Parasites of Crocodylus moreletii (Reptilia: Crocodylidae) Across Habitats with Different Levels of Anthropogenic Disturbance in Southeastern Mexico.

Between July 2021 and July 2022, a cross-sectional parasitological survey was conducted on 97 free-ranging Crocodylus moreletii individuals across four Mexican states: Campeche, Quintana Roo, Yucatán, and Tabasco. Sampling was conducted out at 12 sites representing varying degrees of anthropogenic disturbance, categorized as conserved, moderately disturbed, and highly disturbed habitats. Parasitological analysis identified seven nematode taxa: Contracaecum sp. type 1, Contracaecum sp. type 2, Terranova crocodili, Micropleura sp., Dujardinascaris helicina, Eustrongylides sp., and Goezia nonipapillata, belonging to four families: Ascarididae, Anisakidae, Micropleuridae, and Dioctophymidae. The most prevalent species were Contracaecum sp. type 1 (51%), followed by Contracaecum sp. type 2 (41%) and D. helicina (28%), while Eustrongylides sp. showed the lowest prevalence (4.1%). Parasite composition differed significantly among sites with varying levels of anthropogenic disturbance (PERMANOVA, p < 0.05). Contracaecum sp. type 1 reached a prevalence of 100% in moderately disturbed habitats. Additionally, Contracaecum sp. type 2, D. helicina, and T. crocodili exhibited moderate to high prevalence across all surveyed localities, irrespective of habitat disturbance levels. Eustrongylides sp. and G. nonipapillata were found exclusively in urban environments. These findings highlight the importance of monitoring host-parasite dynamics across environmental gradients of anthropogenic impact to better assess zoonotic risks and promote both public and wildlife health.