Sarcocystis spp. are protist parasites with strict two-host life cycle and ubiquitous existence. Predatory animals usually serve as the final host of Sarcocystis and their preys serve the intermediate host of the parasite. In this study, we reported a Sarocycstis species infecting muscle of three species of carnivores in the mountain of Taiwan, two mustelids and one viverrid. These animals are Formosan ferret badger (Melogale moschata subaurantiaca), Formosan yellow-throated marten (Martes flavigula chrysospila), and gem-faced civet (Paguma larvata taivana). It was characterized and described by histopathological, transmission electron microscopic and molecular techniques. Five loci were characterized, including 18S rRNA gene, 28S rRNA gene, ITS1 region, mitochondrial cytochrome c oxidase I gene (COXI) and RNA polymerase gene (rpoB). Genetic analysis showed that the three carnivores host one Sarcocystis species. Based on four genetic loci and by microscopical analysis, the discovered Sarcocystis could not be differentiated from S. lurae. Based on ITS1, however, newly detected parasite showed only up to 92.9 % similarity with S. lutrae. The discovered species was provisionally named Sarcocystis lutrae-like. Further examination expanding regional areas and carnivore host should be included to resolved current taxonomical issue. It is the first report of Sarcocystis infection in small carnivores in Taiwan, the first report of parasite morphologically and genetically similar to S. lutrae in Southeast Asia, and the first time discovered in viverrid animals.
Ticks are important vectors of zoonotic pathogens in Europe, but knowledge regarding the presence of Rickettsia spp. and Bartonella spp. in questing Ixodes ricinus in Norway remains limited. This study investigated the occurrence of these bacteria in ticks collected across the Norwegian distribution range of I. ricinus. A total of 564 adult ticks and 3930 nymphs (393 pools) collected in seven counties were analysed by real-time PCR. Rickettsia spp. were detected only in adult ticks, with an overall prevalence of 3.9 % (22/564). Infected ticks were identified in only two counties, Østfold and Agder, with a prevalence of 11.2 and 10.9 %, respectively. Species-specific analysis confirmed R. helvetica in 77.3 % (17/22) of the positive samples. Rickettsia spp. were not detected in any nymph pools. Bartonella spp. were detected in 0.5 % (3/564) of adult ticks, representing the first report of Bartonella spp. in questing I. ricinus in Norway. Infected ticks were found in three counties, Østfold, Telemark, and Nordland. Bartonella spp. were not detected in any nymph pools. These findings demonstrate that Rickettsia spp. and Bartonella spp. are present in questing adult ticks in Norway, highlighting the importance of continued surveillance of emerging tick-borne pathogens in northern Europe.
Gut protists are an important part of the microbial community that is often overlooked or limited to certain "flagship" species, mainly parasites. This also applies to Eurasian beavers (Castor fiber), which act as aquatic engineers in riparian habitats and have been identified as potential reservoirs of the well-known intestinal protist parasite - Giardia intestinalis. In this study, we focus on exploring protistan diversity in Eurasian beavers from freshly collected stool samples using molecular methods, including targeted barcoding of specific parasitic groups (Giardia, Cryptosporidium and Microsporidia) and general metabarcoding of the V4 region of 18S rRNA on the Illumina MiSeq platform. Two individuals were tested positive for Cryptosporidium spp. using the targeted barcoding. The metabarcoding approach revealed that the gut community was predominantly composed of gut commensals, Blastocystis, and trichomonads, found in every individual. More detailed investigation of Blastocystis confirmed the potential existence of a specific beaver subtype. Colpodellids and parasitic Eimeria spp. were only occasionally present. Geographic location of the host, unlike sex, has a significant impact on gut microbiota composition, though more research is needed due to limited sampling. Finally, we tested a new primer set for amplifying the V4 region of 18S rRNA, which shows promise for improving the detection of Metamonada protists in the gut samples.
