Screening employees of services for homeless individuals in Montreal for tuberculosis infection

The results of a tuberculin skin test [TST] screening program offered to employees of services for homeless people in Montr‚al from 1998 to 2005 were analyzed to assess the occupational risk of tuberculosis [TB] infection. Employees with no known contact with TB were selected among volunteer participants. They were followed in two dynamic cohorts: individuals with a negative two-step baseline TST [cohort A] and individuals with a negative single baseline TST [cohort B]. We estimated the prevalences of initial positive TST, boosting effect, and conversion rate. The average age of the workers was 38.9 years. The prevalence of an initial positive TST was 12.9%. A booster effect was observed in 5.1% of workers who completed a two-step TST. The incidence of conversion was 2.3/100 person-years for cohort A [n = 93] and 3.5/100 person-years for cohort B [n = 221]. The incidence of conversion was not significantly associated with any of the demographics or workplace factors investigated. Our findings are comparable to the rates reported among community workers, whose risk is higher than the average health worker. This suggests that there are occasional unidentified contagious cases among the homeless individuals of participating institutions

Type-specific prevalence of human papillomavirus infection among women in the northwest territories, Canada

Certain types of Human Papillomavirus [HPV] are highly associated with cervical cancer and precursor lesions [dysplasia], but the distribution of HPVs in Northern Canada is largely unknown. This study determined the prevalences of HPV infection due to different virus types and the association of different virus types with cervical dysplasia in the Northwest Territories [NWT]. Between April 2008 and March 2009, women who underwent routine Pap testing in the NWT were included in the study. An in-house Luminex assay detected type-specific HPV infections. The HPV prevalence rates and population attributable risk fractions were calculated. In 5725 bio-samples, the overall HPV prevalence was 24.2%, and of the HPV-positive samples, 76.6% harbored high-risk types, 35.2% harbored multi-type infections, and 21.6% harbored HPV16 or 18 infections. The HPV prevalence was approximately 50% higher among Aboriginal than non-Aboriginal women. The age-specific HPV prevalence exhibited a U-shape distribution in the Aboriginal group. The prevalence of HPV16 or 18 infections found in high-grade lesions was 34.1%. Among this study population, 89.5% of the cases with cervical dysplasia were attributable to HPV infection, with 27.1% attributable to HPV16/18. The high prevalence of high-risk HPV in this population, particularly in the Aboriginal group, will require further studies to identify specific predictors of infection