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Fulltext Prevalence of simian malaria parasites in macaques of Singapore

Li MI, Mailepessov D, Vythilingam I, Lee V, Lam P, Ng LC, et al.

PLoS Negl Trop Dis, 2021 Jan;15(1):e0009110.
PMID: 33493205 DOI: 10.1371/journal.pntd.0009110

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. The main reservoir of both parasites is the long-tailed and pig-tailed macaques, which are indigenous in this region. Due to increased urbanization and changes in land use, there has been greater proximity and interaction between the long-tailed macaques and the general population in Singapore. As such, this study aims to determine the prevalence of simian malaria parasites in local macaques to assess the risk of zoonosis to the general human population. Screening for the presence of malaria parasites was conducted on blood samples from 660 peridomestic macaques collected between Jan 2008 and Mar 2017, and 379 wild macaques collected between Mar 2009 and Mar 2017, using a Pan-Plasmodium-genus specific PCR. Positive samples were then screened using a simian Plasmodium species-specific nested PCR assay to identify the species of parasites (P. knowlesi, P. coatneyi, P. fieldi, P. cynomolgi, and P. inui) present. All the peridomestic macaques sampled were tested negative for malaria, while 80.5% of the 379 wild macaques were infected. All five simian Plasmodium species were detected; P. cynomolgi being the most prevalent (71.5%), followed by P. knowlesi (47.5%), P. inui (42.0%), P. fieldi (32.5%), and P. coatneyi (28.5%). Co-infection with multiple species of Plasmodium parasites was also observed. The study revealed that Singapore's wild long-tailed macaques are natural hosts of the five simian malaria parasite species, while no malaria was detected in all peridomestic macaques tested. Therefore, the risk of simian malaria transmission to the general human population is concluded to be low. However, this can be better demonstrated with the incrimination of the vectors of simian malaria parasites in Singapore.

Matched MeSH terms: Singapore/epidemiology
Fulltext Projection of dengue fever transmissibility under climate change in South and Southeast Asian countries

Wang Y, Li C, Zhao S, Wei Y, Li K, Jiang X, et al.

PLoS Negl Trop Dis, 2024 Apr;18(4):e0012158.
PMID: 38683870 DOI: 10.1371/journal.pntd.0012158

Vector-borne infectious disease such as dengue fever (DF) has spread rapidly due to more suitable living environments. Considering the limited studies investigating the disease spread under climate change in South and Southeast Asia, this study aimed to project the DF transmission potential in 30 locations across four South and Southeast Asian countries. In this study, weekly DF incidence data, daily mean temperature, and rainfall data in 30 locations in Singapore, Sri Lanka, Malaysia, and Thailand from 2012 to 2020 were collected. The effects of temperature and rainfall on the time-varying reproduction number (Rt) of DF transmission were examined using generalized additive models. Projections of location-specific Rt from 2030s to 2090s were determined using projected temperature and rainfall under three Shared Socioeconomic Pathways (SSP126, SSP245, and SSP585), and the peak DF transmissibility and epidemic duration in the future were estimated. According to the results, the projected changes in the peak Rt and epidemic duration varied across locations, and the most significant change was observed under middle-to-high greenhouse gas emission scenarios. Under SSP585, the country-specific peak Rt was projected to decrease from 1.63 (95% confidence interval: 1.39-1.91), 2.60 (1.89-3.57), and 1.41 (1.22-1.64) in 2030s to 1.22 (0.98-1.51), 2.09 (1.26-3.47), and 1.37 (0.83-2.27) in 2090s in Singapore, Thailand, and Malaysia, respectively. Yet, the peak Rt in Sri Lanka changed slightly from 2030s to 2090s under SSP585. The epidemic duration in Singapore and Malaysia was projected to decline under SSP585. In conclusion, the change of peak DF transmission potential and disease outbreak duration would vary across locations, particularly under middle-to-high greenhouse gas emission scenarios. Interventions should be considered to slow down global warming as well as the potential increase in DF transmissibility in some locations of South and Southeast Asia.

