Risk factors for Campylobacter colonisation during rearing of broiler flocks in Great Britain (original) (raw)
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Acta Veterinaria Scandinavica, 2007
Background: Following increased rates of human campylobacteriosis in the late 1990's, and their apparent association with increased consumption of fresh chicken meat, a longitudinal study was conducted in Iceland to identify the means to decrease the frequency of broiler flock colonization with Campylobacter. Our objective in this study was to identify risk factors for flock colonization acting at the broiler farm level. Methods: Between May 2001 and September 2004, pooled caecal samples were obtained from 1,425 flocks at slaughter and cultured for Campylobacter. Due to the strong seasonal variation in flock prevalence, analyses were restricted to a subset of 792 flocks raised during the four summer seasons. Flock results were collapsed to the farm level, such that the number of positive flocks and the total number of flocks raised were summed for each farm. Logistic regression models were fitted to the data using automated and manual selection methods. Variables of interest included manure management, water source and treatment, other poultry/livestock on farm, and farm size and management. Results: The 792 flocks raised during the summer seasons originated from 83 houses on 33 farms, and of these, 217 (27.4%) tested positive. The median number of flocks per farm was 14, and the median number of positive flocks per farm was three. Three farms did not have any positive flocks. In general, factors associated with an increased risk of Campylobacter were increasing median flock size on the farm (p ≤ 0.001), spreading manure on the farm (p = 0.004 to 0.035), and increasing the number of broiler houses on the farm (p = 0.008 to 0.038). Protective factors included the use of official (municipal) (p = 0.004 to 0.051) or official treated (p = 0.006 to 0.032) water compared to the use of non-official untreated water, storing manure on the farm (p = 0.025 to 0.029), and the presence of other domestic livestock on the farm (p = 0.004 to 0.028). Conclusion: Limiting the average flock size, and limiting the number of houses built on new farms, are interventions that require investigation. Water may play a role in the transmission of Campylobacter, therefore the use of official water, and potentially, treating non-official water may reduce the risk of colonization. Manure management practices deserve further attention.
Campylobacter spp. in conventional broiler flocks in Northern Ireland: Epidemiology and risk factors
Preventive Veterinary Medicine, 2008
Risk factors for Campylobacter infection in conventional broiler flocks in the time period up to the first removal of birds to slaughter were investigated over a maximum of five consecutive production cycles in a cohort of 88 broiler farms in Northern Ireland. Samples for Campylobacter culture, which consisted of 14 cloacal swabs per flock, were collected from one house on each farm prior to the first depopulation of birds. In total 388 flocks were sampled, of which 163 tested positive for Campylobacter spp. (42.0%; 95% CI 35.1-48.9%).
Risk Factors Associated with the Presence of Campylobacter Species in Norwegian Broiler Flocks
Poultry Science, 2008
A case-control study was conducted in 2005 to identify risk factors for the presence of Campylobacter spp. in Norwegian broiler flocks. A total of 131 broiler farms (44 cases and 87 controls) were included in the study, and 1 flock from each farm was included in the statistical analyses. Data on farm and flock level were collected by means of a questionnaire designed for the present study. The relationship and strength of association between the presence of Campylobacter spp. in the broiler flocks and several factors were in-vestigated by unconditional logistic regression. The following factors were found to be associated with an increased risk of testing positive for Campylobacter spp.: water from a private water source, swine holdings closer than 2 km, a specific slaughterhouse, a hired animal caretaker, transport personnel passing through the hygiene barrier when delivering day-old chickens, less than 9 d between depopulation and restocking, and multiple broiler houses on the farm.
