Comfort and exertion while using filtering facepiece respirators with exhalation valve and an active venting system among male military personnel

<p><b>INTRODUCTION</b>This study aimed to determine if disposable filtering facepiece respirators (FFRs) that come with an exhalation valve (EV) and a novel active venting system (AVS) provided greater perceived comfort and exertion when compared to standard N95 FFRs without these features among male military personnel performing prolonged essential outdoor duties.</p><p><b>METHODS</b>We used a randomised open-label controlled crossover study design to compare three FFR options: (a) standard FFR; (b) FFR with EV; and (c) FFR with EV+AVS. Male military personnel aged between 18 and 20 years completed a questionnaire at the start of outdoor duty (baseline), after two hours of standardised non-strenuous outdoor duty and after 12 hours of duty divided into two-hour work-rest cycles. Participants rated the degree of discomfort, exertion and symptoms using a five-point Likert scale. The association between outcomes and types of FFR was assessed using a multivariate ordered probit mixed-effects model.</p><p><b>RESULTS</b>For a majority of the symptoms, study participants gave FFR with EV and FFR EV+AVS significantly better scores than standard FFR. Both FFR with EV and FFR with EV+AVS had significantly less discomfort (FFR with EV+AVS: 91.1%; FFR with EV: 57.6%) and exertion (FFR with EV+AVS: 83.5%; FFR with EV: 34.4%) than standard FFR. FFR with EV+AVS also had significantly better scores for exertion (53.4%) and comfort (39.4%) when compared to FFR with EV.</p><p><b>CONCLUSION</b>Usage of FFR with EV+AVS resulted in significantly reduced symptoms, discomfort and exertion when compared to FFR with EV and standard FFR.</p>

Utility of COX1 phylogenetics to differentiate between locally acquired and imported Plasmodium knowlesi infections in Singapore

<p><b>INTRODUCTION</b>Although there have been several phylogenetic studies on Plasmodium knowlesi (P. knowlesi), only cytochrome c oxidase subunit 1 (COX1) gene analysis has shown some geographical differentiation between the isolates of different countries.</p><p><b>METHODS</b>Phylogenetic analysis of locally acquired P. knowlesi infections, based on circumsporozoite, small subunit ribosomal ribonucleic acid (SSU rRNA), merozoite surface protein 1 and COX1 gene targets, was performed. The results were compared with the published sequences of regional isolates from Malaysia and Thailand.</p><p><b>RESULTS</b>Phylogenetic analysis of the circumsporozoite, SSU rRNA and merozoite surface protein 1 gene sequences for regional P. knowlesi isolates showed no obvious differentiation that could be attributed to their geographical origin. However, COX1 gene analysis showed that it was possible to differentiate between Singapore-acquired P. knowlesi infections and P. knowlesi infections from Peninsular Malaysia and Sarawak, Borneo, Malaysia.</p><p><b>CONCLUSION</b>The ability to differentiate between locally acquired P. knowlesi infections and imported P. knowlesi infections has important utility for the monitoring of P. knowlesi malaria control programmes in Singapore.</p>

Outbreak of acute norovirus gastroenteritis in a military facility in Singapore: a public health perspective

<p><b>INTRODUCTION</b>Norovirus gastrointestinal disease (GID) outbreaks occur frequently in closed settings, with high attack rates. On October 16, 2008, a norovirus GID outbreak occurred at a Singapore military camp. This study describes the epidemiological investigations conducted to determine the cause of outbreak and the efficacy of the public health measures implemented.</p><p><b>METHODS</b>Epidemiologic investigations included a case-control study of exposure to different food items and an environmental exposure survey. Stool samplings of patients and food handlers for common pathogens, and microbiologic testing of food and water samples were performed. Inspection of dining facilities and health screening of all food-handlers were also conducted.</p><p><b>RESULTS</b>A total of 156 GID cases were reported on October 15-31, 2008. 24 (15.4%) personnel were positive for norovirus. The predominant symptoms were diarrhoea (76.3%) and abdominal pain (69.2%). There was no clinical correlation between any food item and the affected personnel. Testing of food and water samples, dining facility inspections and health screening of food handlers showed satisfactory results. The environmental exposure survey indicated possible transmission due to environmental contamination by vomitus in common areas. Comprehensive environmental decontamination was performed with hypochlorite solution, and personal hygiene measures were enforced. The outbreak lasted 17 days, with a decline in cases post intervention.</p><p><b>CONCLUSION</b>Timely notification and prompt response can curtail disease transmission. Swift implementation of public health measures, such as emphasis on personal hygiene, isolation of affected cases and comprehensive disinfection of the environment, effectively stopped norovirus transmission and may be adapted for future GID outbreaks.</p>

