The Medicine Wheel: informing the management of tuberculosis outbreaks in Indigenous communities

Many Indigenous communities in Canada experience endemic tuberculosis with superimposed periodic epidemic outbreaks. Failures in outbreak management have resulted in the "seeding" of future infection and disease. In this paper we present a model that may be used in planning, implementation and review of tuberculosis outbreak management in Cree Indigenous communities in Canada, based on the Medicine Wheel, a paradigm for holistic living. In the context of tuberculosis management, the Medicine Wheel provides a path for the establishment of respectful cross-cultural relationships, the expression of values through action, true community engagement and partnership, and the establishment of culture-based processes of transparency, accountability and change.

Protective effects of prior third dose mRNA vaccination in rural nursing home residents during SARS-CoV-2 outbreaks

Background

In Canada, mortality due to SARS‐CoV‐2 disproportionately impacted residents of nursing homes (NH). In November 2021, NH residents in the Canadian province of Manitoba became eligible to receive three doses of mRNA vaccine but coverage with three doses has not been universal. The objective of this study was to compare the protection from infection conferred by one, two, and three doses of COVID‐19 mRNA vaccine compared to no vaccination among residents of nursing homes experiencing SARS‐CoV‐2 outbreaks.

Methods

Infection Prevention and Control reports from 8 rural nursing homes experiencing outbreaks of SARS‐CoV‐2 between January 6, 2022, and March 5, 2022, were analyzed. Attack rates and the number needed to vaccinate (NNV) were calculated.

Results

SARS‐CoV‐2 attack rate was 65% among NH residents not vaccinated, 58% among residents who received 1–2 doses of mRNA COVID‐19 vaccine, and 28% among residents who had received 3 vaccine doses. The NNV to prevent one nursing home resident from SARS‐CoV‐2 infection during an outbreak was 3 for a vaccination with 3 doses and 14 for 1–2 doses of COVID‐19 mRNA vaccine. The superiority of receiving the third dose was statistically significant compared to 1–2 doses (Chi‐Squared, p < 0.00001).

Conclusions

Nursing home residents who received three doses of COVID‐19 mRNA vaccine were at lower risk of SARS‐CoV‐2 infection compared to those who received 1–2 doses. Our analyses lend support to the protective effects of the third dose of mRNA vaccine for NH residents in the event of a SARS‐CoV‐2 outbreak.

Functional gene polymorphisms in canadian aboriginal populations with high rates of tuberculosis

The present study determined whether a pattern of functional single-nucleotide polymorphisms (SNPs) was present that could predispose a Dené cohort to a suboptimal response to Mycobacterium tuberculosis. Compared with a Caucasian cohort, the Dené and Cree were found to maintain a significantly higher frequency of SNPs associated with low expression of vitamin D receptor (VDR), interferon (IFN)-gamma (+874), and tumor necrosis factor-alpha (-308) and high production of monocyte chemoattractant protein (MCP)-1 (-2518) and interleukin (IL)-6 (-174). Given the roles played by IFN-gamma and VDR in facilitating macrophage containment of M. tuberculosis and the opposing role of MCP-1 and IL-6, the observed allelic variation by ethnicity may in part contribute to the high rates of tuberculosis among the Dené.

Actinic prurigo: Clinical features and HLA associations in a Canadian Inuit population

BACKGROUND

Actinic prurigo (AP) is an idiopathic familial photodermatitis. AP of the Inuit is rarely reported and poorly characterized.

OBJECTIVE

Our purpose was to examine the clinical features and HLA associations of AP in an Inuit population.

METHODS

Thirty-seven Inuit subjects with AP were administered a questionnaire and underwent a cutaneous examination. Other causes of photosensitivity were excluded. HLA class I typing was performed by polymerase chain reaction and sequence-specific primers and class II typing by polymerase chain reaction and sequence-specific oligonucleotide probes.