Chewing lice are highly host-specific, permanent ectoparasites of birds. This feature potentially places lice infesting endangered hosts at an even greater risk of extinction than the hosts themselves. Despite this ecological significance, research on chewing lice parasitizing endangered birds in the Republic of Korea remains limited. This study aims to document and provide taxonomic information on the chewing lice species infesting the wild population of the endangered Black-faced Spoonbill (Platalea minor) in Korea. In July 2025, five spoonbills were examined for ectoparasites. Collected specimens were morphologically identified using light microscopy and scanning electron microscopy (SEM), focusing on key diagnostic characters. Additionally, we performed a phylogenetic analysis and compared genetic distances. Based on the morphological and molecular analyses, our specimens were identified as Ibidoecus plataleae (Denny, 1842). This study represents the first report of I. plataleae from the Black-faced Spoonbill in Korea.
Cytauxzoon banethi is one of the least characterized members of the genus Cytauxzoon and has so far been reported only from two European wildcats (Felis silvestris) in Romania. Consequently, its host range and geographic distribution remain poorly understood. In the present study, we molecularly characterized a Cytauxzoon isolate detected in a free-ranging striped hyena (Hyaena hyaena) from western Iran. Genomic DNA extracted from blood was analyzed by PCR amplification and sequencing of partial 18S rRNA and mitochondrial cytochrome b (cytb) genes. The 18S rRNA sequence was identical to published C. manul sequences and highly similar to several other Cytauxzoon species, confirming the limited species-level resolution of this conserved marker. In contrast, direct comparison of the cytb sequence with the available C. banethi reference sequence revealed only five synonymous nucleotide substitutions across 1,089 aligned positions (99.5% identity). Phylogenetic analysis of the cytb dataset placed the obtained isolate within the C. banethi lineage as the sister taxon to C. manul, supporting its identification as C. banethi. To the best of our knowledge, this represents the first molecular detection of C. banethi in a member of the family Hyaenidae, the first record in a non-felid feliform host, the first report from Iran and Asia, and the first detection of this species outside Europe. These findings expand the currently recognized host range and geographic distribution of C. banethi and emphasize the importance of multilocus molecular approaches and broader wildlife surveillance for improving our understanding of the diversity and evolution of Cytauxzoon species in general, and for better assessing the genetic diversity and taxonomic boundaries of C. banethi.
Numbers of European bison (Bison bonasus) reintroduction programmes are increasing across Europe. Investigating potential health risks related to translocations is crucial for the long-term success of such programmes. Parasitological analyses play a central role in monitoring the health status and assessing disease transmission risks during the translocation of European bison herds. This study monitored the endoparasite fauna of both a newly relocated European bison herd (n = 7 animals), and of the neighbouring suckler cow herd (n = 25 animals), over the course of one year. The aim of the study was to compare the parasite populations of these two closely related ruminant species kept under similar management conditions, and to assess the risk of parasite transmission by shared grazing areas. From April 2023 to March 2024, faecal samples from both herds were analysed monthly, using direct detection methods such as sedimentation, combined sedimentation-flotation, Baermann funnel, McMaster, and copro-antigen tests (total n = 72 samples). A total of seven helminth groups and four protozoan genera were thereby identified, with a richer parasite diversity in the bison samples. Eggs of Trichuris spp., Nematodirus spp., Moniezia spp., and cysts of Giardia sp. were exclusively shed by the European bison. On the other hand, cysts of Buxtonella sp. were only found in cattle samples. Paramphistomidae eggs and Cryptosporidium spp. were significantly more frequently detected in cattle samples. Both, the suckler cow and the European bison herd, showed constant infection with gastrointestinal strongylids, but the faecal egg counts were tenfold higher in the bison. Infections with Eimeria spp., Strongyloides spp., and Dicrocoelium dendriticum were detected in both species, and no lungworm larvae were detected in either species. Further investigations should include identification of the parasites to species level, and the parasitological monitoring in the two herds should be continued to assess if the observed differences persist or disappear over time.
