Low Levels of Polymorphisms and Negative Selection in Plasmodum knowlesi Merozoite Surface Protein 8 in Malaysian Isolates

Human infections due to the monkey malaria parasite Plasmodium knowlesi is increasingly being reported from most Southeast Asian countries specifically Malaysia. The parasite causes severe and fatal malaria thus there is a need for urgent measures for its control. In this study, the level of polymorphisms, haplotypes and natural selection of full-length pkmsp8 in 37 clinical samples from Malaysian Borneo along with 6 lab-adapted strains were investigated. Low levels of polymorphism were observed across the full-length gene, the double epidermal growth factor (EGF) domains were mostly conserved, and non-synonymous substitutions were absent. Evidence of strong negative selection pressure in the non-EGF regions were found indicating functional constrains acting at different domains. Phylogenetic haplotype network analysis identified shared haplotypes and indicated geographical clustering of samples originating from Peninsular Malaysia and Malaysian Borneo. This is the first study to genetically characterize the full-length msp8 gene from clinical isolates of P. knowlesi from Malaysia; however, further functional characterization would be useful for future rational vaccine design.

Epidemiological Characteristics of Strongyloidiasis in Inhabitants of Indigenous Communities in Borneo Island, Malaysia

Epidemiological study on strongyloidiasis in humans is currently lacking in Malaysia. Thus, a cross-sectional study was carried out to determine the prevalence of Strongyloides stercoralis infection among the inhabitants of longhouse indigenous communities in Sarawak. A single stool and blood sample were collected from each participant and subjected to microscopy, serological and molecular techniques. Five species of intestinal parasites were identified by stool microscopy. None of the stool samples were positive for S. stercoralis. However, 11% of 236 serum samples were seropositive for strongyloidiasis. Further confirmation using molecular technique on stool samples of the seropositive individuals successfully amplified 5 samples, suggesting current active infections. The prevalence was significantly higher in adult males and tended to increase with age. S. stercoralis should no longer be neglected in any intestinal parasitic survey. Combination of more than 1 diagnostic technique is necessary to increase the likelihood of estimating the ‘true’ prevalence of S. stercoralis.

Epidemiological Characteristics of Strongyloidiasis in Inhabitants of Indigenous Communities in Borneo Island, Malaysia

Epidemiological study on strongyloidiasis in humans is currently lacking in Malaysia. Thus, a cross-sectional study was carried out to determine the prevalence of Strongyloides stercoralis infection among the inhabitants of longhouse indigenous communities in Sarawak. A single stool and blood sample were collected from each participant and subjected to microscopy, serological and molecular techniques. Five species of intestinal parasites were identified by stool microscopy. None of the stool samples were positive for S. stercoralis. However, 11% of 236 serum samples were seropositive for strongyloidiasis. Further confirmation using molecular technique on stool samples of the seropositive individuals successfully amplified 5 samples, suggesting current active infections. The prevalence was significantly higher in adult males and tended to increase with age. S. stercoralis should no longer be neglected in any intestinal parasitic survey. Combination of more than 1 diagnostic technique is necessary to increase the likelihood of estimating the ‘true’ prevalence of S. stercoralis.

Clinical characteristics and mortality risk prediction in critically ill children in Malaysian Borneo

<p><b>INTRODUCTION</b>Mortality risk prediction scores are important for benchmarking quality of care in paediatric intensive care units (PICUs). We aimed to benchmark PICU outcomes at our hospital against the Pediatric Index of Mortality 2 (PIM2) mortality risk prediction score, and evaluate differences in diagnosis on admission and outcomes between Malaysian and immigrant children.</p><p><b>METHODS</b>We prospectively collected demographic and clinical data on paediatric medical patients admitted to the PICU of Sabah Women's and Children's Hospital in Kota Kinabalu, Sabah, Malaysia. The PIM2 risk score for mortality was tabulated.</p><p><b>RESULTS</b>Of the 131 patients who met the inclusion criteria, data was available for 115 patients. The mean age of the patients was 2.6 ± 3.8 years, with 79% of the cohort aged less than five years. Patients were mainly of Kadazan (38%) and Bajau (30%) descent, and 26% of patients were non-citizens. Leading diagnoses on admission were respiratory (37%), neurological (18%) and infectious (17%) disorders. Out of the 29 patients who died, 23 (79%) were Malaysians and the main mortality diagnostic categories were respiratory disorder (22%), septicaemia (22%), haemato-oncological disease (17%) and neurological disorder (13%). Calculated standardised mortality ratios (SMRs) were not significantly > 1 for any patient category for variables such as age and admission diagnosis. However, infants less than two years old with comorbidities were significantly worse (SMR 2.61, 95% confidence interval 1.02-6.66).</p><p><b>CONCLUSION</b>The patient profile at our centre was similar to that reported from other PICUs in Asia. The PIM2 score is a useful mortality risk prediction model for our population.</p>

