) infection or in a clinically recognizable disease.
The need for improved detection and treatment of tuberculosis has been significantly increased by the recent outbreaks of multidrug-resistant TB, especially in HIV-infected persons.
The most common disease is pulmonary tuberculosis; however, extrapulmonary cases do occur. In low-incidence areas such as the United States, most TB cases are attributed to endogenous reactivation of latent infection; however, significant outbreaks can occur from exposure to a person with active pulmonary tuberculosis.
Over 26,000 cases of TB were reported in 1991, and an estimated 15 million persons in the United States are infected with tubercle bacilli. Incidence is higher in urban settings, among populations with low socioeconomic status, among racial and ethnic minority groups (particularly Hispanics and African Americans), and in medically underserved areas. The risk of TB is higher for persons living in crowded, confined areas, such as residential drug treatment programs, homeless shelters, nursing homes, correctional institutions, migrant worker camps, and long-term care facilities.
Since 1986, the morbidity from TB has been increasing. The increase has occurred mostly in geographic areas and demographic groups with a high incidence of HIV/AIDS cases. The 1991 data also show:
Twenty-seven percent of cases of active TB occurred in foreign-born persons, compared with 20 percent in 1985. Forty-one percent of these persons had been in the United States less than 5 years.
Seventy-one percent of reported TB cases were in racial and ethnic minorities.
Twenty-three percent of cases occurred in the elderly.
Among children with TB, 86 percent of cases occurred in minority groups. Screening for TB should be provided for any child exposed to a person who is or should be receiving treatment for active TB.
Most persons who are exposed to a person with active TB and become infected do not develop active disease, but rather have latent, asymptomatic infection for long periods of time. Such patients may benefit from preventive therapy with isoniazid.
Active TB is usually the result of reactivation of latent infection. The symptoms of active disease include fatigue, fever, weight loss, cough, pleuritic chest pains, and hemoptysis. TB is, however, a treatable disease. Treatment requires taking multiple anti-TB drugs for at least 6 to 9 months. The length of treatment may vary, especially in HIV-positive persons. Adherence to the appropriate drug regimen and adequate medical followup are required to complete successful treatment.
Although active TB is usually the result of reactivation of latent infection, health care providers need to be aware that with the increasing numbers of cases of active TB, some patients may present with active disease following recent exposure to a person with active tuberculosis. HIV-infected persons are at particular risk for the development of active TB following a recent exposure. Reactivation of latent TB because of the immunosuppression associated with HIV infection, as well as TB following exposure to a person with active TB, occurs more frequently in the HIV-infected person. There may be rapid progression of the TB infection in such an HIV-infected person.
Drug treatment programs funded under the Substance Abuse Prevention and Treatment Block Grant are now required by law to provide tuberculosis services to patients or to ensure that patients receive such services. Section 1924(a) of the ADAMHA Reorganization Act of 1992 (P.L. 102-321) states that
States must require treatment entities receiving funds under grant to make available tuberculosis services to each individual receiving treatment; in the case of an individual denied admission due to lack of capacity, the treatment entity will refer the individual to another provider of tuberculosis services (defined as counseling, testing, treatment).
Transmission of tuberculosis is most effectively reduced by identifying and treating persons with active pulmonary tuberculosis. A full course of isoniazid preventive therapy can reduce the risk of developing active TB in infected persons (i.e., persons with positive skin tests) by more than 90 percent.
Because patients receiving methadone maintenance come to drug treatment centers frequently - often on a daily basis - for extended time periods, methadone maintenance treatment programs are in a unique position to provide daily or twice weekly preventive therapy for the recommended 6- to 12-month period. This preventive service can usually be provided in collaboration with the public health agency.
In general, all persons entering drug treatment programs should have a Mantoux intradermal skin test for tuberculosis.
Persons who have a negative skin test for TB, as well as nonreactive control skin tests, should be considered to be anergic. HIV-infected persons are especially at high risk for the development of TB. Any person who fails to react to the TB skin test as well as the skin tests controls and is, therefore, anergic needs to be carefully evaluated to be certain there is no evidence of active TB and to be tested for HIV if the person's HIV status is unknown.
Persons who have a positive skin test or who have symptoms compatible with TB should be medically evaluated for possible active TB and appropriate treatment or for TB preventive therapy.
Tuberculin skin tests using the Mantoux method should be repeated annually for patients whose initial skin test is negative.
