Environmental changes in the Brazilian Pantanal and Cerrado facilitate the spread of parasitic diseases in wildlife, with significant implications for public health owing to their zoonotic potential. This study aimed to examine the occurrence and diversity of gastrointestinal parasites in wild felids within these regions to assess their ecological and health impacts. We collected and analyzed helminth-positive samples from 27 wild felids using specific taxonomic keys. Diverse parasitic taxa were detected, including zoonotic helminths, such as Ancylostoma braziliense, Ancylostoma caninum, Ancylostoma pluridentatum, Toxocara cati, Toxocara canis, Dipylidium caninum, Taenia spp., Echinococcus spp., and Spirometra spp. Other nematodes, such as Physaloptera praeputialis and Physaloptera anomala, were identified, along with acanthocephalans from the genus Oncicola and a trematode, Neodiplostomum spp. (potentially the first record of this parasite in wild felids in the Americas). Human encroachment into natural habitats has profound effects on wild populations, influencing parasitic infection rates and patterns. This study underscores the importance of continuous monitoring and research on parasitic infections as a means of safeguarding both wildlife and human populations and highlights the role of wild felids as bioindicators of environmental health.

Gigantorhynchus echinodiscus (Diesing, 1851) is a parasite of anteaters in South America. Although described by Diesing in 1851, there is still a lack of taxonomic and phylogenetic information regarding this species. In the present study, we redescribe G. echinodiscus collected from a giant anteater, Myrmecophaga tridactyla Linnaeus, 1758, from the Brazilian Cerrado (Savannah) in the State of Sao Paulo by light and scanning electron microscopy. In addition, phylogenies were inferred from partial DNA gene sequence of the nuclear large subunit ribosomal RNA gene (28S rRNA). We provide for the first time details of the proboscis with a crown having 18 large hooks and numerous small hooks, a lateral papilla at the base of the proboscis, a ringed pseudo-segmented body, large testes, cemented glands in pairs, and a non-segmented region in the posterior end of the body, which contributed to the diagnosis of the species. Molecular phylogenetic analyses recovered G. echinodiscus forming a well-supported monophyletic group with Mediorhynchus sp., which was congruent with morphological studies that allocate both genera within the family Gigantorhynchidae. In conclusion, the present work adds new morphological and molecular information, emphasizing the importance of adopting integrative taxonomic approaches in studies of Acanthocephala.

Dioctophyme renale (Nematoda: Dioctophymidae) is a globally distributed monotypic nematode species of significant zoonotic relevance. This parasite infects a broad range of mammalian hosts, including wild and domestic carnivores, as well as humans. In Brazil, infections have been reported in both domestic and wild animals, although morphological and molecular data remain limited. This gap, combined with its zoonotic potential, highlights the need for further research. The present study provides an integrative taxonomic description of D. renale specimens recovered from mammals in the Brazilian Atlantic Forest biome, including 22 wild carnivores that were roadkill victims and one domestic dog. This highly urbanized biome is considered a conservation hotspot. A total of 68 nematodes were recovered from the maned wolf (Chrysocyon brachyurus), brown-nosed coati (Nasua nasua), lesser grison (Galictis cuja), and one domestic dog (Canis lupus familiaris). These wild species, affected by deforestation and roadkill, are increasingly exposed to humans and domestic dogs. Ultrastructural analyses revealed novel morphological features relevant to species diagnosis, including five cephalic papillae in the lateral field and distinctive details on the ventral surface of the copulatory bursa. Phylogenetic analyses based on the 18 S rRNA gene placed D. renale into two well-supported clades differentiated by geographic region, whereas the mitochondrial COI marker grouped Brazilian samples within a South American clade alongside sequences from Argentina and Peru, suggesting genetic structuring driven by geography rather than host species. A more comprehensive understanding of this structuring will require broader sampling across hosts and localities. The novel morphological traits identified herein, together with molecular data, refine the species diagnosis and provide new insights into the phylogeny of D. renale, contributing to the understanding of genetic diversity within the genus.