High incidence of nasopharyngeal cancer: similarity for 60% of mitochondrial DNA signatures between the Bidayuhs of Borneo and the Bai-yue of Southern China / 癌症

Populations in Southern China (Bai-yue) and Borneo (Bidayuh) with high incidence of nasopharyngeal cancer(NPC) share similar mitochondrial DNA signatures, supporting the hypothesis that these two populations may share the same genetic predisposition for NPC, which may have first appeared in a common ancestral reference population before the sea levels rose after the last ice age.

Is nasopharyngeal cancer really a "Cantonese cancer"? / 癌症

Nasopharyngeal cancer (NPC) is endemic in Southern China, with Guandong province and Hong Kong reporting some of the highest incidences in the world. The journal Science has called it a "Cantonese cancer". We propose that in fact NPC is a cancer that originated in the Bai Yue ("proto Tai Kadai" or "proto Austronesian" or "proto Zhuang") peoples and was transmitted to the Han Chinese in southern China through intermarriage. However, the work by John Ho raised the profile of NPC, and because of the high incidence of NPC in Hong Kong and Guangzhou, NPC became known as a Cantonese cancer. We searched historical articles, articles cited in PubMed, Google, monographs, books and Internet articles relating to genetics of the peoples with high populations of NPC. The migration history of these various peoples was extensively researched, and where possible, their genetic fingerprint identified to corroborate with historical accounts. Genetic and anthropological evidence suggest there are a lot of similarities between the Bai Yue and the aboriginal peoples of Borneo and Northeast India; between Inuit of Greenland, Austronesian Mayalo Polynesians of Southeast Asia and Polynesians of Oceania, suggesting some common ancestry. Genetic studies also suggest the present Cantonese, Minnans and Hakkas are probably an admixture of northern Han and southern Bai Yue. All these populations have a high incidence of NPC. Very early contact between southern Chinese and peoples of East Africa and Arabia can also account for the intermediate incidence of NPC in these regions.

Contribution of pitcher fragrance and fluid viscosity to high prey diversity in a Nepenthes carnivorous plant from Borneo.

Mechanisms that improve prey richness in carnivorous plants may involve three crucial phases of trapping:attraction, capture and retention.Nepenthes rafflesiana var. typica is an insectivorous pitcher plant that is widespread in northern Borneo.It exhibits ontogenetic pitcher dimorphism with the upper pitchers trapping more flying prey than the lower pitchers.While this difference in prey composition has been ascribed to differences in attraction,the contribution of capture and retention has been overlooked.This study focused on distinguishing between the prey trapping mechanisms, and assessing their relative contribution to prey diversity.Arthropod richness and diversity of both visitors and prey in the two types of pitchers were analysed to quantify the relative contribution of attraction to prey trapping.Rate of insect visits to the different pitcher parts and the presence or absence of a sweet fragrance was recorded to clarify the origin and mechanism of attraction.The mechanism of retention was studied by insect bioassays and measurements of fluid viscosity. Nepenthes rafflesiana was found to trap a broader prey spectrum than that previously described for any Nepenthes species,with the upper pitchers attracting and trapping a greater quantity and diversity of prey items than the lower pitchers.Capture efficiency was low compared with attraction or retention efficiency.Fragrance of the peristome,or nectar rim,accounted mainly for the observed non-specific, better prey attraction by the upper pitchers, while the retentive properties of the viscous fluid in these upper pitchers arguably explains the species richness of their flying prey.The pitchers of N. rafflesiana are therefore more than simple pitfall traps and the digestive fluid plays an important yet unsuspected role in the ecological success of the species.

Smokeless tobacco use among rural Kadazan women in Sabah, Malaysia.

