Rhabditis (Rhabditella) axei is a predominantly free-living nematode commonly found in sewage systems and decomposing organic matter. While primarily saprophytic, it has been documented as an opportunistic pathogen in human urinary and gastrointestinal tracts. The Chinese red panda (Ailurus styani), a rare and protected species in China, has not previously been reported as a host for Rhabditis (Rhabditella) spp. infections. This study reports the first documented occurrence of R. axei in red panda feces, unambiguously confirmed through integrative taxonomic approaches combining morphological and molecular analyses. The nematodes exhibited key morphological features consistent with R. axei, including a cylindrical rhabditiform esophagus, sexually dimorphic tail structures, and diagnostic spicule morphology. Molecular analysis based on 18S-ITS-28S rDNA sequencing confirmed their identity, showing >99% sequence similarity to R. axei reference strains (GenBank: PP135624.1, PP135622.1). Phylogenetic reconstruction using 18S rDNA and ITS rDNA sequences placed the isolate within a well-supported R. axei clade, clearly distinguishing it from related species such as R. blumi and R. brassicae. The findings demonstrate the ecological plasticity of R. axei as a facultative parasite capable of infecting non-traditional hosts and further highlight potential zoonotic risks associated with environmental exposure in captive wildlife populations. Our results emphasize the indispensable role of molecular diagnostics in accurately distinguishing morphologically similar nematodes within the Rhabditidae family, while providing essential baseline data for health monitoring in both in situ and ex situ conservation programs for this endangered species.

Toxoplasma gondii is a globally distributed zoonotic parasite that infects a wide range of warm-blooded animals and poses serious threats to many endangered species. Effective serological detection is critical for disease surveillance and control, yet the accuracy of commercial assays varies significantly across host species. Validated serological methods for the Chinese red panda (Ailurus styani) remain scarce, limiting effective monitoring and conservation efforts. A total of 57 serum samples were collected from captive red pandas. Three commercial serological kits—the modified agglutination test (MAT), indirect hemagglutination assay (IHA), and enzyme-linked immunosorbent assay (ELISA)—were used to detect T. gondii antibodies. Statistical analyses included agreement assessment (Cohen’s kappa), McNemar’s test, and receiver operating characteristic (ROC) curve analysis, with MAT as the reference standard. MAT detected T. gondii antibodies in 36.84% (21/57; 95% CI: 24.32–49.36) of samples, while ELISA identified 42.11% (24/57; 95% CI: 29.29–54.92). IHA failed to detect any positive samples (0%). MAT and ELISA showed almost perfect agreement (κ = 0.817; 95% CI: 0.66–0.97) with no significant difference (p > 0.05). Compared to MAT, ELISA exhibited 95.2% sensitivity and 88.9% specificity. The combined MAT/ELISA approach with retesting of discordant samples yielded a final seroprevalence of 35.09% (20/57), with 8.77% (5/57) indeterminate results. MAT and ELISA are reliable methods for serological surveillance of T. gondii in red pandas, while IHA is unsuitable. We recommend MAT for initial screening followed by ELISA confirmation. The high seroprevalence highlights the need for integrated control strategies, including management of stray felids and rodents in captive environments to reduce transmission risks.