Survey of rodent-borne pathogens in Singapore reveals the circulation of Leptospira spp., Seoul hantavirus, and Rickettsia typhi.

Rodents living alongside humans increases the probability of encounter and also the transmission of rodent-borne diseases. Singapore's cosmopolitan urban landscape provides a perfect setting to study the prevalence of four rodent-borne pathogens: Seoul hantavirus (SEOV), Leptospira species, Rickettsia typhi and Yersinia pestis, and identify the potential risk factors which may influence rodent density and transmission of rodent-borne diseases. A total of 1143 rodents were trapped from 10 unique landscape structures throughout Singapore.

Prevalence of simian malaria parasites in macaques of Singapore.

Plasmodium knowlesi is a simian malaria parasite currently recognized as the fifth causative agent of human malaria. Recently, naturally acquired P. cynomolgi infection in humans was also detected in Southeast Asia.

Evidence for Cross-Protection Against Subsequent Febrile Respiratory Illness Episodes From Prior Infections by Different Viruses Among Singapore Military Recruits 2009-2014.

Background: Few studies have evaluated the relative cross-protection conferred by infection with different groups of viruses through studies of sequential infections in humans. We investigated the presence of short-lived relative cross-protection conferred by specific prior viral infections against subsequent febrile respiratory illness (FRI).

Methods: Men enlisted in basic military training between December 2009 and December 2014 were recruited, with the first FRI as the study entry point.

Epidemiologic analysis of respiratory viral infections among Singapore military servicemen in 2016.

Background: Respiratory illnesses have been identified as a significant factor leading to lost training time and morbidity among Singapore military recruits. A surveillance programme has been put in place to determine etiological agents responsible for febrile, as well as afebrile respiratory illnesses in a military camp. The goal of the study is to better understand the epidemiology of these diseases and identify potential countermeasures to protect military recruits against them.

Epidemiology and Relative Severity of Influenza Subtypes in Singapore in the Post-Pandemic Period from 2009 to 2010.

Background: After 2009, pandemic influenza A(H1N1) [A(H1N1)pdm09] cocirculated with A(H3N2) and B in Singapore.

Methods: A cohort of 760 participants contributed demographic data and up to 4 blood samples each from October 2009 to September 2010. We compared epidemiology of the 3 subtypes and investigated evidence for heterotypic immunity through multivariable logistic regression using a generalized estimating equation.

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

Introduction: 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.

Methods: 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.

Combined interventions for mitigation of an influenza A (H1N1) 2009 outbreak in a physical training camp in Beijing, China.

Objectives: Many studies have suggested the effectiveness of single control measures in the containment and mitigation of pandemic influenza A (H1N1) 2009. The effects of combined interventions by multiple control measures in reducing the impact of an influenza A (H1N1) 2009 outbreak in a closed physical training camp in Beijing, China were evaluated.

Methods: Oseltamivir was prescribed for the treatment of confirmed cases and possible cases and as prophylaxis for all other participants in this training camp.

Detection of viral respiratory pathogens in mild and severe acute respiratory infections in Singapore.

To investigate the performance of laboratory methods and clinical case definitions in detecting the viral pathogens for acute respiratory infections (ARIs) from a prospective community cohort and hospital inpatients, nasopharyngeal swabs from cohort members reporting ARIs (community-ARI) and inpatients admitted with ARIs (inpatient-ARI) were tested by Singleplex Real Time-Polymerase Chain Reaction (SRT-PCR), multiplex RT-PCR (MRT-PCR) and pathogen-chip system (PathChip) between April 2012 and December 2013. Community-ARI and inpatient-ARI was also combined with mild and severe cases of influenza from a historical prospective study as mild-ARI and severe-ARI respectively to evaluate the performance of clinical case definitions. We analysed 130 community-ARI and 140 inpatient-ARI episodes (5 inpatient-ARI excluded because multiple pathogens were detected), involving 138 and 207 samples respectively.

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

Introduction: 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.

Methods: Phylogenetic analysis of locally acquired P.

Comparison of Infrared Thermal Detection Systems for mass fever screening in a tropical healthcare setting.

Objectives: Fever screening systems, such as Infrared Thermal Detection Systems (ITDS), have been used for rapid identification of potential cases during respiratory disease outbreaks for public health management. ITDS detect a difference between the subject and ambient temperature, making deployment in hot climates more challenging. This study, conducted in Singapore, a tropical city, evaluates the accuracy of three different ITDS for fever detection compared with traditional oral thermometry and self-reporting in a clinical setting.

Risk factors for febrile respiratory illness and mono-viral infections in a semi-closed military environment: a case-control study.

Background: Febrile respiratory illness (FRI) results in substantial burden in semi-closed environments. Tackling risk factors may reduce transmission and infection. However, risk factors involved in one setting may not be generalizable in all settings due to differences in climate, residential environment, population genetic and cultural backgrounds.

Emerging and re-emerging infectious diseases: challenges and opportunities for militaries.

The communal nature of living and training environments, alongside suboptimal hygiene and stressors in the field, place military personnel at higher risk of contracting emerging infectious diseases. Some of these diseases spread quickly within ranks resulting in large outbreaks, and personnel deployed are also often immunologically naïve to otherwise uncommonly-encountered pathogens. Furthermore, the chance of weaponised biological agents being used in conventional warfare or otherwise remains a very real, albeit often veiled, threat.

