Tuberculosis in British Columbia among immigrants from five Asian countries, 1982-85

Clinico-diagnostic experience with tuberculous lymphadenitis in Saudi Arabia

OBJECTIVES

To describe the diagnosis and outcomes of tuberculous lymphadenitis in a low HIV-seroprevalence population at a hospital in Riyadh, Saudi Arabia.

METHODS

Retrospective case series of tuberculous lymphadenitis from 1983 to 1998 were examined.

RESULTS

There were 99 cases with a median age of 38 years and a female preponderance (female/male ratio of 1.3 : 1). Eighty per cent had cervical involvement and 36% had systemic symptoms. Eighty-nine per cent had their lymphadenopathy for more than 1 month. The diagnostic yield of tuberculin skin testing was 83%, of chest X-ray was 27%, of fine-needle aspiration was 46%, and of excisional lymph node biopsy was 97%. Only one-third of patients received a tuberculin test. There was no significant difference in outcome between 6 and 9 months of chemotherapy, and paradoxical enlargement of nodes occurred in only 6%.

CONCLUSIONS

Tuberculous lymphadenitis in our study population was predominantly cervical in location. The diagnostic yield of FNA was lower than that reported in the literature, and might be improved by more frequent tuberculin skin testing, multiple aspirations of lymph nodes, or use of excisional biopsy as the initial diagnostic procedure. Most patients responded well to chemotherapy, with few complications.

Tuberculosis among foreign-born persons in Los Angeles County, 1992-1994

OBJECTIVES

To describe the epidemiology of foreign-born tuberculosis (TB) cases in Los Angeles County and to evaluate current TB screening and follow-up of immigrants and refugees (I&R) to the USA.

DESIGN

Retrospective analysis of the Los Angeles County TB registry between October 1992 and December 1994. We matched all cases who entered the USA during fiscal year 1993 (FY93) with a database from the tracking system of I&R with suspected TB.

RESULTS

Foreign-born persons accounted for 64% of all reported TB cases. Half were born in Mexico or Central America. Standardized incidence rates were 3-5 times higher than those of US-born persons for Mexicans and Central Americans, 6-7 times higher for North-east Asians, and 10-15 times higher for South-east Asians. Among foreign-born cases who arrived during FY93, 5% of the Mexicans and Central Americans, 48% of the North-east Asians and 67% of the South-east Asians were registered by the tracking system.

CONCLUSION

Mexicans and Central Americans accounted for the majority of cases but had a lower incidence of TB than Asians. The current screening procedures identify a large proportion of cases among recently arrived South-east Asians, but contribute little to the control of TB among Mexicans and Central Americans.

The epidemiology of tuberculosis among foreign-born persons in the United States, 1986 to 1993

BACKGROUND

One third of the world's population is infected with Mycobacterium tuberculosis, and in the developed countries immigration is a major force that sustains the incidence of tuberculosis. We studied the effects of immigration on the epidemiology of tuberculosis and its recent resurgence in the United States.

METHODS

We analyzed data from the national tuberculosis reporting system of the Centers for Disease Control and Prevention. Since 1986 reports of tuberculosis have included the patient's country of origin. Population estimates for foreign-born persons were derived from special samples from the 1980 and 1990 censuses.

RESULTS

The proportion of persons reported to have tuberculosis who were foreign-born increased from 21.6 percent (4925 cases) in 1986 to 29.6 percent (7346 cases) in 1993. For the entire eight-year period, most foreign-born patients with tuberculosis were from Latin America (43.9 percent; 21,115 cases) and Southeast Asia (34.6 percent; 16,643 cases). Among foreign-born persons the incidence rate was almost quadruple the rate for native residents of the United States (30.6 vs. 8.1 per 100,000 person-years), and 55 percent of immigrants with tuberculosis had the condition diagnosed in their first five years in the United States.

CONCLUSIONS

Immigration has had an increasingly important effect on the epidemiology of tuberculosis in the United States. It will be difficult to eliminate tuberculosis without better efforts to prevent and control it among immigrants and greater efforts to control it in the countries from which they come.