Biological invasions by apex predators can restructure the destination range through ecological turbulence. This study investigates the co-i,markedntroduction and establishment of parasites associated with the invasive northern pike, Esox lucius, in Zrebar Lake (Tigris River basin, Iran). A total of 100 specimens of pike were collected during 2020 and 2025, and two alien parasites were found: the monogenean Tetraonchus monenteron and the nematode Raphidascaris acus. The obtained ITS sequences showed 100% identity with R. acus sequences from Anzali (KM047505) and Turkey (KT633862). Compared with populations from the native range, the invasive pike population showed reduced parasite richness, prevalence, and infection intensity. However, these reductions alone are insufficient to explain the invasion success of E. lucius under the framework of the Enemy Release Hypothesis (ERH), and further evidence is required to evaluate this mechanism. Larval stages of R. acus were detected in the non-native cyprinid Carassius gibelio, indicating successful completion of the parasite life cycle in the invaded ecosystem. The present study provides evidence for parasite co-invasion and establishment associated with northern pike in Zrebar Lake. It highlights the ecological importance of invasive host–parasite interactions in freshwater ecosystems.
Human-induced environmental changes can modify the transmission patterns of arthropod-borne infections across multiple ecological scales. This study evaluated the influence of habitat alteration on Hepatozoon sp. infection in wild rodents (Phyllotis darwini Waterhouse, 1837) inhabiting the semi-arid Mediterranean Coquimbo region of north-central Chile. Rodents were captured and sampled at two sites with contrasting levels of anthropogenic disturbance–a protected area (Bosque Fray Jorge National Park) and an altered rural site (El Tangue Farm)–across seven consecutive seasons from austral spring 2021 to autumn 2023. Hepatozoon sp. infection was assessed in rodent blood samples using conventional PCR targeting the 18S rRNA gene and phylogenetic analyses. Statistical models were conducted to evaluate environmental and host-related factors. Overall, 144 of 446 (32.3%) blood samples were positive for Hepatozoon sp. by PCR. The likelihood of Hepatozoon sp. infection varied seasonally and was higher in rodents from the altered site and in individuals with higher body mass index. These findings highlight the potential effects of anthropogenic disturbance and seasonality on the Hepatozoon infection status on wildlife populations. By characterizing patterns of Hepatozoon sp. infection in small mammals inhabiting anthropogenically altered environments, this study contributes to a better understanding of arthropod-borne infections under human-induced pressures, with implications for biodiversity conservation.
Anthropogenic environmental changes have intensified interactions among wildlife, domestic animals, and humans, reshaping parasite transmission dynamics. In this context, anteaters may play an important role as hosts within sylvatic transmission networks of Trypanosoma cruzi. This study investigated the occurrence and molecular characterization of T. cruzi in anteaters from São Paulo State, Brazil. Whole blood samples from 26 individuals were analyzed using PCR assays targeting the 18S rRNA gene, followed by sequencing and Bayesian phylogenetic inference. Trypanosoma cruzi DNA was detected in 42.3% (11/26) of the samples. Sequence analysis revealed high similarity (93.66-99.65%) with reference strains available in GenBank, and phylogenetic reconstruction confirmed that all sequences clustered within the T. cruzi clade with low intraspecific divergence. No statistically significant associations were observed between infection status and host-related variables, including host species (p = 0.348), sex (p = 1.000), age class (p = 0.674), and sampling season (p = 0.275), indicating no evidence of these factors as determinants of infection in the studied population. Positive individuals were identified across multiple municipalities, with a spatial concentration in the central-western region of São Paulo State, suggesting widespread circulation of the parasite in anthropogenically influenced landscapes. Although no clear temporal pattern could be established due to opportunistic sampling, the detection of infected individuals across different years supports the persistence of T. cruzi in these host populations. These findings provide molecular evidence of T. cruzi infection in anteaters from southeastern Brazil and reinforce their relevance as hosts in sylvatic transmission networks. The results highlight the importance of wildlife in maintaining parasite circulation and emphasize the need for integrative approaches combining molecular, ecological, and epidemiological data to better understand host-parasite dynamics and potential transmission interfaces.