A survey was conducted to document and bring attention to the use of smokeless tobacco among rural Kadazan women in Sabah, East Malaysia. Of the 472 women interviewed, 59.5% had used tobacco among the ingredients that they habitually chewed. Women with low education were more likely to be chewers. The chewing habit was usually acquired during the teenage years and the practice was perceived mainly as a cultural norm. 73.3% of these smokeless tobacco users were unaware of any adverse health effect of this type of tobacco use as compared to 53.9% of the non-tobacco users. The high prevalence of smokeless tobacco use is easily maintained as tobacco is cheap, locally produced and its use is socially accepted. The low level educational status of the women compounds the problem and intervention programs to curb this form of tobacco use is warranted.

A blood pressure profile of rural Kadazans and Bajaus in Sabah, east Malaysia.

A survey was conducted to document the blood pressures of two indigenous groups (Kadazans and Bajaus) who reside in rural Sabah in East Malaysia. Their health knowledge status is also recorded. Fifty percent of those surveyed were unable to associate high blood pressure with a risk factor and as high as 38% were unaware of the consequences of high blood pressure. A total of 16.2% had blood pressures > or = 140/or 90mm Hg while 3.9% had blood pressures > or = 160/or 95mm Hg. While these figures are low compared to those of developed countries, lifestyle changes associated with rapid urbanization in Malaysia may be expected to increase hypertension prevalence. The strengthening of health education programs is timely as health knowledge is limited and many hypertensives default treatment.

Low prevalence of antibody to human herpesvirus-6 (HHV-6) in Kadazans.

The prevalence of antibody to human herpesvirus type 6 (HHV-6) and Epstein-Barr virus (EBV) viral capsid antigens (VCA) were analysed in sera from Kadazans of Sabah, North Borneo. At a serum dilution of 10, about 34% were positive for HHV-6 antibody but in contrast all 95 individuals studied were positive for EBV VCA antibody. The study shows that HHV-6 and EBV infection occur independently. The low frequency of seropositive individuals in this community suggests that other than socioeconomic factors are responsible for the spread of the virus.

Absence of plague in certain mammals from Java and Kalimantan (Borneo).

Antibodies against plague were lacking in 237 wild mammal sera from Java and 103 from Kalimantan. Wild mammal spleens, 114 from Java and 18 from Kalimantan were negative for plague bacilli. A variety of mammalian species and areas was examined.

Studies on filariasis in the Pacific. 5. Brugia malayi filariasis in treated and untreated populations of South Borneo.

A blood survey employing membrane filter concentration (MFC) and examination of stained 20 c.mm thick blood films as diagnostic methods was carried out in Banjar Regency of South Borneo, an area of endemic B. malayi filariasis. In untreated populations the mf rate, as revealed by MFC, ranged from 23.2% for the 5-9 year old group to 43.7% for the greater than 50 year old group. For all age groups approximately one half of the microfilaraemias were of a low grade nature, diagnosed by MFC only. In a population that had been subjected to mass DEC administration 1 1/2 years prior to this survey, the MFC-diagnosed rate was 15%. Approximately two thirds of these infections were of very low density, the average density being 2.2 mf/ml.

Parasitology survey and seroepidemiology of amoebiasis in South Kalimantan (Borneo), Indonesia.

A parasitology surevy was conducted among inhabitants of 7 villages in 3 regencies in South Kalimantan Province, Indonesia. A total of 2,169 stool specimens, 2,756 blood smears and 1,027 serum specimens were obtained, representing samples from approximately 10%, 12% and 5% of the population, respectively. One to 8 different intestinal parasitic infections were detected in 97% of the people. Those parasites most frequently found were Trichuris trichiura (83%), Ascaris lumbricoides (79%), and hookworm (65%), followed by Entamoeba coli (37%), Endolimaxnana (12%), Entamoeba histolytica (12%), Iodamoeba bütschlii (11%), Giardia lamblia (5%), Entamoeba hartmanni (2%), Chilomastix mesnili (2%). Other parasites found were Enterobius vermicularis, Strongyloides stercoralis, Capillaria sp., Echinostoma sp., Hymenolepis diminuta, and Trichomonas hominis. Giardia lamblia was found more often in younger people and Entamoeba coli, Iodamoeba bütschlii and hookworm in the older age group. Ascaris lumbricoides occurred more frequently in females, and hookworm in males. Plasmodium vivax and Plasmodium falciparum were found in the blood smears of 4.4% of the people, mostly in the younger age groups. Seroepidemiological studies on amoebiasis were done by use of the indirect hemagglutination test with antigens prepared from the HK9 strain of Entamoeba histolytica maintained in axenic cultures. The frequency distribution of the reciprocal antibody titers showed a bimodal distribution with 34% of the population demonstrating positive reactions at titers of 1:128 or greater.