Avian schistosomes are blood flukes parasitizing aquatic birds and snails, which are responsible for a zoonotic disease known as cercarial dermatitis, a hypersensitive reaction associated to the cutaneous penetration of furcocercariae. Despite its worldwide distribution, its knowledge is fragmentary in the Neotropics, with most of data coming from Argentina and Brazil. In Chile, there are only two mentions of these parasites from birds, and one human outbreak was associated to the genus “Trichobilharzia”. However, the identity of such parasites is pending. The aim of this study was to identify the furcocercariae of avian schistosomes from Southern Chile using an integrative approach. Thus, a total of 2283 freshwater snails from different families were collected from three different regions. All snails were stimulated for the shedding of furcocercariae, but only Chilina dombeyana (Chilinidae) from the Biobío region was found to be parasitized. The morphology and phylogenetic analyses of 28S and COI genes stated two lineages, different from Trichobilharzia, shared with Argentina. This study provides new information on Neotropical schistosomes, highlighting the need for major research on these neglected trematodes, which are considered to be emerging/re-emerging parasites in other parts of the globe as consequence of anthropogenic disturbances and climatic change. Highlights: 1. Two different lineages (Lineage I and II) were described and molecularly characterized (28S and COI genes); 2. Cercaria chilinae I y II are proposed as a synonymous of Lineage II. Thus, a total of four different lineages of avian schistosomes are related to Chilina spp.; 3. Chilina spp. represents an important intermediate host for avian schistosomes in South America, constituting a reservoir de schistosomes with zoonotic potential; 4. Coinfection between the two different lineages was found, a finding previously not reported for avian schistosomes; 5. Expansion in the geographic distribution of Nasusbilharzia melancorhypha from its original record in Argentina, with Chilina dombeyana as an additional intermediate host.

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Cervids are important hosts for ticks and although they are refractory to some tick‐borne agents such as Borrelia, they do act as reservoirs for others such as Babesia. Babesia and Borrelia are commonly transmitted by Ixodes spp. associated with deer, and most of the knowledge on their biological cycles comes from northern latitudes of the globe. In this study, we performed genetic screenings to detect tick‐borne agents in blood and Ixodes stilesi ticks collected from an insular population of threatened pudu (Pudu puda), a pygmy deer species that inhabits temperate rainforests of southern South America. Inferred by phylogenetic analyses for 18S rRNA, COI and cytb genes, our results unveiled a novel genospecies of Babesia (Babesia sp. pudui) genetically related to Babesia odocoilei, a species that infects Odocoileus virginianus deer in North America. Although blood of the deer was negative for Borrelia infection, multilocus sequencing typing performed in one I. stilesi tick revealed the occurrence of a novel genetic variant of Borrelia chilensis, differing 0.93% and 0.18% in flaB and pepX genes with the type of strain for the species, respectively. Such a genetic divergence could be the result of thousands of years of isolation because of recent glaciation events that separated pudus and their tick populations at Chiloé Island approximately 437,000 years ago. The finding of a Babesia sp. has no precedents for wild and domestic ungulates in Chile and shows a novel piroplasmid that must be considered now on in rehabilitation centres and zoos that attend pudu deer. Further research is now necessary to confirm pathogenic roles.

All the birds from this study were found positive for the endoparasitic nematode Heterakis dispar. In one of the birds, proglotides were found which, from a morphological analysis, belong to the family Hymenolepidae. The total number of specimens of H. dispar was greater in male geese than in females. The female/male ratio was 1.22. The larva/adult ratio was 0.41. No parasites were found in a study of goose faeces. An 87.5% of the birds were parasitised by one or more of the following louse species: Holomenopon brevithoracicum, Anaticola marginella, Anatoecus dentatus and Anatoecus icterodes, all of them belonging to the Order Phthiraptera. All these species represent new louse records from Magellan geese for Chile, as well as a new host-louse record for A. dentatus on C. picta.

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