Abstract
Recently, the major viral diseases, Newcastle disease (ND), infectious bronchitis (IB), low pathogenic avian influenza (LPAI), avian pneumovirus infection (APV), Marek's disease (MD) and infectious bursal disease (IBD), have led to huge economic losses in chicken industry of Korea. To evaluate prevalence of the major viral disease infections in broiler breeder and broiler farms, epidemiological survey has been conducted in Jeonbuk province from 2005 to 2007 by serological ELISA test for APV, PCR for MD, and RT-PCR for ND, IB, LPAI and IBD, respectively. A total of 424 cases was submitted to our laboratory for diagnosis of the major viral disease from broiler breeder and broiler farms in the above period. The diagnosed results were analysed for the detection rate of infections on basis of years, seasons and ages, respectively. This study was showed that the detection rates of ND and APV were considerably high for every years regardless of seasons and ages in both broiler breeder and commercial broiler. In comparison with detection rates of ND and APV, IB and LPAI were lower but detected around 10% for every years. Especially, detection rate of IB was significantly high in commercial broiler than in broiler breeder. Therefore, to minimize economic losses for broiler breeder and broiler farms, it will need for effective countermeasures to decrease detection rate of the viral respiratory diseases. Although the detection rates of MD and IBD were gradually decreased from 2005 to 2007 in both broiler breeder and commercial broiler, it will continually make an effort about disease control for increasing productivity in chicken industry.