An outbreak of Salmonella gastrointestinal illness in a military camp

<p><b>INTRODUCTION</b>Non-typhoidal Salmonellae are important causes of bacterial food-borne infection, especially in institutional settings. An outbreak of gastrointestinal infection occurred in a military camp in January 2007, and an epidemiological outbreak investigation was conducted.</p><p><b>MATERIALS AND METHODS</b>A survey was conducted on soldiers in the camp on their clinical symptoms, and recent meals consumed. After determining the affected meal, a subsequent survey was conducted on those who had eaten the meal. A case-control study was then performed to determine the outbreak's likely food source. Laboratory tests were also conducted to determine the bacteriological cause.</p><p><b>RESULTS</b>Of the 94 responders, 55 (58.5%) met our case definition of gastrointestinal illness. The dinner on 9 January was the most likely affected meal, with the onset of symptoms occurring within 6 to 36 hours. The mashed potato was the most likely food source with an attack rate of 80.7% for those who consumed it versus 32.7% for those who did not (P <0.01). From the multivariate analysis, the mashed potato remained the only food item independently and significantly associated with infection, with a relative risk of infection 9.49 times those who did not consume it (95% CI, 2.73-32.97). Salmonella group E was cultured from 4 individuals. Although no specific contamination was identified, the mashed potato was stored for more than 5 hours before the last serving.</p><p><b>CONCLUSION</b>Risk during preparation of large quantities of food should be identified a priori, and measures taken to reduce them, to prevent outbreaks.</p>

Twentieth century influenza pandemics in Singapore

<p><b>INTRODUCTION</b>Singapore was substantially affected by three 20th Century pandemics. This study describes the course of the pandemics, and the preventive measures adopted.</p><p><b>MATERIALS AND METHODS</b>We reviewed and researched a wide range of material including peer-reviewed journal articles, Ministry of Health reports, Straits Settlements reports and newspaper articles. Monthly mortality data were obtained from various official sources in Singapore.</p><p><b>RESULTS</b>The 1918 epidemic in Singapore occurred in 2 waves--June to July, and October to November--resulting in up to 3500 deaths. The 1957 epidemic occurred in May, and resulted in widespread morbidity, with 77,000 outpatient attendances in government clinics alone. The 1968 epidemic occurred in August and lasted a few weeks, with outpatient attendances increasing by more than 65%. The preventive measures instituted by the Singapore government during the pandemics included the closure of schools, promulgation of public health messages, setting up of influenza treatment centres, and screening at ports. Students, businessmen and healthcare workers were all severely affected by the pandemics.</p><p><b>CONCLUSIONS</b>Tropical cities should be prepared in case of a future pandemic. Some of the preventive measures used in previous pandemics may be applicable during the next pandemic.</p>

Travel characteristics and health practices among travellers at the travellers' health and vaccination clinic in Singapore

<p><b>INTRODUCTION</b>Singapore has a fast-growing travel industry, but few studies have been done on travel characteristics and travel health practices. This study describes the profile and healthseeking behaviour of travellers attending a travel health clinic in Singapore.</p><p><b>MATERIALS AND METHODS</b>A cross-sectional survey was conducted on travellers attending the Traveller's Health and Vaccination Centre (THVC) between September and November 2002 using a standardised questionnaire. Information obtained included individual demographic and medical information, travel patterns, vaccination status and travel health practices.</p><p><b>RESULTS</b>Four hundred and ninetyfive (74%) eligible travellers seen at THVC responded to the questionnaire. Their mean age was 36 years; 77% were professionals, managers, executives, and businessmen, students, and white collar workers. Asia was the main travel destination, and most travelled for leisure and resided in hotels or hostels. The median duration of travel was 16 days. Although >90% had previously travelled overseas, only 20% had previously sought pre-travel advice. Malays were significantly underrepresented (P < 0.01); and Caucasians and Eurasians were significantly more likely (P < 0.01) to have previously sought pre-travel advice compared with Chinese, Indians and Malays. Factors associated with seeking pre-travel advice included travel outside of Asia, especially Africa and South America.</p><p><b>CONCLUSION</b>Singaporean travellers travel more often to cities rather than rural areas, compared with non-Asian travellers. Asia is the preferred destination, and travel outside of Asia is perceived as more risky and is associated with seeking pre-travel advice and vaccinations. Travel patterns and behaviours need to be taken into account when developing evidence-based travel medicine in Asia.</p>