Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, People's Republic of China.
Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, People's Republic of China.
Vet Microbiol. 2020 Dec;251:108870. doi: 10.1016/j.vetmic.2020.108870. Epub 2020 Sep 29.
Tembusu virus (TMUV) infection most commonly affects breeder and layer ducks during laying period, and can also affect young ducks below 7 weeks of age. Here, we report our investigation of a TMUV-caused fatal disease of Jingding ducklings (Anas platyrhynchos domesticus) in Northeast China. The disease resulted in mortalities of up to 40 % in 2 to 4-week-old ducks, up to 25 % in 5 to 6-week-old ducks, and less than 10 % in 7 to 8-week-old ducks. Using a TMUV-specific reverse transcription-PCR assay, all 44 ducks collected from 10 different farms were found positive for TMUV. Phylogenetic analysis of the E nucleotide sequence revealed that five of the six TMUV strains detected from three young ducks and three laying ducks were grouped within cluster 2.1. Inoculation of the liver sample of a 40-day-old sick duck in BHK-21 cells resulted in isolation of cluster 2.1 TMUV strain H. In experimental infections performed using 3-week-old Pekin ducklings (Anas platyrhynchos domesticus) (n = 30; 10 birds/group), high mortality (60 %) was caused by strain H, in sharp contrast with a very low mortality (10 %) caused by strain Y which was isolated during outbreaks of the TMUV-related disease of young Jinding ducks in 2014 in the same region. These findings clearly demonstrated that the cluster 2.1 TMUV strain H is more pathogenic for 3-week-old ducklings as compared to the cluster 2.2 TMUV strain Y. The present study may enhance our understanding of pathogenicity of TMUV in young ducks, and will stimulate further studies on the pathogenesis of TMUV infection.
腾布苏病毒（TMUV）感染在产蛋期最常影响种鸭和蛋鸭，也可影响 7 周龄以下的雏鸭。在这里，我们报告了在中国东北地区对景定鸭雏鸭（Anas platyrhynchos domesticus）由 TMUV 引起的致命疾病的调查。该病导致 2 至 4 周龄鸭死亡率高达 40%，5 至 6 周龄鸭死亡率高达 25%，7 至 8 周龄鸭死亡率低于 10%。使用 TMUV 特异性逆转录-PCR 检测，从 10 个不同农场收集的 44 只鸭均为 TMUV 阳性。E 核苷酸序列的系统进化分析显示，从 3 只雏鸭和 3 只产蛋鸭中检测到的 6 株 TMUV 中有 5 株属于簇 2.1。用 40 日龄病鸭的肝样接种 BHK-21 细胞，分离出簇 2.1 TMUV 株 H。用 3 周龄北京鸭（Anas platyrhynchos domesticus）进行的实验感染（n = 30；每组 10 只），H 株引起高死亡率（60%），而 2014 年同一地区景定鸭暴发 TMUV 相关疾病时分离的 Y 株引起的死亡率非常低（10%）。这些发现清楚地表明，与簇 2.2 TMUV 株 Y 相比，簇 2.1 TMUV 株 H 对 3 周龄鸭更具致病性。本研究可能有助于我们了解 TMUV 在雏鸭中的致病性，并将刺激对 TMUV 感染发病机制的进一步研究。
