Morphological characteristic of Skrjabinema ovis (Nematoda, Oxyuridae) obtained from domestic sheep

V V Melnychuk,O I Reshetylo

doi:10.15421/022058

Abstract

Skrjabinemosis is a widely prevalent helminthiasis of sheep, goats and wild ruminants. It is caused by Skrjabinema ovis Skrjabin, 1915. Parasitization by S. ovis induces inflammatory processes of the large intestine, in skin around the anus and tail base, resulting in reduced productivity and weight loss. The measures of prevention and control of skrjabinemosis on sheep farms depend on the timely and accurate diagnosis, based on the reliable identification of nematodes. We studied the identification morphometric characters of this species The nematodes were obtained from the large intestine of 710 pasture-kept sheep (Ovis aries) on farms of Kyiv, Poltava and Zaporizhzhia regions ( Central and South-Eastern Ukraine). In total, 5723 adult S. ovis nematodes were collected, 1981 of which were males and 3742 were females. Sexual dimorphism was found in S. ovis both in metric and morphological parameters. The size dimorphism is characterized by values larger by 43.9–64.6% of 11 parameters in females compared to males. The differential characters of mature S. ovis males and females are morphological specifics of the mouth organ complex and the distribution of cuticular formations on the head end of the parasite. The lips of the female nematodes are anchor-shaped and adorned with tooth-like lamellae, and the lips of the males are oval and lack the tooth-like lamellae. Cuticular nodes on the head ends of the females are considerably longer and wider than in the males. The species-specific morphological characters of the males are the features of morphology and sizes of the pseudobursa, the shape and length of the spicule and gubernaculum, and their width parameters in different areas. In the identification of females, the morphology of the vulva and tail end, and the metric parameters of the location of the vulva, anus, and sizes of eggs in the uterus should be considered. Additional metric and morphological parameters are presented for use in the differentiation of males and females for better identification.

Highlights

The main aim of sheep farming is a full utilization of the biological potential of meat, wool and dairy productivity of sheep breeds (Rasali et al, 2006; Banerjee et al, 2009; Anteneh & Yadav, 2017)
It is established that the morphological and metric parameters of males and females should be considered in the species identification of Skrjabinema ovis Skrjabin, 1915 nematodes
The sexual dimorphism in S. ovis is significant and distinct, the females are larger by 11 parameters than males

Summary

Introduction

The main aim of sheep farming is a full utilization of the biological potential of meat, wool and dairy productivity of sheep breeds (Rasali et al, 2006; Banerjee et al, 2009; Anteneh & Yadav, 2017). One of the approaches used is careful monitoring and prediction of the parasitological situation, the implementation of measures for the prevention and treatment of invasive diseases, especially nematodes of the gastrointestinal tract of sheep. Sheep helminths are widely prevalent and form parasitic systems with multiple levels of protection They cause infectious diseases that are stable and enzootic in various countries in most of the natural climatic zones. Skrjabinemosis is found on sheep farms in Italy, Brazil, Africa, and Macedonia (Balbo et al, 1977; Theodoridis et al, 2000; Belem et al, 2005; de Souza et al, 2012) This prevalence of skrjabinemosis is likely related to the biological features of the parasite. The egg becomes infectious, and is released into the environment where the alimentary infection of hosts occurs (Schad, 1957; Anderson, 2000)

Objectives

Methods

Results

Discussion

Conclusion