Investigation of Parasitic Ticks and the Potential Tick-Borne Pathogenic Fungi in Yunnan Province, Southwest China

Ticks are hematophagous arthropods that parasitize livestock, humans, and wild animals, posing serious threats to public health worldwide. Diverse pathogens have been discovered in ticks, including viruses, bacteria, protozoa, and filarial nematodes; however, ticks also harbor a variety of fungal microbes, which remain largely unexplored. In this study, we isolated and identified culturable fungi associated with ticks collected on cattle and goats in Yunnan Province, China. Of the 1730 ticks obtained, 1690 were identified as Rhipicephalus microplus, and only 40 as Haemaphysalis longicornis via morphology and 16S rRNA gene analysis. A total of 90 fungal strains were isolated from the ticks and identified by morphological examination and ITS sequencing, representing 25 species across 20 genera, with Fusarium being the most prevalent. Among these isolates, Fusarium verticillioides (19 isolates) poses a threat to grains, animals, and humans; Cladosporium cladosporioides (six isolates) and Sarocladium zeae (one isolate) are primarily pathogenic to plants, while Schizophyllum commune (eight isolates), Rhizopus arrhizus (two isolates), Diaporthe phaseolorum (two isolates), and Purpureocillium lilacinum (two isolates) are recognized animal-associated pathogens. The diversity of isolated fungi with documented pathogenicity suggests that ticks may serve as potential vectors for fungal transmission, raising concerns about their role in cross-kingdom disease spread across agriculture and livestock. Furthermore, fungi with entomopathogenic potential, such as P. lilacinum, offer valuable resources for developing biocontrol agents against ticks. Our findings highlight the dual role of ticks as both potential vectors of phytopathogenic fungi and reservoirs of entomopathogenic biocontrol agents. This necessitates a paradigm shift in tick surveillance, integrating mycological monitoring to mitigate agricultural losses and exploring tick-borne fungi for sustainable vector control strategies.