Anthelmintics are central to parasite control in companion animals, but drug targets in helminths remain limited. Anthelmintic resistance is a clinically significant threat, with emerging multiple anthelmintic drug-resistant Ancylostoma caninum, macrocyclic lactone-resistant Dirofilaria immitis and praziquantel-resistant Dipylidium caninum. Each treatment is a selection event which eliminates susceptible parasites and enriches resistant survivors. Drug-resistant helminths often go undetected due to limited diagnostics and sole reliance on treatment. While some molecular tools can detect gene polymorphisms associated with resistance, their use is somewhat limited. Sustainable control will require strategic evidence-based use, targeted surveillance, and continued research into resistance mechanisms and detection tools.

Dogs are the definitive hosts of Echinococcus granulosus sensu stricto (s.s.), the causative agent of cystic echinococcosis (CE) in livestock and humans. As canine infections are usually asymptomatic, early and reliable detection of active adult infections is essential for effective control and surveillance. In this study, two in-house sandwich ELISA assays were developed using purified polyclonal rabbit antibodies raised against E. granulosus s.s. soluble crude antigen (EgSCA) and a recombinant fibronectin antigen (rEgFN162). Experimental infection was established in two dogs (n = 2) by oral administration of viable protoscoleces, while one dog was maintained as a non-infected negative control. Fecal samples were collected throughout the infection period and following anthelmintic treatment. Cross-reactivity was assessed using fecal samples from dogs naturally infected with Toxocara canis (n = 5) and Ancylostoma caninum (n = 2). The diagnostic performance of both assays was evaluated in terms of timing of positivity, sensitivity, specificity, and cross-reactivity. The EgSCA-based sandwich ELISA detected coproantigens as early as 4-5 days post-infection and showed an overall sensitivity of 80% and specificity of 86.7%, with limited cross-reactivity with T. canis (20%) and A. caninum (50%). In contrast, the rEgFN162-based assay showed delayed positivity (18-23 days post-infection), lower sensitivity (46.7%), but higher specificity (93.3%). In both in-house sandwich ELISAs, coproantigen positivity persisted for an extended period after anthelmintic treatment, indicating prolonged antigen detectability despite parasite elimination. Western blot and indirect ELISA confirmed strong antigen-specific humoral responses against both antigens in immunized rabbits. Overall, the findings of this proof-of-concept study suggest that the EgSCA-based in-house sandwich ELISA is more suitable for early coproantigen-based detection of active E. granulosus s.s. infections in dogs, while rEgFN162 may serve as a complementary or confirmatory antigen in combined diagnostic approaches, contributing to improved CE surveillance and control in endemic areas.

Parasitosis in companion animals are of great importance and there are species of zoonotic character, since they affect humans. The large number of dogs, including a significant proportion of stray animals, contributes to the spread of infectious agents in the environment, increasing the human population's exposure. The aim of the present study was to determine the prevalence of intestinal helminths in stray dogs through post-mortem inspection. A total of 266 small intestinal samples were obtained from dogs captured and euthanized at the Centro de Control Canino y Felino at the Miguel Hidalgo Neighborhood from Tlahuac District in Mexico City during the months of February-August. The results showed that 99 (37.2%) of the dogs examined had the presence of at least one type of parasite. Of the 99 dogs, 85 (85.9%) of them had single infection, while 12 (12.1%) had double infection, and 2 (2%) had triple infection. Among the helminths recovered, A. caninum (P < 0.05) was the only nematode recovered in 36 (36.4%) dogs, while D. caninum and T. pisiformis cestodes (P < 0.05) were obtained in 68 (68.7%) and 11 (11.1%) dogs; respectively. Double infections (12.1%) occurred in 12 dogs, of which 11 (91.7%) had A. caninum-D. caninum association and 1 (8.3%) had D. caninum-T. pisiformis association. In relation to triple infections, presented in two of the dogs, A. caninum-D. caninum-T. pisiformis association was present in both (100%). The highest prevalence rate for A. caninum was recorded in February with 29.8% (17/57), while for D. caninum was recorded in August with 30% (12/40), and for T. pisiformis was recorded in March with 11.1% (6/54).. The presence of mixed infections highlights environmental contamination in the sampling region, emphasizing the importance of parasite control to prevent transmission to humans at high risk of contracting infections caused by D. caninum and A. caninum.