Matched MeSH terms: Singapore/epidemiology
Factors affecting life expectancy: evidence from 1980-2009 data in Singapore, Malaysia, and Thailand

Chan MF, Devi MK

Asia Pac J Public Health, 2015 Mar;27(2):136-46.
PMID: 22865722 DOI: 10.1177/1010539512454163

The authors aim to examine the impact of demographic changes, socioeconomic inequality, and the availability of health care resources on life expectancy in Singapore, Malaysia, and Thailand. This is a cross-country study collecting annual data from 3 Southeast Asian countries from 1980 to 2008. Life expectancy is the dependent variable with demographics, socioeconomic status, and health care resources as the 3 main determinants. A structural equation model is used, and results show that the availability of more health care resources and higher levels of socioeconomic advantages are more likely to increase life expectancy. In contrast, demographic changes are more likely to increase life expectancy by way of health care resources. The authors suggest that more effort should be taken to expand and improve the coverage of health care programs to alleviate regional differences in health care use and improve the overall health status of people in these 3 Southeast Asian countries.

Matched MeSH terms: Singapore/epidemiology
Hypertension, hypertension control, and chronic kidney disease in a Malay population in Singapore

Sabanayagam C, Shankar A, Lim SC, Tai ES, Wong TY

Asia Pac J Public Health, 2011 Nov;23(6):936-45.
PMID: 20460283 DOI: 10.1177/1010539510361637

Studies conducted in Western populations demonstrate that blood pressure (BP) is a major risk factor for chronic kidney disease (CKD). The authors examined the cross-sectional association between BP and CKD in 3280 adults of Malay ethnicity aged 40 to 80 years living in Singapore. CKD was defined as (1) estimated glomerular filtration rate (eGFR) of < 60 mL/min/1.73 m(2) and (2) presence of microalbuminuria/macroalbuminuria. They observed a dose-dependent positive association between BP and CKD (P trend < .0001). In multivariable-adjusted analysis, compared with participants with normal BP, the odds ratio (OR; 95% confidence interval [CI]) of eGFR < 60 mL/min/1.73 m(2) was 1.85 (0.95-3.62), 2.95 (1.55-5.64), and 4.96 (2.63-9.37) for prehypertension, and stage 1 and stage 2 hypertension, respectively. Similar results were obtained for microalbuminuria/macroalbuminuria. Stage 2 hypertension had the greatest population-attributable risk of CKD (23%). The strong positive association of hypertension with CKD emphasizes the need to control BP in Asian populations to reduce the burden of kidney disease.

Matched MeSH terms: Singapore; Singapore/epidemiology
BRCA1 c.2845insA is a founder mutation in Singaporean Malay women with early onset breast/ovarian cancer

Sng JH, Ali AB, Lee SC, Zahar D, Wong JE, Cross G, et al.

Ann Acad Med Singap, 2003 Sep;32(5 Suppl):S53-5.
PMID: 14968737
Matched MeSH terms: Singapore/ethnology
The 1996 Runme Shaw Memorial Lecture: malaria--past, present and future

Warrell DA

Ann Acad Med Singap, 1997 May;26(3):380-7.
PMID: 9285035

Falciparum malaria may have infected Homo sapiens (and perhaps H erectus) in the Asia Pacific region for more than 100,000 years. This estimate is based on the gene frequency of alpha-thalassaemia, the protection it affords against falciparum malaria and assumptions of untreated mortality from the infection. Up until the end of the 19th century, there was a high mortality from malaria in the coastal parts of Malaya, but the malaria control campaign, begun in 1901 at Klang, was described by Sir Ronald Ross as the first successful antimalarial work in the (then) British Empire. This was extended to Singapore in 1911. When the Far Eastern Association of Tropical Medicine held its Fifth Biennial Congress in Singapore in 1923, malaria was still a major killing disease in parts of Malaya and Sarawak. The mechanism of life-threatening malaria involves cytoadherence of parasitised erythrocytes in microvascular beds, a process enhanced by the products of macrophage activation induced by malarial pyrogen. Improvements in the chemotherapy of life-threatening falciparum malaria with chloroquine and quinine have been countered by the emergence of resistant strains. Artemisinin derivatives may become the treatment of choice during the coming decade. Apart from traditional anti-mosquito methods, control of malaria now involves the use of insecticide-impregnated bed nets, new entomological strategies, including genetic manipulation of mosquitoes and selective chemoprophylaxis. Antigenic diversity and antigenic variation of the malaria parasite have so far defeated attempts to produce an effective vaccine.

