Modulação das vias do sistema complemento e da coagulação de Chrysocyon brachyurus (Illiger, 1815) e mamíferos domésticos pelas glândulas salivares e intestino de Ctenocephalides felis felis (Siphonaptera: Pulicidae)

Abstract

The maned wolf (Chrysocyon brachyurus), a canid with a wide distribution in South America, faces severe anthropogenic pressures resulting from habitat loss and fragmentation. Increasing circulation through anthropized environments intensifies contact with domestic animals and their ectoparasites, such as fleas of the genus Ctenocephalides, to which this species appears to be more susceptible. Moreover, little is known about the interaction process between this flea species and wild canids. Hematophagous arthropods, in general, have developed multiple adaptive and evolutionary strategies to ensure feeding success. Among these strategies is the ability to modulate host hemostatic and immunological mechanisms, including vasoconstriction, platelet aggregation, blood coagulation, and activation of the complement system, through biomolecules present in the saliva and/or midgut. In this context, the present study aimed to investigate and compare the interactions of salivary gland extracts (SGE) and intestinal extracts (IE) of Ctenocephalides felis felis on blood coagulation and the classical and alternative complement pathways of the maned wolf (C. brachyurus), dog (Canis familiaris), and cat (Felis catus). SGE and IE were obtained from the dissection of C. felis felis fleas and subsequently incubated with host serum or plasma, followed by analysis using immunoenzymatic assays (ELISA). The results demonstrated that SGE exhibited anticoagulant activity, prolonging clotting time by 53% in dogs, 35.5% in maned wolves, and 37% in cats, whereas IE showed no significant anticoagulant activity. In contrast, IE demonstrated the ability to inhibit the classical complement pathway, whereas SGE showed no detectable activity. Inhibition reached 63.7 ± 5.8% in dogs, 30.3 ± 12.1% in maned wolves, and 20.7 ± 1.5% in cats. None of the evaluated samples interfered with the alternative complement pathway. Statistical analyses revealed no significant differences among hosts regarding the anticoagulant and anti-complement activities of the tested extracts (p > 0.05). These findings contribute to a better understanding of immuno-ecological interactions, filling gaps in parasite–host dynamics and providing valuable insights to support management and conservation strategies for the maned wolf.