Characterization of the development of Haemonchus contortus ZJ strain from gerbils

Yi Yang,Aifang Du,Xueqiu Chen,Hongli Zhang,Yan Huang,Xiaolu Guo

doi:10.1186/s13071-017-2465-1

Yi Yang, Aifang Du + Show 4 more

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https://doi.org/10.1186/s13071-017-2465-1

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Abstract

BackgroundHaemonchus contortus is a serious parasitic nematode in domestic ruminants around the world, including China. Haemonchus contortus has developed extensive resistance to commercial anthelmintics, which has produced a demand for new control methods, such as more effective drugs. Gerbils infected with H. contortus have previously been used as a model for anthelmintics selections, and the growth of H. contortus had been briefly examined. To enhance the model, this study provides an additional description of the development of H. contortus ZJ strain in gerbils.ResultsGerbils were infected with H. contortus ZJ strain at a dose of 2000 exsheathed infective larvae (xL3s) and sacrificed at 4, 7 and 18 days post-infection (dpi). Only fourth-stage larvae were found in the stomachs. About 2% of the inoculums were obtained at each of the three sampling time points. Larvae grew more slowly in gerbils than in sheep, but presented almost the same morphology. Rod-like crystalline inclusions were present in the intestinal cells of larvae, indicating that the metabolic rate of larvae was probably greatly reduced. Histological examination of stomach sections showed that larvae are located in the lumens or at the mucosal surfaces, with few inflammatory changes evident.ConclusionsThe development and features of H. contortus ZJ strain in gerbils were described. Our results provide supplementary information of H. contortus growth in gerbils, especially the presence of rod-like crystalline inclusions, and may contribute to improve the anthelmintic selection system.

Highlights

Haemonchus contortus is a serious parasitic nematode in domestic ruminants around the world, including China
Conder et al [1] first described the model for studying anthelmintics against H. contortus, and examined the growth and development of H. contortus in gerbils [2]; this study found that artificially exsheathed larvae were able to grow and establish successfully in gerbil’s
Haemonchus contortus exsheathment and gerbil infection The Infective larvae (iL3s) were exsheathed to Exsheathed infective larvae (xL3s) using 0.2% NaOCl based on the method described by Rothwell & Sangster [12]

Summary

Introduction

Haemonchus contortus is a serious parasitic nematode in domestic ruminants around the world, including China. Haemonchus contortus has developed extensive resistance to commercial anthelmintics, which has produced a demand for new control methods, such as more effective drugs. Gerbils infected with H. contortus have previously been used as a model for anthelmintics selections, and the growth of H. contortus had been briefly examined. Conder et al [1] first described the model for studying anthelmintics against H. contortus, and examined the growth and development of H. contortus in gerbils [2]; this study found that artificially exsheathed larvae were able to grow and establish successfully in gerbil’s. Hutchinson & Slocombe [8] found that H. contortus completed its development at a slower rate than in sheep when they infected laboratory rabbits with exsheathed larvae. Wagland et al [9] demonstrated that H

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