Matched MeSH terms: Singapore/epidemiology
An epidemiological study of developmental dysplasia of the hip in infants in Singapore

Ang KC, Lee EH, Lee PY, Tan KL

Ann Acad Med Singap, 1997 Jul;26(4):456-8.
PMID: 9395810

The incidence of congenital dislocation of the hip (CDH) in Singapore and Malaysia has been reported as being lower than in the West. In our hospital, we have seen an increasing number of congenital hip dislocation as well as dysplastic hips. We undertook a prospective study from December 1989 to December 1994 of 20,000 live births. The neonates were all screened by a consultant neonatologist and the findings were confirmed by a consultant paediatric orthopaedic surgeon. All babies had plain X-rays at 3 months and an acetabular index (AI) of 30 degrees or more was considered dysplastic. All babies with positive signs were followed up for 1 year and again had radiographs taken at 1 year. Comparison of plain X-rays and ultrasound assessment in a subgroup of 130 neonates showed that 64% of patients with AI > 20 degrees had hip dysplasia by ultrasonographic (alpha angle < 60 degrees) The incidence of dysplastic hips was 16.8 per 1000 live births. The overall incidence of neonates with dislocated hips was 4.7 per 1000 live births. The Malays were most affected with an incidence of 5.4 per 1000 live births. The incidence of developmental dysplasia of the hip in Singapore is higher than previously reported, with the Malays having the highest incidence. A significant number of babies with clicking hips have radiological evidence of acetabular dysplasia (AI > 30 degrees). One-third of the babies' hips were still dysplastic at 1 year of age. A well-organised screening programme with experienced examiners has proved to be useful in making early and accurate clinical diagnosis.

Matched MeSH terms: Singapore/epidemiology
Epidemiology of chronic (perennial) rhinitis in Singapore: prevalence estimates, demographic variation and clinical allergic presentation

Ng TP, Tan WC

Ann Acad Med Singap, 1994 Jan;23(1):83-8.
PMID: 8185279

We conducted a population-based study involving a stratified cluster disproportionate random sample of 2868 adults aged 20 to 74 years selected from five housing estates (Yishun, Toa Payoh, Jurong East, Geylang/Eunos and Bukit Merah). Chronic rhinitis was defined as the usual presence of symptoms of blocked or running nose, apart from colds or the flu, lasting for more than a year. Allergic rhinitis was considered to be present if these symptoms were associated with conjunctivitis or recognisable provocation by commonly known allergens, namely house dust, dogs, cats, birds, pollen, or medicines. The estimated general population prevalence of chronic rhinitis was 10.8% (95% confidence interval (CI) 8.8-12.7). Higher prevalences were noted in males, in younger adults, in Indians and Chinese, in those with higher socio-economic status, and in Toa Payoh, Jurong East and Geylang/Eunos. The prevalence of allergic rhinitis was 5.5% (95% CI 4.5-6.5). The most common 'allergenic' factor in allergic rhinitis was house dust (73%); provocation by birds, cats or dogs (5%), grass or tree pollens (5%), and medicine (5%) was less common but likely to have been under-recognised. Provocation by change in temperature (54%) and early in the morning (64%) was equally frequent in both 'allergic' and 'non-allergic' rhinitis; cigarette smoke, petrol and diesel fumes, food and work environment were less common (4-12%). Allergic rhinitis was highly significantly associated with asthma (13.9% in allergic rhinitis, 4.4% in non-allergic rhinitis, and 2.2% in non-rhinitic subjects).

Matched MeSH terms: Singapore/epidemiology
Fulltext Accuracy of self-reported height, weight and BMI in a multiethnic Asian population

Roystonn K, Abdin E, Sambasivam R, Zhang Y, Chang S, Shafie S, et al.

Ann Acad Med Singap, 2021 04;50(4):306-314.
PMID: 33990818 DOI: 10.47102/annals-acadmedsg.2020183