RESULTS

Subjects were 81.1% female, 67.6% had a family history of photosensitivity, and all experienced seasonal variation. The average age at onset of photosensitivity was 29 years, and only 27% had a trend toward improvement in photosensitivity. Involvement of eyes and nonexposed skin was reported in 62.2% and 18.9% of subjects, respectively. Physical examination revealed involvement of the face (64.9%), lip (32.4%), ear (13.5%), and dorsal aspect of the hand (24.3%). HLA-DRB1*14 was present in 51.2% of subjects and 26.2% of controls (P =.022, odds ratio = 2.975). This is a previously unreported HLA association.

CONCLUSION

AP in the Inuit is a seasonal, pruritic photodermatitis, often commencing in adulthood and worsening over time. A novel association with HLA-DRB1*14 has been discovered. Overall, this novel HLA association, the absence of HLA associations previously reported in non-Inuit populations, and clinical distinguishing features support the concept that AP in the Inuit may have a distinct immunopathogenic basis that translates into a different phenotype. It also raises the question of whether AP in the Inuit is a distinct photosensitivity disorder specific to this group that has been genetically isolated because of geographic and cultural seclusion.

Prevalence of diabetes mellitus and obesity in the Keewatin District of the Canadian Arctic

Through a medical chart review, the prevalence of diagnosed diabetes mellitus in Inuit of the Keewatin District of the Canadian Northwest Territories was determined to be 0.27%. All cases were in adults, and no cases of gestational diabetes were noted. The prevalence and pattern of obesity were determined from measurements of body mass index (BMI), skinfold thickness, and waist-hip ratio obtained during the 1990-91 Keewatin Health Assessment Study. Thirty-one percent of 414 randomly identified adults (29% of men, 37% of women) were overweight (BMI > 27). Central fat patterning was more prevalent in women and less prevalent in men from the Keewatin compared to the general Canadian population. Comparison of skinfold thickness values to published measurements obtained from earlier arctic surveys supports the hypothesis that changes in diet and activity levels associated with urbanization have resulted in increased obesity in the Inuit.

Incidence of ectopic pregnancy and sexually transmitted disease in the Canadian Central Arctic

A retrospective review of all medical evacuations from 1987-1994 of women in the Keewatin District of the Canadian Central Arctic was undertaken to determine the incidence of ectopic pregnancy. The incidence of N. gonorrhoeae and C. trachomatis as major risk factors for ectopic pregnancy was also determined. The average annual incidence of ectopic pregnancy in the Keewatin over the study period was 178/100,000 women age 15-44 years, or 9.6/1,000 reported pregnancies; for Southern Canada the corresponding average annual incidence is 118.3/100,000 women age 15-44 years, or 15.7/1,000 reported pregnancies. The high general fertility rate in the Keewatin (189/1,000 population) accounts for the difference in ectopic pregnancy rates expressed per population versus per pregnancy. The average annual incidence of gonorrhea and chlamydia infection were 1,444 and 3,695/100,000 population, respectively; these rates were 27- and 22-fold higher than those seen in the general Canadian population. The incidence of chlamydia was particularly high (16,194/100,000) in women age 15-24 years. Despite the high incidence of gonorrhea and chlamydia in the Keewatin, the rate of ectopic pregnancy expressed per 1,000 pregnancies is comparable to that seen in Southern Canada. Possible differences between populations in the determinants of tubal damage, including time from exposure to infection to pregnancy, host immunity and bacterial virulence, may account for this observation.

Nosocomial pneumonia on general medical and surgical wards in a tertiary-care hospital

OBJECTIVE

To describe the demographic, clinical, and microbiologic characteristics of patients who develop nosocomial pneumonia on general medical and surgical wards of a tertiary-care hospital.

DESIGN

A 1-year, prospective, descriptive study.

SETTING

A 1,100-bed, tertiary-care, urban hospital.

POPULATION

Patients experiencing nosocomial pneumonia were identified through surveillance on general medical and surgical wards, using a standard case definition.