Infection Ecology & Epidemiology, 2016
Background: Campylobacter jejuni is the leading bacterial food-borne pathogen within the European Union (EU), and poultry meat is the primary route for transmission to humans. Material and methods: This study examined the impact of partial depopulation (thinning), season, and farm performance (economic, hygiene, and biosecurity) on Campylobacter prevalence in Irish broilers over a 13-month period. Ten caecal samples were taken per flock, for a total of 211 flocks from 23 farms during the duration of the study. Campylobacter was isolated and enumerated according to modified published ISO methods for veterinary samples. Biosecurity was evaluated through a questionnaire based on risk factors for Campylobacter identified in previous studies. Hygiene compliance was assessed from audit records taken over the course of 1 year. All information relating to biosecurity and hygiene was obtained directly from the processing company. This was done to ensure farmers were unaware they were being monitored for Campylobacter prevalence and prevent changes to their behaviour. Results and discussion: Farms with high performance were found to have significantly lower Campylobacter prevalence at first depopulation compared with low-performance farms across all seasons (P50.01). Peak Campylobacter levels were observed during the summer season at first thin in both the high-and lowperformance groups. Campylobacter prevalence was found to increase to ]85% in both high-and lowperformance farms across all seasons at final depopulation, suggesting that Campylobacter was introduced during the first depopulation. On low-performance farms, four biosecurity interventions were found to significantly reduce the odds of a flock being Campylobacter positive (physical step-over barrier OR 00.17, house-specific footwear OR 00.13, absence of water body within 0.5 km OR 00.13, two or more broiler houses on a farm OR00.16), compared with farms without these interventions. For high-performance farms, no single biosecurity intervention was identified as significant as this group had full compliance with multiple factors. High-performance farms had significantly better feed conversion ratios compared with lowperformance farms (1.61 v 1.67 (P50.01)). No differences in flock mortality rates were observed (P ]0.05). This highlights the impact of season, biosecurity, partial depopulation, and farm performance on Campylobacter prevalence in Irish broilers.
Risk factors and likelihood of Campylobacter colonization in broiler flocks
Brazilian Journal of Poultry Science, 2007
Campylobacter was investigated in cecal droppings, feces, and cloacal swabs of 22 flocks of 3 to 5 week-old broilers. Risk factors and the likelihood of the presence of this agent in these flocks were determined. Management practices, such as cleaning and disinfection, feeding, drinkers, and litter treatments, were assessed. Results were evaluated using Odds Ratio (OR) test, and their significance was tested by Fisher's test (p<0.05). A Campylobacter prevalence of 81.8% was found in the broiler flocks (18/22), and within positive flocks, it varied between 85 and 100%. Campylobacter incidence among sample types was homogenous, being 81.8% in cecal droppings, 80.9% in feces, and 80.4% in cloacal swabs (230). Flocks fed by automatic feeding systems presented higher incidence of Campylobacter as compared to those fed by tube feeders. Litter was reused in 63.6% of the farm, and, despite the lack of statistical significance, there was higher likelihood of Campylobacter incidence when litter was reused. Foot bath was not used in 45.5% of the flocks, whereas the use of foot bath associated to deficient lime management increased the number of positive flocks, although with no statiscal significance. The evaluated parameters were not significantly associated with Campylobacter colonization in the assessed broiler flocks.
Preventive Veterinary Medicine, 2007
The aim of this cross-sectional survey was to identify risk factors for Campylobacter spp. colonization in French free-range broiler flocks at the end of the indoor rearing period (between 35 and 42 days old). Seventy-three broiler farms were studied from March 2003 to March 2004 in France. A questionnaire was administered to the farmers and samples of fresh droppings were taken to assess the flocks' Campylobacter status by bacteriology. Campylobacter species were determined by PCR. A logistic regression analysis was used to assess the influence of various factors on flocks' Campylobacter status. 71.2% of the sampled flocks excreted Campylobacter spp. before going out on the range. The risk of a flock being colonized with Campylobacter was increased in the spring/ summer period (RR = 1.8, p = 0.02) and autumn (RR = 2.2, p = 0.02) compared to winter, on total freedom rearing farms (RR = 3.3, p = 0.04) in comparison with farms with a fenced run, when the first disinfection of the poultry-house was performed by the farmer (RR = 2.4, p = 0.04) instead of a hygiene specialist, when rodent control was carried out by a contractor (RR = 1.8, p < 0.01) and not by the farmer and when the farmer came into the house twice a day as opposed to three time a day or more (RR = 1.5, p = 0.02). Use of a specific gate for chick placement decreased the risk of a flock being colonized with Campylobacter (RR = 0.5, p = 0.01) in comparison with using the gate for manual disposure or the door of the change room.