INTRODUCTION: The study assessed whether self-reported height, weight and derived body mass index (BMI) can provide an accurate measure of anthropometric data in a multiethnic adult population in Singapore.
METHODS: Standardised anthropometric measurements were compared against the self-reported values from 5,132 adult residents in a cross-sectional, epidemiological survey. Discrepancies in self-reports from measurements were examined by comparing overall mean differences. Intraclass correlations, Cohen's kappa and Bland-Altman plots with limits of agreement, and sub-analysis by sex and ethnicity were also explored.
RESULTS: Data were obtained from 5,132 respondents. The mean age of respondents was 43.9 years. Overall, the height was overestimated (0.2cm), while there was an underestimation of weight (0.8kg) and derived BMI (0.4kg/m2). Women had a larger discrepancy in height (0.35cm, 95% confidence interval [CI] 0.22 to 0.49), weight (-0.95kg, 95% CI -1.11 to -0.79) and BMI (-0.49kg/m2, 95% CI -0.57 to -0.41) compared with men. Height reporting bias was highest among Indians (0.28cm, 95% CI 0.12 to 0.44) compared with Chinese and Malays, while weight (-1.32kg, 95% CI -1.53 to -1.11) and derived BMI (-0.57kg/m2, 95% CI -0.67 to -0.47) showed higher degrees of underreporting among Malays compared with Chinese and Indians. Substantially high self-reported versus measured values were obtained for intraclass correlations (0.96-0.99, P<0.001) and kappa (0.74). For BMI categories, good to excellent kappa agreement was observed (0.68-0.81, P<0.0001).
CONCLUSION: Self-reported anthropometric estimates can be used, particularly in large epidemiological studies. However, sufficient care is needed when evaluating data from Indians, Malays and women as there is likely an underestimation of obesity prevalence.

Matched MeSH terms: Singapore/epidemiology
A population-based survey of mental disorders in Singapore

Chong SA, Abdin E, Vaingankar JA, Heng D, Sherbourne C, Yap M, et al.

Ann Acad Med Singap, 2012 Feb;41(2):49-66.
PMID: 22498852

INTRODUCTION: Mental illnesses are not only a growing public health concern but also a major social and economic issue affecting individuals and families throughout the world. The prevalence of mental disorders, the extent of disability caused by these disorders, and services utilisation of these patients has been well studied in developed countries. The aim of this study was to establish the prevalence of select mental disorders and their associated sociodemographic correlates in the adult Singapore resident population.
MATERIALS AND METHODS: This was a cross-sectional, populationbased, epidemiological study of adult Singapore residents aged 18 years and above. The subjects were randomly selected using a disproportionate stratified sampling method. The diagnoses of selected mental disorders including major depressive disorder (MDD), dysthymia, bipolar (bipolar I & II) disorders, generalised anxiety disorder (GAD), obsessive compulsive disorder (OCD), alcohol abuse and alcohol dependence were established using the Composite International Diagnostic Interview, which is a fully structured diagnostic instrument that assesses lifetime and 12-month prevalence of mental disorders.
RESULTS: Among the 6616 respondents (response rate of 75.9%), 12.0% had at least one lifetime affective, anxiety, or alcohol use disorders. The lifetime prevalence of MDD was 5.8% and that of bipolar disorder was 1.2%. The combined lifetime prevalence of the 2 anxiety disorders, GAD and OCD was 3.6%, with the latter being more common than GAD (0.9% and 3.0% respectively). The lifetime prevalence of alcohol abuse and dependence were found to be 3.1% and 0.5% respectively. Age, gender, ethnicity, marital status and chronic physical illnesses were all significant correlates of mental disorders.
CONCLUSION: The identified associated factors would help guide resource allocation, policy formulation and programme development in Singapore.

Matched MeSH terms: Singapore/epidemiology
Fulltext Detection of Japanese Encephalitis Virus in Culex Mosquitoes in Singapore

Yap G, Mailepessov D, Lim XF, Chan S, How CB, Humaidi M, et al.

Am J Trop Med Hyg, 2020 09;103(3):1234-1240.
PMID: 32700679 DOI: 10.4269/ajtmh.19-0377

Mosquito-borne flaviviruses are emerging pathogens of an increasing global public health concern because of their rapid increase in geographical range and the impact of climate change. Japanese encephalitis virus (JEV) and West Nile virus (WNV) are of concern because of the risk of reemergence and introduction by migratory birds. In Singapore, human WNV infection has never been reported and human JEV infection is rare. Four sentinel vector surveillance sites were established in Singapore to understand the potential risk posed by these viruses. Surveillance was carried out from August 2011 to December 2012 at Pulau Ubin, from March 2011 to March 2013 at an Avian Sanctuary (AS), from December 2010 from October 2012 at Murai Farmway, and from December 2010 to December 2013 at a nature reserve. The present study revealed active JEV transmission in Singapore through the detection of JEV genotype II in Culex tritaeniorhynchus collected from an Avian Sanctuary. Culex flavivirus (CxFV), similar to the Quang Binh virus isolated from Cx. tritaeniorhynchus in Vietnam and CxFV-LSFlaviV-A20-09 virus isolated in China, was also detected in Culex spp. (vishnui subgroup). No WNV was detected. This study demonstrates the important role that surveillance plays in public health and strongly suggests the circulation of JEV among wildlife in Singapore, despite the absence of reported human cases. A One Health approach involving surveillance, the collaboration between public health and wildlife managers, and control of mosquito populations remains the key measures in risk mitigation of JEV transmission in the enzootic cycle between birds and mosquitoes.

