【摘要】 为了解我国黄鸡Ⅰ群禽腺病毒（Fowl adenovirus, FAdV）的流行情况及其致病性，试验于2017—2022年采集东北、西北、华北、华东、华中、华南地区的疑似FAdV感染黄鸡的肝脏、心包积液样本共300份，提取病毒DNA后采用PCR方法对Ⅰ群FAdV进行检测，并根据PCR检测结果分别统计不同品种黄鸡、不同地区、不同月份、不同周龄黄鸡病料样本的Ⅰ群FAdV阳性率；利用鸡肝癌（LMH）细胞从Ⅰ群FAdV阳性病料中分离病毒，并对分离毒株进行遗传进化分析；最后选取发病率高、临床症状典型的分离毒株进行动物回归试验，记录试验鸡的死亡情况和精神、食欲状态，14 d后剖检试验鸡，观察肝脏的病理变化，并取试验鸡的肝脏，制作组织切片，于显微镜下观察。结果表明：300份病料样本中，有164份为Ⅰ群FAdV阳性，阳性率为54.67%;不同品种黄鸡中，黄羽肉鸡阳性率（85.96%）最高，然后依次为三黄鸡（41.33%）、麻黄鸡（37.21%）、黄油肉鸡（33.33%）,矮脚黄鸡阳性率（22.86%）最低；不同地区中，华东地区阳性率（94.00%）最高，然后依次为华中地区（86.00%）、华北地区（58.00%）、东北地区（46.00%）地区，西北地区和华南地区阳性率（22.00%）最低；不同月份中，1月份阳性率（76.67%）最高，然后依次为7月份（64.58%）、9月份（62.50%）、8月份（56.52%）、3月份（41.46%）、6月份（29.17%）,12月份（27.27%）、10月份（18.18%）和11月份（18.18%）阳性率较低；随着周龄的增大，阳性率呈先升高后降低的趋势，其中4～6周龄为感染高发期，阳性率（分别为64.41%、76.71%、60.38%）较高。共分离到26株Ⅰ群FAdV,分离毒株无菌检验、支原体检验结果均合格，病毒效价在1×10^5.1TCID₅₀/mL～1×10^8.6TCID₅₀/mL之间。经遗传进化分析可知，在26株Ⅰ群FAdV中，E种FAdV-8b有10株，E种FAdV-8a有9株，C种FAdV-4有1株，A种FAdV-1、D种FAdV-11、D种FAdV-2各有1株。另有3株属于C种，血清型未确定。动物回归试验中，接种3株分离毒株（FAdV-4分离菌株HZ220538、FAdV-8a分离菌株SD220651和FAdV-8b分离菌株HZ2212149）24 h后，试验鸡均表现为精神沉郁、食欲不振、被毛杂乱。接种HZ220538的试验鸡168 h后死亡率为90%,剖检后肝脏呈浅褐色“花斑肝”、边缘坏死、质地变脆、表面有明显出血点；组织切片中大量肝细胞脂肪变性，胞质可见圆形小泡，汇管区周围偶见肝细胞小灶性坏死，胞核碎裂或溶解，胞质嗜酸性增强，有少量血管淤血。接种SD220651和HZ2212149的试验鸡虽未发生死亡，但接种SD220651的试验鸡肝脏呈浅褐色、质地变脆、表面有散在出血点，接种HZ2212149的试验鸡肝脏呈深褐色，边缘坏死，二者组织切片中肝实质及汇管区周围均见淋巴细胞小灶性浸润。说明近年来Ⅰ群FAdV中FAdV-8b和FAdV-8a为我国黄鸡群主要流行血清型，但其分离毒株致病性较FAdV-4分离毒株弱。更多还原

【Abstract】 In order to understand the prevalence and pathogenicity of fowl adenovirus（FAdV） Group I in Yellow chickens in China, in the experiment, a total of 300 liver and pericardial effusion samples were collected from suspected FAdV-infected Yellow chickens from Northeast, Northwest, North China, East China, Central China, and South China from 2017 to 2022. Viral DNA was extracted and PCR was used to detect FAdV. According to the PCR results, the positive rate of Yellow chicken samples of different breeds, different regions, different months and different weeks of age were counted respectively. The virus was isolated from FAdV Group Ⅰ positive disease materials using chicken hepatocellular carcinoma（LMH） cells, and the isolates were analyzed for genetic evolution. Finally, the isolates with high incidence and typical clinical symptoms were selected for the animal regression test; the death of the test chickens and their mental and appetite status were recorded. After 14 d, the test chickens were dissected to observe the pathological changes in the liver. The liver of the test chicken was taken; tissue sections were made, and the pathological changes were observed under the microscope. The results showed that 164 out of 300 diseased samples were FAdV positive, with a positive rate of 54.67%. Among different breeds of Yellow chicken, the positive rate of Yellow-Feathered broiler（85.96%） was the highest, followed by Three-Yellow chicken（41.33%）, Sesame chicken（37.21%）, Butterflying broiler（33.33%）, and the positivity rate of Dwarf Yellow chicken（22.86%） was the lowest. Among different regions, East China had the highest positive rate（94.00%）, followed by Central China（86.00%）, North China（58.00%） and Northeast China（46.00%）; South China and Northwest China had the lowest positive rate（both 22.00%）. Among different months, the highest positive rate was found in January（76.67%）, followed by July（64.58%）, September（62.50%）, August（56.52%）, March（41.46%）, June（29.17%）, and the lower positive rates were in December（27.27%）, October（18.18%） and November（18.18%）. As the age of week increased, the positive rate of Yellow chicken showed a tendency of increasing and then decreasing, with 4-6 weeks of age being the high infection period and the positive rate was higher, which was 64.41%, 76.71% and 60.38%, respectively. A total of 26 strains of FAdV Group I were isolated, and the results of sterility test and Mycoplasma test of the isolated strains were qualified; the viral titers ranged from 1×10^5.1 TCID₅₀/mL to 1×10^8.6 TCID₅₀/mL. Genetic evolution analysis showed that in 26 strains of Group I FAdV,there were 10 strains of FAdV-8b of species E,9 strains of FAdV-8a of species E, 1 strains of FAdV-4 of species C, each 1 strain of FAdV-1 of species A, FAdV-11 of species D, and FAdV-2 of species D. The other isolates belonged to species C but the serotype was not determined.In the animal regression test, 24 h after inoculation with the three isolates（FAdV-4 isolate HZ220538,FAdV-8a isolate SD220651 and FAdV-8b isolate HZ2212149）, the chickens showed depression, loss of appetite, and disorganized coat. The mortality rate of the test chickens inoculated with HZ220538 was 90% in 168 h; after autopsy, the liver showed light brown “blotchy liver”, necrotic margins, brittle texture, and obvious hemorrhagic spots on the surface; in the tissue section, a large number of hepatocytes were steatotic, with rounded vesicles in the cytoplasm, occasional small foci of hepatocyte necrosis around the confluence area, fragmented or lysed nuclei, increased cytoplasmic eosinophilicity, and a small amount of vascular stasis. Although no deaths occurred in the chickens inoculated with SD220651 and HZ2212149, the livers of the chickens inoculated with SD220651 were light brown in color, brittle, and had scattered hemorrhagic spots on the surface. The livers of test chickens inoculated with HZ2212149 were dark brown with necrotic margins; small focal infiltrations of lymphocytes were seen around the liver parenchyma and the confluent area in both tissue sections. These results indicated that FADV-8b and FADV-8a of group I FAdV were the main prevalent serotypes in Chinese yellow chickens in recent years, but their isolates were less pathogenic than the FAdV-4 isolates.更多还原