Living in big houses: the role of parasitism on anacondas (Boidae: Eunectes), with new records, parasites catalog, and assessment perspectives.

Anacondas rank among the largest snakes on Earth. Found throughout South America, including urban areas, they are commonly traded globally. However, information on anacondas' parasites and pathogens is scattered, necessitating a comprehensive summary. Using morphological and molecular approaches, we provide new records of the ticks <italic>Amblyomma</italic> <italic>dissimile</italic> and <italic>A. rotundatum</italic> hosted on ethanol-preserved specimens of<italic> Eunectes murinus</italic> and <italic>E. deschauenseei</italic>. The presence of <italic>A. rotundatum</italic> on <italic>E. deschauenseei</italic> represents the first record to this rare and poorly known species. Our literature review revealed 45 organisms living on anacondas (13 animal species, four protozoans, 10 fungi, 17 bacteria, and one viral lineage), mostly on <italic>E. murinus</italic>. Anacondas rescued in urban areas or kept in zoos provide a fortuitous opportunity for collecting data on parasites and pathogens, useful for measuring the impacts of habitat anthropization, as well as for preventing the spread of diseases disseminated by traded animals. Withal, characterizing anacondas' parasites and pathogens is paramount to establishing appropriate treatment of diseases caused by these agents, and in cases of accidents involving humans.