Patients with chronic cough (over 3 weeks duration), fever, and other symptoms should be rapidly evaluated for possible active tuberculosis disease. If active tuberculosis is suspected or confirmed, the client should be immediately placed on multiple anti-TB medication and placed in respiratory isolation if institutionalized.
Persons with close contact to a person with untreated tuberculosis of the lungs or larynx are at greatest risk of acquiring infection.
The treating physician should inform the case manager in the drug treatment program about patients who are being treated for active TB concerning activity restrictions and possible need for isolation methods to ensure compliance, and about precautions for staff. The need to monitor drug adherence and to determine drug efficacy and potential drug toxicity all highlight the importance of monitoring. For short-term treatment programs, treatment needs to be supervised and aftercare should be provided, including followup with a specific provider and case manager.
Medications for TB preventive therapy and treatment may interact with other drugs, such as methadone and disulfiram (Antabuse), thus requiring careful monitoring and possible dosage adjustment. Rifampin (RIF) may interact with either methadone or disulfiram and may require an increase in methadone dosage. Isoniazid (INH) must be given with care to patients on disulfiram, since such patients can have psychotic episodes or ataxia.
All health care personnel should have PPD skin tests every 6 to 12 months and at the time of and 3 months after any exposure to a patient with active, untreated TB. The following testing should be done:
In general, all staff of drug treatment programs should receive a PPD skin test using the Mantoux method when they are first employed.
Staff with initial negative skin tests should be retested every 6 to 12 months.
Staff with positive skin tests should receive a prompt medical evaluation for possible active TB, should be considered for TB preventive therapy, and should be evaluated if symptoms of active TB develop.
Staff reading the results of tuberculin skin tests should be trained in the procedure. Training materials on skin testing produced by the Centers for Disease Control and Prevention (CDC) are available through each State health department TB program. See also the section at the end of this chapter, Role of the Health Department, on assistance that the local or State health department may offer to drug treatment centers in setting up a screening program.
The patient should have the right to refuse screening. However, to protect the safety and health of the other patients and staff, an individual seeking treatment who is thought to have active tuberculosis may be denied admission until it has been medically determined if the patient needs treatment prior to being admitted to the program. A program's drug treatment policies and procedures must be consistent with current local, State, and Federal laws. See section on Access to Treatment in "Legal and Ethical Issues" for further guidance on patients who refuse to be tested.
Local legal guidelines should be consulted for dealing with noncompliant patients who are public health risks, especially given cases of multidrug-resistant TB. (Any patient who is noncompliant with treatment for drug-susceptible or MDR-TB should not be allowed to enter the drug treatment facility; see the following MDR-TB guideline.)
Prompt, correct drug treatment of an active case of TB is essential. For persons with active or suspected tuberculosis, initiation of treatment as an outpatient may be considered if the person is only mildly ill and is able to care for himself or herself at home. For those with complicated illness or unable to care for themselves, hospitalization is indicated. Hospitalization should be strongly considered for persons with MDR-TB, and the decision not to hospitalize such a patient should be made only after consultation with a physician experienced in caring for patients with MDR-TB. Patients in residential drug treatment programs should be hospitalized unless appropriate respiratory isolation can be provided at the facility.
An active case of TB is usually not communicable once the sputum smears are negative for acid-fast bacilli (AFB) and the patient's symptoms, e.g., cough, have improved. The drug susceptibility of any given TB isolate may not be available, however, for 6 to 12 weeks. If there is any concern that the infected person may have resistant tuberculosis, appropriate respiratory isolation, with hospitalization if it is deemed necessary, should be continued until the person has smear-negative sputum samples or until the drug susceptibilities are known. When the drug susceptibilities are available, the therapy must be reevaluated to be certain that the person is on appropriate therapy and that the patient's adherence can be ensured by placing him or her on directly observed therapy.
Programs should develop guidelines and procedures for decreasing transmission of tuberculosis through identification, appropriate isolation, and treatment of persons with infectious TB. For general environmental guidelines, refer to the CDC Guidelines in the Summary Statement in chapter 6; see also chapter 4, "Issues for Treatment Program Administrators." There should be adequate ventilation of living and work areas where persons with possible or proven TB congregate. Persons with known infectious TB should not be allowed to enter the living and work areas of a treatment facility until three sputum specimens have been obtained and are smear negative for AFB.
Sputum induction, sputum collection, and aerosolized pentamidine treatments should be done in areas with correct exhaust. If such areas are not available, sputum collection may be done outside the building. Consideration should be given to placing ultraviolet lights in clinic and residential areas where adequate ventilation and air exchange are not possible.
