Sarah E. Valway

Transmission of Multidrug-Resistant Mycobacterium tuberculosis during a Long Airplane Flight

BACKGROUND In April 1994, a passenger with infectious multi-drug resistant tuberculosis traveled on commercial-airline flights from Honolulu to Chicago and from Chicago to Baltimore and returned one month later. We sought to determine whether she had infected any of her contacts on this extensive trip. METHODS Passengers and crew were identified from airline records and were notified of their exposure, asked to complete a questionnaire, and screened by tuberculin skin tests. RESULTS Of the 925 people on the airplanes, 802 (86.7 percent) responded. All 11 contacts with positive tuberculin skin tests who were on the April flights and 2 of 3 contacts with positive tests who were on the Baltimore-to-Chicago flight in May had other risk factors for tuberculosis. More contacts on the final, 8.75-hour flight from Chicago to Honolulu had positive skin tests than those on the other three flights (6 percent, as compared with 2.3, 3.8, and 2.8 percent). Of 15 contacts with positive tests on the May flight from Chicago to Honolulu, 6 (4 with skin-test conversion) had no other risk factors; all 6 had sat in the same section of the plane as the index patient (P=0.001). Passengers seated within two rows of the index patient were more likely to have positive tuberculin skin tests than those in the rest of the section (4 of 13, or 30.8 percent, vs. 2 of 55, or 3.6 percent; rate ratio, 8.5; 95 percent confidence interval, 1.7 to 41.3; P=0.01). CONCLUSIONS The transmission of Mycobacterium tuberculosis that we describe aboard a commercial aircraft involved a highly infectious passenger, a long flight, and close proximity of contacts to the index patient.

Interpretation of Restriction Fragment Length Polymorphism Analysis of Mycobacterium tuberculosis Isolates from a State with a Large Rural Population

Epidemiologic relatedness of Mycobacterium tuberculosis isolates from Arkansas residents diagnosed with tuberculosis in 1992-1993 was assessed using IS6110- and pTBN12-based restriction fragment length polymorphism (RFLP) and epidemiologic investigation. Patients with isolates having similar IS6110 patterns had medical records reviewed and were interviewed to identify epidemiologic links. Complete RFLP analyses were obtained for isolates of 235 patients; 78 (33%) matched the pattern of > or = 1 other isolate, forming 24 clusters. Epidemiologic connections were found for 33 (42%) of 78 patients in 11 clusters. Transmission of M. tuberculosis likely occurred many years in the past for 5 patients in 2 clusters. Of clusters based only on IS6110 analyses, those with > or = 6 IS6110 copies had both a significantly greater proportion of isolates that matched by pTBN12 analysis and patients with epidemiologic connections, indicating IS6110 patterns with few bands lack strain specificity. Secondary RFLP analysis increased specificity, but most clustered patients still did not appear to be epidemiologically related. RFLP clustering in rural areas may not represent recent transmission.

Extensive Transmission of Mycobacterium tuberculosis from a Child

BACKGROUND AND METHODS Young children rarely transmit tuberculosis. In July 1998, infectious tuberculosis was identified in a nine-year-old boy in North Dakota who was screened because extrapulmonary tuberculosis had been diagnosed in his female guardian. The child, who had come from the Republic of the Marshall Islands in 1996, had bilateral cavitary tuberculosis. Because he was the only known possible source for his female guardians tuberculosis, an investigation of the childs contacts was undertaken. We identified family, school, day-care, and other social contacts and notified these people of their exposure. We asked the contacts to complete a questionnaire and performed tuberculin skin tests. RESULTS Of the 276 contacts of the child whom we tested, 56 (20 percent) had a positive tuberculin skin test (induration of at least 10 mm), including 3 of the childs 4 household members, 16 of his 24 classroom contacts, 10 of 32 school-bus riders, and 9 of 61 day-care contacts. A total of 118 persons received preventive therapy, including 56 young children who were prescribed preventive therapy until skin tests performed at least 12 weeks after exposure were negative. The one additional case identified was in the twin brother of the nine-year-old patient. The twin was not considered infectious on the basis of a sputum smear that was negative on microscopical examination. CONCLUSIONS This investigation showed that a young child can transmit Mycobacterium tuberculosis to a large number of contacts. Children with tuberculosis, especially cavitary or laryngeal tuberculosis, should be considered potentially infectious, and screening of their contacts for infection with M. tuberculosis or active tuberculosis may be required.

