Tick diversity and tick-borne pathogens in livestock and companion animals in Cambodia: A narrative review and new field data (2022−2023)

Abstract

Ticks are important vectors for pathogens that affect both animal and human health. Research on ticks and tick-borne diseases (TBDs) in Cambodia remains limited. This study addresses existing knowledge gaps through two complementary approaches including an evidence synthesis and new field data providing updated data on tick fauna and pathogens.

Evidence Synthesis is a review of scientific publications and veterinary student theses reveal substantial knowledge gaps. To date, five tick-borne pathogens have been documented in dogs through peer-reviewed studies: Babesia vogeli (formerly Babesia canis vogeli), Ehrlichia canis, Hepatozoon canis, Mycoplasma haemocanis, and Rickettsia felis. Veterinary theses suggest the possible presence of anaplasmosis, babesiosis, theileriosis, and ehrlichiosis in cattle; however, there is no peer-reviewed data on TBDs in other domestic animals or humans.

New Field Sampling (2022–2023) is the primary field study that was conducted to investigate tick diversity across various ecological settings, including domestic animals, wildlife, and environmental sites. A total of 7461 ticks were collected from 853 animals across 13 host species, with cattle and dogs showing the highest tick burdens. Fourteen tick species were identified, including seven species recorded in Cambodia for the first time: Carios batuensis, Dermacentor steini, D. filippovae, Haemaphysalis canestrinii, H. hystricis, H. formosensis, and H. wellingtoni.

These findings reveal a considerable gap in our current understanding of tick species and TBDs in Cambodia. The confirmed presence of various tick species, several previously unrecorded species and multiple pathogens emphasize the need for sustained surveillance to better characterize pathogen presence and distribution.