Predictive tools for severe dengue conforming to World Health Organization 2009 criteria.

Background: Dengue causes 50 million infections per year, posing a large disease and economic burden in tropical and subtropical regions. Only a proportion of dengue cases require hospitalization, and predictive tools to triage dengue patients at greater risk of complications may optimize usage of limited healthcare resources. For severe dengue (SD), proposed by the World Health Organization (WHO) 2009 dengue guidelines, predictive tools are lacking.

Effectiveness of seasonal influenza vaccinations against laboratory-confirmed influenza-associated infections among Singapore military personnel in 2010-2013.

Background: Limited information is available about seasonal influenza vaccine effectiveness (VE) in tropical communities.

Objectives: Virus subtype-specific VE was determined for all military service personnel in the recruit camp and three other non-recruit camp in Singapore's Armed Forces from 1 June 2009 to 30 June 2012.

Methods: Consenting servicemen underwent nasal washes, which were tested with RT-PCR and subtyped.

Respiratory viral pathogens among Singapore military servicemen 2009-2012: epidemiology and clinical characteristics.

Background: Few studies have comprehensively described tropical respiratory disease surveillance in military populations. There is also a lack of studies comparing clinical characteristics of the non-influenza pathogens with influenza and amongst themselves.

Methods: From May 2009 through October 2012, 7733 consenting cases of febrile respiratory illness (FRI) (temperature [greater than or equal to]37.

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

Introduction: 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.

Differing clinical characteristics between influenza strains among young healthy adults in the tropics.

Background: Influenza infections may result in different clinical presentations. This study aims to determine the clinical differences between circulating influenza strains in a young healthy adult population in the tropics.

Methods: A febrile respiratory illness (FRI) (fever ≥ 37.

Effectiveness of pandemic H1N1-2009 vaccination in reducing laboratory confirmed influenza infections among military recruits in tropical Singapore.

Background: Limited information is available about pandemic H1N1-2009 influenza vaccine effectiveness in tropical communities. We studied the effectiveness of a pandemic H1N1 vaccination program in reducing influenza cases in Singapore.

Methods: A surveillance study was conducted among military personnel presenting with febrile respiratory illness from mid-2009 to mid-2010.

A clinical diagnostic model for predicting influenza among young adult military personnel with febrile respiratory illness in Singapore.

Introduction: Influenza infections present with wide-ranging clinical features. We aim to compare the differences in presentation between influenza and non-influenza cases among those with febrile respiratory illness (FRI) to determine predictors of influenza infection.

Methods: Personnel with FRI (defined as fever ≥ 37.

Investigation of causes of oseltamivir chemoprophylaxis failures during influenza A (H1N1-2009) outbreaks.

Background: Antiviral post-exposure prophylaxis with oseltamivir has been used as a strategy in mitigating the Influenza A (H1N1-2009) pandemic. There have been few reports of well-documented prophylaxis failures and the reasons for failure.

Objectives: We report herein a series of 10 cases of prophylaxis failures and explore the reasons behind their prophylaxis failure.

Aedes albopictus control with spray application of Bacillus thuringiensis israelensis, strain AM 65-52.

A Bacillus thuringiensis israelensis (Bti) formulation, VectoBac WG (strain AM 65-52), was evaluated for mosquito control in a training area with dense vegetation. Bti was spray applied to target Aedes albopictus larval habitats of 130 ha once every 2 weeks using a motorized back pack mist blower, Stihl SR420, and a vehicle mounted ultra low volume generator (ULV), IGEBA U40. Ovitrap index (OI) and larval density (LD) were used to measure the efficacy of larviciding.

Effectiveness of public health measures in mitigating pandemic influenza spread: a prospective sero-epidemiological cohort study.

Background: Few studies have validated the effectiveness of public health interventions in reducing influenza spread in real‐life settings. We aim to validate these measures used during the 2009 pandemic.

Methods: From 22 June to 9 October 2009, we performed a prospective observational cohort study using paired serum samples and symptom review among 3 groups of Singapore military personnel.

Oseltamivir ring prophylaxis for containment of 2009 H1N1 influenza outbreaks.

Background: From June 22 through June 25, 2009, four outbreaks of infection with the pandemic influenza A (H1N1) virus occurred in Singapore military camps. We report the efficacy of ring chemoprophylaxis (geographically targeted containment by means of prophylaxis) with oseltamivir to control outbreaks of 2009 H1N1 influenza in semiclosed environments.

Methods: All personnel with suspected infection were tested and clinically isolated if infection was confirmed.

Seroconversion and asymptomatic infections during oseltamivir prophylaxis against Influenza A H1N1 2009.

Background: Anti-viral prophylaxis is used to prevent the transmission of influenza. We studied serological confirmation of 2009 Influenza A (H1N1) infections during oseltamivir prophylaxis and after cessation of prophylaxis.

Methods: Between 22 Jun and 16 Jul 09, we performed a cohort study in 3 outbreaks in the Singapore military where post-exposure oseltamivir ring chemoprophylaxis (75 mg daily for 10 days) was administered.