| Chicken hydrocardic syndrome(Hydropericardium Syndrome,HPS),also known as chicken Ankara disease,is a type of avian infectious diseases caused by infection with Fowl Adenovirus serotype 4(FAV-4),with pericardial effusion and inclusion body hepatitis as the main clinical symptoms.In 2015,after the first outbreak of HPS in Shandong,Jiangsu,et al.,the disease is rapidly spreading in our country,with a mortality rate as high as 20% to 80%,which seriously threatens the development of China’s poultry industry.Therefore,understanding the prevalence of HPS in various regions of China,separating local epidemic strains,and making out treatment strategy is of great significance for effective prevention and control of the disease.This study investigated the prevalence of HPS in Changchun and conducted a preliminary screening for the isolation and identification of pathogens and therapeutic scheme,in order to provide data support and experimental basis for epidemic situation and comprehensive prevention and control of HPS in Changchun,Jilin Province.First,this research using a specific PCR for FAV-4,survey on incidence of HPS in 499 cases from 36 farms in Changchun City and surrounding areas from January to December in 2017 in Jilin Province was carried on.The results showed that of 499 samples,63 were HPS positive with rate 12.63%.Among them,there was no difference in the detection rate of HPS between white broilers and commercial hens.The positive rate of HPS in different regions was 10.98% to 15.38%;in the first quarter(January to March),the positive rate of HPS was lowest for 8.42%.From the second quarter to the fourth quarter(April to December),the positive rate of HPS was roughly the same,ranging from 12.63 to 15.00%.The highest positive rate of HPS in white feather broilers over 40 days old was 19.64%.For commercial laying hens,the positive rate(3.45%)was the lowest at 1 to 30 days old;the positive rate at 60 days old(31.11%)The analysis showed that the incidence of HPS was significantly correlated with the age of chickens instead of region,quarter,and breeds.Secondly,a virus was isolated from the livers of diseased chickens from a farm using a allantoic cavity inoculation method,and was tentatively designated as JLNA strain.The isolates were identified by PCR,phylogenetic analysis and animal spathological examination.In addition,a preliminary screening of five medication schemes was conducted on the farm.The results showed that after inoculating chicken embryos,the dead embryos were reduced in size;the head,wings,and leg muscles were bleeding;the virus was identified as FAV-4 by PCR.Genetic phylogenetic tree shows that the JLNA strain shares high homology with domestic FAV-4 isolates(99.8%~100%).The isolates that infected 34 d white broiler chickens caused pericardial effusion,renal swelling hemorrhage,andswollen and hemorrhagic liver,further proving to be FAV-4.In addition,the preliminary screening results of the drug regimens showed that the average daily mortality rate of chickens after treatment with Protocol 5(Chinese and Western medicine combination)was reduced to0.10%,and the large group achieved significant therapeutic effects.The results of this study indicate that HPS infect laying hens more than 30~60d and broilers more than 20~40d,mainly from April to December.The use of angelica,ginseng,glycyrrhiza,mugwort leaf,florfenicol,doxycycline hydrochloride and tilmicosincan significantly reduce the mortality rate of chicken HPS. |
PDF Full Text Request