Helminths of free-ranging dogs and cats in an urban natural reserve in Mexico City and their potential risk as zoonotic agents

Abstract In the Reserva Ecológica del Pedregal San Ángel, located south of Mexico City, Mexico, dogs and cats coexist in freedom with 148 species of birds, 33 of mammals, 23 of reptiles and seven of amphibians, that represent a remnant of the original fauna of the Mexican Plateau. The negative impact that dogs and cats have on local fauna is unobjectionable, however, the fact that these introduced vertebrates may function as potential transmitters of infectious diseases for native fauna and humans, is much less understood. Information about parasitic infections in native and introduced animals in this area is scarce. In order to ameliorate this lack of information, the objective of this study is to characterize the helminth fauna of the free-ranging dogs and cats of the ecological reserve. Between 2018 and 2023, 36 Felis silvestris catus and 7 Canis lupus familiaris were studied from the helminthological perspective. Endoparasites were obtained of the digestive tract and were specifically determined using morphological and molecular evidence. Hosts were parasitized by eight species of helminths: in cats the cestodes Hydatigera taeniaeformis, Mesocestoides sp., Taenia rileyi and the nematode Toxocara cati were recorded, while in dogs, the cestode Taenia pisiformis and the nematodes Ancylostoma caninum, and Uncinaria stenocephala were found. The only species shared was the cestode Dipylidium caninum. These free-ranging animals act as definitive hosts of 5 species known to have zoonotic potential; their presence in the area may generate a public and animal health problem if programs of fauna control are not continued.