Spatio-temporal analysis of tuberculous infection risk among clients of a homeless shelter during an outbreak.

SETTING: British Columbia (BC) has a low incidence of tuberculosis (TB), with the burden of endogenously acquired disease concentrated among vulnerable populations, including the homeless. In May 2008, a TB outbreak began in a BC homeless shelter, with a single index case seeding multiple secondary cases within the shelter. OBJECTIVE: To use nightly shelter records to quantify the risk of latent tuberculous infection (LTBI) among shelter clients as a function of their sleeping distance from and duration of exposure to the index case. DESIGN: Distance and duration of exposure were visualised and assessed using logistic regression with LTBI status as outcome. We used a novel machine learning approach to establish exposure thresholds that optimally separated infected and non-infected individuals. RESULTS: Of 161 exposed shelter clients, 58 had a recorded outcome of infected (n = 39) or non-infected (n = 19). Only duration of exposure to the index was associated with increased odds of infection (OR 1.26); stays of ⩾ 5 nights put shelter clients at higher odds of infection (OR 4.97). CONCLUSION: The unique data set and analytical approach suggested that, in a shelter environment, long-term clients are at highest risk of LTBI and should be prioritised for screening during an outbreak investigation.

A clonal outbreak of tuberculosis in a homeless population in the interior of British Columbia, Canada, 2008-2015.

A tuberculosis (TB) case was reported May 2008 in Kelowna, British Columbia, leading to a multi-year outbreak in homeless persons. The epidemiological characteristics and social networks of cases are described. Outbreak-related cases were identified from epidemiological information in medical records and from genotyping of TB isolates. Social network information from case interviews were used to identify potential locations of TB transmission, where symptom screening and tuberculin skin testing was conducted. Fifty-two cases that were predominantly male (47/52), Canadian-born (44/50), and were homeless or associated with homeless individuals (42/52) were reported from May 2008 to May 2014. Many isolates (40/49) had partial resistance to isoniazid. Transmission primarily occurred at two homeless shelters, with potential further transmission at sites visited by the general population. TB outbreaks in homeless populations can occur in small, low-incidence cities. Social network information helped prioritize sites for TB screening, thereby improving detection of persons with TB disease or latent infection for treatment.

Raising chickens in city backyards: the public health role.

There is increasing interest in raising chickens in urban settings across North America. Current regulations on backyard chickens vary by jurisdiction due to concerns about perceived health threats. Proposed negative impacts on public health and community well-being include infectious diseases acquired through rearing practices or consumption of eggs, inappropriate waste management, interaction with pests and predators and nuisance factors such as noise and odour. Proposed benefits are derived largely from the human-animal bond and from feelings of autonomy over food selection. The importance or validity of claims of positive and negative effects cannot be supported by literature specific to the urban agriculture context. Public health practitioners might approach this issue in a manner analogous to concerns over keeping domestic pets.

Are you prepared? Defining occupational health resource needs to prevent infectious disease transmission in the health care sector.

This article discusses the extent of resource allocation to Occupational Health (OH) to prevent infectious disease exposure and transmission in British Columbia (B.C.). It also characterizes the delineation of roles and responsibilities within OH services in B.C. health care settings and highlights areas where improvements to current OH programs could be made to prevent and control occupational infections. Given the breadth of OH responsibilities, resource allocation in many health care institutions for these services is inadequate and roles and responsibilities may not be clearly delineated.

Sex differences in habitual physical activity and lung function decline in children with cystic fibrosis.

