Synlophe Structure in Pseudomarshallagia elongata (Nematoda: Trichostrongyloidea), Abomasal Parasites Among Ethiopian Ungulates, with Consideration of Other Morphological Attributes and Differentiation within the Osteragiinae

Authors: Hoberg, Eric; KUMSA, BERSISSA - Addis Ababa University; Pilitt, Patricia; Abrams, Arthur

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2009
Publication Date: 6/1/2010
Citation: Hoberg, E.P., Kumsa, B., Pilitt, P.A., Abrams, A. 2010. Synlophe Structure in Pseudomarshallagia elongata (Nematoda: Trichostrongyloidea), abomasal parasites among Ethiopian ungulates, with consideration of other morphological attributes and differentiation within the Osteragiinae. Journal of Parasitology. 96:401-411.

Interpretive Summary: Gastrointestinal nematodes continue to cause major production losses for domestic livestock globally. Further these parasites are disseminated and introduced with the movement and translocation of domestic and free-ranging stock on local, regional and global scales. Medium stomach worms, and the related haemonchines are a major component of this parasite fauna. For example, among small ruminants (sheep and goats) across Ethiopia Pseudomarshallagia elongata and other nematodes cause extensive disease, mortality and annual production losses estimated near $400 million US and represent a major challenge to socioeconomic development and food security. Knowledge of parasite diversity, including host associations and geographic distribution are cornerstones in development of effective strategies for control of parasitism. The continued global translocation and introduction of exotic parasites further establishes a rationale for the development of effective baselines for identification which are necessary to track dissemination of pathogens and emergence of disease in space and time. The current study contributes to a more detailed understanding of nematode diversity among ungulate hosts from Ethiopia and more broadly across sub-Saharan Africa. We emphasize the importance of continued survey and inventory of parasite faunas to establish the limits of diversity on local, regional and global scales. Consequently, we strongly encourage routine deposition of voucher specimens from all survey activities designed to explore faunal diversity. This is particularly important in regions that remain poorly known such as Africa, but the principle applies more broadly. Over time such activities can serve to build a comprehensive picture for the structure of helminth faunas among free ranging and domestic ungulates at local, regional and global scales.

Technical Abstract: The independence of the genus Pseudomarshallagia and its placement among the medium stomach worms of ungulates, Ostertagiinae, is confirmed based on comparative morphological studies of the synlophe and genital attributes among male and female specimens. An emended description of P. elongata is presented based on a series of specimens in sheep from northern Ethiopia. Pseudomarshallagia elongata is retained among the 15 genera of the Ostertagiinae based on presence of a prominent esophageal-intestinal valve, paired “0” papillae, a modified accessory bursal membrane containing the paired “7” papillae, and configuration of the copulatory bursa. The structure of the synlophe in males and females is also typical and within the range of variation demonstrated for Type II and Type A cervical patterns among other ostertagiines. We emphasize the importance of continued survey and inventory of parasite faunas to establish the limits of diversity on local, regional and global scales. Consequently, we strongly encourage routine deposition of voucher specimens from all survey activities designed to explore faunal diversity. This is particularly important in regions that remain poorly known such as Africa, but the principle applies more broadly.