Aedes aegypti and Aedes albopictus mosquitoes are the primary vectors of tropical diseases, including dengue fever (DHF), chikungunya, and Zika, particularly in tropical regions such as Malaysia. Vector control efforts are now increasingly focused on biological and environmentally friendly approaches, one of which is using insect growth regulator (IGR)-based insecticides such as pyriproxyfen. Pyriproxyfen works by disrupting the metamorphosis process of mosquito larvae into adults without causing direct death, but it is effective in inhibiting the emergence of adult mosquitoes by more than 90%, depending on the dose and environmental conditions. This study evaluated the concentration-dependent effects of pyriproxyfen on laboratory and field populations of Aedes spp. Laboratory strains exhibited 100% adult mortality at 1.04 ppm (Ae. aegypti) and 1.08 ppm (Ae. albopictus), whereas field populations required 1.15 – 1.71 ppm depending on locality. LC50 values were lowest in laboratory strains (0.267 ppm for Ae. aegypti and 0.236 ppm for Ae. albopictus), while field strains ranged from 0.326 to 0.571 ppm. LC95 values followed a similar trend, with 1.026 ppm (Ae. aegypti) and 1.107 ppm (Ae. albopictus) in laboratory strains. Inhibition of emergence (IE%) was high in laboratory strains, reaching 97.89% at 0.50 ppm in Ae. aegypti and 63.54% at 0.50 ppm in Ae. albopictus. Field populations required higher concentrations for similar suppression, with IE% ranging from 17.68 – 98.23% in Ae. aegypti and 13.14- 98.24% in Ae. albopictus, peaking at 1.50 ppm. From this finding, it is suggested that pyriproxyfen effectively inhibits adult emergence in both laboratory and field populations, with laboratory strains more sensitive at lower concentrations and field strains responding at higher doses. These results provide strong evidence for pyriproxyfen as an effective, adaptive, and sustainable component of integrated vector management in Malaysia.

A series of new 2,5-disubstituted-1,3,4-oxadiazole derivatives (5a-j and 6a-j) have been designed and synthesized in four-steps. Sixteen compounds among the twenty compounds are reported for the first time. The compounds were characterized and confirmed by the FTIR, 1D- and 2D-NMR and HRMS analyses, and were tested against Mycobacterium smegmatis and Mycobacterium tuberculosis H37Ra. Compound 5d was the most active against M. smegmatis with MIC value of 25 µM, and exhibited cidal activity with MBC of 68 µM, respectively. The time-kill assay showed the good killing rate at 77% with the combination of isoniazid (INH). In addition, checkboard assay confirmed the interaction of compound 5d was categorised as additive. Docking simulation has been performed to position 5d into the pantothenate synthetase active site with binding free energy value –8.6 kcal mol-1. It also occupied the same active site as that of standard native ligand with similar interactions, which clearly indicate their potential as pantothenate synthetase inhibitor.

Some filarial nematodes, such as Wuchereria bancrofti, Brugia malayi, and Brugia timori, cause lymphatic diseases in humans in the tropics, whereas other filarial parasites from wild animals cause zoonotic diseases in humans worldwide. To elucidate the prevalence and diversity of filarial parasites in Malaysia, we investigated the filarial parasites from wild animals in Gemas, Negeri Sembilan. To find adult filarial parasites, we dissected 26 animals, which included five frogs, one skink, one snake, two birds, six common treeshrews, and 11 rats. Then, we examined microfilariae in the blood smears and skin snips obtained from each animal. We found two types of microfilariae in the blood smears of common treeshrews: one was very similar to Malayfilaria sofiani and the other closely resembled Brugia tupaiae. These findings indicate an additional distribution of these filarial parasites in Gemas.

Abstract. The use of ice cubes in beverages is common among patrons of food outlets in Malaysia although its safety for human consumption remains unclear. Hence, this study was designed to determine the presence of faecal coliforms and several useful water physicochemical parameters viz. free residual chlorine concentration, turbidity and pH in ice cubes from 30 randomly selected food outlets in Kubang Kerian, Kelantan. Faecal coliforms were found in ice cubes in 16 (53%) food outlets ranging between 1 CFU/100mL to >50 CFU/ 100mL, while in the remaining 14 (47%) food outlets, in samples of tap water as well as in commercially bottled drinking water, faecal coliforms were not detected. The highest faecal coliform counts of >50 CFU/100mL were observed in 3 (10%) food outlets followed by 11-50 CFU/100mL and 1-10 CFU/100mL in 7 (23%) and 6 (20%) food outlets, respectively. All samples recorded low free residual chlorine concentration (<0.10mg/L) with the pH ranging between 5.5 and 7.3 and turbidity between 0.14-1.76 NTU. Since contamination by faecal coliforms was not detected in 47% of the samples, tap water and commercially bottled drinking water, it was concluded that (1) contamination by faecal coliforms may occur due to improper handling of ice cubes at the food outlets or (2) they may not be the water sources used for making ice cubes. Since low free residual chlorine concentrations were observed (<0.10mg/L) in all samples as well as in both tap water and commercially bottled drinking water, with the pH ranged between 5.5-7.3, ineffective disinfection of water source as a contributing factor to such high counts of faecal coliforms in ice cubes also could not be ruled out. Therefore, a periodical, yet comprehensive check on the food outlets, including that of ice cube is crucial in ensuring better food and water for human consumption.