| Chicken Ankara disease is an acute infectious disease characterized by pericardial hydrocephalus syndrome caused by avian adenovirus group I serotype 4.In 1987,the disease was found in the Angara Gothic region of Pakistan,so the disease was named with the place name.According to reports at the time,the disease occurred in Faisalabad in the summer of 1988 and then spread to all of Pakistan,causing the death of over 100 million chickens[1].Since then,the disease has been reported in many countries including North American countries,European countries,and Asian countries.In 1997,Ankara disease was introduced to China.Because it did not cause widespread epidemics in China,it did not attract the attention of China's poultry industry [2].However,from 2015 onwards,Ankara disease broke out in many provinces and cities in China,such as Liaoning,Henan,Hebei,Hubei,Jiangsu,Jilin,etc.,causing considerable economic losses to the poultry industry.In this experiment,the chickens suspected of broiler chickens in Jiutai,Hexin,Longjia and other chicken farms in Jilin Province were collected.The liver of the dead chickens was collected.A wild strain was isolated and named as FAd V4-JL16865 strain.DNA was extracted and specific.Primer design,PCR amplification,sequencing and sequence analysis.The liver of the infected chicken was selected for grinding,made into a suspension,repeatedly frozen and thawed three times,centrifuged,and the supernatant was taken.The 9-day-old SPF chicken embryo was inoculated through the allantoic cavity,and passed through three generations to observe the growth of the chicken embryo.Development and death.Then,the third-generation allantoic fluid was inoculated into the 5-day-old SPF chicken embryo to observe the clinical symptoms after the chicken embryo infection,whether it died or not.After 7 days,all the culls were collected,and the heart,liver and other tissues and organs were collected for tissue sectioning.Histopathological damage was observed by HE staining.Then,the biological characteristics of the isolated and identified strains were analyzed.The experiment proved that 10 strains of Ankara virus were isolated from 17 samples isolated from different chicken farms suspected to have chicken Ankara disease in Jilin area.After inoculation of chicken embryos,chicken embryos may be depressed and development slowed down.The phenomenon of death began to appear in the sky.Histological observations showed that the strain isolated in this experiment can cause damage to various tissues such as cardiomyocytes and hepatocytes,such as particle deformation,vacuolar degeneration and necrosis.A well-expressed strain was selected and sequenced and analyzed.According to the phylogenetic tree,the isolated strain had the highest homology with the group A avian adenovirus C subgroup and was identical to the serum type 4 On the branch,it was proved that the strain was chicken Ankara virus.Subsequently,the large-scale farms in Jilin Province were sampled and the epidemic situation survey was carried out.It was found that the FAV4 detection rate was 11.57% among 510 samples.Conclusion: This experiment successfully isolated and identified a chicken Ankara virus,named FAd V4-JL16865 strain,which can cause pathological damage such as hepatitis in chicken embryo,and bring tissue changes to heart and liver,and heat sensitivity and p H of the strain.Sensitivity and detection of physical and chemical properties such as organic solvents,to understand the biological characteristics of the strain;The incidence of the disease survey showed that the FAV4 positive detection rate was 11.57% in 510 samples. |
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