Spatio-temporal distribution of malaria in Betong, Sarawak, Malaysia: a five years study

The emergence of malaria has become one of the major public health problems in Betong, Sarawak, Malaysia. The number of reported malaria cases are increasing continuously in recent years. The aim of this study was to analyse the spatio-temporal pattern based on the yearly malaria surveillance data. Descriptive analysis was done to investigate the malaria incidence by time, person and place. Further analysis was done by mapping all malaria cases reported from year 2013 to 2017 by using ArcGIS software. Distribution of malaria cases were mapped in term of crude incidence. The average nearest neighbour was used to determine the distance analysis between malaria cases while Kernel density was applied to detect spatial pattern of locality for malaria hotspots. Distribution of malaria cases was clustered and random based on distance analysis. Based on spatio-temporal analysis pattern, malaria cases were identified as clusters in Betong and Spaoh subdistricts. It was observed that high risk occurrence of malaria cases were reported in the months of July to October each year. All the socio-demographic variables were associated with the malaria infection. After adjusting the relationship of all potential predictors at P<0.05, potential predictors such as gender, ethnicity (excluding the Malays) and occupation had significant association with the malaria infection. Spatial mapping could be beneficial to visualize the distribution of malaria cases for public health prevention

Spatial and temporal variations of water quality and trophic status in Bukit Merah Reservoir, Perak

A study of spatial and temporal variations on water quality and trophic status was conducted twice a month from December 2012 to January 2014 in four sampling stations at Bukit Merah Reservoir (BMR). The concentration of dissolved oxygen (DO), water temperature, conductivity, total dissolved solids (TDS), total phosphorous (TP), PO4-, NO2-, NO3-, NH4+ and net primary productivity had significant differences temporally (p<0.05) except for pH, total suspended solids (TSS) and chlorophyll-a. Based on correlation analysis, the amount of rainfall and rain days has negatively correlated with secchi depth and chlorophyll-a (p<0.01). The water level has significantly decreased the value of the temperature, pH, conductivity, TP and NO2- but it has positive correlation with NO3- and NH4+. Discharged from Sungai Kurau increased the value of conductivity, TSS, TP and NO2- as a result from runoff and erosion, thus decreasing the secchi depth values, NO3- and NH4+. The water quality of BMR is classified in Class II and TSI indicates that the BMR has an intermediate level of productivity (mesotrophic) and meets the objective of this reservoir which was to provide water for paddy irrigation

Assessing Diet & Trophic Position of Fish in Chenderoh Reservoir, Malaysia: SCA & SIA Approach

The present study assessed and compared the diet and trophic positions (TP) of two carnivorous fish H. macrolepidota and C. ocellaris from Chenderoh Reservoir, Malaysia. The focal goal of the study was to understand the effects of invasive non-indigenous species (NIS), C. ocellaris, on the native indigenous (IS) fish species, H. macrolepidota. Data were acquired from September 2014 to February 2015 within the study area. The assessment was grounded in stomach content analysis (SCA) and stable isotope analysis (SIA), which collectively clarified the feeding habits and trophic positions (TP) of these selected fish. In total, 184 fish samples (comprising 64 individuals of H. macrolepidota and 120 individuals of C. ocellaris) underwent stomach content analysis (SCA). Additionally, 24 individuals (12 of H. macrolepidota and 12 of C. ocellaris), sampled from December 2014 to February 2015, were selected for stable isotope analysis (SIA). The mean RGL values for H. macrolepidota and C ocellaris were 0.98 ± 0.18 and 1.10 ± 0.15 (Mean ± SD), respectively, aligning with known ranges for carnivorous fish. These values also clarified that both species occupy higher TP in the food web as tertiary or quaternary consumers. SCA findings also revealed that fish and crustaceans were the predominant food categories for H. macrolepidota, while C. ocellaris predominantly fed on fish. The mean stomach fullness index (MSF) and the gastrosomatic index (GSI) corroborated the differences in the foraging performance of the fishes, with C. ocellaris having a higher MSF (2.03) compared to H. macrolepidota (0.65). These implied that C. ocellaris had plentiful of food and encountered fewer diet-related challenges in the ecosystem. From SIA, δ13C values indicated that the primary carbon sources for both species are C3 plants, particularly aquatic vegetation. Further, δ15N values further ensured that both H. macrolepidota and C. ocellaris are carnivorous in nature and occupy higher TP in the ecosystem