Detection and molecular characterization of chicken parvovirus and chicken megrivirus in layer breeders affected by intestinal dilatation syndrome

Intestinal dilatation syndrome (IDS) is a segmental enteropathy characterized by dilatation of the junction of the ileum and jejunum (Meckel’s diverticulum). IDS severely affects the poultry industry by causing a chronic and irreversible drop in egg laying, reducing feed conversion efficiency, and increasing the mortality rate. The clinical and pathological features of IDS in white laying hens were described, and viral molecular and metagenomic research was conducted. The 50 – to 60-day-old chickens presented pale mucosa, apathy, depression, ruffled feathers, and diarrhoea, accompanied by a 20% loss in fertile egg production, 20% culling of birds, and 5% mortality. The main findings at necropsy were marked intestinal dilatation with intestinal stasis, a narrow distal jejunum in the region of Meckel's diverticulum, and undigested food. Microscopic analysis revealed marked atrophic lymphoplasmacytic and heterophilic enteritis with hyperplastic crypts, ulceration, and heterophilic and lymphoplasmacytic perineuritis. The molecular assays consistently detected the presence of chicken parvovirus in the three segments of the intestine, pancreas, and proventriculus, as well as chicken megrivirus in the intestinal contents. Marked atrophic enteritis with perineuritis and intestinal stasis were associated with clinical manifestations of poor intestinal absorption and secondary bacterial infection. Our data provide useful information about IDS and highlight the importance of further studies to determine the specific role of each detected virus in this syndrome. IDS presented pathognomonic dilatation of the jejunum up to Meckel's diverticulum.IDS caused weight loss, decreased egg production, and increased culling and mortality.Chicken parvovirus (ChPV) was consistently detected through PCR assays.Chicken megrivirus (ChMV) was consistently detected through viral metagenomics. IDS presented pathognomonic dilatation of the jejunum up to Meckel's diverticulum. IDS caused weight loss, decreased egg production, and increased culling and mortality. Chicken parvovirus (ChPV) was consistently detected through PCR assays. Chicken megrivirus (ChMV) was consistently detected through viral metagenomics.

肠道扩张综合征（Intestinal dilatation syndrome, IDS）是一类节段性肠病，以回肠与空肠交界处（梅克尔憩室，Meckel’s diverticulum）的扩张为典型特征。该综合征可引发产蛋量慢性且不可逆的下降、饲料转化效率降低以及死亡率升高，对家禽养殖业造成严重负面影响。本研究对白羽产蛋鸡的肠道扩张综合征临床与病理特征进行了系统描述，并开展了病毒分子生物学及宏基因组学相关研究。
50~60日龄的患病鸡只表现为黏膜苍白、精神沉郁、羽毛蓬乱及腹泻，同时伴随20%的可育产蛋量损失、20%的鸡只淘汰率以及5%的死亡率。尸检可见的主要病变为明显的肠道扩张伴肠淤滞、梅克尔憩室区域的空肠远端狭窄，以及未消化食物残留。镜检结果显示存在显著的萎缩性淋巴浆细胞性与异嗜性肠炎，伴隐窝增生、溃疡形成，以及异嗜性和淋巴浆细胞性神经周围炎。
分子生物学检测可在肠道三段、胰腺及腺胃（proventriculus）中稳定检出鸡细小病毒（chicken parvovirus），同时在肠内容物中检出鸡megrivirus（chicken megrivirus）。显著的萎缩性肠炎伴神经周围炎及肠淤滞，与肠道吸收不良及继发细菌感染的临床表现密切相关。本研究数据为肠道扩张综合征的相关研究提供了有价值的参考，并强调了开展进一步研究以明确本次检出的各病毒在该综合征中具体作用的重要性。
空肠至梅克尔憩室区域可见特征性的肠道扩张。该综合征可导致体重下降、产蛋量降低以及淘汰率与死亡率升高。鸡细小病毒（chicken parvovirus, ChPV）可通过聚合酶链反应（Polymerase Chain Reaction, PCR）稳定检出。鸡megrivirus（chicken megrivirus, ChMV）可通过病毒宏基因组学稳定检出。
空肠至梅克尔憩室区域可见特征性的肠道扩张。该综合征可导致体重下降、产蛋量降低以及淘汰率与死亡率升高。鸡细小病毒（ChPV）可通过聚合酶链反应（PCR）稳定检出。鸡megrivirus（ChMV）可通过病毒宏基因组学稳定检出。