The popularity of sand sports has increased significantly, driven by their recreational appeal combined with health benefits. However, because these sports are typically played barefoot in areas where dogs and cats may roam freely, the risk of human exposure to zoonotic parasites-such as the causative agents of cutaneous and visceral larva migrans (Ancylostoma caninum, A. braziliense, and Strongyloides stercoralis)-increases. This study aimed to investigate the presence of potentially zoonotic helminth larvae in the sand of public sports courts in the municipality of Ilhéus, Bahia, Brazil, a coastal region with high tourist influx. Thirty-eight courts were analyzed during the winter (August 2022) and summer (February 2023), with sand samples collected at three depths (surface, 10 cm, and 20 cm). Samples were processed using the modified Rugai method and examined via light microscopy for morphological identification of the larvae. Statistical analyses to identify environmental and seasonal factors associated with the parasites included chi-square, Fisher's exact, and generalized linear model (GLM) tests. Of the courts evaluated, 18 (47.3%) tested positive for zoonotic helminths in the winter and 19 (50.0%) in the summer. Strongyloides spp. were more frequent in the winter (13 courts; 34.2%), while Ancylostoma spp. were more frequent in the summer (15 courts; 39.5%). Across both seasons, 27 courts harbored at least one parasite, with nine testing positive during both periods. Ancylostoma spp. occurred predominantly in the surface layer during the summer, whereas Strongyloides spp. were more abundant in the shallow and deep layers during the winter. The presence of grass surrounding the courts acted as a protective factor against Ancylostoma spp. (OR = 0.25; p = 0.048), while complete shading favored Strongyloides spp. (OR = 13.71; p = 0.033). These findings highlight elevated contamination of the courts throughout the year and reinforce the need for year-round environmental sanitation measures, properly management of stray or owned dogs and cats populations, and health education to reduce the risk of infection in recreational areas.

About 50 years after their development, the benzimidazole anthelmintic drugs still occupy a key role in the treatment of parasitic diseases. Like other anti-infective drugs, their extensive use has led to resistance development and now requires new solutions to treat these diseases. Organometallic derivatization of existing drugs has become a common strategy to design new drug candidates, which could benefit from enhanced activity against resistant or sensitive strains through the incorporation of an organometallic fragment. In this study, we describe the development of a new series of organometallic derivatives of benzimidazole anthelmintics. Ten derivatives, six of which were organometallic, were synthesized and characterized. In silico and in vitro studies were performed to determine their biological activity. Therefore, they were screened against a range of nematodes and other parasites. Biological activities were found for some of the derivatives against Strongyloides ratti, Ancylostoma ceylanicum, Trichuris muris, Schistosoma mansoni, Echinococcus multilocularis, or Leishmania infantum in similar ranges as the parent anthelmintics. Even if the activity of the benzimidazole scaffold was not systematically enhanced, this strategy is a good starting point for the development of new antiparasitic compounds and for further study of the mode of action of these drugs.

Hookworms of the family Ancylostomatidae are intestinal parasites that infect hundreds of millions of people worldwide, contributing to malnutrition, anemia, and impaired development. Although hookworms are known to secrete immunomodulatory molecules to evade host defenses, it has been unclear whether they also exploit host hormonal signaling. Here, we identify a previously unrecognized family of hookworm peptides, which we term ancylotensins. Ancylotensins share strong sequence similarity with the chordate hormone neurotensin, a key regulator of metabolism, gut-brain communication, and intestinal function. In vitro pharmacological assays, ex vivo gut contractility studies, and cryoelectron microscopy demonstrate that ancylotensins closely replicate both the structural and functional properties of mammalian neurotensin to modulate gut function. Furthermore, ancylotensins do not share common ancestry with chordate neurotensin and likely evolved independently via convergent evolution. These findings reveal the existence of gut peptide mimicry as a mechanism by which intestinal parasites may manipulate host physiology.

Platynosomosis is a parasitic disease of cats and other animal species, caused by trematodes of the genus Platynosomum. These flukes can infect the liver parenchyma, biliary ducts, and gallbladder. In cats, this parasite is most commonly associated with inapparent infections; however, clinical infections with cholangiohepatitis have also been described. Platynosomum spp. are also related to the development of cholangiocarcinoma. Here, we describe 6 cases of cats parasitized by Platynosomum illiciens. Four of these cats were also infected with feline leukemia virus; 5 were parasitized with Spirometra mansoni, 4 with Ancylostoma sp., and 1 with Dirofilaria immitis. Clinical and coprologic evaluations were performed on all individuals. Five cats had severe clinical decline, which prompted euthanasia. On autopsy, these 5 animals had diffuse cholangiohepatitis with intralesional trematodes. Gross and microscopic lesions, parasite and egg morphology, PCR, and DNA sequencing with a Bayesian inference phylogenetic tree and haplotype network confirmed a diagnosis of platynosomosis caused by P. illiciens.

