Characterizing Two New Henneguya Species in the Respiratory Organs of African Sharptooth Catfish

Emeish, Walaa F A; Fawaz, Marwa M; Hussein, Nermean M; Al-Amgad, Zeinab; Abd-ElHafeez, Hanan H; Rutland, Catrin Sian; Bakry, Karima A

Abstract

Henneguya species are myxozoans, a suborder of Cnidaria, which can affect the gills and extrarespiratory organs of the African sharptooth catfish, Clarias gariepinus. This research describes natural infection-induced histological alterations caused by the Henneguya species present. The Henneguya species were also identified molecularly using DNA sequenced from infected tissue cysts, and phylogenetically analyzed. Clinical investigations revealed cyst-like nodules on the fish gill filaments and extrarespiratory organs. Within a milky fluid inside the cysts were several Henneguya-like spores. Henneguya sp. infested 27.5% of the fish, with the highest prevalence in the gills compared to the extrarespiratory organs. The Henneguya species parasitized the gill and the dendritic tissues, resulting in histopathological characteristics. The plasmodia's developmental stages resulted in destructive damage which manifested as marked necrosis, which was replaced by a focal aggregation of inflammatory cells. Amplification of the 18S ribosomal DNA from the fish parasites was followed by sequencing, which confirmed their identities as new species Henneguya qenabranchiae n. sp. and Henneguya qenasuprabranchiae n. sp. with 99.53 and 99.64% identities, respectively, to Henneguya sp. 1 HS-2015. The two C. gariepinus myxozoans shared some characteristics based on morphologic and phylogenetic analysis as previously published, where it was proposed that they were a sister lineage to Henneguya species in Egypt, and it is now proposed that they are new species.

Citation

Emeish, W. F. A., Fawaz, M. M., Hussein, N. M., Al-Amgad, Z., Abd-ElHafeez, H. H., Rutland, C. S., & Bakry, K. A. (2023). Characterizing Two New Henneguya Species in the Respiratory Organs of African Sharptooth Catfish. Microscopy and Microanalysis, 29(5), 1774-1790. https://doi.org/10.1093/micmic/ozad091

• Journal Article Type: Article
• Acceptance Date: Aug 6, 2023
• Online Publication Date: Aug 30, 2023
• Publication Date: 2023-10
• Deposit Date: Sep 4, 2023
• Publicly Available Date: Mar 1, 2024
• Journal: Microscopy and Microanalysis
• Print ISSN: 1431-9276
• Electronic ISSN: 1435-8115
• Publisher: Cambridge University Press
• Peer Reviewed: Peer Reviewed
• Volume: 29
• Issue: 5
• Pages: 1774-1790
• DOI: https://doi.org/10.1093/micmic/ozad091
• Keywords: Clarias gariepinus, Henneguya, myxozoan, phylogenetic analysis
• Public URL: https://nottingham-repository.worktribe.com/output/24870067
• Publisher URL: https://academic.oup.com/mam/article-abstract/29/5/1774/7256132?redirectedFrom=fulltext
• Additional Information: This is a pre-copyedited, author-produced version of an article accepted for publication in Microscopy and Microanalysis; following peer review. The version of record Walaa F A Emeish, Marwa M Fawaz, Nermean M Hussein, Zeinab Al-Amgad, Hanan H Abd-ElHafeez, Catrin Sian Rutland, Karima A Bakry, Characterizing Two New Henneguya Species in the Respiratory Organs of African Sharptooth Catfish, Microscopy and Microanalysis, Volume 29, Issue 5, October 2023, Pages 1774–1790, is available online at: https://doi.org/10.1093/micmic/ozad091