Epidemiology and Infection

Research Article

Epidemiological investigation of risk factors for Campylobacter colonization in Norwegian broiler flocks

G. Kapperuda1a2, E. Skjervea2, L. Vika3, K. Haugea4, A. Lysakera3, I. Aalmena4, S. M. Ostroffa5 and M. Pottera5

a1 National Institute of Public Health, Department of Bacteriology, 0462 Oslo, Norway

a2 Norwegian College of Veterinary Medicine, 0033 Oslo,Norway

a3 The Food Inspection Service in Indre Østfold, 1850 Mysen

a4 The Food Inspection Service in Sør-Østerdal, 2401 Elverum, Norway

a5 Centers for Disease Control, Atlanta, GA 30333, USA

Abstract

An epidemiological investigation was conducted to identify risk factors related to hygiene and husbandry practices which determine the introduction of Campylobacter spp. into broiler chicken flocks. All 176 broiler farms in an area in southeastern Norway participated in the study. Each farm was represented by one flock selected at random during a one-year period. The flocks were examined for Campylobacter colonization at slaughter, and the flock managers were sub-sequently interviewed about hygiene and husbandry practices. Campylobacter spp. were recovered from 32 (18%) of the flocks. The proportion of colonized flocks varied geographically and seasonally with a peak in the autumn. The following variables were found to be independently associated with an increased risk of Campylobacter colonization using logistic regression analysis: (i) feeding the broilers undisinfected water (odds ratio (OR) = 3·42, P = 0·045), (ii) tending other poultry prior to entering the broiler house (OR = 6·43, P = 0·007), (iii) tending pigs before entering the house (OR = 4·86, P = 0·037), (iv) geographic region (Hedmark versus Østfold county) (OR = 2·91), P = 0·023, (v) season (autumn versus other seasons) (OR = 3·43, P = 0·008). Presence of rats on the farm was associated with an increased risk, but this factor did not reach statistical significance (OR = 3·96, P = 0·083). Preventive measures should include dis-infection of drinking water and strict hygienic routines when the farm workers enter the rearing room. The results indicated that disinfection of drinking water is the preventive measure most likely to have the greatest impact on the prevalence of Campylobacter among broiler chicken flocks in the study area (population attributable fraction = 0·53).

(Accepted May 27 1993)

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