Morphological Studies of Developmental Stages of Oculotrema hippopotami (Monogenea: Polystomatidae) Infecting the Eye of Hippopotamus amphibius (Mammalia: Hippopotamidae) Using SEM and EDXA with Notes on Histopathology

Abstract

The present study was performed to observe histopathological effects of Oculotrema hippopotami Stunkard, 1924 infection in the eye of Hippopotamus amphibius, as well as to reveal new details of morphology and structural features of this monogenean and its comparison between 2 age stages of the parasite. This was done using both light and scanning electron microscopy, energy dispersive X-ray analysis (EDXA) and histopathology. The presence of a mixture of different generations (adult and sub-adult) in one host individual is common for Oculotrema Stunkard, 1924 in contrast to Polystoma Zeder, 1800. New metrical and graphical information obtained for adults and sub-adults compared with the previous studies. Here we show the presence of genital papillae in adults, metrical data on the distal part of the vas deferens. SEM micrographs of sperm ejaculatory structures and information about the flattened dorsal side of the body provided for the first time. Histopathological changes, such as necrosis and hemorrhage in host tissues as a result of O. hippopotami attachment structures are described. Structural analysis of different body parts of O. hippopotami of both age groups are also included. We show qualitative differences in the presence of hardening ions (S, P, Ca) in attachment structures (oral and haptor suckers) that increase with the age of the worm. The presence of sub-adults and adults on the same host, together with high levels of infection without high pathogenicity may account for Oculotrema being one of the most successful parasites among the Monogenea.

A comparative assessment of the morphology ofProfilicollis altmani(Acanthocephala, Polymorphidae) from crustaceans and shore birds in Peru, with special notes on hook elemental analysis (EDXA), SEM imaging, histopathology, and molecular profile

“…For example, EDXA is shown to have significant diagnostic value in acanthocephalan systematics, e.g., Moniliformis cryptosaudi Amin, Heckmann, Sharifdini, Albayati, 2019 was erected based primarily on its EDXA pattern [ 18 ]. Our methodology for the detection of the chemical profile of hooks in the Acanthocephala has also been used in other parasitic groups including the Monogenea [ 64 , 66 ] and Cestoda [ 65 ]. We also provide molecular data to explain and clarify our findings.…”

Description and molecular analysis of an Italian population of Centrorhynchus globo caudatus (Zeder, 1800) Lühe, 1911 (Acanthocephala: Centrorhynchidae) from Falco tinnunculus (Falconidae) and Buteo buteo (Accipitridae)

“…For example, EDXA is shown to have significant diagnostic value in acanthocephalan systematicsfor example, Moniliformis cryptosaudi Amin, Heckmann, Sharifdini & Albayati, 2019 was erected based primarily on its EDXA pattern (Amin et al, 2019b). Our methodology for the detection of the chemical profile of hooks in the Acanthocephala has also been used in other parasitic groups including the Monogenea (Rubtsova et al, 2018;Rubtsova & Heckmann, 2019) and Cestoda (Rubtsova & Heckmann, 2020). We also provide chemical and molecular data to explain and clarify our findings.…”

“…There are over 98 valid species of Centrorhynchus Lühe, 1911 known from birds throughout the world (Amin, 2013). Much of the early descriptions of Centrorhynchus globocaudatus (Zeder, 1800) Lühe, 1911 (Centrorhynchidae) by Zeder (1800) and Rudolphi (1802) were repeated by subsequent observers. The distribution of C. globocaudatus appears to extend throughout Europe, Asia and Africa in many species of birds of prey of the genera Anthus Bechstein (Pipits), Aquila Brisson (true eagles), Asio (Linnaeus) (typical owls); Athene Boie (owls), Buteo Lacépède (buzzards), Circus Lacépède (harrier-hawks), Falco Linnaeus (falcons and kestrel), Glaucidium Boie (pigmy owls), Milvus Lacépède (kites), Ottus Pennant (Eurasian, Old World, scops owls), Strix Linnaeus (wood owls) and Tyto Billberg (barn owls) (see Petrochenko, 1950, 1958; Florescu & Ienistea, 1984; Hoklova, 1986; Lisitsyna, 2019).…”

New perspectives on Aspersentis Megarhynchus (Acanthocephala: Heteracanthocephalidae) from Notothenia Coriiceps Richardson (Nototheniidae) in the West Antarctic, with emended generic diagnosis

“…The present findings will provide a baseline for future comparisons with other species of Aspersentis . Our methodology for the detection of the chemical profile of hooks in the Acanthocephala has also been used in other parasitic groups including the Monogenea (Rubtsova et al ., 2018, Rubtsova & Heckmann 2019), and Cestoda (Rubtsova & Heckmann, 2020).…”