Spread of strain W, a highly drug-resistant strain of Mycobacterium tuberculosis, across the United States.

Strain W, a highly drug-resistant strain of Mycobacterium tuberculosis, was responsible for large nosocomial outbreaks in New York in the early 1990s. To describe the spread of strain W outside New York, we reviewed data from epidemiologic investigations, national tuberculosis surveillance, regional DNA fingerprint laboratories, and the Centers for Disease Control and Prevention Mycobacteriology Laboratory to identify potential cases of tuberculosis due to strain W. From January 1992 through February 1997, 23 cases were diagnosed in nine states and Puerto Rico; 8 were exposed to strain W in New York before their diagnosis; 4 of the 23 transmitted disease to 10 others. Eighty-six contacts of the 23 cases are presumed to be infected with strain W; 11 completed alternative preventive therapy. Strain W tuberculosis cases will occur throughout the United States as persons infected in New York move elsewhere. To help track and contain this strain, health departments should notify the Centers for Disease Control and Prevention of cases of tuberculosis resistant to isoniazid, rifampin, streptomycin, and kanamycin.

Simultaneous Infection with Multiple Strains of Mycobacterium tuberculosis

Drug-susceptible and drug-resistant isolates of Mycobacterium tuberculosis were recovered from 2 patients, 1 with isoniazid-resistant tuberculosis (patient 1) and another with multidrug-resistant tuberculosis (patient 2). An investigation included patient interviews, record reviews, and genotyping of isolates. Both patients worked in a medical-waste processing plant. Transmission from waste was responsible for at least the multidrug-resistant infection. We found no evidence that specimens were switched or that cross-contamination of cultures occurred. For patient 1, susceptible and isoniazid-resistant isolates, collected 15 days apart, had 21 and 19 restriction fragments containing IS6110, 18 of which were common to both. For patient 2, a single isolate contained both drug-susceptible and multidrug-resistant colonies, demonstrating 10 and 11 different restriction fragments, respectively. These observations indicate that simultaneous infections with multiple strains of M. tuberculosis occur in immunocompetent hosts and may be responsible for conflicting drug-susceptibility results, though the circumstances of infections in these cases may have been unusual.