All new cases of active TB must be reported to local/State health departments. Reporting is obligatory in all States. All suspected cases of TB should also be reported to the health department. Any cases of INH- or multidrug-resistant TB should be promptly reported. Contact tracing of all active TB cases must be implemented. Contact tracing is not required for most persons with only a positive PPD. However, in the case of a child with a positive PPD, an investigation should be undertaken to identify the source case.
Persons with positive skin tests after exposure to MDR-TB should be reported.
All persons with TB and all suspects, contacts, and others at high risk must have medical services made available by local/State health departments; services to screen for and treat TB should be available to such persons regardless of their ability to pay.
Prompt attention should be given to any household where contacts of the infectious cases include children or immunosuppressed persons.
State and local health departments should initiate prompt followup of contacts.
Many persons entering drug treatment programs may have been exposed to TB in the past because of their socioeconomic situation and living conditions. All patients should be screened for tuberculosis on entry into the program; the screening should be done promptly for any person with respiratory problems. It is particularly important to test all injection drug users and persons with HIV infection.
For the asymptomatic person, screening should consist of a Mantoux purified protein derivative (PPD) skin test. For the person with symptoms related to possible active TB, closer clinical followup is necessary.
The Mantoux skin test should be administered to all persons except those with previously documented positive skin tests. A positive skin test indicates prior infection with the tubercle bacillus, but it does not determine whether the person has clinically active tuberculosis.
The HIV status of each person should also be ascertained at the time of entry into the drug treatment program. Any HIV-infected person as well as any person whose HIV status is unknown but who is at risk of HIV infection should have not only the Mantoux skin test but also delayed type hypersensitivity testing with companion anergy testing as part of routine entry screening.
The following persons need prompt and appropriate medical care after the screening for TB:
Any person with a positive PPD
Any HIV-infected person with a positive PPD
Any person with known or suspected active TB
Any HIV-infected person, person at risk for HIV infection, or person whose HIV status is unknown, who has a negative PPD and no reaction to a companion anergy testing. (See the discussion later in this chapter.)
Periodic screening for TB and HIV infection should be continued during and after the drug treatment program. All persons in treatment programs should have, at a minimum, a yearly PPD and HIV test after the initial screening. This screening is an attempt to slow the spread of TB and HIV as well as to provide care to any individual needing it. It should be remembered that a patient with untreated or inadequately treated TB is a significant hazard for both staff and other patients.
A medical history should be obtained from all patients. A tuberculin skin test should be applied unless there is adequate documentation available that the patient had a positive skin test in the past.
Persons with a positive skin test or symptoms suggesting TB should have a chest radiograph and confirmatory microbiological tests, in addition to the tuberculin skin test and medical history. Other tests may be necessary to exclude extrapulmonary TB.
An HIV-infected person, or a person at risk for HIV infection whose HIV status is not known, should have a chest x-ray to screen for tuberculosis if that person has a positive skin test or is anergic. In cases of possible extrapulmonary tuberculosis, additional tests may be necessary to make the diagnosis.
The Mantoux tuberculin skin test is the most sensitive screening test and should be the skin test used. A multiple-puncture test (Tine test) should not be used as a screening test.
The Mantoux technique for the tuberculin skin test requires the intradermal injection of 0.1 ml of purified protein derivative (PPD) tuberculin containing 5 tuberculin units (TU). The skin test must be read after 48 to 72 hours by a person qualified to interpret and record the results.
A person with a previously documented positive PPD should not be retested.
For persons who have received bacillus Calmette-Gurin (BCG) vaccination, a positive tuberculin skin test usually indicates infection with tuberculosis. Such persons should be evaluated for preventive therapy with isoniazid.
The interpretation of a test as positive or negative (a negative test is not necessarily nonsignificant) is dependent on the exposure history and underlying medical condition of each individual tested.
A negative skin test does not rule out tuberculosis disease or infection. The skin test results alone should not be used to exclude the possibility of active TB in persons for whom the diagnosis is being considered.
See table 1 for interpretation of tuberculosis skin test results.
The following points should be considered when interpreting tests for HIV-positive patients:
HIV-positive persons may have a false-negative PPD because of impairment or absence of the delayed type hypersensitivity (DTH) response seen with HIV infection.
The CDC recommends DTH anergy testing at the time of PPD screening in HIV-positive persons at risk for tuberculosis, and in persons of unknown HIV status who are at risk for HIV infection and tuberculosis.