OBJECTIVES: To evaluate the feasibility of measuring habitual physical activity (HPA) in children with cystic fibrosis (CF) and to assess the relation between HPA and the rate of decline in FEV1 over a period of 2 years. STUDY DESIGN: At regular clinic visits, 109 patients (7 to 17 years; 56 girls) performed pulmonary function testing and completed the Habitual Activity Estimation Scale (HAES). Patients were divided into quartiles, based on activity levels derived from the HAES. RESULTS: Girls in the two lowest activity quartiles had a more rapid rate of decline FEV1 (-3.40% and -3.05% predicted, respectively) than girls in the two highest activity quartiles (-0.93% and +1.17% predicted, respectively) (P = .02). In boys, the rate of decline of FEV1 was similar in all activity quartiles (-1.95% predicted). Patients reported significantly more activity in summer compared with spring, winter, and fall (P < .0001), and boys reported greater activity than girls (6.5 +/- 2.9 vs 5.4 +/- 2.5 h/d, P < .05). CONCLUSIONS: The annual rate of change of FEV1 was related to activity quartile in girls but not in boys. This research suggests that an inactive lifestyle may partially explain the poorer survival of female patients with CF. The HAES is a feasible tool for routine follow-up of HPA in our CF clinic.

A randomized controlled trial of a 3-year home exercise program in cystic fibrosis.

OBJECTIVES: To evaluate the effects of a 3-year home exercise program on pulmonary function and exercise tolerance in mildly to moderately impaired patients with cystic fibrosis (CF) and to assess whether regular aerobic exercise is a realistic treatment option. STUDY DESIGN: Seventy-two patients with CF (7-19 years) were randomly assigned to an exercise group (a minimum of 20 minutes of aerobic exercise, at a heart rate of approximately 150 beats/min, 3 times weekly) or a control group (usual physical activity participation). Pulmonary function, exercise tolerance, clinical status, hospitalizations, and compliance with therapy were monitored during scheduled visits to the hospital's CF clinic. RESULTS: Sixty-five patients were included in the analyses. The control group demonstrated a greater annual decline in percent of predicted forced vital capacity compared with the exercise group (mean slope +/- SD, -2.42 +/- 4.15 vs -0.25 +/- 2.81; P =.02), with a similar trend for forced expiratory volume in 1 second (-3.47 +/- 4.93 vs -1.46 +/- 3. 55; P =.07). Patients remained compliant with the exercise program over the study period. An improved sense of well-being was reported with exercise. CONCLUSIONS: Pulmonary function declined more slowly in the exercise group than in the control group, suggesting a benefit for patients with CF participating in regular aerobic exercise. Consistent compliance with the home exercise program and a self-reported positive attitude toward exercise provide further evidence of the feasibility and value of including an aerobic exercise program in the conventional treatment regimen of patients with CF.

The t(5;17) acute promyelocytic leukemia fusion protein NPM-RAR interacts with co-repressor and co-activator proteins and exhibits both positive and negative transcriptional properties.

The t(5;17) variant of acute promyelocytic leukemia (APL) fuses the genes for nucleophosmin (NPM) and the retinoic acid receptor alpha (RARalpha). Two NPM-RAR molecules are expressed as a result of alternative RNA splicing. Both contain RARalpha sequences that encode the DNA binding, heterodimerization, and ligand activation domains of RARalpha. This study was designed to test the ability of these fusion proteins to act as transcriptional activators of retinoic acid responsive promoters. The NPM-RAR fusion proteins bind to retinoic acid response element sequences as either homodimers or as heterodimers with RXR. Transcription of retinoic acid-inducible promoters is activated by the fusion proteins in the presence of retinoic acid. The level of transactivation induced by the NPM-RAR fusions differs from the level of transactivation induced by wild-type RARalpha in both a promoter and cell specific fashion, and more closely parallels the pattern of activation of the PML-RAR fusion than wild-type RARalpha. In addition, NPM-RAR decreases basal transcription from some promoters and acts in a dominant-negative fashion when co-transfected with wild-type RARalpha. Both NPM-RAR and PML-RAR interact with the co-repressor protein SMRTe in a manner that is less sensitive than RARalpha to dissociation by retinoic acid. Retinoic acid induces binding of the co-activator protein RAC3. These data indicate that the NPM-RAR fusion proteins can modulate expression of retinoid-responsive genes in a positive or negative manner, depending on context of the promoter, and lend support to the hypothesis that aberrant transcriptional activation underlies the APL phenotype. (Blood. 2000;95:2683-2690)