Ticks are blood-feeding ectoparasites and major vectors of pathogens that cause infectious diseases in humans and animals worldwide including mammals, birds and reptiles. Despite the growing scientific effort in the 20th century, there is still limited information on ticks and tick-borne pathogens in Southeast Asia, especially concerning medical, veterinary, socioeconomic and agricultural aspects in the island nations. This review provides an overview of the current state of knowledge of ticks and their pathogens in the island nations of Southeast Asia and peninsular Malaysia. We aim to stimulate further research studies on ticks and tick-borne pathogens of human and veterinary importance in this geographical region.
The traditional concept of "tonic food" and demand for traditional Chinese medicine make pangolins the largest population of illegally smuggled mammals in the world. Illegal hunting and trade are not only responsible for the sharp decline in pangolin populations but also provide conditions for pathogenic transmission. In 2021, we rescued 21 confiscated unhealthy Malayan pangolins, none of which survived. This study aimed to investigate the reasons for their unexpected deaths and the potential pathogens that may be transmitted during smuggling. Physical examination found that more than 80% pangolins were parasitized with A. javanense ticks. Autopsy and pathological staining analysis revealed multiple organ damage in the deceased pangolins. Pathogens nucleic acid detection of 33 tick samples showed that the positive rate of Rickettsia spp., Anaplasma spp., Ehrlichia spp. Babesia spp., and Colpodella spp. were 90.91%, 6.06%, 6.06%, 15.15% and 18.18%, respectively. Furthermore, pangolin samples were positive for Rickettsia spp. (42.86%, 9/21), Ehrlichia sp. (4.76%, 1/21), and Babesia sp. (4.76%, 1/21). This study confirmed that spotted fever triggered by Rickettsia spp. from A. javanense might accelerate the most death of confiscated pangolins, while Ehrlichia sp., and Babesia sp. infection potentially accelerating a few deaths. Of note, A. javanense ticks carrying Colpodella spp. were detected for the first time in Malayan pangolins. However, whether Colpodella spp. are pathogenic to pangolins is unknown. Further research on the diagnosis, treatment, surveillance, and elimination of ticks and tick-borne diseases in humans, livestock, and wildlife should provide insight into wildlife conservation and zoonotic disease prevention.
Tick cell lines are increasingly used in many fields of tick and tick-borne disease research. The Tick Cell Biobank was established in 2009 to facilitate the development and uptake of these unique and valuable resources. As well as serving as a repository for existing and new ixodid and argasid tick cell lines, the Tick Cell Biobank supplies cell lines and training in their maintenance to scientists worldwide and generates novel cultures from tick species not already represented in the collection. Now part of the Institute of Infection and Global Health at the University of Liverpool, the Tick Cell Biobank has embarked on a new phase of activity particularly targeted at research on problems caused by ticks, other arthropods and the diseases they transmit in less-developed, lower- and middle-income countries. We are carrying out genotypic and phenotypic characterisation of selected cell lines derived from tropical tick species. We continue to expand the culture collection, currently comprising 63 cell lines derived from 18 ixodid and argasid tick species and one each from the sand fly Lutzomyia longipalpis and the biting midge Culicoides sonorensis, and are actively engaging with collaborators to obtain starting material for primary cell cultures from other midge species, mites, tsetse flies and bees. Outposts of the Tick Cell Biobank will be set up in Malaysia, Kenya and Brazil to facilitate uptake and exploitation of cell lines and associated training by scientists in these and neighbouring countries. Thus the Tick Cell Biobank will continue to underpin many areas of global research into biology and control of ticks, other arthropods and vector-borne viral, bacterial and protozoan pathogens.