Dirofilaria immitis is a worldwide spread, mosquito-borne nematode of zoonotic concern, with domestic and wild canids serving as the main reservoirs of the infection in Europe. In this study we describe eleven cases of cardiovascular dirofilariosis in Hungarian zoos, including three Eurasian wolves (Canis lupus lupus), two Arctic wolves (Canis lupus arctos), an African lion (Panthera leo), an African leopard (Panthera pardus pardus), a Red panda (Ailurus fulgens), an Arctic fox (Vulpes lagopus), a Harbour seal (Phoca vitulina), and an Asian small-clawed otter (Aonyx cinereus). Heartworm disease presumably contributed to the deaths of three Eurasian wolves, one Red panda, one Arctic fox and one Harbour seal, as indicated by necropsy results, whereas the remaining infections were regarded as incidental findings. These cases represent the first documented occurrence of D. immitis in captive felids in Hungary and the first report of D. immitis in Arctic wolves. The present case series provides data about host range of dirofilariosis and discusses their potential role as reservoirs of the infection in autochthonous wild animals in Europe underlining the need for implemented surveillance and preventive strategies in zoo animal populations.
The Chornobyl Exclusion Zone (ChEZ) is a unique area in the world. It combines two things: the largest man-made disaster site in the world and a radioecological observatory. The observatory has been studying the long-term impact of radioactive contamination on the environment, flora and fauna since 1986. Muridae and Cricetidae rodents being extremely widespread representatives of ChEZ fauna, serve as bioindicators for radioecological research. During 2019-2020, in addition to studying rodents as markers of radioactive contamination, 116 muroids were examined for the presence of parasites and bacteria. Among the rodents studied were bank voles Myodes glareolus from the Cricetidae family, as well as yellow-necked mice Apodemus (Sylvaemus) flavicollis and striped field mice Apodemus agrarius of the Muridae family. Microscopy of muroid rodent blood films revealed the presence of Trypanosoma spp., Hepatozoon spp. and bacterial agents. Molecular analyses led to the first identification of Trypanosoma grosi in A. agrarius in Ukraine. A Hepatozoon spp. SK3-type was found for the first time in A. flavicollis. Three different genotypes of Mollicutes were detected in A. agrarius and A. flavicollis. Bartonella spp. were present in most of the rodents tested. Zoonotic Bartonella grahamii was identified among six isolated genotypes of Bartonella. Co-infections with parasites and bacteria were found in some animals. According to microscopic studies, A. agrarius had the highest prevalence of Trypanosoma spp., whereas Hepatozoon spp. was highest in M. glareolus. Meanwhile, A. flavicollis harboured the greatest diversity of genotypes according to the sequencing results. Interestingly, a 41.7% prevalence of T. grosi and 33.3% of Mycoplasma-like bacteria was detected by PCR among animals from landfill II of the ChEZ, which was the least contaminated of the four experimental sites in the Exclusion Zone. Further research should be conducted to identify pathogens of viral origin and to study more genome loci of parasites in order to determine the impact of radioactive contamination that microorganisms may be exposed to.
During their free-living stage, gastrointestinal nematode (GIN) eggs and larvae may encounter environmental and biomechanical perturbations, such as dung beetle (Coleoptera: Scarabaeidae, including Aphodiinae, Scarabaeinae and Geotrupidae) activity, that could alter their survival. However, dung beetles' influence in promoting or suppressing nematodes' survival is poorly understood. Past work suggests that the burial of dung underground by dung beetles may either suppress nematode infections, limiting larval emergence above ground, or enhance nematode infections by creating favourable microclimates for eggs and larval development. We examined the effect of simulated burial of wildebeest dung at four soil depths on the density of infectious third-stage larvae (L3) on herbage over a 42-day window in the Serengeti ecosystem. GIN larval density was highest from dung buried at 5 and 10 cm depths below the soil surface, and lowest at 0 cm (on the surface) and 15 cm depths. This suggests that dung beetles may facilitate L3 survival and emergence by creating favourable conditions at shallow depths (5-10 cm), protecting them from disturbances (e.g., desiccation) on the surface. Deeper burial depth (15 cm) by dung beetles, however, appears to suppress the emergence of L3 by creating a physical barrier to upward migration. Across burial depths, L3 density peaked on Day 14 and declined on Days 28 and 42, with no evidence that deeper burial led to a prolonged emergence period. These results reveal dung beetles' complex role in parasite ecology, not merely as suppressors of these free-living stages but also as facilitators of their survival through burial activities that vary with depth. Incorporating this knowledge into pasture and insect management could support the use of dung beetles as potential biological control agents against gastrointestinal nematodes.