Matched MeSH terms: Singapore/epidemiology
Frequent intake of high fiber and probiotic diets lowers risks associated with atopic dermatitis and house dust mite allergy: a cross-sequential study of young Chinese adults from Singapore and Malaysia

Lim JJ, Reginald K, Say YH, Liu MH, Chew FT

Eur J Nutr, 2024 Nov 30;64(1):38.
PMID: 39614888 DOI: 10.1007/s00394-024-03524-6

PURPOSE: Dietary fiber intake may influence the risk and severity of atopic dermatitis (AD), a common chronic allergic skin condition. This cross-sequential study investigated the association between dietary fiber intake and various characteristics of AD, including house dust mites (HDM) allergy and dry skin, in 13,561 young Chinese adults (mean years = 22.51, SD ± 5.90) from Singapore and Malaysia.
METHODS: Dietary habits were assessed using a validated semi-quantitative, investigator-administered food frequency questionnaire from the International Study of Asthma and Allergies in Childhood. We derived an amount-based dietary index to estimate fiber intake while studying its correlation with probiotic drinks intake. AD status was determined by skin prick tests for HDM and symptomatic histories of eczema. Multivariable logistic regression analysis, adjusting for demographic, genetic predisposition, body mass index and lifestyle factors, and synergy factor analysis were used to explore the association and interaction of dietary factors on disease outcomes.
RESULTS: High fiber intake (approximately 98.25 g/serving/week) significantly lowered the associated risks for HDM allergy (Adjusted Odds Ratio [AOR]: 0.895; 95% Confidence Intervals [CI]: 0.810-0.989; adjusted p-value

Matched MeSH terms: Singapore/epidemiology
Distribution of PON1 polymorphisms PON1Q192R and PON1L55M among Chinese, Malay and Indian males in Singapore and possible susceptibility to organophosphate exposure

Chia SE, Mohamed Ali S, Yap PH, Gan L, Ong YB, Chia KS

Neurotoxicology, 2009 Mar;30(2):214-9.
PMID: 19135476 DOI: 10.1016/j.neuro.2008.12.004

Organophosphate (OP)-containing pesticides are widely used worldwide for domestic and industrial purposes. Studies on acute and chronic exposure to OPs have revealed numerous health effects attributed mainly to acetylcholinesterase (AChE) inhibition. The enzyme human serum paraoxonase (PON1) is involved in the detoxification of OP compounds. PON1 polymorphisms have been shown to affect susceptibility to OP exposure. We studied the effect of OP exposure on pest control workers and assessed the distribution of two common PON1 polymorphisms in our local population. The exposed group consisted of 103 workers from various pest control companies under the Singapore Pest Management Association while the 91 unexposed workers were from a lead stabilizer factory. For all workers, the mean age was 36.9 (20-70) years and the ethnic distribution was 38.1% Chinese, 44.3% Malay and 17.5% Indian. The mean+/-S.D. exposure duration among the pesticide workers was 10.4+/-8.4 years. The mean+/-S.D. RBC cholinesterase level was 18436.2+/-2078U/L and 18079.6+/-1576U/L for the exposed and unexposed groups, respectively (p=0.216). The mean+/-S.D. serum pseudocholinesterase was 11028.4+/-2867.4U/L and 9433.6+/-2022.6U/L in the exposed and unexposed groups, respectively (p<0.0001). Mean paraoxonase activity was similar among Chinese and Malays (266.5 and 266.3U/L, respectively) whereas that of the Indians was significantly lower (165.6U/L). Our study showed that cholinesterase levels among the exposed were not lower than those in the unexposed group. PON1 polymorphisms differed among ethnic groups, implying that ethnicity could be an important surrogate for identifying susceptible groups in case of OP exposure. Although OP poisoning is rare among occupationally exposed workers in Singapore, this information is useful for other developing countries that have large populations of Chinese, Malays and Indians where OP exposure could be very high especially in agricultural settings.