Transmission of Tuberculosis in a Jail

Tuberculosis is a problem in correctional facilities throughout the United States. In 1996, 3.7% of all cases of tuberculosis nationwide occurred among residents of correctional facilities (1). Although in 1996 the incidence of new cases of active tuberculosis in the United States was 8.0 per 100 000 persons (1), many prison systems have reported rates of 200 per 100 000 persons and higher (2-10). Transmission of tuberculosis from prisons into surrounding communities has been documented (5), and correctional facilities may be important reservoirs of infection (11-13). One study concluded that a prison was potentially linked to 9% of a states tuberculosis cases during a 5-year period (5), and another study indicated that 24% of the tuberculosis cases in a county were associated with its jail (14). Prisons house convicts after sentencing, usually for terms exceeding 1 year (15). In contrast, jails receive prisoners immediately after arrest and generally house inmates awaiting trial or those sentenced to terms less than 1 year (16). Most jails are operated by cities or counties and hold inmates from the local community. In 1993, nearly 10 million inmates were admitted to local jails (16). Only 6% of jails house more than 50% of the nations jail inmates (16). Incarcerated populations have high rates of substance abuse, HIV infection, tuberculous infection, low socioeconomic status, and other risk factors associated with active tuberculosis (15, 17). At least 14 reports of outbreaks of tuberculosis in U.S. prisons have been published since 1985 (3, 5-7, 18, 19), but only two published reports have concerned outbreaks in jails (14, 20). Memphis, Tennessee, has the fifth largest jail in the United States (16). In 1996, the number of reported cases of tuberculosis diagnosed in inmates from the Memphis jail increased. This report summarizes the results of the ensuing investigation. Methods We reviewed the medical records of all persons in whom tuberculosis was diagnosed from 1 January 1995 through 31 December 1997 while they were incarcerated in the Memphis Criminal Justice Center (subsequently referred to as the jail). We obtained medical records from the jail, the Memphis/Shelby County Health Department Tuberculosis Clinic, and the hospital to which inmates were admitted for evaluations. For all inmates with active tuberculosis, computerized jail records were analyzed to determine dates of incarceration and cell locations for the 2 years before their diagnosis. A patient with a confirmed case of active tuberculosis had Mycobacterium tuberculosis isolated from a clinical specimen or met a clinical case definition [21]. Clinical cases met the following criteria: 1) a positive result on a tuberculin skin test, 2) signs and symptoms compatible with tuberculosis [for example, an abnormal, unstable chest radiograph or clinical evidence of current disease], and 3) treatment with at least two antituberculosis medications. Inmate cases were defined as patients in whom confirmed tuberculosis was diagnosed while they were incarcerated in the jail or within 3 weeks of transfer from the jail to another penal facility in the same city. Persons with culture-positive pulmonary tuberculosis were considered infectious from 6 weeks before collection of the first positive specimen until 2 weeks after initiation of appropriate therapy. A positive tuberculin skin test result was defined as at least 10 mm of induration within 48 to 72 hours after administration of five tuberculin units of tuberculin purified-protein derivative by the Mantoux method. Efforts were made to contact inmates who received a diagnosis of active tuberculosis after 1 January 1995, including those living in the community or incarcerated in other correctional facilities. A standardized questionnaire was administered to persons who could be located; the questionnaire asked about the patients lifestyle outside the jail before diagnosis of tuberculosis (for example, places frequented, behaviors, living and working situations, and exposure to persons with tuberculosis). Patients were also asked about incarceration history, possible contacts during incarceration, and activities while in jail. Jail administrators were interviewed and records were reviewed to determine baseline information on the jail population. The average age of inmates was calculated from a sample of 2552 inmates released or transferred from the jail on 12 randomly selected days in 1997. Inmate intake procedures at the jail were observed by two separate investigators on different days. Records from annual tuberculin skin test screening of jail staff, performed by the county health department on site at the jail, were reviewed. Medical records of staff with confirmed tuberculosis between 1 January 1995 and 31 December 1997 were also reviewed. The Tennessee Department of Health registry of all persons in Memphis reported with active tuberculosis from January 1995 through July 1997 