Bivalve mollusks belong to a class of invertebrates that are cosmopolitan and globally traded. Therefore, this study aimed to investigate the occurrence and genetic assessment of Toxoplasma gondii, based on the SAG1 gene in bivalve mollusks from natural growing areas on Maranhão Island in northeastern Brazil. Oysters (Crassostrea sp.), mussels (Mytella sp.) and clams (Anomalocardia sp.) were collected from natural mangrove áreas in São Luís, Paço do Lumiar, Raposa and São José de Ribamar on Maranhão Island during the period of January to December 2022 (rainy and dry seasons). The samples were organized into pools of gills from 3 animals, their DNA was extracted and subjected to detection of T. gondii (SAG-1 gene), and the positive samples subjected to additional nested PCR for the markers APICO, BTUB, SAG3, 3′ SAG2, 5’ SAG2, Alt.SAG2 and GRA6 for genetic characterization. Sequences obtained were analyzed for phylogenetic reconstruction using the MEGA X program. Three mussel samples tested positive (3/60; 1.8%), all collected in the rainy season from Raposa and São José de Ribamar. These samples were subjected to nested-PCR for other T. gondii markers; however, there was no amplification. BLASTn analysis confirmed 98 to 100% genetic similarity with T. gondii sequences. Although based on a single gene, which limits robust genotype inference, phylogenetic analysis of the SAG1 gene indicated clustering of the detected sequences with reference sequences related to classical genotypes. The current study provides an update on the molecular occurrence of the zoonotic protozoan T. gondii in an estuarine area of northeastern Brazil, and highlights the importance of research involving monitoring of shellfish harvesting areas, given their role in public health and food safety.
Passerine birds are highly susceptible to Isospora infections, yet the coccidian fauna of endemic Taiwanese avifauna remains largely unexplored. Here, we describe Isospora kwongchungi n. sp. (Apicomplexa: Eimeriidae) from the Taiwan Blue Magpie (Urocissa caerulea, Corvidae), utilizing an integrative taxonomic approach. Morphological characterization was complemented by Sanger sequencing of the nuclear 18S ribosomal RNA (rRNA) gene (1,679 bp) and Oxford Nanopore Technologies (ONT) long-read sequencing of the complete mitochondrial genome (6,251 bp). Sporulated oocysts are subspherical to spherical (28.9 × 26.4 μm) with a smooth, single-layered wall, possessing both a polar granule and a distinct oocyst residuum. Sporocysts are ovoid (22.3 × 13.6 μm) and feature a knob-like to bubble-shaped Stieda body, a rounded substieda body, and a compact ellipsoidal sporocyst residuum. While the 18S rRNA gene phylogeny exhibited limited intrageneric resolution, the concatenated tree of three mitochondrial protein-coding genes robustly placed I. kwongchungi n. sp. in a clade with Isospora spp. from the invasive Javan myna (Acridotheres javanicus, Sturnidae) and the American robin (Turdus migratorius, Turdidae). This study establishes a molecular anchor for corvid-associated Isospora and highlights the efficacy of combining traditional and next-generation sequencing in resolving the evolutionary dynamics of wildlife parasites.
