Workplace contact investigations in the United States.

SETTING: Five state tuberculosis (TB) control programs in the United States. OBJECTIVES: To determine the prevalence of and treatment for latent TB infection (LTBI) among contacts of active TB cases identified in the workplace, and to describe TB control program policies for the initiation and conduct of workplace investigations. DESIGN: Retrospective review of health department records for all culture-positive pulmonary tuberculosis cases aged > or = 15 years reported in 1996, and their contacts. RESULTS: There were 349 cases of active TB, of whom 134 (38%) were employed. Workplace contact investigations were conducted for 42 cases, resulting in the identification of 724 contacts. The rate of LTBI was 29% overall, varying by worksite from a low of 16% to a high of 51%. LTBI estimates were higher for fully-screened contacts of smear-positive rather than of smear-negative index cases. However, fully-screened contacts of index patients with cavitary disease had lower LTBI estimates than those of index patients without cavitation. Treatment for LTBI was initiated in 45% of infected contacts. The five programs had somewhat variable policies regarding workplace contact investigations. Data on HIV co-infection and place of birth of contacts were largely missing. CONCLUSION: Factors contributing to LTBI among workplace contacts may include the presence of persons with pre-existing LTBI or a positive skin test as a result of BCG vaccination, clinical characteristics of the index case, and workplace environmental characteristics conducive to transmission. Standard guidelines for workplace investigations, written workplace investigation policies, and standard data collection practices are needed to better apportion the causes of observed infection rates in the workplace.

Mycobacterium tuberculosis miniepidemic in a church gospel choir.

BACKGROUND: Conventional contact investigation and molecular fingerprinting of Mycobacterium tuberculosis isolates in tuberculosis (TB) outbreaks have facilitated recognition as well as application of public health control activities. Singing in a choir as an activity that promotes TB transmission has been occasionally recognized. Such avocational transmission in a middle class community can occur with attendant difficulties encountered in contact investigation. METHODS: Five cases of TB (one index case; three secondary cases; one unassociated case) were identified among members of a famous church gospel choir in Newark, NJ. DNA fingerprinting and susceptibility testing were done on all retrieved strains. Of 306 choir members who had tuberculin tests, 19% were reactors. The presumed outbreak site was investigated. RESULTS: Four of the five patients were tenors, and one was an alto. Tenors were approximately twice as likely to be tuberculin reactors than subjects with other vocal ranges combined (relative risk, 2.04; 95% confidence interval, 1.17 to 3.56). An air ventilation outlet was directly in front of the tenor section. Some limited extra-church activity between choir members may have contributed to transmission. CONCLUSION: Conventional contact investigation must be supplemented by newer techniques, such as DNA fingerprinting, in identifying possible outbreak transmission. Singing, location of a ventilation outlet, and exposure time may have contributed to TB transmission in this outbreak. Transmission need not only be in congregate settings among well-defined socioeconomic groups but may occur unexpectedly in middle class communities.

Management after exposure to tuberculosis.

The increased incidence of tuberculosis-coupled with the emergence of mycobacterial strains resistant to the most effective drugs-has highlighted the importance of identifying transmission and preventing active disease. Skin test conversion can document infection, except in most patients vaccinated with bacille Calmette-Guérin. Prophylactic medication is effective, but not without complications.

Incidence of tuberculosis in the United States among HIV-infected persons. The Pulmonary Complications of HIV Infection Study Group.

BACKGROUND: The resurgence of tuberculosis in the United States is largely linked to the human immunodeficiency virus (HIV) epidemic. Despite this link, the epidemiology of tuberculosis and preventive strategies in patients infected with HIV are not completely understood. OBJECTIVES: To determine the incidence and predictors of tuberculosis in HIV-infected persons. DESIGN: Prospective, multicenter cohort study. SETTING: Community-based cohort of persons with and without HIV infection at centers in the eastern, midwestern, and western United States. PARTICIPANTS: 1130 HIV-seropositive patients without AIDS who were followed for a median of 53 months (814 homosexual men, 261 injection drug users, and 55 women who had acquired HIV through heterosexual contact). MEASUREMENTS: Delayed hypersensitivity response to purified protein derivative (PPD) tuberculin and mumps antigen, CD4 T-lymphocyte counts, and frequency of tuberculosis. RESULTS: 31 HIV-seropositive patients developed tuberculosis (0.7 cases per 100 person-years [95% CI, 0.5 to 1.0]). The most important demographic risk factor was location (adjusted risk ratio for eastern compared with midwestern and western United States, 4.1 [CI, 2.0 to 8.4]). Tuberculosis occurred more frequently in persons with CD4 counts of less than 200 cells/mm3 (1.2 cases per 100 person-years [CI, 0.7 to 1.9]) than in those with higher counts (0.5 cases per 100 person-years [CI, 0.3 to 0.8]). The rate of tuberculosis was highest among tuberculin converters (5.4 cases per 100 person-years [CI, 1.1 to 15.7]), lower among patients who were PPD positive at first testing (4.5 cases per 100 person-years [CI, 1.6 to 9.7]), and lowest among patients who remained PPD negative (0.4 cases per 100 person-years [CI, 0.2 to 0.7]). Tuberculosis was not reported among persons who had PPD reactions of 1 to 4 mm. Compared with that of patients who tested positive for mumps, the risk for tuberculosis of those who tested negative was increased about sevenfold if they were PPD positive (P < 0.03) and fourfold if they were PPD negative (P < 0.02). CONCLUSIONS: Incidence of tuberculosis was higher in the eastern United States, in patients with CD4 counts of less than 200 cells/mm3, and in PPD-positive patients. Analysis of tuberculin reaction size supports the current interpretive criteria of the Centers for Disease Control and Prevention. Nonreactivity to mumps antigen indicated increased risk for tuberculosis independent of PPD response.