was cross-matched with the list of persons incarcerated in the Memphis jail since 1979. Deoxyribonucleic acid fingerprinting was performed on all available M. tuberculosis isolates from culture-positive inmates and guards. Fingerprinting was also done for a sample of community cases, chosen by selecting every fifth isolate from a list of all culture-positive cases of tuberculosis in Memphis from 1 January 1995 through 1 September 1997, sorted by date of treatment initiation. If no isolate was available for the case selected, the next community case on the list was substituted. The Tennessee Department of Health Laboratory had processed 99.5% of all specimens from culture-positive cases reported from Memphis during the study period. Isolates were fingerprinted at the Centers for Disease Control and Prevention by IS-6110 restriction fragment length polymorphism analysis (22). Bivariate statistical analyses were performed by using chi-square tests calculated with Epi Info software (23). Results Jail Characteristics The jail housed approximately 2700 inmates at any time. More than 173 000 persons were admitted and discharged during the 3-year period. A mean of 159 inmates were admitted daily; the median length of stay was 1 day, and 8.3% of inmates stayed more than 30 days (Figure 1). Of persons admitted to the jail, 82% had previously been incarcerated there. The inmate population was 90% black and 90% male. The mean age of inmates was 32 years. Figure 1. Distribution of lengths of incarceration of inmates in the Memphis jail, 1995 to 1997. Inmates were housed on seven floors. Some units held up to 36 inmates in a single large room; other units had 18 two-person cells, and the 36 inmates intermingled for much of the day. Inmates lived and ate with members of the same unit, although inmates from different units had the potential to intermingle at visitation; during gym, chapel, infirmary, and legal-room (library) visits; and during transport outside the facility. For security reasons, inmates were moved frequently within the jail. Jail Screening Procedures Routine medical screening at intake to the jail consisted of two questions: Are you seeing a doctor for anything? and Are you taking any medications? This screening process took approximately 15 seconds per inmate. If the screening procedure did not reveal an obvious history of tuberculosis, the inmate was admitted into the general jail population. Jail protocol called for tuberculin skin test screening of all inmates still in the facility 10 days after admission. Inmates with evidence of possible tuberculosis on initial screening, in subsequent medical visits, or on tuberculin skin test screening were transported to a hospital emergency department or the county health department tuberculosis clinic for chest radiographs and evaluation. Those thought to have possible active tuberculosis were then transferred to a local hospital for isolation and completion of evaluation. Inmates given a diagnosis of active tuberculosis were returned to the jail after three sputum smears were negative for acid-fast bacteria. The jail does not have radiography facilities or negative-pressure isolation rooms. From 1995 through 1997, 173 815 inmates were admitted to the jail; 13 239 (7.8%) inmates underwent tuberculin skin testing. These inmates represented 36% of the target population of inmates incarcerated for more than 10 days. Of tuberculin skin tests placed, 10 110 (74%) were read; 431 (4.3%) of these were reported as yielding positive results. Inmates who volunteer are counseled about and tested for HIV at the jail by county health department representatives. Of the inmates admitted to the jail during this 3-year period, less than 1% were screened for HIV there. Of 1622 HIV tests performed, 26 (1.6%) had positive results. Inmate Tuberculosis Cases Active tuberculosis was diagnosed in 38 jail inmates from 1 January 1995 through 31 December 1997 (Figure 2). Ten cases were diagnosed in 1995, 19 in 1996, and 9 in 1997. The calculated incidence of active tuberculosis diagnosed in inmates who were physically in the jail was 274 per 100 000 during this 3-year period. Figure 2. Cases of active tuberculosis disease diagnosed in guards ( top ) and inmates ( bottom ) from the Memphis jail, 1 January 1995 through 31 December 1997, by quarter in which disease was diagnosed. Inmates with tuberculosis had been in the jail a median of 15 times before diagnosis. The median length of continuous incarceration before the diagnosis of tuberculosis was 138 days (range, 10 to 800 days) (Table). By comparison, the median length of incarceration for all inmates in the jail is 1 day (mean, 13.4 days). Ten (26%) of the inmates with active tuberculosis were given the diagnosis during evaluation for symptoms, 25 (66%) were discovered as a result of evaluation of a positive tuberculin skin test result, and 3 (8%) were found during contact investigations of other cases. Table. Characteristics of the 38 Inmates in Whom Tub

