Three sequential outbreaks of Group A Streptococcus over a two-year period at the Canadian Forces Leadership and Recruit School, St. Jean Garrison, Québec.

BACKGROUND: Since December 2016, the basic military training (BMT) facility for the Canadian Armed Forces (CAF) has experienced repeated outbreaks of Group A Streptococcus (GAS). In 2018, a voluntary mass antibiotic prophylaxis (MAP) program was implemented to interrupt GAS transmission among recruits. The objective of this study was to describe the epidemiology of three GAS outbreaks and a period of increased pharyngitis infections at the CAF BMT facility in Québec over a two-year span, and to detail the prevention and control measures implemented to mitigate the risk to recruit health. METHODS: Descriptive data were collected on invasive and severe GAS cases along with laboratory data including genotyping of throat swabs from recruits presenting with pharyngitis. A laboratory-based acute respiratory infection surveillance system was used to aid in monitoring and decision-making. Close contacts of recruits were assessed for asymptomatic GAS carriage and MAP adverse events surveillance was conducted. RESULTS: Three distinct GAS outbreaks occurred at the Canadian Forces Leadership and Recruit School totaling eight invasive (iGAS) and 13 severe (sGAS) cases over two years. All iGAS/sGAS cases, apart from one instructor, were among recruits. The predominant strain in all three outbreaks was type emm6.4. A total of 11,293 recruits received MAP (penicillin G benzathine or azithromycin) between March 7, 2018 and November 18, 2019. There were eight reported serious adverse events related to penicillin administration. CONCLUSION: The CAF BMT facility experienced three GAS outbreaks over the course of two years, and despite the use of enhanced hygiene measures, only MAP has been effective in quelling these outbreaks.

Adverse events following mass antibiotic prophylaxis during a Group A Streptococcus outbreak in the Canadian Forces Leadership and Recruit School.

BACKGROUND: Between December 2016 and March 2018, two outbreaks of Group A Streptococcus (GAS) infection occurred at the Canadian Forces Leadership and Recruit School. A voluntary mass antibiotic prophylaxis (MAP) program was implemented in March 2018, to interrupt an ongoing GAS outbreak, and to prevent future outbreaks. METHODS: Instructors and recruits were offered a one-time intramuscular injection of 1.2 million units penicillin G benzathine (PGB). Individuals with a penicillin allergy were offered azithromycin; 500 mg orally once weekly for four consecutive weeks. Instructors and recruits were also asked to complete a voluntary and anonymous survey one week after receipt of MAP, to detect MAP-related adverse events. RESULTS: MAP was offered to 2,749 individuals; 2,707 of whom agreed to receive it (98.5% uptake). The majority of personnel experienced adverse events in the days following MAP; 92.3% of personnel who received PGB reported localized pain at the injection site, and 70.2% of personnel who received azithromycin reported gastrointestinal symptoms. However, only five cases of serious adverse events were reported, and less than 1% of recruits could not complete their basic military training course because of MAP-related adverse events. CONCLUSION: The MAP program implemented in March 2018 was the first of its kind in the Canadian Armed Forces, and the largest single use of PGB in a defined group in Canada. It resulted in very few serious adverse events and with minimal impact on military recruits' successful completion of recruit training.

Group A Streptococcus Outbreak in a Canadian Armed Forces Training Facility.

Between December 2016 and April 2017, two cases of invasive Group A Streptococcus (GAS) infections were reported at a Canadian military training facility. An outbreak was declared and a field investigation was launched to characterize the outbreak and identify associated risk factors to limit transmission. Throat culture data from military personnel at the garrison were analyzed. Investigators tracked invasive GAS cases and non-invasive hospitalized GAS cases, and conducted site visits and case interviews. Sensitivity and specificity for a rapid antigen detection test were evaluated. Molecular typing and phylogenomic relationships of outbreak isolates were analyzed using whole-genome sequencing. During this outbreak, four invasive cases were reported and six non-invasive cases were hospitalized. In a sample of 705 throat cultures examined, 35.2% were GAS-positive. Among 65 platoon contacts of one invasive case, 30.2% were GAS-positive. Reluctance to seek medical care, challenges in following cough etiquette, and low compliance with antibiotics were identified among recruits. The rapid antigen detection test had low sensitivity (31.6%) during the outbreak. The outbreak sequence type was emm6.4 and outbreak isolates were highly related phylogenetically, differing by 0-4 single nucleotide variants. This is the first report of a GAS outbreak among Canadian military trainees. Increased surveillance of GAS infections, increased control measures and outbreak-specific clinical guidelines were implemented in-garrison. No further invasive GAS cases were identified. A GAS surveillance system was implemented and efforts to improve antibiotic compliance and medical consultation were recommended.

