Morphological and molecular characterization of Austrodiplostomum compactum metacercariae in the eyes and brains of fishes from the Ivaí River, Brazil

Abstract

Austrodiplostomum spp. (Platyhelminthes: Digenea) are endoparasites with a broad geographic distribution in South America. During the larval stage, they parasitize the eyes, brains, muscles, gill, kidneys and swim bladder of a wide variety of fishes. The metacercariae of Austrodiplostomum spp. have several morphological characteristics during development, but are very similar among species, which makes it necessary to use molecular tools to contribute to the elucidation during the larval stage. The objective of this study was to perform morphological and molecular analyses of Austrodiplostomum sp. found in specimens of Hypostomus sourced from the Ivaí River in the state of Paraná, Brazil. Of the 93 analyzed specimens (H. hermanni [n = 50], H. albopunctatus [n = 9], Hypostomus sp. 1 [n = 24], and Hypostomus sp. 2 [n = 10]), 60 were parasitized. A total of 577 Austrodiplostomum sp. metacercariae was collected from the infected hosts; DNA from seven of these samples was extracted, amplified, and sequenced. The morphological data associated with the genetic distance values and the relationships observed in the COI gene tree, indicate that all metacercariae were A. compactum. This is the first record of A. compactum parasitizing H. hermanni, H. albopunctatus, Hypostomus sp. 1, and Hypostomus sp. 2 in the Ivaí River.

Trematodes and acanthocephalans associated with the yellow mojarra (Caquetaia kraussii) in a coastal lagoon system, San Onofre, Colombia

“…Adult forms of Austrodiplostomum are intestinal parasites of cormorants, while metacercariae are parasites of the eyeball and brain of freshwater and brackish water fish (García-Varela et al 2016;Sereno-Uribe et al 2019). This genus includes only two species: A. mordax (Szidat & Nani, 1951), described in South America and A. compactum (Lutz, 1928) reported from the United States, Mexico, El Salvador, Honduras, Costa Rica, Venezuela, Peru, and Brazil (De Fátima Cracco et al 2022). In the Colombian Caribbean, adults of A. compactum and A. ostrowskiae have been reported in piscivorous birds (Rietschel & Werding, 1978) and as metacercariae in C. kraussii (Olivero-Verbel et al 2012) in Oreochromis mossambicus (Peters, 1852) and O. niloticus (Linnaeus, 1758) (Soler-Jiménez et al 2017).…”

“…In the Colombian Caribbean, adults of A. compactum and A. ostrowskiae have been reported in piscivorous birds (Rietschel & Werding, 1978) and as metacercariae in C. kraussii (Olivero-Verbel et al 2012) in Oreochromis mossambicus (Peters, 1852) and O. niloticus (Linnaeus, 1758) (Soler-Jiménez et al 2017). It is important to note that recent molecular analyses propose synonymy between A. compactum and A. ostrowskiae (García-Varela et al 2016;Ostrowski de Núñez, 2017;De Fátima Cracco et al 2022). Austrodiplostomum metacercariae cause verminous cataracts in fish and can affect other organs such as gills, muscle, swim bladder and brain (Amin, 2002).…”

“…In Latin America, fisheries and aquaculture production are fundamental milestones in social, economic, and nutritional development, with about 85% of production resulting from artisanal fisheries (FAO & ECLAC, 2020). This nutritional dependence on fish resources also leads to a potential exposure of human communities to health risks, considering that many of the parasitic infections that affect fish species for consumption are zoonotic (Chai et al 2005). These parasitic zoonoses transmitted through food consumption, including fish, are of high relevance to public health and socioeconomic problematics in some countries, particularly in Asia (Lima dos Santos & Howgate, 2011), in addition to being a key contributor to the transmission of diseases through food webs.…”

“…Zoonotic helminthiases related to the consumption of fish or fish products have been associated with populations in low-and middle-income countries (Chai et al 2005). In the context of countries such as Colombia, Mexico and Peru, the acquisition of fish in local markets or through subsistence fishing can expose people to parasites at different stages of development (Rojas Sánchez et al 2014;Castellanos-Garzón et al 2019;Murrieta Morey et al 2022).…”

“…In the context of countries such as Colombia, Mexico and Peru, the acquisition of fish in local markets or through subsistence fishing can expose people to parasites at different stages of development (Rojas Sánchez et al 2014;Castellanos-Garzón et al 2019;Murrieta Morey et al 2022). However, the geographic distribution of these diseases and the populations at risk have been constantly growing as a consequence of the expansion of international markets and demographic changes, increasing the risk of contagion even in developed countries (Chai et al 2005).…”