Investigation of the distribution and origin of porcine reproductive and respiratory syndrome virus 1 in the swine production chain: A retrospective study of three farms in Thailand

Vet World Vol.17 August-2024 Article - 9

Research Article

Veterinary World, 17(8): 1722-1732

https://doi.org/10.14202/vetworld.2024.1722-1732

Tippawan Jantafong¹, Nattarun Chaisilp², Weena Paungpin², Thatsanee Tibkwang³, Pattama Mutthi⁴, and Teerawin Bouma⁵

1. Department of Preclinical Sciences, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok 10530, Thailand.
2. The Monitoring and Surveillance Center for Zoonotic Diseases in Wildlife and Exotic Animals, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom 73170, Thailand.
3. Office of the Dean, Faculty of Veterinary Science, Mahidol University, Nakhon Pathom 73170, Thailand.
4. Faculty of Veterinary Medicine, Rajamangala University of Technology Tawan-ok, Chonburi 20110, Thailand.
5. Animal Production Innovation and Management Division, Faculty of Natural Resources, Prince of Songkla University, Hat Yai Campus, Songkhla, 90110, Thailand.

Background and Aim: Porcine reproductive and respiratory syndrome (PRRS), caused by PRRS virus (PRRSV), is a global issue that affects Thai swine as well. In Thailand, PRRSV-2 predominates over PRRSV-1. The origin of PRRSV-1 transmission remains undiscovered. This study traced the source of infected pigs responsible for disease transmission among three pig-fattening farms and analyzed the spread of PRRSV-1.

Materials and Methods: A total of 696 swine samples from breeding and pig-fattening farms in Thailand were screened for PRRSV using open reading frames (ORF7) reverse transcription polymerase chain reaction (RT-PCR). Positive samples were identified as PRRSV-1 using ORF5 RT-PCR. The analysis included the study of nucleotide homology, GP5 amino acid sequences, and N-linked glycosylation patterns to assess the spread of PRRSV-1 across these farms.

Results: Genetic examination identified 28 PRRSV-1-positive samples, of which 13 were chosen as representatives. These strains were categorized into three groups based on breeding farm pig houses and showed distinct distribution patterns across pig-fattening farms. Group 1 included piglets transferred from pig house A to Nakhon Pathom, Chonburi, and Sa Kaeo. Groups 2 and 3 showed transfers from pig houses F and H to Chonburi and Sa Kaeo farms. All 13 PRRSV-1 strains were categorized into PRRSV-1 subtype 1/clade H. N-linked glycosylation analysis revealed that nearly all PRRSV-1 strains exhibited a conserved glycosylation pattern at amino acid positions N37, N46, and N53. This pattern is consistent with the glycosylation profile of the previous Thai PRRSV-1 subtype 1/clade H.

Conclusion: The present study highlights the persistent presence of PRRSV-1 in Thai swine, which leads to sporadic outbreaks. The molecular genetic analysis identified three primary strain groups dispersed throughout the pig production system, emphasizing the importance of regular monitoring for new PRRSV strains in this herd. Understanding the PRRSV-1 distribution in swine farms is vital for veterinarians. This knowledge supports strategies for eradicating the virus and managing swine health effectively in Thailand.

Keywords: porcine reproductive and respiratory syndrome virus-1, swine production system, Thailand, virus distribution.

How to cite this article: Jantafong T, Chaisilp N, Paungpin W, Tibkwang T, Mutthi P, and Bouma T (2024) Investigation of the distribution and origin of porcine reproductive and respiratory syndrome virus 1 in the swine production chain: A retrospective study of three farms in Thailand, Veterinary World, 17(8): 1722–1732.

Received: 2024-03-09 Accepted: 2024-07-09 Published online: 2024-08-04

Corresponding author: Tippawan Jantafong and Teerawin Bouma E-mail: tippawan@mut.ac.th and teerawin.b@psu.ac.th

DOI: 10.14202/vetworld.2024.1722-1732

Copyright: Jantafong, 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.