Risk factors for infectious bronchitis virus infection in laying flocks in three provinces of Korea: preliminary results

  • Pak, Son-Il (College of Veterinary Medicine, Kangwon National University) ;
  • Kwon, Hyuk-Moo (College of Veterinary Medicine, Kangwon National University) ;
  • Yoon, Hee-Jun (College of Veterinary Medicine, Kangwon National University) ;
  • Song, Chang-Sun (College of Veterinary Medicine, Konkuk University) ;
  • Son, Young-Ho (College of Veterinary Medicine, Konkuk University) ;
  • Mo, In-Pil (College of Veterinary Medicine, Chungbuk National University) ;
  • Song, Chi-Yong (Boram Animal Hospital)
  • Accepted : 2005.08.22
  • Published : 2005.09.22


To analyze and identify selected risk factors for infectious bronchitis virus (IBV) infection in the growing and laying period of laying-hen flocks, a longitudinal field study was conducted with 27 commercial flocks reared in three provinces of Korea during the period from May 2003 to April 2004. Using monitored data for IBV infection status among study flocks we computed the multivariate odds ratios (ORs) and their corresponding confidence intervals (CIs), and population attributable risks (PARs). Multivariate logistic regression showed significant risk increments for: continuous entry of chick (OR=1.9, 95% CI, 0.7-69.1) and operation years of the layer house greater than or equal to 5 years (OR=3.2, 95%CI, 1.6-389.9). No significant interaction was found between variables. The PAR suggested that continuous entry of chick (PAR=32%) and ${\geq}5years$ of house operation (PAR=84%) had the highest impacts on IB presence in laying-hen flocks under study. Of the two significant factors, however, operation year of the layer house lacks an easy applicability in preventing IB control strategies, and the possibility of confounder cannot be ruled out.


Supported by : Ministry of Agriculture and Forestry, Institute of Veterinary Science, Kangwon National University


  1. Alexander DJ, Chettle NJ. Procedures for the hemaglutination and the hemagglutination inhibition tests for avian infectious bronchitis virus. Avian Pathol 1977, 6, 9-17 https://doi.org/10.1080/03079457708418208
  2. Bhattacharjee PS, Carter SD, Savage CE, Jones RC. Re-excretion of infectious bronchitis virus in chickens induced by cyclosporine. Avian Pathol 1995, 24, 435-441 https://doi.org/10.1080/03079459508419083
  3. Bruzzi P, Green SB, Byar DP, Brinton LA, Schairer C. Estimating the population attributable risk of multiple risk factors using case-control data. Am J Epidemiol 1985, 122, 904-914 https://doi.org/10.1093/oxfordjournals.aje.a114174
  4. Cannon RM, Roe RT. Livestock disease surveys: a field manual for veterinarians. Australian Bureau of Animal Health, Canberra, 1982
  5. Cook JKA. Duration of experimental infectious bronchitis in chickens. Res Vet Sci 1968, 9, 506-514
  6. Cook JKA. The classification of new serotypes of infectious bronchitis virus isolated from poultry flocks in Britain between 1981 and 1983. Avian Pathol 1984, 13, 733-741 https://doi.org/10.1080/03079458408418570
  7. Hitchner SB, Winterfield RW, Appleton GS. Infectious bronchitis virus types-incidence in the United States. Avian Dis 1966, 10, 98-102 https://doi.org/10.2307/1588213
  8. Hosmer DW, Lemeshow S. Applied logistic regression. Wiley, New York, 1989
  9. Ignjatovic J, Sapats S. Avian infectious bronchitis. Res Sci Tech Off Int Epiz 2000, 19, 493-508 https://doi.org/10.20506/rst.19.2.1228
  10. Kim JH, Song CS, Mo IP, Kim SH, Sung HW, Yoon HS. An outbreak of nephropathogenic infectious bronchitis in commercial pullets. Res Reports Rural Develop Admin 1992, 34, 28-31
  11. King DJ, Hopkins SR. Evaluation of the hemagglutination-inhibition test for measuring the response of chickens to avian infectious bronchitis virus vaccination. Avian Dis 1983, 27, 100-112 https://doi.org/10.2307/1590376
  12. King DJ, Hopkins SR. Rapid serotyping of infectious bronchitis virus isolates with the hemagglutinationinhibition test. Avian Dis 1984, 28, 727-733 https://doi.org/10.2307/1590241
  13. Kusters JG, Niesters HGM, Bleumink-Pyuym NMC, Davelaar FG, Horzinek MC, van der Zeijst BAM. Molecular epidemiology of infectious bronchitis virus in the Netherlands. J Gen Virol 1987, 68, 343-352 https://doi.org/10.1099/0022-1317-68-2-343
  14. Kwon HJ, Lee DW, Ahn YK, Yoon JU, Kim SJ. Presence of infectious bronchitis virus in Korea before 1986. Korean J Vet Res 2001, 41, 59-65
  15. Parsons D, Ellis MM, Cavanagh D, Cook JKA. Characterization of an infectious bronchitis virus isolated from vaccinated broiler breeder flocks. Vet Rec 1992, 131, 408-411 https://doi.org/10.1136/vr.131.18.408
  16. Rhee YO, Kim JH, Mo IP, Choi SH, Namgoong S. Outbreaks of infectious bronchitis in Korea. Korean J Vet Res 1986, 26, 277-282
  17. SAS. Statistical analysis system. Version 8.1 for Windows. SAS, Cary, 2001
  18. Song CS, Lee YJ, Kim JH, Sung CW, Lee Y, Izumiya T, Miyazawa T, Jang HK, Mikami T. Epidemiological classification of infectious bronchitis virus isolated in Korea between 1986 and 1997. Avian Pathol 1998, 27, 409-416 https://doi.org/10.1080/03079459808419360
  19. Stephens P, Simmons GC. Neutralising antibodies for avian infectious bronchitis virus in Queensland poultry flocks. Aust Vet J 1968, 44, 29-30 https://doi.org/10.1111/j.1751-0813.1968.tb04911.x
  20. Wells SJ, Dargatz DA, Ott SL. Factors associated with mortality to 21 days of life in dairy heifers in the United States. Prev Vet Med 1996, 29, 9-19 https://doi.org/10.1016/S0167-5877(96)01061-6
  21. Yu L, Jiang Y, Low S, Wang Z, Nam SJ, Liu W, Kwangac J. Characterization of three infectious bronchitis virus isolates from China associated with proventriculus in vaccinated chickens. Avian Dis 2001, 45, 416-24 https://doi.org/10.2307/1592981