A Nosocomial Outbreak of Multidrug-Resistant Tuberculosis

Nosocomial outbreaks of tuberculosis have affected recommendations for infection control practices in hospitals in the United States [1-8]. Administrative and environmental measures and respiratory protection for health care workers have been recommended [9, 10]. Evidence suggests that adherence to these guidelines may be effective in preventing nosocomial transmission of Mycobacterium tuberculosis [11-13]. Of the 34 cases of multidrug-resistant tuberculosis (resistant to at least isoniazid and rifampin) that were reported to the Chicago Department of Health from January 1994 through April 1995, 6 occurred in patients with AIDS who had been admitted to one floor of one hospital. Because nosocomial transmission of multidrug-resistant tuberculosis was suspected, an investigation was initiated. Methods Potential outbreak cases-cases of tuberculosis in persons whose isolates were resistant to at least isoniazid and rifampin-were identified by matching the names of patients and health care workers at the hospital to state and local tuberculosis registries and by reviewing laboratory records and death certificates. We performed DNA fingerprinting of M. tuberculosis isolates using IS6110 and pTBN12 probes [14, 15]. Medical records were reviewed for patients who were admitted to the outbreak floor when a patient whose sputum smears were positive for acid-fast bacilli was present. Patients who died within 30 days of exposure were excluded. Private providers of patients who may have been exposed to M. tuberculosis were contacted by telephone or by mail. All were advised to screen their patients for tuberculous disease and infection by tuberculin skin tests and symptom checks. A positive result on a tuberculin skin test was defined as induration of 5 mm or more, and an increase in induration of at least 5 mm was considered a skin test conversion. Severely immunocompromised patients (CD4+ T-lymphocyte count < 50 cells/mL) who did not receive skin testing were assumed to be anergic [16]. To assess exposure of health care workers to M. tuberculosis, we reviewed work schedules, chart signatures, and patient assignments. Results of testing for fit of respirators with high-efficiency particulate air (HEPA) filters and results of annual tuberculin skin tests were obtained from employee records. Health care workers also completed a form about infection control practices and exposure to M. tuberculosis. Acid-fast bacilli isolation rooms (that is, rooms in which the air pressure is negative in relation to the hallway and that have 6 air changes per hour) were installed in December 1994. The design of the ventilation system on the outbreak floor was reviewed, and smoke tube testing was done to assess the direction of air flow. Data analysis was conducted using Epi Info, version 6 [17]. Categorical variables were compared using the chi-square test, and relative risks with 95% CIs were derived. Continuous variables were compared using the Wilcoxon rank-sum test. Results Seven persons had outbreak cases of tuberculosis: six patients already known and one health care worker identified during the investigation. All of these persons had AIDS. All of their M. tuberculosis isolates were resistant to isoniazid and rifampin and had identical DNA fingerprints. Two generations of nosocomial transmission were identified (Figure 1). Case-patient 1 was admitted to the hospital with a diagnosis of tuberculosis; was placed in a private room; and began receiving therapy with isoniazid, rifampin, pyrazinamide, and ethambutol. From the time this patient was admitted, persons entering the patients room were required to use HEPA-filter respirators. Case-patient 1 refused to remain in the room and was the source of infection for case-patient 2, who was hospitalized at the same time across the hallway. Figure 1. Timeline demonstrating two chains of nosocomial transmission of tuberculous organisms between August 1994 and September 1995 in a hospital in Chicago. Case-patient 2 was readmitted to the hospital 10 weeks later with fever, sinus pressure, and cough. Because the chest radiograph at admission was normal, tuberculosis was not initially suspected. A sputum smear obtained 3 days after admission was positive (3+) for acid-fast bacilli. Treatment with isoniazid, rifampin, and ethambutol was started, and persons entering the patients room were required to use HEPA-filter respirators. It was reported that the door to the patients room was malfunctioning and failed to remain closed. Case-patient 2 remained in his room and yet was the source of infection for case-patients 3, 4, 5, and 6, who were hospitalized on the same ward. Transmission to case-patient 6, who was restricted to bed rest, occurred during this patients short 23-hour hospitalization. Case-patient 7, the health care worker, drew blood from case-patient 2 before case-patient 2 received a diagnosis of tuberculosis and occasionally worked on the outbreak floor