Detection of tick-borne pathogens in blood-fed ticks from animals across nine Asian countries.

Unlabelled: Climate change, land development, and increased outdoor human activity have increased the prevalence and distribution of tick-borne pathogens, causing public health issues. Asia is a pivotal region of emerging infectious diseases caused by zoonotic disease. Therefore, this study aimed to construct effective surveillance systems and establish preventive strategies against novel tick-borne diseases. Next-generation sequencing (NGS) was performed to detect tick-borne pathogens from animal blood-fed ticks. Ticks ( = 261) were collected from different animals across nine Asian countries between 2022 and 2023. Five genera of adults and nymphal ticks were used, namely, , , , , and . The animals from which the ticks were collected were wild, domestic animals, birds, and reptiles, living in the natural environment. After NGS, clean reads of 18,382,262-30,460,619 DNA viruses, 22,744,384-32,400,471 RNA viruses, 134,506-286,282 16S rRNA of bacteria, and 147,154-352,826 18S rRNA of protozoa were obtained from nine Asian countries. After analysis of the species, 28 RNA, 13 DNA viruses, 16 bacteria, and 4 protozoa were detected. Several tick-borne pathogens, including those in families that cause zoonotic diseases, such as , , , and , were identified. This study is distinctive in that it involved cooperative studies with nine Asian countries to prevent the spread of tick-borne diseases. The results suggest that pathogens, which were detected in animal blood-fed ticks, can circulate in animals and may be transmitted to humans. In addition, this study can provide a basis for effective surveillance systems to prevent novel pathogens.

Importance: Surveillance systems against novel tick-borne diseases are significant for global health. Climate and other environmental changes have contributed to an expanding range of ticks and tick-borne diseases. Areas in Asia constitute key areas of emerging infectious diseases. Through analysis of blood-fed ticks, collected from various animals living in the natural environment, we suggest that tick-borne pathogens may harbor animals and environment and have potential risk of transmission in humans. Understanding the distribution of tick-borne pathogens requires cooperative studying and, thus, can construct standardized surveillance systems.