RESULTS

92 pneumonias in 85 patients on general wards were identified. The mean age of patients was 63 +/- 17 years, 55 patients (65%) were male, and 75 cases of pneumonia (81%) were acquired on surgical wards. Bacteremia was identified in 8 (13%) of 62 episodes, and 48 (52%) grew potential pathogens from respiratory specimens. Twenty-six patients (28%) required transfer to the intensive-care unit (ICU), and 20 (22%) received mechanical ventilation. By multivariate analysis, patients with a thoracic surgical procedure or with Staphylococcus aureus isolated from respiratory secretions were more likely to require ICU admission. The overall mortality rate was 20% (17/85), with a directly associated mortality of 14% (12/85). Patients who died were older, more frequently resided on a medical ward, and had a greater mean number of comorbidities. These patients often were treated nonaggressively and were not considered candidates for ICU admission due to advanced age and poor underlying clinical status.

CONCLUSIONS

Although the morbidity of nosocomial pneumonia in this population was high, as evidenced by high rates of transfer to ICU, the directly associated mortality was relatively low. Those requiring ICU admission require further study to identify preventive measures that could decrease the morbidity in this group. Interventions to prevent pneumonia or to improve prognosis may not be feasible for the majority of these patients who die from nosocomial pneumonia.

Serological study of responses to selected pathogens causing respiratory tract infection in the institutionalized elderly

In a prospective 2-year study, serological responses to selected pathogens were analyzed in 224 episodes of fever attributable to respiratory tract infection (51.8%) or of unknown source (48.2%) in 131 residents of two long-term-care facilities. A serological response was identified in 45 episodes (20.1%): Chlamydia pneumoniae (14 episodes), Haemophilus influenzae type b (1), influenza virus type A (14), respiratory syncytial virus (RSV;2), parainfluenza virus type 3 (7), C. pneumoniae and H. influenzae (3), C. pneumoniae and influenza virus type A (2), C. pneumoniae and RSV (1), and C. pneumoniae and parainfluenza virus type 3 (1). No serological responses to Chlamydia psittaci, Chlamydia trachomatis, parainfluenza virus types 1 and 2, influenza virus type B, or Mycoplasma pneumoniae were seen. Vaccination did not affect the duration of fever in those residents with serologically confirmed influenza A. Serologically confirmed C. pneumoniae infection was detected in 9.4% of all febrile episodes. Serological responses to a second agent were detected in 33% of the patients with C. pneumoniae infections, and these dual infections were associated with an underlying malignancy (P = .02). C. pneumoniae should be recognized as a potential pathogen when choosing empirical antimicrobial therapy for respiratory tract infection in residents of long-term-care facilities.

Febrile urinary infection in the institutionalized elderly

PURPOSE

Bacteriuria is common among institutionalized elderly populations, but the contribution of urinary infection to febrile morbidity is unknown because of difficulties in clinical ascertainment. This study was undertaken to febrile morbidity using both clinical and serologic criteria.

METHODS

Episodes of fever in residents of two long-term care institutions were identified prospectively for 2 years. Serum and urine specimens were obtained initially and at 4 weeks. The proportion of episodes attributable to urinary infection was determined by both standard clinical criteria proposed for use in these populations and serum antibody response to uropathogens.

RESULTS

For 372 fewer episodes, 211 met clinical criteria for infection: 147 (40%) of the respiratory tract; 26 (7%) of the genitourinary tract; 25 (6%) of the gastrointestinal tract; and 13 (3%) of skin and soft tissue. Of the remaining 161 fever episodes, 2 (1%) were noninfectious and 159 (43%) were of unknown origin. The prevalence of bacteriuria for residents with nongenitourinary sources of fever varied from 32% to 75%. An antibody response meeting serologic criteria for urinary infection occurred in 26 (8.3%) of 314 episodes with paired sera obtained; 10 (43%) of 23 identified clinically as genitourinary infection, 14 (11%) of 132 unknown, 1 (4%) of 25 gastrointestinal, and 1 (0.8%) of 122 respiratory. The positive predictive value of bacteriuria for febrile urinary infection identified by clinical criteria was was 11% (95% confidence interval [CI] 4%, 18%) and identified by serologic criteria was 12% (95% CI 7%, 17%).