while case-patients 1 and 2 were present. For case-patients 2, 3, 4, 5, 6, and 7, no exposure to M. tuberculosis other than that which occurred in the hospital was identified. Case-patients 1 and 2 were never in an acid-fast bacilli isolation room while they were infectious because no such rooms were available until December 1994. Case-patients 4, 5, 6, and 7 were all placed in acid-fast bacilli isolation rooms when tuberculosis was suspected; case-patient 3 did not have sputum samples smear-positive for acid-fast bacilli. Smoke tube testing done in April 1995 revealed that the rooms occupied by case-patients 1 and 2 while these patients were infectious had air pressure that was positive in relation to the hallway. The acid-fast bacilli isolation rooms had air pressure that was negative in relation to the hallway. Ultraviolet germicidal irradiation was not used in the hospital. The outbreak floor was composed of two separate wings with a central nursing station. Of the 169 patients on the floor, 5 had tuberculosis (case-patients 2, 3, 4, 5, and 6). Of the 164 patients who did not have tuberculosis, 71 (43%) had AIDS. Fifty-three of the 164 patients died before completing screening; none (including 37 patients with AIDS) received a diagnosis of tuberculosis. Of the remaining 111 patients, 5 had positive results on tuberculin skin testing, 34 had negative results, 5 had previously had positive results, 27 were anergic, and 40 had unknown test results. All 5 patients with positive test results had other risk factors for M. tuberculosis infection (for example, foreign birth). All 5 patients were on the same ward as case-patients 1 or 2 while these patients were infectious. No evidence of transmission among patients who did not have AIDS or patients exposed only to case-patients 3, 4, 5, or 6 was identified. Twenty-six patients with AIDS (all of whom were known or presumed to be anergic) were exposed to case-patients 1 or 2. At the time of exposure, case-patients had lower CD4+ T-lymphocyte counts than non-case-patients and were more likely to be ambulatory (Table 1). Table 1. Risk Factors for Nosocomial Transmission of Mycobacterium tuberculosis among Patients and Staff Of the 104 exposed health care workers, 17 who had previously had positive results on skin tests and 13 who had resigned from the hospital were excluded from analysis. Of the remaining 74, 11 (15%) had tuberculin skin test conversions (6 nurses, 4 housestaff physicians, and 1 ward secretary) and 4 had positive skin test results, but no baseline test results. None had any other identified exposure to tuberculosis. The remaining 59 (80%) had negative results on skin testing at least 12 weeks after exposure. Except for case-patient 7, no health care worker developed tuberculosis. Case-patient 2 was the source of most of the episodes of transmission to health care workers. While case-patient 2 was hospitalized with infectious tuberculosis, health care workers with skin test conversions worked more days on the floor than did health care workers with negative test results. Health care workers who had conversion were no more likely to have provided direct care to a case-patient, including case-patient 2, than were workers with negative test results (Table 1). Forty-two (57%) of 74 exposed health care workers responded to questions about infection control practices. Those with negative test results were no more likely than those with skin test conversion to report always wearing a HEPA-filter respirator when entering the room of a patient with tuberculosis (25 of 29 workers compared with 4 of 5 workers; 8 workers did not recall whether they used HEPA-filter respirators). The results of respirator-fit testing before exposure were available for 68 health care workers; 62, including 80% of those with skin test conversions, passed this testing. Discussion This investigation provides evidence of nosocomial transmission of multidrug-resistant M. tuberculosis, including 1) exposure of case-patients who had secondary cases of tuberculosis to a source case-patient on the same floor of the hospital; 2) consistency of incubation periods with those of previous nosocomial outbreaks among patients with AIDS [1-3]; 3) isolates with matching patterns of drug susceptibility and DNA fingerprints; 4) lack of any other identified exposure to tuberculosis; and 5) exposure of all health care workers with skin test conversion to a case-patient who was not in an acid-fast bacilli isolation room. Several factors may have contributed to the transmission of M. tuberculosis, but the evidence for the role of insufficient environmental controls is most compelling. Case-patients 1 and 2 were both infectious, and the flow of contaminated air from their rooms (which had air pressure that was positive in relation to the hallway) facilitated the spread of infectious droplet nuclei throughout the outbreak floor. Organisms were transmitted to health care workers who did not directly care for a patient with infectious

