Field-based and molecular evaluation of anthelmintic resistance in gastrointestinal strongyle nematodes of meat goats in Southern Thailand

Vet World Vol.18 August-2025 Article - 28

Research Article

Veterinary World, 18(8): 2467-2478

https://doi.org/10.14202/vetworld.2025.2467-2478

Narin Sontigun^1,2, Chalutwan Sansamur³, Tunwadee Klong-Klaew⁴, Raktham Mektrirat^5,6,7, Morakot Kaewthamasorn⁸, and Punpichaya Fungwithaya¹

1. Office of Administrative Interdisciplinary Program on Agricultural Technology, School of Agricultural Technology, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand.

2. Akkhraratchakumari Veterinary College, Walailak University, Nakhon Si Thammarat 80160, Thailand.

3. Akkhraratchakumari Veterinary College, Walailak University, Nakhon Si Thammarat 80160, Thailand.

4. Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand.

5. Veterinary Academic Office, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.

6. Veterinary Research Center for Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand.

7. Center of Excellence in Pharmaceutical Nanotechnology, Faculty of Pharmacy, Chiang Mai University, Chiang Mai 50200, Thailand.

8. Center of Excellence in Veterinary Parasitology, Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.

Background and Aim: Gastrointestinal nematodes (GINs) such as Haemonchus contortus and Trichostrongylus colubriformis are major health threats in goats, exacerbated by growing anthelmintic resistance (AR). Despite the widespread use of albendazole and ivermectin in Nakhon Si Thammarat, Southern Thailand, data on AR status in goats remain scarce. This study aimed to evaluate the resistance of GINs to albendazole and ivermectin using fecal egg count reduction (FECR) tests and to determine benzimidazole (BZ) resistance through molecular detection of the F200Y mutation in the β-tubulin isotype 1 gene.

Materials and Methods: A total of 192 meat goats from six farms were randomly divided into four groups: untreated control, albendazole-treated, ivermectin-treated, and combination-treated. FECR was assessed on day 14 post-treatment. Larval cultures and semi-nested polymerase chain reaction (PCR) were used to identify nematode genera. BZ resistance was determined through allele-specific PCR on H. contortus and T. colubriformis third-stage larvae, pre- and post-albendazole treatment.

Results: FECR revealed confirmed resistance (FECR < 95%) to albendazole (−35.48%–62.5%), ivermectin (−2.41%–51.47%), and their combination (−25%–48.36%) across all farms. Haemonchus and Trichostrongylus were the predominant genera post-treatment. Molecular analysis showed high pre-treatment frequencies of the F200Y resistance allele in H. contortus (75.0%–80.6%) and T. colubriformis (88.6%–100%), which reached 100% post-treatment. Susceptible genotypes were entirely eliminated following albendazole treatment.

Conclusion: This is the first comprehensive study confirming widespread AR to albendazole and ivermectin in meat goats in southern Thailand. The fixation of the BZ resistance allele in both nematode species highlights the urgency for revising current deworming practices. Immediate adoption of integrated parasite management strategies, including drug rotation, targeted selective treatment, and exploration of alternative anthelmintics, is critical to mitigate economic losses and protect public health.

Keywords: albendazole, allele-specific polymerase chain reaction, anthelmintic resistance, F200Y mutation, Haemonchus contortus, ivermectin, meat goats, Thailand, Trichostrongylus colubriformis, β-tubulin gene.

How to cite this article: Sontigun N, Sansamur C, Klong-Klaew T, Mektrirat R, Kaewthamasorn M, and Fungwithaya P (2025) Field-based and molecular evaluation of anthelmintic resistance in gastrointestinal strongyle nematodes of meat goats in Southern Thailand, Veterinary World, 18(8): 2467-2478.

Received: 07-04-2025 Accepted: 23-07-2025 Published online: 26-08-2025

Corresponding author: Narin Sontigun E-mail: narin.so@kmitl.ac.th

DOI: 10.14202/vetworld.2025.2467-2478

Copyright: Sontigun, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.