Respiratory disease trends in the Pulmonary Complications of HIV Infection Study cohort. Pulmonary Complications of HIV Infection Study Group.

We examined trends in the incidence of specific respiratory disorders in a multicenter cohort with progressive human immunodeficiency virus (HIV) disease during a 5-yr period. Individuals with a wide range of HIV disease severity belonging to three transmission categories were evaluated at regular intervals and for episodic respiratory symptoms using standard diagnostic algorithms. Yearly incidence rates of respiratory diagnoses were assessed in the cohort as a whole and according to CD4 count or HIV transmission category. The most frequent respiratory disorders were upper respiratory tract infections, but the incidence of lower respiratory tract infections increased as CD4 counts declined. Specific lower respiratory infections followed distinctive patterns according to study-entry CD4 count and transmission category. Acute bronchitis was the predominant lower respiratory infection of cohort members with entry CD4 counts > or = 200 cells/mm3. In cohort members with entry CD4 counts of 200 to 499 cells/mm3, the incidence of bacterial and Pneumocystis carinii pneumonia each increased an average of 40% per year. In members with entry CD4 counts < 200 cells/mm3, acute bronchitis, bacterial pneumonia, and P. carinii pneumonia occurred at high rates without discernible time trends, despite chemoprophylaxis in more than 80% after Year 1, and the rate of other pulmonary opportunistic infections increased over time. Each year, injecting drug users had a higher incidence of bacterial pneumonia than did homosexual men. The yearly rate of tuberculosis was < 3 episodes/100 person-yr in each entry CD4 and HIV-transmission group. We conclude that the time trends of HIV-associated respiratory disorders are determined by HIV disease stage and influenced by transmission category. Whereas acute bronchitis is prevalent during all stages of HIV infection, incidence rates of bacterial pneumonia and P. carinii pneumonia rise continuously during progression to advanced disease. In advanced disease, the incidence of acute bronchitis, bacterial pneumonia and P. carinii pneumonia is high despite widespread chemoprophylaxis.

An incentive in tuberculosis preventive therapy for an inner city population.

SETTING: Measures known to improve adherence such as short course chemoprophylaxis and directly observed therapy can be enhanced to a significant extent/by the use of incentives. Adherence to tuberculosis therapy is influenced by several factors, including the health care system, complexity of therapeutic regimens and patient's characteristics. Individual factors that negatively influence patient's adherence are the most difficult to counter. Preventive tuberculosis therapy is doubly challenging because the benefit of treatment is not felt, while toxicity from the medication, when it occurs, is experienced immediately. Ingenious incentives therefore have to make it worth the patient's while. During a study on preventive regimens, a request for an incentive, Sustacal, was observed to help completion of preventive regimens. Components of individual TB programs may help in patient adherence; it is important for health care staff to identify these aspects and, if they are successful, utilize these as an incentive to complete treatment.

Bacterial pneumonia in persons infected with the human immunodeficiency virus. Pulmonary Complications of HIV Infection Study Group.

BACKGROUND: Patients with human immunodeficiency virus (HIV) infection are at increased risk for bacterial pneumonia in addition to opportunistic infection. However, the risk factors for bacterial pneumonia and its incidence in this population are not well defined. METHODS: In a multicenter, prospective, observational study, we monitored 1130 HIV-positive and 167 HIV-negative participating adults for up to 64 months for pulmonary disease. The HIV-positive group comprised 814 homosexual or bisexual men, 261 injection-drug users, and 55 female partners of HIV-infected men. RESULTS: There were 237 episodes of bacterial pneumonia among the HIV-positive participants (rate, 5.5 per 100 person-years), as compared with 6 episodes among the HIV-negative participants (rate, 0.9 per 100 person-years; P < 0.001). The rate of bacterial pneumonia increased with decreasing CD4 lymphocyte counts (2.3, 6.8, and 10.8 episodes per 100 person-years in the strata with more than 500, 200 to 500, and fewer than 200 cells per cubic millimeter, respectively; P < or = 0.022 for each comparison). Injection-drug users had a higher rate of bacterial pneumonia than did homosexual or bisexual men or female partners. In the stratum with the fewest CD4 lymphocytes, cigarette smoking was associated with an increased rate of pneumonia. Mortality was almost four times higher among participants with an episode of pneumonia than among the others. Prophylaxis with trimethoprim-sulfamethoxazole was associated with a 67 percent reduction in confirmed episodes of bacterial pneumonia (P = 0.007). CONCLUSIONS: Bacterial pneumonia is more frequent in HIV-positive persons than in seronegative controls, and the risk is highest among those with CD4 lymphocyte counts below 200 per cubic millimeter and among injection-drug users.

