The objective of this study was to evaluate the circulation of Chicken Anemia Virus (CAV), Infectious Bursal Disease Virus (IBDV), Avian Reovirus (ARV) and Avian Encephalomyelitis virus (AEV) in properties of backyard...The objective of this study was to evaluate the circulation of Chicken Anemia Virus (CAV), Infectious Bursal Disease Virus (IBDV), Avian Reovirus (ARV) and Avian Encephalomyelitis virus (AEV) in properties of backyard chickens and carry out an epidemiological analysis. We evaluated 200 samples of chickens from 19 backyard chicken property. Only one property (P10) did not present serological titers for the diseases evaluated. This property is close to industrial farms as well as the other properties, however, P10 remained a few years without the breeding of chicks and these were the first poultry to be housed on site. This reinforces the importance of the fallow period for poultry production. The prevalence of virus-seroreactive birds was 78% (156/200), 64.5% (129/200), 78% (156/200), 78% (156/200) for CAV, IBDV, ARV and, EA, respectively. All the free-range farms studied are within a radius of 500 meters to 6 Km away from some establishments of industrial poultry. There was a correlation between serological titers for CAV and the frequency of disease in poultry (r = 0.6178). In places where birds are frequently sick, 30.76% reported that the disease occurs in chicks, 30.76% in broilers, 23.07% in broiler chickens and 7.69% in birds of all ages. Birds get sick more often in the summer period. The owners reported that the most common signs of disease were respiratory signs (snoring and nasal discharge) (46.15%), diarrhea (30.76%), and paralysis of wings and/or paws (38.46%). There was a correlation between the presence of untreated water in the property and serological titers for ARV (r = 0.5576). This report draws attention not only to high serological prevalence for the viruses studied but also important epidemiological aspects of backyard chicken diseases that may indirectly influence the industrial production.展开更多
Avian reovirus(ARV) has been responsible for many cases of chicken tenosynovitis in China in recent years,causing high morbidity among layer and broiler chickens.To study the degree of genetic divergence and evolution...Avian reovirus(ARV) has been responsible for many cases of chicken tenosynovitis in China in recent years,causing high morbidity among layer and broiler chickens.To study the degree of genetic divergence and evolution among ARVs,the fulllength nucleotide sequences of the σC-encoding gene of eight ARV field isolates and the entire coding-region sequences of four isolates were determined and analyzed.The sequence analysis revealed that the eight aC-encoding genes shared99.0-99.9%nucleotide sequence identity with each other and over 99%with the chicken reovirus reference strain S1133.However,the nucleotide sequences of the eight aC-encoding genes varied extensively from that of isolate AVS-B(GenBank accession no.FR694197),with only 55.5%identity.A sequence analysis of the whole ARV-coding region showed some nucleotide substitutions in the open reading frames encoding AA,AB,AC,uA,uB,uNS,aC,aA,aB,and aNS in the field strains.A phylogenetic analysis showed that all eight isolates clustered in group I with S1133,but that four field isolates shared less homology with strain S1133 than the others,indicating that they had been evolved in the field.We also studied the pathogenicity of two strains.No characteristic lesions were observed in vaccinated chickens,and no virus was detected in sampled tissues.However,an enzyme-linked immunosorbent assay revealed significant differences between the antibody responses of the inoculated groups and the negative controls.These results revealed that Chinese isolates shared the highest sequence homologies with S1133,grouped together in one cluster.Although the vaccination against ARV is used in farms,the pathogens still persist in Chinese poultry flocks.展开更多
文摘The objective of this study was to evaluate the circulation of Chicken Anemia Virus (CAV), Infectious Bursal Disease Virus (IBDV), Avian Reovirus (ARV) and Avian Encephalomyelitis virus (AEV) in properties of backyard chickens and carry out an epidemiological analysis. We evaluated 200 samples of chickens from 19 backyard chicken property. Only one property (P10) did not present serological titers for the diseases evaluated. This property is close to industrial farms as well as the other properties, however, P10 remained a few years without the breeding of chicks and these were the first poultry to be housed on site. This reinforces the importance of the fallow period for poultry production. The prevalence of virus-seroreactive birds was 78% (156/200), 64.5% (129/200), 78% (156/200), 78% (156/200) for CAV, IBDV, ARV and, EA, respectively. All the free-range farms studied are within a radius of 500 meters to 6 Km away from some establishments of industrial poultry. There was a correlation between serological titers for CAV and the frequency of disease in poultry (r = 0.6178). In places where birds are frequently sick, 30.76% reported that the disease occurs in chicks, 30.76% in broilers, 23.07% in broiler chickens and 7.69% in birds of all ages. Birds get sick more often in the summer period. The owners reported that the most common signs of disease were respiratory signs (snoring and nasal discharge) (46.15%), diarrhea (30.76%), and paralysis of wings and/or paws (38.46%). There was a correlation between the presence of untreated water in the property and serological titers for ARV (r = 0.5576). This report draws attention not only to high serological prevalence for the viruses studied but also important epidemiological aspects of backyard chicken diseases that may indirectly influence the industrial production.
基金supported by the China Animal Disease Prevention and Control Centerthe China Agriculture Research System Poultry-Related Science and Technology Innovation Team of Peking, China (CARS-PSTP)
文摘Avian reovirus(ARV) has been responsible for many cases of chicken tenosynovitis in China in recent years,causing high morbidity among layer and broiler chickens.To study the degree of genetic divergence and evolution among ARVs,the fulllength nucleotide sequences of the σC-encoding gene of eight ARV field isolates and the entire coding-region sequences of four isolates were determined and analyzed.The sequence analysis revealed that the eight aC-encoding genes shared99.0-99.9%nucleotide sequence identity with each other and over 99%with the chicken reovirus reference strain S1133.However,the nucleotide sequences of the eight aC-encoding genes varied extensively from that of isolate AVS-B(GenBank accession no.FR694197),with only 55.5%identity.A sequence analysis of the whole ARV-coding region showed some nucleotide substitutions in the open reading frames encoding AA,AB,AC,uA,uB,uNS,aC,aA,aB,and aNS in the field strains.A phylogenetic analysis showed that all eight isolates clustered in group I with S1133,but that four field isolates shared less homology with strain S1133 than the others,indicating that they had been evolved in the field.We also studied the pathogenicity of two strains.No characteristic lesions were observed in vaccinated chickens,and no virus was detected in sampled tissues.However,an enzyme-linked immunosorbent assay revealed significant differences between the antibody responses of the inoculated groups and the negative controls.These results revealed that Chinese isolates shared the highest sequence homologies with S1133,grouped together in one cluster.Although the vaccination against ARV is used in farms,the pathogens still persist in Chinese poultry flocks.
