Displaying publications 1 - 20 of 362 in total

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  1. Benacer D, Thong KL, Min NC, Bin Verasahib K, Galloway RL, Hartskeerl RA, et al.
    Acta Trop, 2016 May;157:162-8.
    PMID: 26844370 DOI: 10.1016/j.actatropica.2016.01.031
    Leptospirosis is an emerging disease, especially in countries with a tropical climate such as Malaysia. A dramatic increase in the number of cases has been reported over the last decade; however, information on the epidemiological trends of this disease is lacking. The objective of this study is to provide an epidemiological description of human leptospirosis cases over a 9-year period (2004-2012) and disease relationship with meteorological, geographical, and demographical information. A retrospective study was undertaken to describe the patterns of human leptospirosis cases and their association with intrinsic (sex, age, and ethnicity) and extrinsic (location, rainfall, and temperature) factors. Data was grouped according to age, sex, ethnicity, seasonality and geographical distribution, and analyzed using statistical tools to understand the influence of all the different factors on disease incidence. A total of 12,325 cases of leptospirosis were reported between 2004 and 2012 with an upward trend in disease incidence, with the highest in 2012. Three hundred thirty-eight deaths were reported with an overall case fatality rate of 2.74%, with higher incidence in males (9696; 78.7%) compared with female patients (2629; 21.3%), and overall male to female ratio of 3.69:1. Patients aged cohorts between 30-39 years old (16.22 per 100,000 population) had the highest disease incidence while the lowest incidence occurred between <1 to 9 years old (3.44 per 100,000 population). The average incidence was highest amongst Malays (10.97 per 100,000 population), followed by Indians (7.95 per 100,000 population). Stratification according to geographical distribution showed that the state of Malacca had the highest average disease incidence (11.12 per 100,000 population) followed by Pahang (10.08 per 100,000 population). The states of Terengganu, Kelantan, and Perak recorded similar rates of incidence (≈8.00 per 100,000 population), while Johor with the least number of reported cases (1.80 per 100,000 population). Positive relationships were recorded between the number of reported cases with the number of raining days per month and monthly average temperature (p-value<0.05). However, no significant association was noted between rainfall volume and number of reported Leptospirosis cases. This collaborative efforts between medical, academic and governmental institutions has enabled the construction of this comprehensive database that is essential to understand the disease trends in Malaysia and add insights into the prevention and control of this disease.
    Matched MeSH terms: Tropical Climate
  2. Hotez PJ
    Acta Trop, 2020 Feb;202:105182.
    PMID: 31550453 DOI: 10.1016/j.actatropica.2019.105182
    While the East Asia Pacific (EAP) region has experienced tremendous economic growth and development, the resulting public health gains from reductions in its neglected tropical diseases (NTDs) have been less than expected due to opposing forces of urbanization, political instability, food insecurity, and climate change, together with co-morbidities with non-communicable diseases, including diabetes and hypertension. To be sure there's been progress towards the elimination of lymphatic filariasis and trachoma through mass drug administration, and there are opportunities to extend MDA to yaws and scabies, but for most of the other NTDs we'll require new biotechnologies. So far, EAP's major technology hubs in China, Japan, Malaysia, Singapore, South Korea, and Taiwan have mostly failed to shift their attention towards new innovations for the NTDs, including new drugs, diagnostics, and vaccines, and vector control. Unless this situation changes the EAP could be facing a new grim reality of unhealthy megacities beset by emerging arbovirus infections, widespread antimicrobial resistance, and urban helminth infections.
    Matched MeSH terms: Tropical Climate
  3. Lau XC, Chong KH, Poh BK, Ismail MN
    Adv. Food Nutr. Res., 2013;70:49-101.
    PMID: 23722094 DOI: 10.1016/B978-0-12-416555-7.00002-3
    The tropics cover a large section of the world in which both developed and developing countries are situated. Rapid socioeconomic development, modernization, urbanization, and globalization have affected both the food market and physical activity (PA), which in turn have propelled the obesity epidemic in the tropics. There is growing concern that overweight and obesity are emerging as major health problems among children and adolescents in the tropics, despite the fact that undernutrition still exists in many of these countries. Physical inactivity, a low metabolic rate, and lack of physical fitness (PF) have been linked to overweight and obesity. Moreover, PF in several tropical countries is declining, and these changes may be a threat to future health, as low PA and PF levels are important risk factors for noncommunicable chronic diseases. Previous studies have reported that the relationships among PA, PF, overweight, and obesity are inconsistent and inconclusive. There is no indication that variances in the energy cost of physical activities lead to obesity. Despite a lack of definite evidence to prove a causal relationship, there is enough certainty that physical inactivity and low fitness levels are linked to overweight and obesity. Hence, people living in tropical countries need to be encouraged to lead a healthier lifestyle by increasing their PA levels and reducing sedentary behaviors to prevent overweight or obesity.