A Preventable Outbreak of Tuberculosis Investigated through an Intricate Social Network

In 1998, a city in Indiana reported 4-fold increase in the number of cases of tuberculosis (TB). An investigation to assess the increase in cases and to identify possible epidemiologic links among persons with TB identified 41 cases of active TB. Epidemiologic links and/or matching DNA fingerprints were identified for 31 patients (76%). The majority of these patients were members of a single social network within the community. Links for most of these patients were identified after multiple interviews with patients and their contacts. TB control activities in the county were limited prior to the identification of the outbreak. At least 24 cases may have been preventable. This outbreak may have been prevented with prompt case identification and effective contact tracing and screening during the years before the outbreak. The use of social networks should be considered in the investigation of outbreaks that involve difficult-to-reach populations. TB control measures should be maintained in areas with historically low TB incidence.

Outbreak of drug-resistant tuberculosis with second-generation transmission in a high school in California

BACKGROUND In spring 1993, four students in a high school were diagnosed with tuberculosis resistant to isoniazid, streptomycin, and ethionamide. METHODS To investigate potential transmission of drug-resistant tuberculosis, a retrospective cohort study with case investigation and screening by tuberculin skin tests and symptom checks was conducted in a high school of approximately 1400 students. Current and graduated high-school students were included in the investigation. DNA fingerprinting of available isolates was performed. RESULTS Eighteen students with active tuberculosis were identified. Through epidemiologic and laboratory investigation, 13 cases were linked; 8 entered 12th grade in fall 1993; 9 of 13 had positive cultures for Mycobacterium tuberculosis with isoniazid, streptomycin, and ethionamide resistance, and all 8 available isolates had identical DNA fingerprints. No staff member had tuberculosis. One student remained infectious for 29 months, from January 1991 to June 1993, and was the source case for the outbreak. Another student was infectious for 5 months before diagnosis in May 1993 and was a treatment failure in February 1994 with development of rifampin and ethambutol resistance in addition to isoniazid, streptomycin, and ethionamide. In the fall 1993 screening, 292 of 1263 (23%) students tested had a positive tuberculin skin test. Risk of infection was highest among 12th graders and classroom contacts of the two students with prolonged infectiousness. An additional 94 of 928 (10%) students tested in spring 1994 had a positive tuberculin skin test; 22 were classroom contacts of the student with treatment failure and 21 of these had documented tuberculin skin test conversions. CONCLUSION Extensive transmission of drug-resistant tuberculosis was documented in this high school, along with missed opportunities for prevention and control of this outbreak. Prompt identification of tuberculosis cases and timely interventions should help reduce this public health problem.

Tuberculosis in children younger than five years old : New York City

We examined medical and health department records for children < 5 years of age with suspected or confirmed tuberculosis reported to the New York City Health Department from January, 1992, through June, 1992, in order to describe the epidemiology of tuberculosis in young children and identify prevention strategies. Forty-seven children were treated for suspected or confirmed tuberculosis. Sixty-two percent (21 of 34) were foreign-born (n = 11) or had foreign-born caretakers (n = 10). A source case was found for 10 of 47 (21%) children; for 8 the adult source was diagnosed before the child. One child was human immunodeficiency virus-seropositive, however, 83% of children and 70% of adult source cases did not have human immunodeficiency virus test results available. Health care providers should test children at high risk for tuberculosis infection as recommended by the American Academy of Pediatrics and improve contact tracing to identify children exposed to adults with tuberculosis. Because most cases of tuberculosis in children are diagnosed clinically rather than by isolating Mycobacterium tuberculosis, identification of the source case is important for selecting appropriate treatment.