禽腺病毒血清4型Y17215-1株对SPF鸡胚及SPF鸡的致病性研究

Pathogenicity of fowl aviadenovirus serotype 4 Y17215-1 strain on SPF chicken embryos and SPF chickens

为了探究一株禽腺病毒血清4型(FAdV-4)天津分离株Y17215-1对SPF鸡胚及SPF鸡的致病力,试验将Y17215-1株(病毒效价为1×10^(6.5) TCID_(50)/0.1 mL)经卵黄囊和尿囊膜两种接种途径分别接种6,10日龄SPF鸡胚,经滴鼻点眼和肌肉注射两种途径分别接种7,14,21日龄的SPF鸡,观察SPF鸡胚死亡情况和病理变化情况,统计SPF鸡发病死亡情况,检测试验鸡不同组织及不同采集时间的泄殖腔中的病原,观察试验鸡的临床病变和组织病理学变化。结果表明:两种接种途径均可致鸡胚死亡,经卵黄囊途径接种致死的鸡胚可见胚体全身出血,经尿囊膜途径接种致死的鸡胚尿囊膜明显增厚;两种接种途径均可引起不同日龄SPF鸡发病和死亡,且肌肉注射组试验鸡较滴鼻点眼组试验鸡发病快、病程短,致死率高,发病鸡临床表现为精神沉郁、采食量明显下降、排黄绿色粪便。心脏、肝脏、脾脏、肺脏、肾脏、腺胃等器官病原检测结果均为阳性,各试验组的泄殖腔拭子样品在感染后第2天即可检测到FAdV-4。剖检可见典型的心包积水、肝脏肿大、肾脏肿大等病变,肝细胞内有嗜酸性包涵体。说明FAdV-4天津分离株Y17215-1对鸡胚及鸡具有较高致病性。

In order to explore the pathogenicity of an isolate of Fowl aviadenovirus serotype 4(FadV-4) Tianjin strain Y17215-1 to SPF chicken embryos and SPF chickens, in the experiment, strain Y17215-1(virus titer of 1×10^(6.5)TCID_(50)/0.1 mL) was inoculated into SPF chicken embryos of 6 and 10 days old respectively through the yolk sac and allantoic membrane, and SPF chickens of 7, 14, and 21 days old respectively through intranasal-eye dropping and intramuscular inoculation. The death and pathological changes of SPF chicken embryos were observed;the incidence and death of SPF chickens were counted;the pathogens were detected in different tissues and the cloaca of different collection times of the experimental chickens, and clinical lesions and histopathological changes of the experimental chickens were observed. The results showed that both inoculation routes could cause the death of chicken embryos;whole body hemorrhage could be seen in the dead chicken embryos by inoculation via the yolk sac route, and the allantoic membrane of dead chicken embryos was significantly thickened by inoculation via the allantoic membrane. Both inoculation routes could cause morbidity and mortality in SPF chickens of different ages;the test chickens in the intramuscular injection group had faster onset, shorter course of disease, and higher mortality than those in the intranasal-eye dropping group;the clinical manifestations of the diseased chickens were depression, significantly decreased feed intake, and discharge of yellow-green feces. The heart, liver, spleen, lung, kidney, glandular stomach and other organs were tested positive for the pathogen;FAdV-4 could be detected on the 2 nd day after infection in cloacal swab samples of each experimental group;Necropsy showed typical lesions such as hydropericardium, hepatomegaly, and kidney enlargement, and eosinophilic inclusions in hepatocytes. The results suggested that FAdV-4 Y17215-1 isolate had high pathogenicity to chicken embryos and chickens.