    Matched MeSH terms: Tropical Climate*
  4. DeVantier L, Alcala A, Wilkinson C
    Ambio, 2004 Feb;33(1-2):88-97.
    PMID: 15083654
    The Sulu-Sulawesi Sea, with neighboring Indonesian Seas and South China Sea, lies at the center of the world's tropical marine biodiversity. Encircled by 3 populous, developing nations, the Philippines, Indonesia and Malaysia, the Sea and its adjacent coastal and terrestrial ecosystems, supports ca. 33 million people, most with subsistence livelihoods heavily reliant on its renewable natural resources. These resources are being impacted severely by rapid population growth (> 2% yr-1, with expected doubling by 2035) and widespread poverty, coupled with increasing international market demand and rapid technological changes, compounded by inefficiencies in governance and a lack of awareness and/or acceptance of some laws among local populations, particularly in parts of the Philippines and Indonesia. These key root causes all contribute to illegal practices and corruption, and are resulting in severe resource depletion and degradation of water catchments, river, lacustrine, estuarine, coastal, and marine ecosystems. The Sulu-Sulawesi Sea forms a major geopolitical focus, with porous borders, transmigration, separatist movements, piracy, and illegal fishing all contributing to environmental degradation, human suffering and political instability, and inhibiting strong trilateral support for interventions. This review analyzes these multifarious environmental and socioeconomic impacts and their root causes, provides a future prognosis of status by 2020, and recommends policy options aimed at amelioration through sustainable management and development.
    Matched MeSH terms: Tropical Climate
  5. Brosius JP
    Am Anthropol, 1999;101(1):36-57.
    PMID: 19280759
    Matched MeSH terms: Tropical Climate*
  6. Tnah LH, Lee CT, Lee SL, Ng KK, Ng CH, Nurul-Farhanah Z, et al.
    Am J Bot, 2012 Nov;99(11):e431-3.
    PMID: 23108468 DOI: 10.3732/ajb.1200165
    Aggressive collections and trade activities in recent decades have resulted in heavy pressure on the natural stands of Aquilaria malaccensis and concerns over its long-term survival potential. To aid DNA profiling and assessment of its genetic diversity, microsatellite markers were developed for the species.
    Matched MeSH terms: Tropical Climate
  7. Duncan MT, Husain R, Chen HM, Horvath SM
    Am J Hum Biol, 1995;7(3):329-337.
    PMID: 28557027 DOI: 10.1002/ajhb.1310070309
    The interaction of race and climatic adaptation on patterns of cardiovascular reactivity among young adult males was examined. Malay and Chinese subjects living in a tropical climate in the Orient and Caucasians living in a sub-tropical climate in North America were investigated. The cold pressor test with hand immersion in cold water was used as the stressor. Systolic and diastolic blood pressures, cardiac frequency, cardiac output, and stroke volume were measured. The results provided limited evidence for absence of differences in cardiac reactivity among racial groups and for greater vascular reactivity in the Caucasians. Cold immersion also elicited differential responses which could be partially attributed to differences in acclimatizations status. © 1995 Wiley-Liss, Inc.
    Matched MeSH terms: Tropical Climate
  8. Nwunuji TP, Mayowa OO, Yusoff SM, Bejo SK, Salisi S, Mohd EA
    Anim Sci J, 2014 May;85(5):611-6.
    PMID: 24612236 DOI: 10.1111/asj.12174
    The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty-four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post-transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity.
    Matched MeSH terms: Tropical Climate*
  9. Tani N, Tsumura Y, Kado T, Taguchi Y, Lee SL, Muhammad N, et al.
    Ann Bot, 2009 Dec;104(7):1421-34.
