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Avian Infectious Bronchitis (infectious bronchitis, IB) is caused by the avian infectious bronchitis virus (IBV) chicken an acute, highly contagious disease. Virus serotypes is complex, due to the clinical manifestations of the disease vary widely, the main symptoms are difficulty breathing, egg drop, nephritis and glandular stomach go far. In recent years, the prevalence of IB is rising, especially kidney and proventriculus type avian infectious bronchitis occurred, supplies poultry industry causing huge economic losses. The virus genome is a linear, non-segmented, single-stranded positive strand RNA, the full-length 27.6kb, the major structural protein of the spike (S) protein, membrane (M) protein and nucleocapsid (N) protein, in which the sole located membrane consisting of 409 amino acids consisting of N protein, capable of specifically binding to the boot on the RNA, to participate in the replication, transcription and translation of the viral RNA. In the past, people IBV research mainly concentrated on the S1 gene, the N gene is highly conserved in the evolution of IBV; However, in recent years, the study found that the N gene also exists a wide range of variation, and the distribution of these variants in epitopes and functional areas certain biological characteristics, indicative of different strains of N gene variation may lead to the virus changed. Province Putian some kind of Muscovy duck farm disease in December 2008: The sharp drop in peak egg production Muscovy duck egg, egg production rate decreased from 85% to 30% to 40%, after gradually recovered after two months to 60 % decline in egg quality, soft shell eggs, deformed eggs increased hatchability sick muscovy duck accompanied by a transient respiratory symptoms, the mortality rate is very low, the necropsy incidence of Muscovy duck found theca congestion, other solid organ lesions. Take sick muscovy duck ovarian tissue for virus isolation (strain named PTFY strains), chick embryo passage, physical and chemical characteristics of the test, hemagglutination test, electron microscopy, and sequencing contrast the identification PTFY strains of IBV, the results are as follows: 1, 9 day-old SPF chicken passage, the 5th generation dwarf embryo allantoic cavity of a large number of white floc deposition. Physicochemical properties test and found that by chloroform, ether, sodium deoxycholate treatment of the virus, the infectivity is reduced. Electron microscopy negative staining virus particle diameter of 100 nm capsule, slightly spherical, the sac membrane visible petals like Spike, in line with the characteristics of coronavirus. 2, taking the 5th generation allantoic fluid was measured after different time titer of hemagglutination using 1% trypsin treatment, found hemagglutination price with trypsin digestion the time prolonging improve, 4h highest, followed in a steady state; different culture (36h, 48h, 72h, 96h, 120h) chick embryo allantoic fluid, treated with 1% trypsin measured the hemagglutination price, found that the the hemagglutination price increase with prolonged incubation time. 3, the virus solution through the eye, intranasal SPF chickens infected, began three days the breathing difficult mental Weidun. Clinical symptoms. Necropsy not obvious characteristic lesions. The control group without exception. Taken after kidney tissue detected by RT-PCR, prove IBV. 4 the PTFY strains of Newcastle disease virus interference test, found PTFY strains of Newcastle disease virus replication inhibition. 5, the 5th generation allantoic fluid with tracheal ring culture infectivity determination obtained its the TOC-ID50 = 10-5.413/0.1ml; save PTFY strains of the laboratory strains of PT serum neutralization test learned that the antigen low correlation between the two. 6, the reference GenBank IBV strains (GenBank: DQ001338.1), primers were designed by reverse transcription-polymerase chain reaction (Reverse-translation polymerase-chain reaction, RT-PCR) amplification product of 600bp fragment by sequencing than found with the homology of the American Journal of Respiratory virulent strain Mass41 97.3%, Shandong kidney-type strains CK/CH/LSD/03I homology to 99%, and 97.8% homology with H52 confirmed PTFY strains for the IBV. 7, with DNAstar, DNAman analysis software, the PTFY isolates N gene fragment (345 to 945), 14 domestic and foreign amplification product sequences in GenBank reference strains for nucleotide sequence comparison and homology analysis, drawing out the evolutionary tree, the nucleotide sequence of the system derived nucleotide sequence homology, evolutionary tree branch status not necessarily linked with viral tropism and virulence. This test to a virus strain isolated from Muscovy duck ovarian (named PTFY) after the identification of the chick embryo passage, the physical and chemical properties, electron microscopy, sequencing contrast IBV IBV can infect waterfowl. Seen not only terrestrial poultry such as chickens, peacocks IBV pathogenicity, infectious waterfowl (muscovy duck).
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