Companion anergy testing should be done using Candida, mumps, or tetanus antigens (two of the three).
Reactivity to any of the antigens implies a "working" immune system. In conjunction with a negative PPD, these results would indicate a true negative or no TB infection. Any reaction with induration to the mumps, tetanus, or Candida skin tests means that the person is not anergic. For the PPD tuberculin skin test, a reaction of less than 5 mm implies that a person is not anergic. At the same time, it is not considered a positive skin test when screening for TB. No reaction to the antigens, including PPD, indicates anergy. Skin testing will not detect latent TB in an anergic person.
The CDC recommends consideration of preventive therapy in HIV-positive persons who are anergic, have negative PPD skin tests and are known contacts of infectious TB patients, or are from groups, such as persons in addiction treatment programs, in which the prevalence of TB infection is 10 percent or more. If the contact has MDR-TB, preventive therapy should be administered to an HIV-infected person. Recommendations for the appropriate preventive therapy for an HIV-positive person exposed to a person with MDR-TB should be made by a physician knowledgeable about this subject and the drug susceptibility of the MDR-TB isolates in that area.
The anergic HIV-positive person should be clinically evaluated for evidence of active tuberculosis. If there is no evidence of active disease, such persons should be given preventive therapy if they have had possible exposure to TB in the past.
The medical history should cover the signs and symptoms of tuberculosis: persistent cough, hemoptysis, weight loss, loss of appetite, fever, chills, night sweats, pleuritic chest pain, or unexplained lymphadenopathy.
If the patient is HIV-positive, there should be a review of risk factors associated with HIV infection.
Known contact with a person with active tuberculosis is a risk factor. Socioeconomic risk factors include residence in a long-term care facility; homelessness; living in a shelter or correctional facility; injection drug use; crack use; immigration from an area endemic for TB, such as Haiti, Africa, Southeast Asia, South and Central America, Caribbean Basin; having moved from an urban setting where possible exposure to TB may have occurred.
At the time of enrollment in a drug treatment program, the following persons should have a chest x-ray:
Persons with a history of a positive PPD
Persons with a positive PPD at screening
Persons with a negative screening PPD whose medical history/physical examination is consistent with possible active tuberculosis infection (e.g., cough of 3 or more weeks duration, pleuritic chest pain, fatigue, weight loss, fever, night sweats, loss of appetite), regardless of the skin test reaction
HIV-infected persons who are anergic (i.e., had a negative PPD and negative controls)
Persons at high risk for HIV infection whose HIV status is unknown and who are anergic (i.e., have a negative screening PPD as well as negative controls)
For persons with a medical history/physical examination and a chest x-ray consistent with possible active tuberculosis, the principal way to diagnose pulmonary tuberculosis is the smear and culture examination of three sputum specimens collected on different days.
A positive sputum culture with Mycobacterium tuberculosis gives a definitive diagnosis of tuberculosis. If a smear is reported to reveal acid-fast bacilli (AFB), a person should be referred for immediate medical care.
The following persons should be medically evaluated for the presence of active TB infection (that is, they should have a medical history/physical examination and a chest x-ray):
Persons with a positive skin test in the following groups, regardless of age, should receive preventive therapy unless there are medical contraindications.
HIV-infected persons (5 mm or greater)
Close contacts of infectious newly diagnosed TB cases (5 mm or greater)
Recent PPD skin test converters (10 mm or greater increase within a 2-year period if less than 35 years old; 15 mm or greater increase for those 35 years and older)
Previously untreated or inadequately treated persons with abnormal chest x-rays (5 mm or greater)
Injection drug users (10 mm or greater)
Persons with medical conditions that increase the risk of developing active TB. (See medical conditions listing in screening section.) (10mm or greater)
Persons with positive skin tests in the following high-risk groups who are less than 35 years of age should receive preventive therapy:
Foreign-born persons from high-prevalence countries (Africa, Southeast Asia, Latin America) (10 mm or greater)
Low-income populations, including low-income minorities at high risk (African Americans, Hispanics, and Native Americans) (10 mm or greater)
Residents of long-term care facilities (including prisons, nursing homes, correctional institutions) (10 mm or greater)
Persons not at high risk for tuberculosis with a PPD 15 mm or greater if they are less than 35 years old
INH preventive therapy should be considered for the anergic HIV-positive patient if he or she has been exposed to TB or is from a population where the prevalence of TB infection is greater than 10 percent.