    PMID: 19808773 DOI: 10.1093/aob/mcp252
    BACKGROUND AND AIMS: Knowledge of pollen dispersal patterns and variation of fecundity is essential to understanding plant evolutionary processes and to formulating strategies to conserve forest genetic resources. Nevertheless, the pollen dispersal pattern of dipterocarp, main canopy tree species in palaeo-tropical forest remains unclear, and flowering intensity variation in the field suggests heterogeneity of fecundity.

    METHODS: Pollen dispersal patterns and male fecundity variation of Shorea leprosula and Shorea parvifolia ssp. parvifolia on Peninsular Malaysian were investigated during two general flowering seasons (2001 and 2002), using a neighbourhood model modified by including terms accounting for variation in male fecundity among individual trees to express heterogeneity in flowering.

    KEY RESULTS: The pollen dispersal patterns of the two dipterocarp species were affected by differences in conspecific tree flowering density, and reductions in conspecific tree flowering density led to an increased selfing rate. Active pollen dispersal and a larger number of effective paternal parents were observed for both species in the season of greater magnitude of general flowering (2002).

    CONCLUSIONS: The magnitude of general flowering, male fecundity variation, and distance between pollen donors and mother trees should be taken into account when attempting to predict the effects of management practices on the self-fertilization and genetic structure of key tree species in tropical forest, and also the sustainability of possible management strategies, especially selective logging regimes.

    Matched MeSH terms: Tropical Climate
  10. 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: Tropical Climate
  11. Lee-Cruz L, Edwards DP, Tripathi BM, Adams JM
    Appl Environ Microbiol, 2013 Dec;79(23):7290-7.
    PMID: 24056463 DOI: 10.1128/AEM.02541-13
    Tropical forests are being rapidly altered by logging and cleared for agriculture. Understanding the effects of these land use changes on soil bacteria, which constitute a large proportion of total biodiversity and perform important ecosystem functions, is a major conservation frontier. Here we studied the effects of logging history and forest conversion to oil palm plantations in Sabah, Borneo, on the soil bacterial community. We used paired-end Illumina sequencing of the 16S rRNA gene, V3 region, to compare the bacterial communities in primary, once-logged, and twice-logged forest and land converted to oil palm plantations. Bacteria were grouped into operational taxonomic units (OTUs) at the 97% similarity level, and OTU richness and local-scale α-diversity showed no difference between the various forest types and oil palm plantations. Focusing on the turnover of bacteria across space, true β-diversity was higher in oil palm plantation soil than in forest soil, whereas community dissimilarity-based metrics of β-diversity were only marginally different between habitats, suggesting that at large scales, oil palm plantation soil could have higher overall γ-diversity than forest soil, driven by a slightly more heterogeneous community across space. Clearance of primary and logged forest for oil palm plantations did, however, significantly impact the composition of soil bacterial communities, reflecting in part the loss of some forest bacteria, whereas primary and logged forests did not differ in composition. Overall, our results suggest that the soil bacteria of tropical forest are to some extent resilient or resistant to logging but that the impacts of forest conversion to oil palm plantations are more severe.
    Matched MeSH terms: Tropical Climate
  12. Lim SP, Gan SN, Tan IK
    Appl Biochem Biotechnol, 2005 Jul;126(1):23-33.
    PMID: 16014996
    Bacterial polyhydroxyalkanoates (PHAs) are perceived to be a suitable alternative to petrochemical plastics because they have similar material properties, are environmentally degradable, and are produced from renewable resources. In this study, the in situ degradation of medium-chain-length PHA (PHAMCL) films in tropical forest and mangrove soils was assessed. The PHAMCL was produced by Pseudomonas putida PGA1 using saponified palm kernel oil (SPKO) as the carbon source. After 112 d of burial, there was 16.7% reduction in gross weight of the films buried in acidic forest soil (FS), 3.0% in the ones buried in alkaline forest soil by the side of a stream (FSst) and 4.5% in those buried in mangrove soil (MS). There was a slight decrease in molecular weight for the films buried in FS but not for the films buried in FSst and in MS. However, no changes were observed for the melting temperature, glass transition temperature, monomer compositions, structure, and functional group analyses of the films from any of the burial sites during the test period. This means that the integral properties of the films were maintained during that period and degradation was by surface erosion. Scanning electron microscopy of the films from the three sites revealed holes on the film surfaces which could be attributed to attack by microorganisms and bigger organisms such as detritivores. For comparison purposes, films of polyhydroxybutyrate (PHB), a short-chain-length PHA, and polyethylene (PE) were buried together with the PHAMCL films in all three sites. The PHB films disintegrated completely in MS and lost 73.5% of their initial weight in FSst, but only 4.6% in FS suggesting that water movement played a major role in breaking up the brittle PHB films. The PE films did not register any weight loss in any of the test sites.
