Molecular epidemiological survey of group A porcine rotavirus in selected areas of China during 2022-2023

Abstract

[Objective] To investigate the molecular epidemiological characteristics of group A porcine rotavirus (RVA) in some areas of China, the current dominant genotypes were identified to provide theoretical basis for RVA prevention and control as well as vaccine research and development.

[Method] From January 2022 to March 2023, 434 stool samples of diarrheal piglets were collected from 36 large-scale pig farms in provinces of Jiangsu, Jiangxi, Fujian, Shanxi and Guizhou. RVA positive status of the samples was detected by RT-PCR. VP7 and VP4 genes of some RVA positive samples were amplified and sequenced, and multiple sequences were compared with various reference sequences. The nucleotide sequence homology analysis was performed by MegAlign, and the phylogenetic evolutionary tree was constructed by the adjacency method of MEGA 7.0.

[Result] RT-PCR results showed that 196 of 434 piglet diarrhea samples were RVA positive, with an detected positive rate of 45.16%. The detected positive rates in 2022 and early 2023 were 40.37% (132/327) and 59.81% (64/107), respectively. According to the regional analysis, the RVA detected positive rate was the highest in Jiangsu (57.70%), followed by Jiangxi (55.71%), the RVA detected positive rates of Fujian, Guizhou and Shanxi were 35.66%, 30.00% and 22.33%. The VP4 and VP7 gene sequences of 12 strains of RVA from different areas were obtained. The results of genetic evolution analysis showed that G9 was the dominant genotype (83.4%), G4 and G5 accounted for 8.3% respectively. In P type, P7 was the dominant genotype (75.0%), followed by P13 and P23, accounting for 16.7% and 8.3% respectively. The 12 RVA strains were classified into four genotypic combinations, namely G9P[7] (75%), G5P[13] (8.3%), G9P[13] (8.3%) and G4P[23] (8.3%).

[Conclusion] The detected positive rate of RVA in pig farms in some provinces of China continues to increase, and the RVA genotypes in pig herds are complex and diverse, and the dominant combination genotype is G9P[7]. Therefore, it is necessary to continuously monitor the prevalence of RVA in pigs, develop preventive measures combined with genotypic pathogenicity, and develop targeted vaccines in the future.

Abstract

摘要：【目的】 探究我国部分地区猪A群轮状病毒 (RVA) 的分子流行病学特征, 明确当前的优势基因型, 为RVA科 学防控与疫苗研发提供理论依据。 【方法】2022年1月—2023年3月收集江苏、江西、福建、山西和贵州5省36个规模化猪 场送检的434份腹泻仔猪粪便样品, 采用RT-PCR检测样品RVA阳性情况, 对部分RVA阳性样品的VP7和VP4基因进行 扩增及测序, 与各型参考序列进行多序列比对, 使用MegAlign进行核苷酸序列同源比对分析, 并采用MEGA 7.0的邻 接法构建系统发育进化树。 【结果】RT-PCR检测结果显示, 434份腹泻仔猪粪便样品中RVA阳性样品为196份, 阳性检 出率为45.16%。2022年与2023年初的阳性检出率分别为40.37% (132/327) 和59.81% (64/107)。根据样品来源地区, RVA阳性检出率最高的是江苏 (57.70%), 其次是江西 (55.71%), 福建、贵州和山西的RVA阳性检出率分别是35.66%、30.00%和22.23%。共获得各地区12株RVA的VP4和VP7基因序列信息, 遗传进化分析结果表明, G型中G9为优势基 因型 (占83.4%), G4和G5分别占8.3%; 而P型中P7为优势基因型 (占75.0%), 其次为P13和P23, 分别占16.7%和8.3%; 12株RVA分属4种基因型组合, 分别为G9P[7] (占75.0%)、G5P[13] (占8.3%)、G9P[13] (占8.3%) 和G4P[23] (占8.3%)。 【结论】我国部分省份猪场RVA阳性检出率持续升高, 猪群中RVA基因型复杂多样, 优势基因型组合为G9P[7]。因 此, 今后有必要对猪群中RVA的流行情况进行持续监测, 结合基因型致病性制定预防措施并开发针对性疫苗。