A morphological, molecular and life cycle study of the capybara parasite Hippocrepis hippocrepis (Trematoda: Notocotylidae)

Abstract

Hippocrepis hippocrepis is a notocotylid that has been widely reported in capybaras; however, the molluscs that act as intermediate hosts of this parasite remain unknown. Furthermore, there are currently no molecular data available for H . hippocrepis regarding its phylogenetic relationship with other members of the family Notocotylidae. In the present study, we collected monostome cercariae and adult parasites from the planorbid Biomphalaria straminea and in the large intestine of capybaras, respectively, from Belo Horizonte, Minas Gerais, Brazil. We subjected them to morphological and molecular (amplification and sequencing of partial regions of 28S and cox-1 genes) studies. Adult parasites collected from the capybaras were identified as H . hippocrepis and the sequences obtained for both molecular markers showed 100% similarity with monostome cercariae found in B . straminea . The sequences obtained for H . hippocrepis were compared with data available in public databases; analysis revealed this species differs from other notocotylids with available sequences (1.5–3.8% with respect to 28S and 11.4%–13.8% with respect to cox-1 ). On the phylogenetic analyses, H . hippocrepis appeared to be a distinct lineage in relation to other notocotylids. Some ecological aspects related to the infection of capybaras with H . hippocrepis are briefly discussed.

Exploring Neotropical anuran parasites: a morphological, life cycle and phylogenetic study of Catadiscus marinholutzi (Trematoda: Diplodiscidae)

“…Both larval stages (cercariae and metacercariae) have a constricted acetabulum, as observed in their adult counterparts. Interestingly, in other genera of the Paramphistomoidea, including in some species of Diplodiscidae, the shape of acetabulum and arrangement of intestinal caeca in adults and cercariae are similar (Yamaguti, 1975;Besprozvannykh et al, 2018). Such similarities between larvae and adults are thought to be common among 'primitive' trematodes (Galaktionov and Dobrovolskij, 2003).…”

“…Knowledge of taxonomy and life cycles of trematodes has advanced over time, both through classical experimental studies (revised by Yamaguti, 1975;Galaktionov and Dobrovolskij, 2003;Bolek et al, 2016;Blasco-Costa and Poulin, 2017) and molecular tools (Blasco-Costa et al, 2016;Assis et al, 2019, Gonchar et al, 2019Locke et al, 2020). However, studies focused on life cycle of trematodes parasitizing cold-blooded tetrapods, especially amphibians, are comparatively scarce worldwide.…”

“…Despite the high diversity of species, the knowledge about the life cycle of these amphibian parasites is restricted to species of the genus Diplodiscus Diesing, 1836, Megalodiscus Chandler, 1923and Opisthodiscus Cohn, 1904 from Europe, North America and Asia (Sey, 1991). These studies have shown that either a tadpole or adult becomes infected when ingesting encysted metacercariae in food or its own cast-off skin; an alternative route of infection by swallowing the cercariae was also proposed (Yamaguti, 1975;Grabda-Kazubska, 1980;Bolek and Janovy Jr., 2008;Besprozvannykh et al, 2018). The paucity of knowledge on the life cycle of anuran amphistomes can be due to difficulties in the maintenance of this host under laboratory conditions for experimental infection studies.…”

It is marine: distinguishing a new species of Catatropis (Digenea: Notocotylidae) from its freshwater twin

“…Moreover, representatives of Notocotylus also appear in four different clades on the tree. Similar observations were also made in previous studies (Assis et al ., 2019; Gonchar et al ., 2019; Izrailskaia et al ., 2019). These are alarm bells for the fundamentals of notocotylid taxonomy, where the structure of ventral organs (ridges and papillae – their number, combination or absence) served to characterize genera.…”

“…On our tree (Fig. 1), two well-supported clades unite species with molluscan hosts mostly from the Heterobranchia (A) and mostly from the Caenogastropoda (B) (see also Assis et al ., 2019; Gonchar et al ., 2019). However, the position of many species, including C. onobae , is not resolved, most likely indicating a significant lack of sampling across the family.…”