Into the unknown: a literature review of helminths of amphibians and reptiles in Mesoamerica.

backgroundHelminths are an important but understudied component of amphibian and reptile biodiversity, particularly in Mesoamerica, a global biodiversity and cultural hotspot.

methodsWe conducted a comprehensive literature review of helminth parasites reported from amphibians and reptiles across Mesoamerica, yielding 71 publications with 1195 specimen records. Data extracted from each article included geographical location of the report, co-author affiliation and country of origin, host and parasite taxonomic details, deposition in taxonomic collections, and pathological data. In addition, a host-parasite association network was built to depict the most studied relationships.

resultsThis scoping review analyzed publications on helminths in Mesoamerican amphibians and reptiles, revealing clear geographic, taxonomic, and research biases. Most studies were published after 2000, peaking between 2006 and 2010, and focused largely on host-parasite relationships and species descriptions, likely reflecting the early consolidation of parasitological research in the region and the need to establish baseline biodiversity data. Research was concentrated in Costa Rica and Mexico, with Costa Rica contributing nearly half of all studies, and countries such as Honduras and El Salvador with no reports at all. However, much of the work was led by foreign, especially United States, institutions, highlighting the dominance of exogenous research efforts. Helminth diversity was dominated by nematodes (64.1%), followed by platyhelminths and acanthocephalans. A small number of parasite species and host species accounted for a disproportionately large share of records, particularly amphibians like Rhinella horribilis and Leptodactylus melanonotus, as well as Anolis lizards. Network analysis showed that these hosts act as key hubs supporting diverse parasite communities. Most parasite specimens were deposited in North American collections rather than local institutions, especially in the United States. Additionally, studies rarely included ecological or pathological data, focusing mainly on descriptive taxonomy. Overall, the findings highlight strong sampling biases, limited regional research capacity, and a need for more integrative ecological and pathological approaches in Mesoamerican parasitology.

conclusionsOur review underscores significant gaps in current knowledge, advocating for increased endogenous research and genuine international cooperation, systematic sampling of understudied host groups, and integration of One Health approaches to enhance understanding of host-parasite dynamics, biodiversity conservation, and potential zoonotic risks in Mesoamerica.