科研動態(tài)

為了解雞傳染性支氣管炎病毒（IBV）在我國的流行規(guī)律，通過RT-PCR方法，對2019—2021年從我國29個省級行政區(qū)送檢的38 442份疑似IBV感染樣品進行病原檢測和鑒定，對檢出的陽性樣品進行S1基因測序分型，然后對檢測結(jié)果進行時間、空間和群間統(tǒng)計分析。結(jié)果顯示：共檢出6 436份IBV陽性樣本，陽性檢出率為16.7%。2019—2021年的IBV陽性檢出率分別為12.5%、16.4%、21.0%，呈逐年增長趨勢：陽性檢出率呈現(xiàn)一定的季節(jié)性變化特點，7—9月檢出率（11.3%~15.4%）較低，而3—6月（17.3%~19.3%）和10—12月（17.5%~19.0%）較高。全國29個省級行政區(qū)中有27個檢出陽性樣品，其中東部和中部家禽養(yǎng)殖密集區(qū)陽性檢出率較高，而西部和北部地區(qū)較低。白羽肉雞陽性檢出率最高（28.9%），肉種雞陽性檢出率最低（5.0%），0~6周齡階段IBV感染較為嚴重。共檢出5種基因型，其中QX型（66.5%）、GVI型（27.7%）占比較高，為當前流行的優(yōu)勢基因型；不同品種雞群中流行的基因型存在一定差異，白羽肉雞群中以QX和GVI型為主，而其他雞群中流行的基因型較為復雜；QX型0~3周齡（33.2%）、GVI型3~6周齡（66.4%）陽性檢出數(shù)量占比較高，6周齡以后占比均較低（＜14.0%）。結(jié)果表明：我國雞群中IBV感染普遍，尤其是家禽養(yǎng)殖密集區(qū)，且流行呈逐年加重趨勢；冬春或秋冬季節(jié)多發(fā)，小日齡雞群感染嚴重；流行基因型復雜，以QX型和GVI型多見。結(jié)果提示，我國的IB防控面臨較大壓力與挑戰(zhàn)，需要加強優(yōu)勢基因型疫苗的研發(fā)，重點做好小日齡雞群的IB防控。

Epidemiological Investigation on Avian Infectious Bronchitis in 29 Provincial Administrative Regions of China from 2019 to 2021

In order to identify the prevalence rule of avian infectious bronchitis virus（IBV）in China，38 442 samples with suspected IBV infection submitted by 29 regions at provincial levels from 2019 to 2021 were detected and identified by RT-PCR. The S1 genes of positive samples were sequenced and typed，and then the results were statistically analyzed from the aspects of time，space and intergroup. The results showed that 6 436 IBV positive samples were detected，with the positive detection rate of 16.7%.The positive detection rates of IBV for the three years were 12.5%，16.4% and 21.0% respectively，tending to increase year by year：the positive detection rate changed with seasons to certain extent，which was lower from July to September（11.3% to 15.4%），and higher from March to June（17.3% to 19.3%）and October to December（17.5% to 19.0%）. Positive samples were detected from 27 out of 29 regions，the detection rates were higher in intensive poultry areas in the eastern and central regions，and lower in the western and northern regions. The detection rate of white feather broilers was highest（28.9%），and that of broiler breeders was lowest（5.0%）. The infection with IBV was more serious in chickens at the age of 0~6 weeks. Five genotypes were detected，especially QX（66.5%）and GVI（27.7%）that were dominant genotypes；the prevalent genotypes were different in different breeds，QX and GVI were the main genotypes in white feather broiler flocks，while the prevalent genotypes were complex in other flocks；the positive rates of QX and GVI were higher in the flocks at 0 to 3 weeks old（33.2%）and 3 to 6 weeks old（66.4%），and lower in those at more than 6 weeks old（＜14.0%）. In conclusion，IBV was widely distributed in chicken flocks in China，especially in intensive areas where the prevalence tended to increase year by year；it occurred frequently in winter，spring or autumn，and was serious in the flocks at young day old；the prevalent genotypes were complex，especially QX and GVI were common. In conclusion，there was a huge pressure and challenge to prevent and control IB in China，thus it was necessary to strengthen the development of vaccines of dominant virus genotypes，and a priority should be given to IB control of chicken flocks at young day old.

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