Dogs are popular companions in our daily lives for company, hunting, protection or shepherding, but they also serve as reservoirs for zoonotic parasites. We analysed faecal samples from urban and rural environments in Qinghai Province on the Qinghai-Tibet Plateau of China to determine the prevalence of intestinal parasites. A total of 682 faecal samples were collected from four urban and two rural environments from October 2019 to December 2020. The samples were analysed for common intestinal parasites using a species-specific PCR approach. The total number of samples with parasites was 40 (5.87%): 23 (3.37%) were positive for helminths, and 17 (2.49%) were positive for protozoa. The following parasites were identified, and their respective prevalence rates were calculated: Cryptosporidium canis (1.32%), Giardia duodenalis (1.17%, assemblages D (n = 6) and C (n = 2)), Taenia hydatigena (1.03%), Taenia multiceps (0.59%), Toxocara canis (0.59%), Echinococcus shiquicus (0.29%), Dipylidium caninum (0.29%), Taenia pisiformis (0.15%), Mesocestoides lineatus (0.15%), Trichuris vulpis (0.15%), and Ancylostoma spp. (0.15%). The overall prevalence was significantly higher in dog faecal samples from rural environments than in those from urban environments (16.19% vs. 3.99%). E. shiquicus, T. pisiformis, M. lineatus, T. vulpis, and Ancylostoma spp. were only found in dog faecal samples from rural environments. The results of the present study indicate that intestinal parasite-positive dogs are important sources of environmental contamination, suggesting a significant zoonotic infection risk in humans and other animals. This has implications for the ongoing control of intestinal parasite infections in dogs in Qinghai Province, China.

Ovine theileriosis is a tick-borne hemoparasitic disease caused by protozoan parasites of the genus Theileria, which poses a substantial threat to sheep and goats. The disease is prevalent in northwestern China, yet studies on the diversity of its pathogens in Qinghai Province remain limited. From 2014 to 2025, 1062 blood samples were collected from sheep in 11 counties of Qinghai Province, and the Theileria spp. were investigated by PCR targeting the 18S rRNA gene. Genetic diversity analysis was performed to assess sequence variations and phylogenetic relationships. The results show that 424 samples tested positive for Theileria spp., with an overall infection rate of 39.92%, including T. uilenbergi 26.74%, T. luwenshuni 22.41%, T. ovis 18.17%, T. capreoli 0.56%, and Theileria sp. OT3 0.09%. The co-infection rate was 22.69%. Six haplotypes were detected in both T. uilenbergi and T. ovis, and fifteen in T. luwenshuni. Hap 1 was the dominant haplotype for all three species, with respective proportions of 73.08%, 77.06% and 82.17%. Phylogenetic analysis showed the strains were most closely related to those from Hunan, Turkey, Shaanxi, etc. These findings reveal a high diversity of Theileria species in Qinghai sheep, which provides crucial epidemiological insights into the transmission dynamics of ovine theileriosis in Qinghai and vital support for developing effective control strategies.

Echinococcosis is a zoonotic disease currently causing significant public health issues worldwide. The emerging and the expansion of Echinococcus spp. tapeworms in wildlife species and habitats are indeed underrecognized. Here, using infrared camera surveillance followed by morphological and genetic characterization, Echinococcus shiquicus (E. shiquicus), tapeworms were unexpectedly detected from Asian badgers in the QinghaiTibetan Plateau of China for the first time. In specific, an area of 3,939km² at an altitude of 3,6915,339m above sea level was monitored, from which fecal samples were collected, and fecal DNA was sequenced to solidify its match with the genome of Asian badgers before fecal egg examination. We further revealed that the isolated fecal eggs were morphologically representing E. shiquicus being oval in shape and containing a hexacanth embryo, and genetically formed a unique clade with diverse registered E. shiquicus isolates as illustrated by phylogenetic analysis. Overall, our investigation suggested Asian badger as a potential new definitive host of E. shiquicus tapeworm. More extensive surveillance for E. shiquicus tapeworm should be conducted in neglected host species and their habitats in the QinghaiTibetan Plateau.

Background: Alveolar echinococcosis is a lethal zoonotic parasitic disease caused by Echinococcus multilocularis . The activation and subsequent evagination of protoscoleces (PSCs) in the host digestive tract are critical steps for establishing infection in definitive hosts, yet the underlying molecular mechanisms remain poorly understood. Methods: In this study, we employed an in vitro PSC activation model combined with transcriptomic analysis to identify activation-associated genes. A novel gene, designated P158 , was further characterized by transcriptional unit analysis and functional knockdown assays to assess its role in PSC evagination, viability, tegument integrity, energy metabolism, and early metacestode development. Results: We confirmed that P158 constitutes an independent transcriptional unit from the adjacent DDX1 gene of E. multilocularis and found that P158 expression was significantly upregulated following activation. Knockdown of P158 led to a significant reduction in PSC evagination rate and impaired metacestode vesicular development in vitro. Concurrently, decreased cellular viability and damage to the microtriches indicated compromised tegument structural integrity. Further mechanistic analysis showed that P158 knockdown triggered metabolic dysregulation, characterized by reduced ATP levels, shrinkage of glycogen storage cells, and depletion of intracellular glycogen reserves. Conclusions: These findings demonstrate that P158 plays an essential role in promoting PSC evagination and early development by maintaining tegument structural integrity and regulating energy metabolism homeostasis. This study highlights P158 as a potential target for interventions aimed at blocking parasite development at the definitive host stage.