Tuberculosis, incarceration, and HIV at a crossroads in Guyana.

OBJECTIVES: The objective of this study was to describe the sociodemographic and clinical characteristics of patients dually infected with HIV and tuberculosis (TB) in Guyana. METHODS: The data for this study were obtained as part of a related project conducted to determine the prevalence of diabetes mellitus among TB patients in Guyana. From April to June 2006, a convenience sample of 100 patients was selected from those attending three TB clinics in Guyana and a structured questionnaire was used to collect relevant sociodemographic and risk factor data. The sociodemographic and clinical data of HIV-negative and HIV-positive patients with pulmonary TB were compared. Logistic regression was conducted to determine independent relationships between sociodemographic and clinical features. RESULTS: One hundred TB patients were considered for enrolment in the study, but since the HIV status was known for only 77 persons, these were included in the analysis. Thirty-one of the 77 (40.3%) were HIV-positive. Seventy-two of the 77 (93.5%) patients had pulmonary TB, 28 of whom were HIV-positive; the other five had extrapulmonary TB, three of whom were dually infected. Several social factors and clinical manifestations including incarceration at the time of TB diagnosis (p=0.01), cigarette smoking (p=0.05), homelessness (p=0.07), chest pain (p=0.001), hemoptysis (p=0.02), cough (p=0.08), and being acid-fast bacillus (AFB) sputum smear-positive (p=0.06) were associated with HIV-negative pulmonary TB. In the logistic regression model, HIV-negative TB patients demonstrated higher frequencies of complaints of chest pain (odds ratio (OR) 34.48, 95% confidence interval (CI) 4.35-250) and were more likely to be AFB sputum smear-positive (OR 11.97, 95% CI 1.91-74.76) than HIV-positive TB patients. CONCLUSIONS: Guyana is faced with a particularly high burden of HIV infection among TB patients. Given the impact of HIV on the clinical presentation of TB, physicians managing HIV patients should demonstrate a high level of suspicion for TB among these patients. Incarceration is a strong correlate of TB, overall.

Tuberculosis and diabetes in Guyana.

OBJECTIVES: This study was conducted to determine the prevalence of diabetes mellitus among tuberculosis (TB) patients attending three TB clinics in Guyana. METHODS: A cross-sectional study was conducted among TB patients attending TB clinics in three regions in Guyana. A structured questionnaire was used to collect demographic, clinical, and risk factor data. Random blood sugar testing was done using the OneTouch UltraSmart glucometer (LifeScan, Inc., 2002). RESULTS: One hundred TB patients were recruited; 90 had pulmonary TB and 10 had extrapulmonary disease. Fourteen patients were classified as diabetic: 12 had been previously diagnosed as diabetic by a physician and two had abnormally high random blood sugar at the time of enrolment. Of the 12 known diabetics, seven had been diagnosed before TB was discovered, three were identified at the time TB was diagnosed, and two after TB was diagnosed. All 14 diabetic patients presented with pulmonary TB. Thirty-one patients were HIV-positive and 28 of these had pulmonary TB, whereas three had extrapulmonary TB. None of the diabetics were infected with HIV. TB-diabetic patients tended to be older than non-diabetics (median age 44 vs. 36.5 years), were more likely to have been incarcerated at the time of TB diagnosis than non-diabetics (p=0.06), and were more likely to have an elevated (random) blood sugar level (p=0.02). Clinically, diabetes did not influence the presentation of TB. CONCLUSIONS: This study clearly highlights that diabetes and HIV are frequent in Guyanese TB patients. Routine screening of TB patients for diabetes and diabetic patients for TB should be speedily implemented. The National TB Programme should work closely with the diabetes clinics so that TB patients who are diabetics are optimally managed.

The lack of association between bacille Calmette-Guerin vaccination and clustering of Aboriginals with tuberculosis in western Canada.

BACKGROUND: Tuberculosis (TB) remains a major health problem for Aboriginal people in Canada, with high rates of clustering of active TB cases. Bacille Calmette-Guerin (BCG) vaccination has been used as a preventive measure against TB in this high-risk population. OBJECTIVES: The study was designed to determine if BCG vaccination in Aboriginal people influenced recent TB transmission through an analysis of the clustering of TB cases. METHODS: A retrospective analysis of all culture-positive Mycobacterium tuberculosis cases in Aboriginal people in western Canada (1995 to 1997) was performed. Isolates were analyzed using standard methodology for restriction fragment length polymorphism and spoligotyping. RESULTS: Of 256 culture-positive Aboriginal TB cases, BCG status was confirmed in 216 (84%) cases; 34% had been vaccinated with BCG, 57% were male and 56% were living on-reserve. Patients who had been vaccinated with BCG were younger than unvaccinated individuals (mean age 32.4+/-1.65 years versus 45.0+/-1.8 years, P<0.0001). Clustering was found in 62% of cases: 59% of non-BCG vaccinated cases were clustered versus 68% of those vaccinated with BCG (P=0.16). Younger patients (younger than 60 years of age) were more likely to be clustered in the univariate analysis (P<0.01). When age, sex, province, and HIV and reserve status were controlled for, BCG vaccination was not associated with clustering (OR 1.3, 95% CI 0.7 to 2.6). CONCLUSIONS: BCG vaccinated Aboriginal people were no less likely to have active TB from recently transmitted disease. BCG vaccination appears to have limited value in preventing clustering of TB cases within this high-risk community.