    Matched MeSH terms: Tropical Climate
  13. Ho YH, Gan SN, Tan IK
    Appl Biochem Biotechnol, 2002 10 25;102-103(1-6):337-47.
    PMID: 12396135
    The medium-chain-length polyhydroxyalkanoate (PHA(MCL)) produced by Pseudomonas putida PGA1 using saponified palm kernel oil as the carbon source could degrade readily in water taken from Kayu Ara River in Selangor, Malaysia. A weight loss of 71.3% of the PHA film occurred in 86 d. The pH of the river water medium fell from 7.5 (at d 0) to 4.7 (at d 86), and there was a net release of CO2. In sterilized river water, the PHA film also lost weight and the pH of the water fell, but to lesser extents. The C8 monomer of the PHA was completely removed after 6 d of immersion in the river water, while the proportions of the other monomers (C10, C12, and C14) were reversed from that of the undegraded PHA. By contrast, the monomer composition of the PHA immersed in sterilized river water did not change significantly from that of the undegraded PHA. Scanning electron microscopy showed physical signs of degradation on the PHA film immersed in the river water, but the film immersed in sterilized river water was relatively unblemished. The results thus indicate that the PHA(MCL) was degraded in tropical river water by biologic as well as nonbiologic means. A significant finding is that shorter-chain monomers were selectively removed throughout the entire PHA molecule, and this suggests enzymatic action.
    Matched MeSH terms: Tropical Climate
  14. Dahlan ND, Gital YY
    Appl Ergon, 2016 May;54:169-76.
    PMID: 26851476 DOI: 10.1016/j.apergo.2015.12.008
    The study was done to identify affective and sensory responses observed as a result of hysteresis effects in transient thermal conditions consisting of warm-neutral and neutral - warm performed in a quasi-experiment setting. Air-conditioned building interiors in hot-humid areas have resulted in thermal discomfort and health risks for people moving into and out of buildings. Reports have shown that the instantaneous change in air temperature can cause abrupt thermoregulation responses. Thermal sensation vote (TSV) and thermal comfort vote (TCV) assessments as a consequence of moving through spaces with distinct thermal conditions were conducted in an existing single-story office in a hot-humid microclimate, maintained at an air temperature 24 °C (± 0.5), relative humidity 51% (± 7), air velocity 0.5 m/s (± 0.5), and mean radiant temperature (MRT) 26.6 °C (± 1.2). The measured office is connected to a veranda that showed the following semi-outdoor temperatures: air temperature 35 °C (± 2.1), relative humidity 43% (± 7), air velocity 0.4 m/s (± 0.4), and MRT 36.4 °C (± 2.9). Subjective assessments from 36 college-aged participants consisting of thermal sensations, preferences and comfort votes were correlated against a steady state predicted mean vote (PMV) model. Local skin temperatures on the forehead and dorsal left hand were included to observe physiological responses due to thermal transition. TSV for veranda-office transition showed that no significant means difference with TSV office-veranda transition were found. However, TCV collected from warm-neutral (-0.24, ± 1.2) and neutral-warm (-0.72, ± 1.3) conditions revealed statistically significant mean differences (p < 0.05). Sensory and affective responses as a consequence of thermal transition after travel from warm-neutral-warm conditions did not replicate the hysteresis effects of brief, slightly cool, thermal sensations found in previous laboratory experiments. These findings also indicate that PMV is an acceptable alternative to predict thermal sensation immediately after a down-step thermal transition (≤ 1 min exposure duration) for people living in a hot-humid climate country.
    Matched MeSH terms: Tropical Climate*
  15. Venugopal Y, Hatta SFWM, Musa N, Rahman SA, Ratnasingam J, Paramasivam SS, et al.
    Asia Pac J Clin Nutr, 2017 May;26(3):412-420.
