<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_jvetres-2021-0047_s_005">
<h3>Introduction</h3>
<p>The control of gastrointestinal nematodes (GINs) in small ruminants is principally dependent on anthelmintic therapy, which encounters the rising problem of anthelmintic resistance (AR) development. Veterinarians reported anthelmintic failure in several sheep farms in Arbat District, Sulaymaniyah, northern Iraq, which called for a systematic study about the efficacy of three commonly used drugs: albendazole, ivermectin, and levamisole.</p></sec>
<sec id="j_jvetres-2021-0047_s_006">
<h3>Material and Methods</h3>
<p>A faecal egg count reduction test (FECRT) was conducted to elucidate the anthelmintics’ efficacies, with coprocultures to determine the GINs parasitising sheep in the study area. Larval development assays (LDAs) were conducted to determine the drugs’ median inhibitory concentrations (IC<sub>50</sub>).</p></sec>
<sec id="j_jvetres-2021-0047_s_007">
<h3>Results</h3>
<p>The FECRT revealed that AR was widespread to all three drugs, and ivermectin was the least effective, reducing the faecal egg counts (FECs) by 50.5% to 57.1%. The coprocultures revealed that the GIN genera of sheep in Arbat District were <italic>Trichostrongylus</italic>, <italic>Nematodirus</italic>, and <italic>Trichuris</italic>, and the resistance was mainly due to <italic>Trichostrongylus</italic> species. The mean IC<sub>50</sub> of albendazole, ivermectin, and levamisole were 0.073 ng/mL, 7.97 ng/mL, and 1.43 ng/mL, respectively.</p></sec>
<sec id="j_jvetres-2021-0047_s_008">
<h3>Conclusion</h3>
<p>This study is the first Iraqi report of AR confirmed by both <italic>in vivo</italic> FECRT and <italic>in vitro</italic> LDA methods.</p></sec></abstract>

Introduction
The control of gastrointestinal nematodes (GINs) in small ruminants is principally dependent on anthelmintic therapy, which encounters the rising problem of anthelmintic resistance (AR) development. Veterinarians reported anthelmintic failure in several sheep farms in Arbat District, Sulaymaniyah, northern Iraq, which called for a systematic study about the efficacy of three commonly used drugs: albendazole, ivermectin, and levamisole.

Material and Methods
A faecal egg count reduction test (FECRT) was conducted to elucidate the anthelmintics’ efficacies, with coprocultures to determine the GINs parasitising sheep in the study area. Larval development assays (LDAs) were conducted to determine the drugs’ median inhibitory concentrations (IC50).

Results
The FECRT revealed that AR was widespread to all three drugs, and ivermectin was the least effective, reducing the faecal egg counts (FECs) by 50.5% to 57.1%. The coprocultures revealed that the GIN genera of sheep in Arbat District were Trichostrongylus, Nematodirus, and Trichuris, and the resistance was mainly due to Trichostrongylus species. The mean IC50 of albendazole, ivermectin, and levamisole were 0.073 ng/mL, 7.97 ng/mL, and 1.43 ng/mL, respectively.

Conclusion
This study is the first Iraqi report of AR confirmed by both in vivo FECRT and in vitro LDA methods.

First report of multiple drug-resistant gastrointestinal nematodes of sheep in Arbat District, Sulaymaniyah, Iraq detected by <italic>in vivo</italic> and <italic>in vitro</italic> methods

Journal of Veterinary Research

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

First report of multiple drug-resistant gastrointestinal nematodes of sheep in Arbat District, Sulaymaniyah, Iraq detected by  and  methods

Introduction
The control of gastrointestinal nematodes (GINs) in small ruminants is principally dependent on anthelmintic therapy, which encounters the rising...

Farm	IC₅₀
Farm	Albendazole (μg/mL)	Ivermectin (ng/mL)	Levamisole (μg/mL)
1	0.076 ± 0.004	8.030 ± 0.692	1.470 ± 0.090
2	0.071 ± 0.004	7.670 ± 0.622	1.450 ± 0.140
3	0.072 ± 0.007	8.200 ± 0.615	1.390 ± 0.120

Farm	Pre-treatment FEC* (eggs/g)	Percentage of larvae by genus
Farm	Pre-treatment FEC* (eggs/g)	Trichostrongylus	Nematodirus	Trichuris
1	764.1 ± 45.2	82.0	12.0	6.0
2	760.0 ± 48.1	76.0	15.0	9.0
3	604.2 ± 37.8	86.0	8.0	6.0

First report of multiple drug-resistant gastrointestinal nematodes of sheep in Arbat District, Sulaymaniyah, Iraq detected by in vivo and in vitro methods

Published Online: Aug 19, 2021

Page range: 293 - 299

Received: Mar 22, 2021

Accepted: Aug 03, 2021

DOI: https://doi.org/10.2478/jvetres-2021-0047

Keywords
albendazole, anthelmintic resistance, ivermectin, levamisole, larval development assay

© 2021 H.O. Dyary, H.Q. Banaz. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Median inhibitory concentration (IC50) of anthelmintics preventive of nematode egg hatchability

Percentage of third-stage larvae in the first 100 larvae isolated from a pooled post-treatment faecal sample of the control and treated groups

First report of multiple drug-resistant gastrointestinal nematodes of sheep in Arbat District, Sulaymaniyah, Iraq detected by in vivo and in vitro methods

Published Online: Aug 19, 2021

Page range: 293 - 299

Received: Mar 22, 2021

Accepted: Aug 03, 2021

DOI: https://doi.org/10.2478/jvetres-2021-0047

Keywordsalbendazole, anthelmintic resistance, ivermectin, levamisole, larval development assay

© 2021 H.O. Dyary, H.Q. Banaz. published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Fig. 1

Fig. 2

Median inhibitory concentration (IC50) of anthelmintics preventive of nematode egg hatchability

Percentage of third-stage larvae in the first 100 larvae isolated from a pooled post-treatment faecal sample of the control and treated groups

Keywords
albendazole, anthelmintic resistance, ivermectin, levamisole, larval development assay