With no evidence of active TB (after medical history/physical examination and chest x-ray), the person requiring preventive treatment should be treated with isoniazid (INH) unless there are medical contraindications. A full course of preventive therapy (see table 2) reduces the risk of developing active TB in infected persons by up to 90 percent.
Persons with previous INH-associated hepatic disease
Persons with a history of an allergic reaction to INH
Acute liver disease of any etiology; hepatitis B surface antigen (HBsAg) positivity is not a contraindication unless associated with chronic active hepatitis.
INH preventive therapy should be given with special precautions to persons with the following conditions:
Age greater than 35 years (due to toxicity of INH)
Concurrent use of other medications on a long-term basis
Daily use of alcohol or excessive intermittent alcohol consumption
Alcoholism
Persons on disulfiram (Antabuse), who may have psychotic episodes or ataxia if given INH
Diabetes
Pregnancy
Current known chronic liver disease
Presence of peripheral neuropathy
For anyone receiving INH preventive therapy, INH should be discontinued if the liver function tests (LFTs) increase three to five times above normal, consistent with possible drug-induced hepatitis. Persons taking INH should be advised to seek medical attention if they develop any symptoms suggestive of possible hepatitis, such as jaundice, fatigue, weakness, malaise, anorexia, nausea, or vomiting.
For a person unable to tolerate INH, prophylaxis of non-MDR-TB with rifampin (600 mg by mouth daily) may be given for 6 to 12 months.
Monthly monitoring of persons on INH preventive therapy should be done for the following conditions:
Symptoms consistent with those of liver damage or other toxicities: Anorexia, jaundice, fatigue, or weakness lasting greater than 3 days; persistent numbness or tingling in hands or feet. If nausea or vomiting occurs, the patient should promptly stop taking the drug and seek medical care.
Signs of active liver damage: Persistently dark urine, icterus, jaundice, rash, elevated temperature for 3 days or more, abdominal pain or tenderness.
For asymptomatic persons under 35 years of age, a baseline liver function test should be obtained; the liver function test should be repeated periodically, since the drug-using population is at a higher risk for liver disease.
For persons older than 35 years of age, transaminase liver function tests (LFTs) should be done at the initiation of therapy and periodically during the course of therapy. If LFTs are greater than three to five times normal, or the patient has symptoms of hepatitis, INH should be discontinued.
All injection drug users and alcoholics - regardless of age - should have baseline LFTs.
All persons should have yearly PPD skin tests. Any person with a positive PPD who develops symptoms consistent with active TB should have a medical examination and a chest x-ray.
All persons with active TB must be treated; they must have close medical followup while on anti-TB medications and upon completion of therapy. Persons with positive AFB sputum smears or persons presumed to have extrapulmonary TB should be given anti-TB medications prior to TB culture results.
Regardless of the frequency of therapy (whether it is daily, twice a week, or three times a week), it should be directly observed. The reason for this is that directly observed therapy increases compliance.
CDC regimen options for the initial treatment of active TB in HIV-negative and HIV-positive persons are shown in table 3. Table 4 gives dosage recommendations for the initial treatment of TB among children and adults. The current recommendations are that four drugs be given as initial treatment except in areas where the rate of INH resistance is less than 4 percent. In areas with less than 4 percent INH resistance reported, treatment may be initiated with only three drugs.
Rifampin (RIF) may accelerate the clearance of drugs metabolized in the liver, including methadone, disulfiram (Antabuse), anticonvulsants (e.g., Dilantin), oral hypoglycemics, coumarin, estrogen, birth control pills, digitalis, ketoconazole, glucocorticoids, and cyclosporine. Rifampin will turn body fluids and soft contact lenses orange. Women taking oral contraceptives while on rifampin are at risk for becoming pregnant because of increased metabolism of the oral contraceptives.
INH may cause hepatitis, peripheral neuropathy, and an increase in the level of phenytoin (Dilantin). Phenytoin levels should be monitored. INH decreases the metabolism of phenytoin and disulfiram (Antabuse).
Pyrazinamide (PZA) may cause an elevated uric acid although acute gout is rare. Patients who are asymptomatic with an elevated uric acid should continue PZA. PZA may also be hepatotoxic.
Ethambutol (SUPB) may cause a skin rash and optic neuritis. Patients placed on SUPB should report any changes in their vision. Visual acuity and red/green color perception should be tested every 4 to 6 weeks.