Soil-transmitted strongylid nematodes are common intestinal parasites of African great apes, yet most surveys have relied on microscopy or targeted PCR assays that are limited in taxonomic breadth and comparability across hosts. I reanalyzed 46 publicly available shotgun fecal metagenomes from sympatric central chimpanzees (Pan troglodytes troglodytes; n = 18) and western lowland gorillas (Gorilla gorilla gorilla; n = 28) in the Goualougo Triangle, Nouabalé-Ndoki National Park, Republic of the Congo, to test whether host species structures genus-level strongylid community composition and relative read signal. Non-host reads were classified against a custom strongylid-focused database targeting 4 genera repeatedly reported from African apes: Ancylostoma, Necator, Oesophagostomum, and Trichostrongylus. All 4 focal genera were detected in every library under baseline filtering, and multi-genus detection remained robust under increasingly stringent read-count thresholds. However, host species differed strongly in community composition. Chimpanzee libraries had relatively even genus-level profiles, whereas gorilla libraries were consistently Necator-dominated. Gorillas also had substantially higher relative strongylid read abundance. The results show that shotgun metagenomic reanalysis can recover host-structured strongylid community signals from wildlife samples and can complement targeted parasitological surveys in conservation and One Health surveillance.

Domestic cats (Felis catus) are ubiquitous companion animals that provide substantial psychological and social benefits to children and adults alike, but they also serve as reservoirs and vectors for a wide range of zoonotic pathogens. Close physical contact between cats and children, frequent use of shared environments such as homes, playgrounds, and sandboxes, and still-developing hygiene behaviours increase opportunities for exposure to protozoa, helminths, bacteria, fungi, and ectoparasite-borne agents. This review synthesizes current evidence on key feline-associated zoonoses of pediatric concern-including Toxoplasma gondii, Toxocara cati, Ancylostoma spp., Dipylidium caninum, Bartonella henselae, Salmonella enterica, Campylobacter jejuni, Pasteurella multocida, Microsporum canis, flea-borne Rickettsia species, and rabies-with emphasis on transmission routes, clinical manifestations, and risk modifiers in children, pregnant women, and immunocompromised individuals. Within a One Health framework, we also summarize global publication trends on feline zoonoses, discuss how urban cat ecology and management (including free-ranging cats in child-frequented environments) may shape pediatric risk, and outline practical prevention strategies centred on hygiene, veterinary care, and targeted education for caregivers and children.

Hookworms are zoonotic helminths that cause intestinal diseases in pets and humans, as well as cutaneous larva migrans in the latter; therefore, they are of importance to animal and public health. Stray and domestic dogs play a significant role in the transmission of hookworm disease. This study examines the prevalence of Ancylostoma spp. infections in dogs in Ecuador through a systematic review and meta-analysis. Although based exclusively on canine data, the findings are discussed in the context of available evidence on zoonotic transmission and potential One Health implications. A total of 370 records were screened, of which 9 studies published between 2010 and 2025 met the PRISMA 2020 inclusion criteria. Using a random-effects model with Freeman-Tukey double arcsine transformation, the pooled prevalence was estimated at 32% (95% CI: 17-49%), with substantial heterogeneity across studies (I[2] = 98.3%). Regional analysis revealed significantly higher prevalence in the Insular region (50%) and the Coastal region (43%), compared to the Sierra (Andean region) (12%). These findings indicate marked spatial variability in canine Ancylostoma infections across Ecuador, likely reflecting underlying environmental, epidemiological, and methodological differences. While this study does not directly assess human or environmental data, the observed patterns are consistent with epidemiological conditions that may favor zoonotic transmission. Overall, this study highlights the need for integrated approaches consistent with a One Health perspective, including improved surveillance, veterinary interventions, and further research incorporating human and environmental components to better understand the epidemiology and potential zoonotic implications of hookworm infections.