Studies on the helminth fauna of the booted eagle (Hieraaetus pennatus) remain limited, with only four parasitic species previously described and a single study reporting prevalence data. Accordingly, the objective of the present study was to characterize the helminth community parasitizing H. pennatus individuals from southern Spain (Andalusia). Between 2008 and 2023, a total of 28 specimens were examined. Recovered parasites were taxonomically identified, and prevalence, intensity, and mean abundance were calculated. The overall parasitism rate was 67.8%, comprising nematodes (53.5%), trematodes (21.4%), cestodes (25.0%), and acantocephalans (7.1%). Twelve genera of helminth were detected, eight of which are reported for the first time in this host. Among the eight helminths' genera identified, six were fully identified and newly documented in H. pennatus. Physaloptera alata was the most prevalent species (25.0%), followed by Capillaria tenuissima (17.9%). Other detected taxa with lower prevalence (7.1%) included Porrocaecum angusticolle, Platynosomum illiciens, Strigea falconis, Matabelea fuhrmanni, and Centrorhynchus buteonis. The helminth community exhibited low diversity, with species richness of 1.6 (95% CI: 1.2-1.9), total abundance of 7.1 (95% CI:3.5-12.7), a Brillouin diversity index of 0.3 (95% CI: 0.09-0.35), and a Berger-Parker dominance index of 0.84 (95% CI: 0.74-0.95). These metrics reflect a depauperate parasitic community, with P. alata and C. tenuissima as dominant species that do not achieve the status of core taxa. This study represents the largest parasitological survey of helminths infecting booted eagles in Europe and the first conducted in southern Spain.
The Aeolian wall lizard (Podarcis raffonei) is an endangered lacertid species endemic to the Aeolian Archipelago (Sicily, Italy). Its populations are threatened by several factors, including habitat fragmentation and reduction, competition with the invasive Podarcis siculus, and potential health risks associated with disease dynamics. To prevent the extinction of this unique species an ex-situ captive breeding program was established in the Reptile House at the Bioparco of Rome within the LIFE project EOLIZARD. Most animals were housed in outdoor enclosures, favoring the exposure of these naïve lizards to new ectoparasitic mite species, that may negatively impact host fitness through direct effects and pathogen transmission. Therefore, given the lack of antiparasitic strategies for small lacertid lizards, this study evaluated the safety and efficacy of oral administration of afoxolaner for controlling mite infestations. A total of 178 lizards were clinically examined and treated with a single oral dose of afoxolaner (2.5 mg/kg). Mite infestation was monitored before treatment (T0) in all lizards. In addition, 20 specimens kept in individual enclosures and 30 from outdoor enclosures, were checked at 24 h (T1), 7 days (T2), 14 days (T3), and 28 days (T4) post-treatment. Ectoparasites were identified using both morphological and molecular methods as Ophionyssus lacertinus, and molecular screening was performed to detect vector-borne pathogens. Before treatment, 90 out of 178 lizards (50.6%) were infested with mites, with the prevalence rapidly declining in the follow up, until mite clearance at day 28 post-administration, in single housed lizards, and as low as 5% prevalence in those kept outdoors. Other lizard species (captive and free-living) (i.e., Podarcis muralis, P. siculus, Timon lepidus) were also infested, potentially being the source of mites. These findings suggest that oral afoxolaner is an effective treatment for controlling mite infestations in small lacertid lizards, with important implications for conservation management.
The present report describes the first record of the tapeworm Taenia krabbei Moniez, 1879, represented by its larval stage, in roe deer (Capreolus capreolus) from two hunting districts in Carinthia, Austria. The cysticerci of T. krabbei were found during gross meat inspection and isolated from the muscle. The specific identification was based on molecular analysis of a partial sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene. The definitive host was not identified in this report. Grey wolves (Canis lupus lupus) are suspected to be the definitive host, as they are reported to be resettling in the area. The finding of muscle cysts of T. krabbei raises concerns for hunters and producers of venison, as affected carcasses are often rejected based on visual inspection criteria. Consequently, systematic assessment of the distribution of T. krabbei across both intermediate and definitive host populations is warranted. In parallel, targeted sanitary education initiatives for hunters are essential to discourage practices that may facilitate transmission and perpetuation of the parasite's life cycle.