Tuberculous lymphadenitis in Manitoba: incidence, clinical characteristics and treatment.

BACKGROUND: Tuberculous lymphadenitis (TBL) is an important form of extrapulmonary tuberculosis (TB). Recent studies have shown an increase in TBL in Canada. OBJECTIVES: To determine the incidence of TBL in Manitoba and to identify the characteristics associated with its presentation, diagnosis and treatment METHODS: Population data from the Manitoba Health Population Registry, the First Nations and Inuit Health Branch of Health Canada, and Statistics Canada were used to calculate incidence. Case characteristics and outcomes were determined by a systematic, retrospective review of all cases between January 1, 1990 and December 31, 2000. RESULTS: One-hundred forty seven cases of TBL were identified during the study period; 77% confirmed by culture; 68% women. TBL was found in Canadian-born/nonstatus Aboriginal (12%), status Aboriginal (29%) and foreign-born (59%) populations. Incidence of TBL was 1.17 per 100,000 person years (95% CI 0.98 to 1.36). The highest incidence was in status Aboriginals over 65 years (16.85 per 100,000 person years; 95% CI 3.37 to 30.33). TBL is seen most often in Western Pacific women. The most common presentation was a single, enlarged cervical node (80%). No atypical mycobacterium was found. Drug resistance occurred in 13% of cases and only in the foreign-born. Cure rates (81%) were influenced by comorbidity and burden of TB disease. Relapse occurred in 8.1 per 1000 person years of follow-up (95% CI 1.7 to 23.7). CONCLUSIONS: Respiratory physicians, who manage the majority of TB disease in Canada, need to remain aware that TB is an important and treatable cause of enlarged lymph nodes.

Conventional and molecular epidemiology of tuberculosis in Manitoba.

BACKGROUND: To describe the demographic and geographic distribution of tuberculosis (TB) in Manitoba, thus determining risk factors associated with clustering and higher incidence rates in distinct subpopulations. METHODS: Data from the Manitoba TB Registry was compiled to generate a database on 855 patients with tuberculosis and their contacts from 1992-1999. Recovered isolates of M. tuberculosis were typed by IS6110 restriction fragment length polymorphisms. Bivariate and multivariate logistic regression models were used to identify risk factors involved in clustering. RESULTS: A trend to clustering was observed among the Canadian-born treaty Aboriginal subgroup in contrast to the foreign-born. The dominant type, designated fingerprint type 1, accounts for 25.8% of total cases and 75.3% of treaty Aboriginal cases. Among type 1 patients residing in urban areas, 98.9% lived in Winnipeg. In rural areas, 92.8% lived on Aboriginal reserves. Statistical models revealed that significant risk factors for acquiring clustered tuberculosis are gender, age, ethnic origin and residence. Those at increased risk are: males (p < 0.05); those under age 65 (p < 0.01 for each age subgroup); treaty Aboriginals (p < 0.001), and those living on reserve land (p < 0.001). CONCLUSION: Molecular typing of isolates in conjunction with contact tracing data supports the notion of the largest ongoing transmission of a single strain of TB within the treaty-status population of Canada recorded to date. This data demonstrates the necessity of continued surveillance of countries with low prevalence of the disease in order to determine and target high-risk populations for concentrated prevention and control measures.

Epidemiology and clinical spectrum of blastomycosis diagnosed at Manitoba hospitals.

Blastomyces dermatitidis is a dimorphic fungus endemic to Canada and the United States. Few reports regarding blastomycosis in Canada have been published. We retrospectively reviewed the medical charts of 143 patients with confirmed cases of blastomycosis diagnosed in hospitals in Manitoba, Canada, from 1988 through 1999. The annual incidence rate of blastomycosis in Manitoba was 0.62 cases per 100,000 population, compared with 7.11 cases per 100,000 population in the Kenora, Ontario district. The average age of patients was 38.0 years, and males accounted for 65.0% of cases. An increased incidence of blastomycosis was observed in the Aboriginal subpopulation. Organ systems involved were as follows: respiratory system (93.0% of cases), skin (21.0%), bone (13.3%), genitourinary tract (1.4%), and the central nervous system (1.4%); 6.3% of patients died, and death was associated with a short clinical course. This study provides a summary of the current status of blastomycosis in this area of endemicity in Canada.