Henneguyosis in gills of Metynnis hypsauchen: an Amazon freshwater fish

Abstract

This study describes aspects of infection caused by Myxozoa of the genus Henneguya sp. in gills of fish belonging to the species Metynnis hypsauchen. Two sampling were made in the Capim river, close to the Ribeira community, in the municipality of Ipixuna do Pará, State of Pará, Brazil, during the months of August 2018 and March 2019. The animals were captured and transported live to the Laboratório de Pesquisa Carlos Azevedo, at the Universidade Federal Rural da Amazônia (UFRA), in Belém, Pará, Brazil. The animals were examined, and after parasitism was confirmed, Differential Interference Contrast Microscopes were used, to evaluate the parasite spores. Ziehl-Neelsen stain techniques were used in histology. Necroscopic analyses of Metynnis hypsauchen specimens found parasites in 80% of the hosts (16/20), with whitish-colored cysts in the branchial filaments, containing mature spores of the genus Henneguya. The histopathological analysis indicated large areas with cystic lesions with associated ischemic necrosis. The descriptions from this study indicate that the parasite drastically compromises the host's respiratory system. Additionally, it is worth noting that parasite fauna studies of fishes in the Capim river are still a vast topic for research; this is the first record of infection by Henneguya sp. in Metynnis hypsauchen, captured in the Capim river in Ipixuna do Pará.

Co-infection of Candidatus Piscichlamydia Trichopodus (Order Chlamydiales) and Henneguya sp. (Myxosporea, Myxobolidae) in Snakeskin Gourami Trichopodus pectoralis (Regan 1910)

“…resulted in marked dilatation and discrete epithelial hyperplasia, and continued growth of the parasitic cyst resulted in tissue necrosis in the surrounding infected area. The observation of areas of cystic lesions associated with tissue necrosis caused by the compression of cysts in the epithelial cells of the gill lamellae in this study has also been reported in previous studies ( 55 ). The growth of Henneguya plasmodia results in a displacement and distortion of the lamellar structures, possibly adversely affecting gas exchange and associated with mortality in the fish population.…”

Henneguya sacacaensis n. sp. (Myxozoa: Myxosporea) parasitizing gills of the acará bicudo Satanoperca jurupari (Osteichthyes: Cichlidae) in eastern Amazon

“…Henneguya sacacaensis n. sp. parasitizing Satanoperca jurupari in eastern Amazonia Similar changes have been described previously in other Amazon hosts such as Astyanax keithi (Vita et al, 2003), Cichla temensis (Velasco et al, 2016), Phractocephalus hemioliopterus (Naldoni et al, 2018), and Metynnis hypsauchen (Figueredo et al, 2020).…”

Parasitic fauna of farmed freshwater ornamental sutchi catfish (Pangasiandon hypophthalmus) and silver dollar (Metynnis hypsauchen) in Alborz province, Iran

“…In addition, Figueredo et al. (2020) detected the myxozoan Henneguya sp. in the gills of the silver dollar ( M. hypsauchen ) in Brazil.…”