| Summary |
Infectious bronchitis (IB) virus was first isolated in Taiwan in 1964. The isolated viruses were resistent to IUDR treatment, but sensitive to ethyl ether and 0.1 % sodium deoxycholate treatments. Specific intracytoplasmic immunofluorseeence was demonstrated in infected chicken kidney cells by an immunofluorescent assay. The viruses had a typical morphology of coronavirus as demonstrated by an electron microscopy. Exc-ept one isolate, all the other viruses isolated during 1964-1968 belonged to Massachusetts type IB virus according to a cross neutralization test. From 1969 to 1991, a total of 208 IB cases were diagnosed in our Institute. Although IB occurred all year round, it was more often seen in winter. All age and all breeds of chickens were susceptible to IB. Yet, yo-unger birds had higher mortality. Respiratory disease was first observed in 1964 and the nephrosis/nephritis lesions were first observed in 1968 in IB infected chickens. From 1969 to 1991, 89 % of the IB cases had nephrosis/nephritis lesions, and only 65.5 % of the cases had respiratory lesions.
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