Streptomycin (SM) should be used with caution in any persons who have impaired renal function and in the elderly. The renal toxicity is increased in persons with a dosage of greater than 1 gram per day. In addition, all patients should have a baseline audiogram because of the ototoxicity of SM, and repeat exams should be done periodically. SM should not be given to pregnant women as it may cause congenital deafness.
One must remember that all of these regimens are for INH-susceptible TB; however, the patient is placed on therapy pending the TB culture susceptibility results, which may take several weeks to months. The current CDC recommendations for treatment of TB are that the initial therapy should include four drugs, except in areas where INH resistance is less than 4 percent; in these areas, initial therapy with three drugs is recommended (see table 3). Further, if a patient is on empiric treatment but not improving, consideration should be given to prescribing two or more additional drugs. A single drug should never be added to a failing regimen. Many of these management decisions will have to be made prior to having any drug susceptibility test results and will require consultation with a physician knowledgeable about these management issues.
TB skin testing and anergy testing are safe during pregnancy.
Pregnant women with active tuberculosis or who are suspected of having active TB should be referred to a specialist. Treatment should not be delayed.
An HIV-positive pregnant woman with a positive TB skin test and no clinical evidence of active TB should receive INH prophylaxis for 12 months. An HIV-positive pregnant woman at risk for TB who is anergic and has no clinical evidence of active TB should receive INH prophylaxis for 12 months. The prophylaxis should be initiated at the end of the first trimester of pregnancy.
An HIV-positive pregnant woman who has recently been exposed to a person with infectious TB should be given INH prophylaxis regardless of the stage of pregnancy. An HIV-negative pregnant woman who has recently been exposed to a person with infectious TB and has a positive skin test should be given INH prophylaxis during pregnancy. The drug, however, should not be initiated until the end of the first trimester.
Any pregnant woman with radiographic evidence of possible past TB that was never treated should be given 1 year of INH prophylaxis. Treatment should begin during pregnancy, but not until the end of the first trimester. For other pregnant women who have positive skin tests, INH preventive therapy should be delayed until after delivery.
There is an increased incidence of active TB in the postpartum period in infected women who were not given preventive therapy in the past.
The State health department can aid the drug treatment program by establishing working relationships with staff who are providing health-care services to high-risk populations. The health department will assist the drug treatment program in developing and instituting appropriate screening programs. Specifically, health departments should
Assist in training staff to perform, read, and record tuberculin skin tests; to evaluate positive tuberculin reactors for clinical tuberculosis and preventive therapy; to provide preventive therapy and monitor for compliance and adverse drug reactions; and to educate clients regarding the need for preventive therapy. Some health departments certify staff who complete this training. CDC-produced staff training and patient education materials are available through each State health department TB program.
Identify medical consultants who can assist with diagnosing and managing tuberculosis cases and suspects and, as needed, managing persons on preventive therapy.
Assist with arrangements, upon request, for referring and following persons on preventive therapy who develop clinical tuberculosis or adverse drug reactions.
Assist in evaluating screening programs.
Recommend continuation or discontinuation of screening programs on the basis of their effectiveness.
Conduct contact investigation on each new TB case or suspect case reported.
Resurgent tuberculosis in New York City: Human immunodeficiency virus, homelessness, and the decline of tuberculosis control programs. American Review of Respiratory Disease 144:745'749, 1991.
Guidelines for preventing the transmission of tuberculosis in health-care settings, with special focus on HIV-related issues. Morbidity and Mortality Weekly Report 39(RR-17):1'29, 1990.
Screening for tuberculosis and tuberculous infection in high-risk populations: Recommendations of the Advisory Committee for Elimination of Tuberculosis. Morbidity and Mortality Weekly Report 39(RR-8):1'7, 1990.
Nosocomial transmission of multi-drug resistant tuberculosis among HIV-infected persons - Florida and New York, 1988-1991. Morbidity and Mortality Weekly Report 40(34):585'591, Aug. 30, 1991.
Purified protein derivative (PPD) - Tuberculin anergy and HIV infection: Guidelines for anergy testing and management of anergic persons at risk of tuberculosis. Morbidity and Mortality Weekly Report 40(RR-5): 27--33, 1991.
Prevention and control of tuberculosis in migrant farm workers. Recommendations of the Advisory Council for the Elimination of Tuberculosis. Morbidity and Mortality Weekly Report 40(RR-10): 14, 1992.
Initial therapy for tuberculosis in the era of multidrug resistance. Recommendations of the Advisory Council for the Elimination of Tuberculosis. Morbidity and Mortality Weekly Report 42(RR-7), 1--8, 1993.
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