Matched MeSH terms: Singapore/ethnology; Singapore/epidemiology
Epidemiology and characteristics of the dengue outbreak in Guangdong, Southern China, in 2014

Huang L, Luo X, Shao J, Yan H, Qiu Y, Ke P, et al.

Eur J Clin Microbiol Infect Dis, 2016 Feb;35(2):269-77.
PMID: 26700953 DOI: 10.1007/s10096-015-2540-5

Dengue is a rapidly spreading mosquito-borne disease caused by the dengue virus (DENV) and has emerged as a severe public health problem around the world. Guangdong, one of the southern Chinese provinces, experienced a serious outbreak of dengue in 2014, which was believed to be the worst dengue epidemic in China over the last 20 years. To better understand the epidemic, we collected the epidemiological data of the outbreak and analyzed 14,594 clinically suspected dengue patients from 25 hospitals in Guangdong. Dengue cases were then laboratory-confirmed by the detection of DENV non-structural protein 1 (NS1) antigen and/or DENV RNA. Afterwards, clinical manifestations of dengue patients were analyzed and 93 laboratory-positive serum specimens were chosen for the DENV serotyping and molecular analysis. Our data showed that the 2014 dengue outbreak in Guangdong had spread to 20 cities and more than 45 thousand people suffered from dengue fever. Of 14,594 participants, 11,387 were definitively diagnosed. Most manifested with a typical non-severe clinical course, and 1.96 % developed to severe dengue. The strains isolated successfully from the serum samples were identified as DENV-1. Genetic analyses revealed that the strains were classified into genotypes I and V of DENV-1, and the dengue epidemic of Guangdong in 2014 was caused by indigenous cases and imported cases from the neighboring Southeast Asian countries of Malaysia and Singapore. Overall, our study is informative and significant to the 2014 dengue outbreak in Guangdong and will provide crucial implications for dengue prevention and control in China and elsewhere.

Matched MeSH terms: Singapore
Fulltext Susuk - black magic exposed "white" by dental radiographs

F AT, Mohammed F

J Clin Diagn Res, 2014 Jul;8(7):ZD03-4.
PMID: 25177646 DOI: 10.7860/JCDR/2014/8671.4546

Susuk or charm needles are a facial cum body art widely practiced among women of Malaysia, Brunei, Singapore, Thailand and Indonesia. These are small, needle-shaped metallic talismans inserted subcutaneously in different parts of the body. The concealed art of susuk was "exposed" by routine radiographic examination in the oral and maxillofacial region. This paper reports two such cases of unusual incidental radiographic finding in dental radiographs which were taken on a routine basis as part of the diagnostic work up. This article will also primarily enlighten the importance of radiographs in detecting such charm needles as the wearer keeps the body art a "hidden secret" thereby avoiding misdiagnosis.

Matched MeSH terms: Singapore
Fulltext Insecticide resistance and its underlying mechanisms in field populations of Aedes aegypti adults (Diptera: Culicidae) in Singapore

Koou SY, Chong CS, Vythilingam I, Lee CY, Ng LC

Parasit Vectors, 2014;7:471.
PMID: 25301032 DOI: 10.1186/s13071-014-0471-0

In Singapore, dose-response bioassays of Aedes aegypti (L.) adults have been conducted, but the mechanisms underlying resistance to insecticides remain unclear. In this study, we evaluated insecticide resistance and its underlying mechanism in field populations of Ae. aegypti adults.

Matched MeSH terms: Singapore
The energy cost of water independence: the case of Singapore

Vincent L, Michel L, Catherine C, Pauline R

Water Sci Technol, 2014;70(5):787-94.
PMID: 25225924 DOI: 10.2166/wst.2014.290

Finding alternative resources to secure or increase water availability is a key issue in most urban areas. This makes the research of alternative and local water resources of increasing importance. In the context of political tension with its main water provider (Malaysia), Singapore has been implementing a comprehensive water policy for some decades, which relies on water demand management and local water resource mobilisation in order to reach water self-sufficiency by 2060. The production of water from alternative resources through seawater desalination or water reclamation implies energy consumptive technologies such as reverse osmosis. In the context of increasing energy costs and high primary energy dependency, this water self-sufficiency objective is likely to be an important challenge for Singapore. The aim of this paper is to quantify the long-term impact of Singapore's water policy on the national electricity bill and to investigate the impact of Singapore's projects to reduce its water energy footprint. We estimate that 2.0% of the Singaporean electricity demand is already dedicated to water and wastewater treatment processes. If its water-energy footprint dramatically increases in the coming decades, ambitious research projects may buffer the energy cost of water self-sufficiency.

