First Report of Rickettsia Asembonensis in Small Ruminants

Abstract Rickettsioses is an emerging infectious disease in Southeast Asia caused by different organisms in the Rickettsiae bacterial tribe, a gram-negative obligate intracellular bacterium. There is limited information regarding the vertebrate hosts of Rickettsia spp. This study aims to detect and identify Rickettsia agents present in wildlife and domesticated animals in Malaysia using Polymerase Chain Reaction (PCR) and sequencing approach with phylogenetic analysis. Rickettsia sp. was detected in 2 (0.67%) of 300 animal blood samples. The positive samples were derived from a goat (5.56% of 18) and a sheep (2.22% of 45). Based on the analysis of the Rickettsia citrate synthase gene (gltA), both sequences demonstrated 99.64% sequence similarity to Rickettsia asembonensis, a species that is known to infect humans and macaques. This study reported for the first time the detection of R. asembonensis in sheep and goats in Malaysian farms, suggesting this species may be adapting in a wider range of animals, specifically farm animals, therefore, poses a zoonotic threat to the local populace particularly to the farm workers or animal handlers. The low infection rate of this pathogen yet is of public health importance highlighted the needs of continuous surveillance of emerging and reemerging pathogens among animal reservoirs.