Risk factors for Campylobacter spp. colonization in broiler flocks in Iceland
Preventive Veterinary Medicine, 2006
We sampled 1091 Icelandic broiler flocks at slaughter from May 2001 to December 2003 to determine the prevalence of, and investigate risk factors for the presence of, Campylobacter spp. at the flock level. Approximately 15% of the flocks were positive for Campylobacter spp.; most (95%) of the infected flocks being raised during the months of April-September. Based on the data from the latter months, and using multivariable logistic regression with random effects for herd, we found that the odds of a flock being positive for Campylobacter spp. increased with age and flock size. Additionally, vertical ventilation systems were strongly associated with positive flocks (OR = 5.3). After controlling for these variables, we found no evidence of an effect of: year; company; Campylobacter being carried over from one flock to the next; time interval between flocks; using www.elsevier.com/locate/prevetmed Preventive Veterinary Medicine 74 (2006) 264-278 (at the hatcheries) eggs laid on the floor; density of bird housing, or the number of catch lots a flock was divided into for slaughtering purposes on the risk of a Campylobacter-positive flock. #
Correlations between Campylobacter spp. prevalence in the environment and broiler flocks
Journal of applied microbiology, 2007
To investigate (i) possible correlations between the presence of Campylobacter spp. in the surroundings of broiler farms and their incidence in flocks, and (ii) possible associations between weather conditions and the occurrence of Campylobacter spp. Farms were selected according to previous results from the Swedish Campylobacter programme. Samples were collected in and around broiler houses during the rearing period from 131 flocks on 31 farms, including sock samples from the ground outside, from the floor in the broiler houses and anterooms, and samples from insects, water, feed and ventilation shafts. As expected, there was a difference in Campylobacter isolation rates for different categories of farms regarding samples taken in the houses. However, there were no differences regarding the presence of Campylobacter spp. in the environment between producers that often deliver Campylobacter-positive slaughter batches and those that rarely deliver positive batches. Campylobacter spp....
Microbial Risk Analysis, 2016
This study presents on-farm risk factors for the colonization of broiler flocks with Campylobacter based on comparable data from six European countries: Denmark, the Netherlands, Norway, Poland, Spain, and the UK. The study includes explanatory variables from a large questionnaire concerning production, farm management procedures and farm conditions, climate data on mean temperature, sunshine hours, and precipitation, as well as data on Campylobacter status of broiler flocks. All together the study comprises data from more than 60 0 0 flocks. The data were analysed using a generalized linear model. Due to a large number of parameters, some collinearity and relatively many missing values, the model was analysed by a method using all available cases at each step in the modelling process. The modelling process includes backwards elimination and forward selection. Several approaches were furthermore explored by applying different strategies for categorizing explanatory variables and for selecting and eliminating variables in the model. Despite national differences in broiler production, common risk factors for Campylobacter colonization of broiler flocks were identified across all six countries. These were generally related to inadequate biosecurity. Identified risk factors were: broiler houses older than 15 years, absence of anterooms and barriers in each house, shared tools between houses, long downtime, and drinker systems with bells or cups. Also, the risk of broiler flocks becoming colonized with Campylobacter was clearly affected by country. In descending order, broiler flocks were more likely to be colonized in Poland, the UK, Spain, the Netherlands, Denmark and Norway due to country specific factors that could not be explained by the identified risk factors or any other variables from the questionnaire. The seasonality observed for prevalence values was described by the monthly mean temperature reported in the study, i.e. the higher the temperature, the higher the prevalence of positive flocks.
PLoS ONE, 2011
Campylobacter successfully colonizes broiler chickens, but little is known about the longer term natural history of colonization, since most flocks are slaughtered at an immature age. In this study, the prevalence and genetic diversity of Campylobacter colonizing a single free-range broiler breeder flock was investigated over the course of a year. The age of the flock was the most important factor in determining both the prevalence and diversity of Campylobacter over time. There was no correlation with season, temperature, the amount of rain and sunshine, or the dynamics of colonization amongst geographically and temporally matched broiler flocks. The higher prevalence rates coincided with the age at which broiler chickens are typically slaughtered, but then in the absence of bio-security or other intervention methods, and despite changes in flock management, the prevalence fell to significantly lower levels for the remainder of the study. The genetic diversity of Campylobacter increased as the flock aged, implying that genotypes were accumulated within the flock and may persist for a long time. A better understanding of the ecology of Campylobacter within commercial chicken flocks will allow the design of more effective farm-based interventions.