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.

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.

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.

Clinical differences between respiratory viral and bacterial mono- and dual pathogen detected among Singapore military servicemen with febrile respiratory illness.

Background: Although it is known that febrile respiratory illnesses (FRI) may be caused by multiple respiratory pathogens, there are no population-level studies describing its impact on clinical disease.

Methods: Between May 2009 and October 2012, 7733 FRI patients and controls in the Singapore military had clinical data and nasal wash samples collected prospectively and sent for PCR testing. Patients with one pathogen detected (mono-pathogen) were compared with those with two pathogens (dual pathogen) for differences in basic demographics and clinical presentation.

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.

Scrub typhus with sepsis and acute respiratory distress syndrome.

Scrub typhus is a major infectious threat in the Asia-Pacific region. We report an unusual case of scrub typhus in a patient in Singapore who presented with sepsis and acute respiratory distress syndrome but lacked the pathognomonic eschar. The patient recovered after appropriate diagnosis and doxycycline treatment.

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.

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.

Serological response in RT-PCR confirmed H1N1-2009 influenza a by hemagglutination inhibition and virus neutralization assays: an observational study.

Background: We describe the serological response following H1N1-2009 influenza A infections confirmed by reverse-transcriptase polymerase chain reaction (RT-PCR).

Methodology And Principal Findings: The study included patients admitted to hospital, subjects of a seroepidemiologic cohort study, and participants identified from outbreak studies in Singapore. Baseline (first available blood sample) and follow-up blood samples were analyzed for antibody titers to H1N1-2009 and recently circulating seasonal influenza A virus strains by hemagglutination inhibition (HI) and virus micro-neutralization (VM) assays.

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.

Rapid identification of chloroquine and atovaquone drug resistance in Plasmodium falciparum using high-resolution melt polymerase chain reaction.

Background: Drug resistance determination for Plasmodium falciparum infections are important to determining the type of treatment to be given. Besides in vivo experiments, molecular methods, such as sequencing and PCR, are now increasingly being used. Here a cheaper alternative to sequencing or the use of multiplex 5'nuclease PCR assay for detection and differentiation of drug resistance haplotypes for chloroquine and atovaquone using polymerase chain reaction-high resolution melt (PCR-HRM) is reported.

Naturally acquired human Plasmodium knowlesi infection, Singapore.

We report a case of naturally acquired Plasmodium knowlesi in Singapore, a malaria-free country. Diagnosis was confirmed by PCR with validated species-specific primers. In industrialized countries, free-ranging primates are a potential source of P.

In vitro inhibition of human influenza A virus replication by chloroquine.

Chloroquine is a 9-aminoquinolone with well-known anti-malarial effects. It has biochemical properties that could be applied to inhibit viral replication. We report here that chloroquine is able to inhibit influenza A virus replication, in vitro, and the IC50s of chloroquine against influenza A viruses H1N1 and H3N2 are lower than the plasma concentrations reached during treatment of acute malaria.

Rapid molecular typing of Burkholderia pseudomallei, isolated in an outbreak of melioidosis in Singapore in 2004, based on variable-number tandem repeats.

An increase in the number of reported melioidosis cases was observed in the first 4 months of 2004. These cases were associated with a significant increase in case-fatality rate compared with the past 5 years. In order to exclude the possibility of a single source, including the possibility of intentional release of Burkholderia pseudomallei, we applied a multiplex PCR-based multilocus variable-number tandem repeat (VNTR) assay to determine the clonality of the clinical isolates.