Jantafong Tippawan, Saenglub Wimontiane, Chaisilp Nattarun, Paungpin Weena, Tibkwang Thatsanee, Mutthi Pattama, Bouma Teerawin, Lekcharoensuk Porntippa
Department of Preclinical Sciences, Faculty of Veterinary Medicine, Mahanakorn University of Technology, Bangkok 10530, Thailand.
Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, 50th Ngamwongwan Rd., Chatuchak, Bangkok, 10900, Thailand.
Vet World. 2024 Aug;17(8):1722-1732. doi: 10.14202/vetworld.2024.1722-1732. Epub 2024 Aug 4.
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.
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.
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.
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.
由猪繁殖与呼吸综合征病毒（PRRSV）引起的猪繁殖与呼吸综合征（PRRS）是一个全球性问题，也影响着泰国的猪群。在泰国，PRRSV - 2比PRRSV - 1更为常见。PRRSV - 1的传播源头仍未被发现。本研究追踪了三个育肥猪场中导致疾病传播的感染猪的来源，并分析了PRRSV - 1的传播情况。
使用开放阅读框（ORF7）逆转录聚合酶链反应（RT - PCR）对泰国繁殖场和育肥场的696份猪样本进行PRRSV筛查。使用ORF5 RT - PCR将阳性样本鉴定为PRRSV - 1。分析包括核苷酸同源性、GP5氨基酸序列和N - 连接糖基化模式的研究，以评估PRRSV - 1在这些猪场中的传播情况。
基因检测确定了28份PRRSV - 1阳性样本，其中13份被选为代表。这些毒株根据繁殖场猪舍分为三组，并在育肥场呈现出不同的分布模式。第1组包括从A猪舍转移到佛统府、春武里府和沙缴府的仔猪。第2组和第3组显示从F猪舍和H猪舍转移到春武里府和沙缴府农场。所有13株PRRSV - 1毒株均被归类为PRRSV - 1亚型1/进化枝H。N - 连接糖基化分析表明，几乎所有PRRSV - 1毒株在氨基酸位置N37、N46和N53处都呈现出保守的糖基化模式。这种模式与先前泰国PRRSV - 1亚型1/进化枝H的糖基化特征一致。
本研究突出了PRRSV - 1在泰国猪群中的持续存在，这导致了散发性疫情爆发。分子遗传学分析确定了三个主要毒株组分散在整个生猪生产系统中，强调了对该猪群中新PRRSV毒株进行定期监测的重要性。了解PRRSV - 1在猪场中的分布情况对兽医至关重要。这些知识有助于泰国制定根除该病毒和有效管理猪群健康的策略。
