Studies were conducted on the potential use of cholecalciferol as an alternative to anticoagulant rodenticides to control common rat pest in oil palm plantations, i.e., wood rats, Rattus tiomanicus, and the secondary poisoning impact of cholecalciferol on barn owls, Tyto javanica javanica. The laboratory efficacy of cholecalciferol (0.075% a.i.) was compared with commonly used first-generation anticoagulant rodenticides (FGARs): chlorophacinone (0.005% a.i) and warfarin (0.05% a.i). The 6-day wild wood rat laboratory feeding trial showed cholecalciferol baits had the highest mortality rate at 71.39%. Similarly, the FGAR chlorophacinone recorded a mortality rate of 74.20%, while warfarin baits recorded the lowest mortality rate at 46.07%. The days-to-death of rat samples was in range of 6-8 days. The highest daily consumption of bait by rat samples was recorded for warfarin at 5.85 ± 1.34 g per day while the lowest was recorded in rat samples fed cholecalciferol, i.e., 3.03 ± 0.17 g per day. Chlorophacinone-treated and control rat samples recorded consumption of about 5 g per day. A secondary poisoning assessment on barn owls in captivity fed with cholecalciferol-poisoned rats showed after 7 days of alternate feeding, the barn owls appeared to remain healthy. All the barn owls fed with cholecalciferol-poisoned rats survived the 7-day alternate feeding test and throughout the study, up to 6 months after exposure. All the barn owls did not show any abnormal behavior or physical change. The barn owls were observed to be as healthy as the barn owls from the control group throughout the study.
Nymphal and larval Amblyomma cordiferum ticks, a relatively rare species, were collected from the Malaysian house rat (Rattus rattus diardii) in Peninsular Malaysia. Redescription and molecular analysis of nymphs and larvae, based on the 12S rRNA, 16S rRNA, and COI genes, revealed divergence from A. cordiferum in Taiwan, suggesting that the Taiwanese tick specimens may represent a different taxon. Molecular analysis of the pathogens in these specimens revealed three sequences of Rickettsia closely related or identical to Rickettsia raoultii (99.71-100%), two sequences of relapsing fever Borrelia identical to Borrelia theileri, and four sequences of Bartonella identical to Bartonella phoceensis. This study also identifies a new host record for A. cordiferum in R. r. diardii and reports the first detection of Rickettsia, Borrelia, and Bartonella in this tick species.