Tuberculosis in young adults and the elderly. A prospective comparison study

OBJECTIVES

To compare the clinical, bacteriologic, and radiologic features of pulmonary and pleural tuberculosis in young adults and the elderly and determine if any differences exist between both groups.

DESIGN

Prospective recruitment of all patients diagnosed as having pulmonary and pleural tuberculosis in British Columbia, Canada.

SETTING

A population-based sample from a provincial control program TB registry.

PATIENTS

A total of 218 consecutive patients whose conditions were diagnosed between January 1990 and May 1991. We excluded 15 HIV-positive patients whose conditions were diagnosed during this study.

INTERVENTION

Standardized data collection of symptoms, bacteriology, and review of radiology by two readers blind to the clinical and epidemiologic data.

MAIN RESULTS

There were 142 young adult patients and 76 elderly patients. The young adults had a mean age of 41.2 years and the elderly group had a mean age of 75 years of age. Fever (p = 0.002) and night sweats (p = 0.02) were more common in young adults. In culture-proven disease, hemoptysis, fever, and cough were more common in young adult (p = 0.03, 0.02, and 0.01, respectively). There was no difference in the duration of symptoms between the two groups. The odds ratio for cancers other than lung cancer, 3.98 (confidence interval, 1.49, 10.65) in the elderly group was the only significant risk factor to differ between the two groups. Skin test responses to 5TU PPD were positive in 86.2 percent of young adults and 67.6 percent of elderly patients tested (p = 0.03). A total of 79.6 percent of young adults and 88.15 percent of the elderly patients (not significant) were culture positive. Comparison of radiologic findings in young adults vs elderly patients showed no significant differences apart from those with miliary TB 0.7 percent vs 6.7 percent (p = 0.04).

CONCLUSIONS

In this population-based study, young adults were more likely to have hemoptysis, fever, and cough and to have a positive PPD response. Cancer was significantly associated as a risk factor in the older age group. There was no difference in bacteriologically proven disease or radiologic findings between the two groups, apart from the more common occurrence of miliary TB in the elderly.

International migration and control of communicable diseases

The epidemiology and policy implications of communicable disease (CD) transmission associated with international migration have received little systematic study. This is a review of clinical and epidemiological reports in search of strategies to assess and manage the impact of international migration on the transmission of CDs. The economics and demography of migration from less developed to industrialized nations is considered. Migration-related transmission should differentiate between actual transmission as opposed to geographic relocation of disease. Limitations of current screening and disease prevention strategies are discussed. Social and ecological processes through which migration can contribute to increased CD transmission are described, including placement in refugee camps, unclear legal status of migrants in recipient nations, and temporary return migration. Strategies for non-discriminatory and non-punitive control of migration-related CDs, needed changes in clinical practice, and complexities presented by CDs of long latency (such as HIV infection) are reviewed.

Tuberculosis in recent Asian immigrants to British Columbia, Canada: 1982-1985

The prevalence and incidence of active tuberculosis among 21,959 recently arrived (1982-1985) immigrants from 7 selected Asian countries into British Columbia (BC), Canada, were reviewed. Among these newly arrived immigrants, 1173 (5.3%) were judged to have inactive tuberculosis at the immigration examination in their country of origin. In this subgroup, 14 of 932 (1.5%) were found to have active tuberculosis at the initial examination after arrival in Canada. Subsequently, 7 further cases arose in this group of inactive cases giving an average annual incidence rate of 0.33% over the 4-year period of study. Only 3 of these 21 cases had had previous antituberculosis chemotherapy. The remaining 20,786 recent immigrants with normal X-rays at the immigration examination contributed 30 cases during the next 4 years--an average annual incidence rate of 0.08% or 8 times the comparable rate for BC (0.01%). The limitations of the immigration screening process are illustrated and the value of early surveillance of immigrants designated as having inactive tuberculosis is underlined. The apparent failure to exclude active disease prior to the arrival of these immigrants is one factor elevating the incidence of active tuberculosis in the first few years after arrival in the host country. Other factors include the relatively high prevalence of inactive tuberculosis among the immigrants from certain countries and their high rate of early relapse after entry, especially in those not previously treated. Such immigrants should be considered for chemoprophylaxis immediately after entry.