Date Published: June 6, 2006
Publisher: BioMed Central
Author(s): G Johnsen, K Zimmerman, B-A Lindstedt, T Vardund, H Herikstad, G Kapperud.
In a survey conducted in 1999–2001, the carriage of thermotolerant Campylobacters in cattle was investigated, and the genetic diversity of C. jejuni within one herd was examined and compared with human isolates. C. jejuni, C. coli and other thermotolerant Campylobacter spp. were isolated from intestinal contents from 26%, 3% and 2% of 804 cattle, respectively. The carriage rate was higher in calves (46%) than in adults (29%). Twenty-nine C. jejuni isolates from one herd and 31 human isolates from the study area were genotyped with amplified-fragment length polymorphism (AFLP). Eighty-three % of the bovine isolates fell into three distinct clusters with 95–100% similarity, persistent in the herd for 5–10 months. Among human isolates, 58% showed >90% similarity with bovine isolates. The results show that cattle are a significant and stable reservoir for C. jejuni in the study area. Transmission between individuals within the herd may be sufficient to maintain a steady C. jejuni population independent of environmental influx. The results of this study have provided new information on C. jejuni and C. coli transmission, and also on the carriage in cattle, genotypes stability and similarity between bovine and human isolates.
During the last 30 years, campylobacteriosis has emerged as an important food-borne bacterial zoonosis causing acute diarrhoea in humans at low infection doses [1-4]. In many developed countries, the disease is currently the most frequently reported bacterial enteric infection in humans [1,3,4]. Since the beginning of the 1990’s, a substantial increase has been observed in several countries . In Norway, the incidence of campylobacteriosis doubled from 1994 to 1999, according to the Norwegian Surveillance System for Communicable Diseases . Case control studies of sporadic cases, including a recent one from Norway, have identified a number of risk factors [1,3,6]. The most frequently reported factors are consumption of poultry meat, contact with animals, including farm animals as cattle, poultry and sheep, drinking un-disinfected water, barbequing, and drinking un-pasteurized milk [1,3,4]. The sources most frequently incriminated in outbreaks of campylobacteriosis are drinking water, un-pasteurized milk and poultry [1,3,4,7].
In the present study, we isolated C. jejuni and C. coli from about one-third of healthy cattle from South-western Norway. This is higher than reported from Denmark  and Sweden , but lower than what is found in the UK and Ireland .
The results show that cattle are a significant and stable reservoir for C. jejuni in the study area. In one of the herds, three distinct genetic clones were present over several months. The genetic similarity between human and bovine isolates may reflect infection from a common source. The highest carriage rates were found among calves versus adults.
Forekomst av Campylobacter jejuni og Campylobacter coli i tarm fra storfe fra sørvest Norge og genotypisk sammenligning av bovine og humane isolat ved metoden AFLP