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.

Canine monocytic ehrlichiosis (CME) is an infectious disease caused by Ehrlichia canis, a globally recognized obligate intracellular bacterium. In addition to dogs, other animals, including humans, may be affected. Despite its epidemiological importance and impact on public health, there is currently no commercial vaccine against E. canis. This study aimed to present relevant aspects of the challenges and advances encountered in the development of vaccines for CME and highlight perspectives for future investigations. High genetic variability, along with the various evasion mechanisms employed by E. canis, has hindered the identification of an antigen that targets Th1 cells and is immunogenic to most E. canis isolates, considering their distinct antigenic characteristics. To achieve robust immunity, the vaccine must predominantly confer cellular and humoral immunity. Early production efforts have been challenging owing to low immunogenicity, difficulties in establishing long-term protection, and limitations of the techniques used. However, with the refinement of bioinformatic tools, research in this area will be facilitated, thereby accelerating the development of effective vaccines for CME. According to these authors, a vaccine should consist of multiple epitopes.

Brazil has a high abundance of monkey species, including Mico melanurus. In general, primates are vulnerable to parasites owing to their behavior. We aimed to identify the occurrence of gastrointestinal parasites in M. melanurus in the Brazilian Cerrado and to perform morphometric and morphological analyses of these helminths. Helminths of 21 M. melanurus were collected from Cuiabá in the Brazilian Cerrado. The animals were found dead within the urban perimeter, necropsied, and tested for parasites. Parasites found in the gastrointestinal tract were fixed in 70% ethanol for morphological identification. We identified Trypanoxyuris spp. in two samples (mean intensity of 63 and mean abundance of 6.3) and Primasubulura jacchi in the other 18 samples (mean intensity of 34.22 and mean abundance of 30.8). One sample was deteriorated; therefore, it was not necropsied. P. jacchi infections in same cases are asymptomatic or have gastrointestinal signs such as diarrhea. Trypanoxyuris spp. are commonly found in the primates of Mato Grosso. Only these two parasites were identified, provided by a small parasite richness, and were associated with the impact of habitat fragmentation in an anthropized area, indicating an imbalance in the environment in which they lived.

Wild canids inhabiting anthropized landscapes can act as environmental indicators and potential reservoirs of zoonotic parasites, connecting transmission cycles among wild, domestic, and human hosts. We aimed to identify and characterize helminths in wild canids from the Cerrado, Pantanal, and Amazon biomes of Brazil, describing occurrence patterns and ecological and One Health implications. A total of 19 individuals belonging to four wild canid species (Cerdocyon thous, Chrysocyon brachyurus, Lycalopex vetulus, and Speothos venaticus) were examined, yielding 1041 helminths representing 17 taxa, with nematodes predominating. Several taxa of recognized zoonotic importance were recovered, including Toxocara canis, Ancylostoma spp., Dioctophyme renale, and Spirometra spp. These are agents associated with visceral and cutaneous larva migrans, dioctophymosis, and sparganosis. Novel host records were documented, including Athesmia foxi and Pterygodermatites affinis in L. vetulus, a sparganum infection in C. thous, and the first report of Spirocerca lupi in the stomach of S. venaticus in the Brazilian Cerrado. These findings expand the knowledge of the helminth fauna of Neotropical wild canids and reinforce the relevance of parasitological surveillance in wildlife as a tool for zoonotic disease monitoring, biodiversity conservation, and environmental health assessment, reaffirming the role of wild canids as ecological indicators.