Matched MeSH terms: Singapore
Fulltext Predicting survival of de novo metastatic breast cancer in Asian women: systematic review and validation study

Miao H, Hartman M, Bhoo-Pathy N, Lee SC, Taib NA, Tan EY, et al.

PLoS One, 2014;9(4):e93755.
PMID: 24695692 DOI: 10.1371/journal.pone.0093755

BACKGROUND: In Asia, up to 25% of breast cancer patients present with distant metastases at diagnosis. Given the heterogeneous survival probabilities of de novo metastatic breast cancer, individual outcome prediction is challenging. The aim of the study is to identify existing prognostic models for patients with de novo metastatic breast cancer and validate them in Asia.
MATERIALS AND METHODS: We performed a systematic review to identify prediction models for metastatic breast cancer. Models were validated in 642 women with de novo metastatic breast cancer registered between 2000 and 2010 in the Singapore Malaysia Hospital Based Breast Cancer Registry. Survival curves for low, intermediate and high-risk groups according to each prognostic score were compared by log-rank test and discrimination of the models was assessed by concordance statistic (C-statistic).
RESULTS: We identified 16 prediction models, seven of which were for patients with brain metastases only. Performance status, estrogen receptor status, metastatic site(s) and disease-free interval were the most common predictors. We were able to validate nine prediction models. The capacity of the models to discriminate between poor and good survivors varied from poor to fair with C-statistics ranging from 0.50 (95% CI, 0.48-0.53) to 0.63 (95% CI, 0.60-0.66).
CONCLUSION: The discriminatory performance of existing prediction models for de novo metastatic breast cancer in Asia is modest. Development of an Asian-specific prediction model is needed to improve prognostication and guide decision making.

Matched MeSH terms: Singapore
Silver lining of Singapore's haze

Carrasco LR

Science, 2013 Jul 26;341(6144):342-3.
PMID: 23888020 DOI: 10.1126/science.341.6144.342-b
Matched MeSH terms: Singapore
Fulltext Recruitment constraints in Singapore's fluted giant clam (Tridacna squamosa) population--a dispersal model approach

Neo ML, Erftemeijer PL, van Beek JK, van Maren DS, Teo SL, Todd PA

PLoS One, 2013;8(3):e58819.
PMID: 23555597 DOI: 10.1371/journal.pone.0058819

Recruitment constraints on Singapore's dwindling fluted giant clam, Tridacna squamosa, population were studied by modelling fertilisation, larval transport, and settlement using real-time hydrodynamic forcing combined with knowledge of spawning characteristics, larval development, behaviour, and settlement cues. Larval transport was simulated using a finite-volume advection-diffusion model coupled to a three-dimensional hydrodynamic model. Three recruitment constraint hypotheses were tested: 1) there is limited connectivity between Singapore's reefs and other reefs in the region, 2) there is limited exchange within Singapore's Southern Islands, and 3) there exist low-density constraints to fertilisation efficacy (component Allee effects). Results showed that connectivity among giant clam populations was primarily determined by residual hydrodynamic flows and spawning time, with greatest chances of successful settlement occurring when spawning and subsequent larval dispersal coincided with the period of lowest residual flow. Simulations suggested poor larval transport from reefs located along the Peninsular Malaysia to Singapore, probably due to strong surface currents between the Andaman Sea and South China Sea combined with a major land barrier disrupting larval movement among reefs. The model, however, predicted offshore coral reefs to the southeast of Singapore (Bintan and Batam) may represent a significant source of larvae. Larval exchange within Singapore's Southern Islands varied substantially depending on the locations of source and sink reefs as well as spawning time; but all simulations resulted in low settler densities (2.1-68.6 settled individuals per 10,000 m(2)). Poor fertilisation rates predicted by the model indicate that the low density and scattered distribution of the remaining T. squamosa in Singapore are likely to significantly inhibit any natural recovery of local stocks.

Matched MeSH terms: Singapore

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