CONCLUSIONS

Urinary infection contributes to less than 10% of episodes of clinically significant fever in this high-prevalence bacteriuric population. A restrictive clinical definition for genitourinary infection has poor sensitivity and specificity compared with serologic criteria for identification of fever of urinary source, and bacteriuria has a low predictive value for identifying febrile urinary infection.

P1 blood group antigen expression and epidemic hemolytic uremic syndrome

P1 blood group positivity has been postulated as a host factor which may provide protection against the development of post-enteropathic hemolytic uremic syndrome (HUS). In this study, blood group status in 20 Inuit survivors of Escherichia coli O157:H7-associated HUS was compared with age- and sex-matched controls from the same community who had experienced uncomplicated diarrheal illness due to the same pathogen. Of 20 HUS survivors, 6 were P1 antigen positive compared with 8 of the 20 controls (P = 0.7). We conclude that P1 antigen positivity was not protective against HUS in this population. Further studies of this condition to clarify the role of host factors in verotoxin-induced endothelial damage are indicated.

Risk factors for infection in women undergoing testing for Chlamydia trachomatis and Neisseria gonorrhoeae in Manitoba, Canada

BACKGROUND AND OBJECTIVES

Despite sharing common modes of transmission, characteristics of individuals infected with Chlamydia trachomatis differ in several respects from those with Neisseria gonorrhoeae infection. Further characterization of women at high risk for chlamydial infection is needed to deliver appropriate and effective preventive, diagnostic, and therapeutic care to this population.

GOAL OF THIS STUDY

The demographic and socioeconomic characteristics of women with laboratory confirmed chlamydia, gonorrhea, or coinfection were compared with those of control women who tested negative for both pathogens.

STUDY DESIGN

A random sample of 400 women in Manitoba, Canada, who had undergone testing for sexually transmitted diseases at a public health laboratory in 1988 were studied. After linkage with medical insurance and census databases, logistic regression analysis was used to compare age, ethnicity, urban status, and mean income (using postal codes) of women with gonorrhea alone, chlamydia alone, and coinfection, with the same data for women who tested negative for both organisms.

RESULTS

Young age, North American Indian status, urban residence, and low mean income according to postal code were significantly associated with gonococcal and chlamydial infection in the study population, compared with women who tested negative for both infections. Young age, Indian status, and urban residence also were associated with gonorrhea infection alone. Only young age and Indian status were associated with chlamydial infection. Mean incomes of women with chlamydial infection alone and control subjects were higher than those of women with gonorrhea and gonorrhea and chlamydia coinfection.

CONCLUSIONS

Differences in the demographic and socioeconomic characteristics of women with gonorrhea, chlamydia, and coinfection suggest the existence of multiple reservoirs of infection due to these agents in the study population. The preventive, diagnostic, and therapeutic strategies of sexually transmitted disease control programs must be adapted to the individual needs of identified high-risk groups.

Randomized placebo-controlled trials of antibiotics for acute bronchitis: a critical review of the literature

BACKGROUND

Acute bronchitis is a common clinical problem that causes considerable morbidity and presents both diagnostic and treatment dilemmas for the physician. An evaluation of all published randomized controlled trials of antibiotics in the treatment of acute bronchitis was conducted to (1) quantitatively assess methodologic rigor, (2) determine if effectiveness of antimicrobial therapy is known, and (3) analyze strengths and weaknesses of randomized controlled trials in family practice settings.

METHODS

A scoring system for the evaluation of randomized controlled trials was adapted for this study. Four raters, who were blinded to which journals published the studies and the type of antibiotic used in each study, assessed the six-randomized clinical trials for treatment of bronchitis identified through a literature search. The trials were rated according to criteria that measured internal validity.