Tuberculin and anergy testing in HIV-seropositive and HIV-seronegative persons. Pulmonary Complications of HIV Infection Study Group.

OBJECTIVE: To determine the prevalence and predictors of reactivity to tuberculin purified protein derivative (PPD) and skin test anergy in patients with human immunodeficiency virus (HIV) infection and in HIV-seronegative controls. DESIGN: Cross-sectional analysis of baseline data from a prospective, multicenter study of pulmonary complications of HIV infection. SETTING: Community-based cohort of persons with and without HIV infection. PATIENTS: A total of 1171 HIV-seropositive patients without AIDS (841 homosexual men, 274 intravenous drug users, and 56 women with heterosexually acquired infection); 182 HIV-seronegative persons (125 homosexual men and 57 intravenous drug users). MEASUREMENTS: Delayed-type hypersensitivity response to tuberculin PPD, trichophytin, mumps, and Candida antigens; T-lymphocyte subsets. RESULTS: The prevalence of tuberculin PPD reactivity was higher among intravenous drug users than among homosexual men, in both HIV-seronegative (19.1% compared with 6.8%, P = 0.03) and HIV-seropositive persons (15.1% compared with 2.5%, P < 0.001). Among HIV-infected patients, the prevalence of tuberculin reactivity varied directly and that of anergy inversely with the absolute CD4 lymphocyte count. Prevalences were 1% and 72%, respectively, in patients with fewer than 200 CD4 cells/mm3, and 8.4% and 25.5%, respectively, in those with 600 CD4 cells/mm3 (P < 0.001 for both comparisons). Patients with HIV infection and fewer than 400 CD4 lymphocytes/mm3 had a lower prevalence of PPD reactivity than HIV-seronegative controls (2.7% compared with 10.0%, P < 0.001). The strongest predictors of tuberculin reactivity were intravenous drug use, black race, a previous positive PPD test result, and a history of Calmette-Guérin bacillus vaccination. The strongest predictor of anergy was HIV seropositivity. CONCLUSIONS: The response to delayed-type hypersensitivity antigens depends on immune status. The value of PPD and anergy testing in HIV-seropositive patients depends on the ability of such testing to predict subsequent tuberculosis, which is imprecisely known. Until more data or better methods are available, these tests should be done as early as possible in the course of HIV infection.

Tuberculosis and the atypical pneumonia syndrome.

Literature over the last 30 years has warned of the atypical or unusual characteristics of pulmonary TB. Shifts in the demographic distribution of the disease in the US are ascribed in part to the occurrence of HIV disease outbreaks in group settings, and to recent influxes of immigrants from developing countries. Unsuspected pulmonary TB is particularly common among the elderly. Socioeconomic categories not traditionally thought of as being high risk also are affected. In the low-risk setting, TB can be treacherous because misdiagnosis is likely. Tuberculosis is a great mimicker, and it can appear to be any acute community-acquired pneumonia such as atypical pneumonia. Symptoms and signs are few. A high index of awareness is therefore essential. The approach to atypical pneumonia emphasizes the need to include TB in the differential diagnosis to be aware of the total disease spectrum of TB and understand the risk factors. The atypical pneumonia syndrome is only a portion of the clinical spectrum of TB.

Rib cage and abdominal volume displacements during breathing in pregnancy.

To examine the effect of abdominal distension upon the actions of both rib cage and abdomen, we made serial determinations of tidal volume with a chest wall volume-displacement method in 8 pregnant women. Enhancement of tidal volume, long recognized in pregnancy, was achieved usually by augmentation of rib cage volume displacement. By contrast, abdominal volume displacement during quiet breathing is not altered in a predictable fashion by the gravid state. Given these findings, we hypothesize that the increased diaphragmatic contraction of pregnancy is accompanied by the transmission of that force to the lower rib cage via the area of apposition and that diaphragmatic contraction accounts for enhancement of the tidal breath. Diminished abdominal compliance might contribute to the augmentation of rib cage volume displacement as well. Konno-Mead diagrams suggest that this hypothesis is true in some, but not all, subjects.