Gastrointestinal nematodes (GIN) are a major health concern in dogs, particularly in high-density environments such as shelters. Toxocara canis, Ancylostoma spp., and Trichuris vulpis are widely distributed, with recognised veterinary and zoonotic relevance. Effective prevention requires improved understanding of environmental and management-related risk factors driving transmission. This study investigated determinants of GIN infections in shelter dogs across Portugal. Faecal samples (n = 189), collected between November 2021 and October 2022 from 19 shelters, were analysed using coprological (mini-FLOTAC) and molecular (targeted PCR) methods. Infection risk was assessed using Boosted Regression Trees, Random Forest models, and ecological niche modelling (ENM), integrating climate, land use, shelter management, and host-related variables. Key risk factors included housing density (number of dogs per enclosure), age group, and deworming regimen, with parasite-specific patterns. Environmental predictors varied across species, with solar radiation, temperature, and soil characteristics influencing T. canis distribution, while land cover and precipitation were more relevant for T. vulpis and A. caninum. Marked spatial differences in the ecological suitability of the three GIN were evident. Spatial predictions indicated widespread risk of T. canis and T. vulpis across mainland Portugal, whereas higher-risk areas for A. caninum were concentrated in southern regions. Altogether, our findings highlight the combined influence of environmental conditions and shelter management on GIN transmission. The integration of eco-epidemiological and spatial modelling approaches using machine learning and ENM provide a useful framework for understanding local and regional nematode transmission dynamics and identifying high-risk settings, supporting targeted surveillance and more effective, shelter- and region-specific parasite control strategies.

This study aimed to assess soil contamination with Ancylostoma spp. eggs in public parks and playgrounds in Hue City. A total of 240 soil samples were collected from 60 public parks and playgrounds located in two urban zones (central urban and peri-urban areas) during both the rainy and dry seasons. Ancylostoma spp. eggs were detected at 48 of 60 sampling sites (80%). The proportion of contaminated sites was significantly higher in central urban areas compared with peri-urban areas and during the rainy season compared with the dry season. In contrast, no significant differences were observed between sampling locations within individual parks, including areas near garbage bins and playground areas. Most positive sites showed low contamination intensity, with 1-4 eggs per 200 g of soil. Conventional PCR confirmed the presence of Ancylostoma caninum DNA in positive soil samples, indicating that dogs are the primary source of environmental contamination. These findings provide baseline data on soil-transmitted hookworm contamination in Hue City and highlight the need for improved dog faeces management, ecological sanitation, and public health education to reduce the risk of community exposure.

Free-roaming cats (Felis catus) can serve as reservoirs of various zoonotic parasites in urban settings. Despite a large population of free-roaming cats around New York City, studies assessing the prevalence and shedding of various parasites in the New York urban landscape are scarce. This study utilized fecal and blood samples opportunistically collected during the Trap Neuter Return (TNR) program from 87 free-roaming cats in New York City between May and July 2023. Samples were analyzed using centrifugal fecal flotation, coproantigen immunoassays, serologic assays, and PCR-based assays for gastrointestinal and vector-borne parasites. Fecal flotation (n = 87) results revealed that 57.5% (50/87; 95% CI: 46.9-67.4) of cats were infected with at least one species of parasite. The most prevalent infection was Toxocara spp. (54%; 95% CI: 43.4-64.3), followed by Ancylostoma spp. (13.8%; 95% CI: 8.2-22.6) and coccidia (11.5%; 95% CI: 6.4-19.9). Coproantigen testing (n = 43) identified Giardia spp. in 11.6% (5/43; 95% CI: 5.1-24.5) and Cryptosporidium spp. in 2.3% (1/43; 95% CI: 0.4-12.1) of cats. Antibodies to Toxoplasma gondii were detected in 8.9% (4/45; 95% CI: 3.5-20.7) of serum samples; no Dirofilaria immitis antigen and Cytauxzoon felis DNA were found in the blood samples (n = 45). Male cats were significantly more likely to be infected with Toxocara spp. (OR = 4.36) and, along with juvenile cats (<1 year), shed significantly higher numbers of eggs (p < 0.05), identifying young males as high-intensity "super-shedders" driving environmental contamination. The high prevalence of zoonotic helminths, particularly Toxocara spp., underscores the public health risks associated with unmanaged feline populations in densely populated urban centers. These findings highlight the utility of integrating disease surveillance into TNR programs to monitor urban ecosystem health and mitigate zoonotic risks.