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
- PMID:30419732
- PMCID: PMC6243182
- DOI: 10.3347/kjp.2018.56.5.463
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.
Keywords: Hippopotamus amphibius; Oculotrema hippopotami; Polystomatidae; adult; histopathology; structural analysis; sub-adult.
Conflict of interest statement
We have no conflict of interests related to this work.
Figures







References
- Thurston JP, Laws RM. Oculotrema hippopotami (Trematoda: Monogenea) in Uganda. Nature. 1965;205:1127. - PubMed
- Jooste R. A checklist of the helminth parasites of the larger domestic and wild mammals of Zimbabwe. Trans Zimbabwe Sci Assoc. 1990;64:15–32.
- McCully RW, van Niekerk JW, Kruger SP. Observation of the pathology of bilharsiasis and other parasitic infestations of Hippopotamus Linnaeus, 1758, from the Kruger National Park. Onderstepoort J Vet Res. 1967;34:563–617. - PubMed
- Du Preez LH, Moeng IA. Additional morphological information on Oculotrema hippopotami Stunkard, 1924 (Monogenea: Polystomatidae) parasitic on the African hippopotamus. Afr Zool. 2004;39:225–233.
- Stunkard HW. A new trematode, Oculotrema hippopotami n.g., n.sp, from the eye of the hippopotamus. Parasitology. 1924;16:436–440.
MeSH terms
Grants and funding
LinkOut - more resources
Full Text Sources
