Raw data of "Novel avian metapneumovirus subtype C variant is a newly emerged pathogen causing hydrosalpinx fluid syndrome in Sheldrake ducks in China"

Since 2021, an epidemic disease characterized with hydrosalpinx fluid syndrome (HFS) has been circulating in the laying Sheldrake ducks in China, which seriously endangers the healthy development of the duck industry. The causative agent of this disease has been traced to avian metapneumovirus subtype C (aMPV/C), known to cause acute upper respiratory tract infections and egg-drop in poultry. To date, no reports have been made to isolate and characterize aMPV/C infection in Sheldrake ducks in China. Here, a strain of virus, designated aMPV-FJ21, was successfully isolated from the diseased ducks exhibiting HFS. Transmission electron microscopy revealed that the virus is an enveloped particle with a spherical or pleomorphic morphology. Indirect immunofluorescence assays demonstrated that the aMPV-FJ21 strain had an obvious reactive activity with the ploy-antibody against aMPV/C F protein. The complete genome of aMPV-FJ21 was determined to be 14,149 nucleotides in length. Notably, the G protein of this strain showed only 55.6%-78.7% identical to that of other aMPV/C reference strains. Phylogenetic analysis indicated that aMPV-FJ21 forms a distinct lineage within the aMPV/C group and is genetically distant from the North American and Eurasian lineages, suggesting that it may represent a novel genetic lineage. In vivo infection of laying Sheldrake ducks with aMPV-FJ21 reproduced the typical clinical symptoms and pathological lesions observed in the original infected cases. Altogether, we had isolated a novel aMPV/C variant from Sheldrake ducks exhibiting HFS, distinct from previously reported strains, and provided the first evidence confirming its role as the causative agent of HFS in ducks.

自2021年以来，一种以输卵管积液液综合征（hydrosalpinx fluid syndrome, HFS）为特征的传染病在中国产蛋翘鼻麻鸭群中流行，严重威胁了鸭产业的健康发展。该病的病原已被追溯为禽偏肺病毒C亚型（avian metapneumovirus subtype C, aMPV/C），该病毒可导致禽类发生急性上呼吸道感染并引发产蛋下降。截至目前，中国境内尚未见从翘鼻麻鸭中分离并鉴定aMPV/C感染的相关报道。本研究从表现出HFS症状的病鸭中成功分离到一株病毒，将其命名为aMPV-FJ21。透射电子显微镜观察显示，该病毒为有包膜的球形或多形性颗粒。间接免疫荧光试验结果表明，aMPV-FJ21株与针对aMPV/C F蛋白的多克隆抗体具有显著的反应活性。aMPV-FJ21的完整基因组长度为14149个核苷酸。值得注意的是，该毒株的G蛋白与其他aMPV/C参考毒株的同源性仅为55.6%~78.7%。系统发育分析结果显示，aMPV-FJ21在aMPV/C群中形成了一个独立的进化分支，且与北美及欧亚进化分支遗传距离较远，提示其可能代表一个全新的遗传进化分支。用aMPV-FJ21人工感染产蛋翘鼻麻鸭，成功复刻了自然感染病例中出现的典型临床症状与病理损伤。综上，本研究从表现出HFS症状的翘鼻麻鸭中分离到一株与此前报道毒株均不同的新型aMPV/C变异株，并首次证实其为鸭群中HFS的病原。