Parasitic diseases are a major but frequently overlooked health concern in reptiles, with consequences that extend beyond individual health issues to broader ecological and conservation concerns. A male red-tailed green rat snake (Gonyosoma oxycephalum), imported from Indonesia, died in quarantine one month after purchase, lacking any signs of illness except for a brief period of anorexia. Following its death, the owner observed a vermicular parasite emerging from the snake's oral cavity, which prompted submission of the animal to necropsy. A high-grade infection with 40 specimens of the pentastomid Raillietiella orientalis was confirmed by morphological and DNA analyses (18s rRNA). Moreover, histological examinations revealed macroscopic and histological evidence of larval migration. This case represents the first documented infection in red-tailed green rat snakes and signifies one of few reports on R. orientalis for Europe. It illustrates the potential introduction of invasive parasites through the exotic pet trade in the absence of adequate pre-import health screening. While the risk of establishment in European ecosystems remains uncertain, such introductions may pose challenges for captive reptiles, zoological collections and the native fauna. In addition, co-infections may alter disease progression and contribute to the pathogenicity of pentastomid infections.
Wildlife rehabilitation plays a central role in the conservation of threatened primates, yet parasite dynamics during captivity are rarely reported, particularly in relation to release readiness. We investigated gastrointestinal helminth infection patterns in rehabilitating Javan slow lorises (Nycticebus javanicus), a Critically Endangered species heavily impacted by the illegal wildlife trade. Using repeated fecal sampling (147 samples from 19 adults) and Bayesian mixed-effects models, we examined parasite richness, Shannon diversity, infection probability, and egg-shedding intensity in relation to release readiness status, sex, housing condition, and time since anthelmintic treatment. Four nematode taxa identifiable through egg morphology were detected: Strongyloides spp., strongylids, oxyurids, and Trichuris spp. Parasite richness and Shannon diversity showed no credible associations with release readiness or other host and management variables. In contrast, infection probability for Strongyloides spp. and strongylids increased with time since deworming, and Strongyloides egg counts exhibited a similar temporal pattern, consistent with post-treatment reinfection dynamics. Release readiness did not predict detection probability or parasite intensity for any parasite group, despite marked differences in captivity duration and health history between individuals deemed ready for release or not. These findings indicate that gastrointestinal helminth dynamics in rehabilitating slow lorises are driven primarily by treatment-related temporal processes and individual-level heterogeneity rather than coarse host classification. They also highlight the need for longitudinal parasite monitoring and for future work evaluating how infection dynamics, management interventions, and host health relate to rehabilitation and translocation outcomes.
We evaluated the effects of fipronil bait pellets on two cricetids that commonly occupy colonies of black-tailed prairie dogs (Cynomys ludovicianus; BTPDs): western deer mice (Peromyscus sonoriensis) and northern grasshopper mice (Onychomys leucogaster). In one experiment, bait pellets (0.96 mg fipronil/bait) were applied at 75 baits/ha to three 1.44-ha plots on a BTPD colony. Mouse abundance declined by 70% from before to 6-10 d after treatment. In a second experiment, bait pellets (0.46 or 1.52 mg fipronil/bait) were applied at 125 baits/ha to four plots (0.85-1.86 ha) on two BTPD colonies; two non-treated plots were baselines (1.09 and 2.06 ha). From before to 11-15 d after treatment, mouse abundance declined by 51%- 67% on the treated plots vs. a decline of 9% on the non-treated plots. Mouse survival from before to 11-15 d after treatment was 51% lower on the treated plots. In a third experiment, bait pellets (0.84 mg fipronil/bait) were applied at 125 baits/acre on two 1.44-ha plots on a BTPD colony; two 1.44-ha non-treated plots were baselines. Mouse survival from before to 30-44 d after treatment was 45% lower on the treated plots; the abundance of deer mice on the treated plots remained similar from before to 30-44 d after treatment, perhaps due to juvenile recruitment and/or immigration. In a laboratory experiment, 33 deer mice offered one bait pellet (0.86 mg fipronil/bait) consumed 27% of their bait, on average (range = 0-100%). Over 3 d, deer mouse mortality was estimated at 53%; mortality increased with fipronil dose, which averaged 11 mg fipronil/kg body mass (range = 3-46 mg/kg). Brain samples were available from 31 deer mice; all tested positive for fipronil sulfone, the primary mammalian metabolite of fipronil, at 19 to 61,205 ng fipronil sulfone/g. Additional experiments could determine if these findings scale up to larger landscapes.