RESULTS

Scores for internal validity ranged from 65.5 to 102.5 points with a maximum possible score of 120 points (54.6% to 85.4%). The two trials with the highest scores assessed doxycycline and showed no benefit from use of this antibiotic. Single trials that studied erythromycin and trimethoprim-sulfamethoxazole showed improvement in outcome from use of these drugs; however, of the six trials, these two studies ranked fourth and fifth for internal validity. Low scores resulted from small sample size, possible contamination with other treatment measures, and poor assessment of subjects' compliance with antibiotic regimen.

CONCLUSIONS

An evaluation of the current literature does not support antibiotic treatment for acute bronchitis. Further studies of this common illness are indicated. It is hoped that this critical review of randomized control trials will prove useful in the planning of future studies, in placing greater emphasis on methodologic rigor, and in giving greater consideration to the practical constraints of research in the family practice setting.

Deuterium nuclear magnetic resonance studies of potato starch hydration

Deuterium Nuclear Magnetic Resonance (NMR) measurements at 4.7 Tesla were used to study the hydration properties of potato starch suspensions as a function of the starch-to-water ratio. The deuterium NMR spectrum of potato starch suspensions consisted of a relatively tall, single Lorentzian (D2O) peak and a resolved doublet ('powder' pattern) of about 1 kHz quadrupole splitting and low amplitude. The deuterium NMR transverse relaxation rate (R*2) was measured for the single Lorentzian, deuterium oxide peak; this rate increased with increasing starch-to-water ratio. Deviations of such R*2 dependences from linearity were observed only at high ratios of starch-to-water, above approximately 40% solids. In addition to the 'free' or bulk population (which has a very fast rotational correlation time of 5 ps), a second population of water weakly sorbed on the starch granule surface was monitored and found to be in fast exchange with the bulk water; this second water population has a rotational correlation time of 17 ps at 298 K, only about three times slower than that of bulk water. Additionally, a third population of slowly exchangeable water is present, which is "anisotropically bound" and has a highly restricted motion within the potato starch granule structure; well-defined quadrupole splittings are observed from this latter population of water in potato starch. Potato starch exhibits unique hydration properties that have not been found in cereal starches.

Tuberculosis surveillance in immigrants to Manitoba

Despite a decrease in the incidence of tuberculosis in Canada over the last decade, the proportion of cases in people not born in Canada has increased. To determine the prevalence of active tuberculosis at the first surveillance clinic visit and the incidence of the disease over a 2-year to 6-year follow-up period, we reviewed the records of all 523 immigrants admitted to Manitoba between 1981 and 1985 who were placed under surveillance. Of the 523, 429 (82%) were seen at least once in the clinic. Among the 429, active tuberculosis was diagnosed at the first visit in 12 (3%) and during the follow-up period in 7 (2%). The relative risk of tuberculosis was 4.5 times higher for immigrants under surveillance than for those not under surveillance. Of the 483 immigrants who were to be seen in Winnipeg 232 (48%) were noncompliant: 94 were not seen at any time, and 138 did not attend for the full follow-up period. Active disease was not reported to have developed in any of the noncompliant subjects. Noncompliers were significantly older than compliers (p less than 0.005), and variations in compliance were noted according to region of origin. Further attempts to improve compliance with surveillance without resorting to punitive measures are indicated.

Hereditary polymorphic light eruption in Canadian Inuit

Twelve Canadian Inuit patients from the Keewatin District of the Northwest Territories were found to have hereditary polymorphic light eruption. The clinical manifestations were similar to those described in the North American Indian, with a photodermatitis occurring in the sunlight-exposed area. The onset occurred prior to the age of 15 years in 70% of subjects, and the condition was seasonally recurrent, starting in February and lasting until September. Patients demonstrated improvement on a combined regime of local therapy and oral trioxalen. Seventy-five percent of patients had a family history of photosensitivity, suggesting an autosomal dominant trait with incomplete penetrance. Indian ancestry was not demonstrated in these patients.