    PMID: 28429905 DOI: 10.6133/apjcn.042016.10
    BACKGROUND AND OBJECTIVES: Vitamin D3 (cholecalciferol) dose required to maintain sufficiency in non- Caucasian women with postmenopausal osteoporosis (PMO) inthe tropics has not been well studied. Some guidelines mandate 800-1000 IU vitamin D/day but the Endocrine Society (US) advocates 1500-2000 IU/day to maintain 25-hydroxyvitamin-D (25(OH)D) concentration at >75 nmol/L. We aimed to establish oral cholecalciferol dose required to maintain 25(OH)D concentration at >75 nmol/L in PMO Chinese Malaysian women, postulating lower dose requirements amongst light-skinned subjects in the tropics.

    METHODS AND STUDY DESIGN: 90 Chinese Malaysian PMO women in Kuala Lumpur, Malaysia (2°30'N) with baseline serum 25(OH)D levels >=50 nmol/L were recruited. Prior vitamin D supplements were discontinued and subjects randomized to oral cholecalciferol 25,000 IU/4-weekly (Group-A) or 50,000 IU/4-weekly (Group- B) for 16 weeks, administered under direct observation. Serum 25(OH)D, PTH, serum/urinary calcium were measured at baseline, 8 and 16 weeks.

    RESULTS: Baseline characteristics, including osteoporosis severity, sun exposure (~3 hours/week), and serum 25(OH)D did not differ between treatment arms. After 16 weeks, 91% of women sufficient at baseline, remained sufficient on 25,000 IU/4-weekly compared with 97% on 50,000 IU/4-weekly with mean serum 25(OH)D 108.1±20.4 and 114.7±18.4 SD nmol/L respectively (p=0.273). At trial's end, 39% and 80% of insufficient women at baseline attained sufficiency in Group A and Group B (p=0.057). Neither dose was associated with hyperparathyroidism or toxicity.

    CONCLUSIONS: Despite pretrial vitamin D supplementation and adequate sun exposure, 25.6% Chinese Malaysian PMO women were vitamin D insufficient indicating sunshine alone cannot ensure sufficiency in the tropics. Both ~900 IU/day and ~1800 IU/day cholecalciferol can safely maintain vitamin D sufficiency in >90% of Chinese Malaysian PMO women. Higher doses are required with baseline concentration <75 nmol/L.
    Matched MeSH terms: Tropical Climate
  16. Golding KM
    Aust Dent J, 1971 Dec;16(6):389-93.
    PMID: 5291233
    Matched MeSH terms: Tropical Climate
  17. Gherardin T
    Aust Fam Physician, 2000 Mar;29(3):259.
    PMID: 10785992
    Shirley is a 42 year old woman who has rung you 5 days after returning from a 3 week resort holiday in Malaysia and Thailand. You saw her before her trip and administered a hepatitis A vaccine and advised her that she did not require anti malarial drugs as she was only going to large cities and beach resorts. She says she has had a high fever, headache and body aches for several days and that she feels exhausted, but is well enough to come to the surgery. When you see her later that morning, she looks fairly well, although she is moving rather gingerly. She says she has been resting, is drinking lots of fluids, has some anorexia, but no other significant symptoms. Examination reveals a temperature of 38 degrees C and she has a fine morbilliform rash on her body, limbs and neck. There are no other abnormal findings.
    Matched MeSH terms: Tropical Climate*
  18. Gardiner MR, Craig J
    Aust. Vet. J., 1970 Feb;46(2):65-9.
    PMID: 5463722
    Matched MeSH terms: Tropical Climate
  19. Miler K, Yahya BE, Czarnoleski M
    Behav Processes, 2017 Nov;144:1-4.
    PMID: 28843392 DOI: 10.1016/j.beproc.2017.08.010
    Some ants display rescue behaviour, which is performed by nearby nestmates and directed at individuals in danger. Here, using several ant species, we demonstrate that rescue behaviour expression matches predicted occurrences based on certain aspects of species' ecological niches. Rescue occurred in sand-dwelling ants exposed both to co-occurring antlion larvae, representing the threat of being captured by a predator, and to nest cave-ins, representing the threat of being trapped in a collapsed nest chamber. Rescue also occurred in forest groundcover ants exposed to certain entrapment situations. However, rescue never occurred in species associated with open plains, which nest in hardened soils and forage largely on herbaceous plants, or in ants living in close mutualistic relationships with their host plants. In addition, because we tested each species in two types of tests, antlion larva capture tests and artificial entrapment tests, we highlight the importance of accounting for test context in studying rescue behaviour expression.
    Matched MeSH terms: Tropical Climate
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