Epidemiological Studies on Nematode Parasites of Domestic Geese (Anser anser f. domesticus) and First Molecular Identification and Phylogenetic Analysis of Heterakis dispar (Schrank, 1790) in Egypt.

Purpose: Gastrointestinal nematodes are one of the most important constraints of poor geese health and productivity, in addition to being involved in great economic losses for various poultry sectors. This study primarily aimed at determining the epidemiological profile and risk factors associated with the occurrence of gastrointestinal (GI) nematode parasites in geese in Egypt. The phylogenetic relationships between heterakids were the second aim.
Methods: For achieving these aims, a total 180 of intestinal samples were screened for the presence of gastrointestinal nematodes over a period of one year from December 2018 to November 2019. Furthermore, A PCR-based DNA sequencing of the mitochondrial NADH dehydrogenase subunit1 gene (nad1) was conducted for characterization of adult Heterakis dispar.
Results: The current search revealed that the overall prevalence was 33.33% (60/180). Five species of nematode species was encountered in this study, namely Capillaria spp., Heterakis gallinarum (Schrank, 1788), Ascaridia galli (Schrank, 1788), Subulura brumpti (Lopez-Neyra, 1922) and Heterakis dispar (Schrank, 1790). A positive relationship was found between the prevalence of nematode infection and age of tested geese revealing that the high prevalence was found in adults rather than young birds (P = 0.03). Moreover, there was no significant difference in the prevalence of nematode infection between male and female geese (P > 0.05). Also, there was strong significant seasonal trends in the prevalence of the recovered helminths with the maximum infection was observed in summer season and lowest in winter (P = 0.002). The BLAST analysis of H. dispar nad1 sequence showed a 96.4% similarity with the sequences of H. dispar Heilongjiang. It also showed a lower similarity to the mitochondrial gene sequences of H. gallinarum (84.4%). This is the first molecular identification and report of genetic diversity of Heterakis dispar in geese from Egypt.
Conclusions: The current finding initially provides a concise account of knowledge about the epidemiology of gastrointestinal nematodes infecting geese and are considered as a starting point for the implementation of appropriate control and prophylactic schemes for GIT nematodiasis. It also confirms the potential uses of genetic techniques for taxonomic studies of different parasites.
(© 2021. Witold Stefański Institute of Parasitology, Polish Academy of Sciences.)