Good interventions that few use: uptake of insect bite precautions in a group of Canadian Forces personnel deployed to Kabul, Afghanistan.

We evaluated use of interventions to prevent insect bites in Canadian personnel deployed to Kabul, Afghanistan. Data were collected through a self-report written survey. The response rate was 92%, and intervention uptake was 11% applied repellent that day, 21% slept under a bednet their last sleep, and 78% wore insecticide-treated clothing. Two associations were usually evident in multivariate analyses: persons perceiving risk of exposure as high were more likely to use bednets and repellent, and individuals reminded to use an intervention had higher odds of doing so. However, even if perception of exposure risk was high and reminders were received, the use of bednets (60%) and repellent (40%) was relatively low. Hence, on the one hand, increased uptake of interventions through targeted messaging might be possible. On the other hand, effectiveness of these interventions might be substantially constrained because of nonuse, even in a motivated and informed population.

Pandemic (H1N1) 2009 outbreak at Canadian Forces cadet camp.

We conducted a case-control study to describe the clinical and epidemiologic characteristics of an outbreak of pandemic (H1N1) 2009 at a Canadian military cadet training center. We found that asthma and obesity confer greater risk for infection. Viral shedding was detected by PCR up to 18 days after symptom onset.

Laboratory and field evaluation of the impact of exercise on the performance of regular and polymer-based deet repellents.

Studies were done in Manitoba, Canada, to evaluate the impact of exercise on repellent performance against mosquitoes. Two products containing the active ingredient N,N-diethyl-3-methylbenzamide (deet) were tested; one product was a polymer-based cream (3M Ultrathon Insect Repellent) and the other product was an alcohol-based pump spray formulation (Muskol Insect Repellent). Assessments were done in the laboratory using Aedes aegypti (L.) and in the field with naturally occurring populations of mosquitoes. Repellent was applied to the forearms (laboratory) or a lower leg (field) of test subjects at 1.5 g of test product per 600 cm2 surface area (0.75 or 0.83 mg deet/cm2). For a given test day, subjects exercised or did not. Exposure to mosquito attack was for 1 min at 30-min intervals in laboratory procedures, and it was continuous in field tests. Performance was measured as complete protection time (CPT). Moderate levels of physical activity resulted in a >40% decline in mean CPT, from 468 to 267 min in the laboratory experiments and from 359 to 203 min in field tests. Repellent product did not affect the magnitude of the decline. Mean biting pressure during field trials was 21.3 bites per min, and mosquito collections were made up primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen).

Field evaluation against mosquitoes of regular and polymer-based deet formulations in Manitoba, Canada, with comment on methodological issues.

Studies were carried out in Manitoba, Canada, to evaluate the efficacy of three repellent products for protection of human subjects against mosquito bites. All test substances contained the active ingredient N,N-diethyl-3-methylbenzamide (deet); two were polymer-based creams (3M Ultrathon Insect Repellent and Morflex DEET Insect Repellent 30) and the third (Muskol Insect Repellent) was an alcohol-based pump spray formulation. Application of repellent was to the forearm and lower legs of subjects at 0.75 or 0.83 mg deet/cm2. Exposure to mosquito attack was continuous, and efficacy was determined by measuring complete protection time (CPT). Regardless of whether delivered as a polymer cream or in alcohol, mean CPT was similar for the tested repellents at 623 +/- 107 to 644 +/- 163 min. By contrast, mean CPT for the different test subjects showed significant variation, ranging from 531 +/- 42 to 756 +/- 54 min. Mosquito collections from untreated human test subjects, Centers for Disease Control and Prevention (CDC) light traps and sweep-netting consisted primarily of Ochlerotatus sticticus (Meigen) and Aedes vexans (Meigen). Relative catch of these two species was similar for different sampling methods through much of the day, but not in the evening, when CDC light traps oversampled Ae. vexans relative to untreated human subjects. Results are used to highlight the need to account for intersubject variation when designing repellent studies, and also are used as a basis to discuss limitations associated with using relatively few subjects when testing repellents.

Malaria risk assessment and preventive recommendations: a new approach for the Canadian military.

Western militaries deploying to international locations are often confronted with the threat of malaria. For the Canadian military, the consequent response has been prescriptive-any risk of malaria warrants use of personal protective measures and chemoprophylaxis. In reality, however, malaria risk is highly variable and a one-size-fits-all strategy to mitigation may not be appropriate. In line with this, the Canadian military has revised its approach to malaria risk assessment and preventive response. More effort is now spent on predictive modeling and, where risk is deemed to be low, chemoprophylaxis may not be recommended. We describe here an application of the revised methodology to the recent Canadian military deployment to Kandahar province, Afghanistan.