RESUMEN
Campylobacter species, particularly thermophilic campylobacters, have emerged as a leading cause of human foodborne gastroenteritis worldwide, with Campylobacter jejuni, Campylobacter coli, and Campylobacter lari responsible for the majority of human infections. Although most cases of campylobacteriosis are self-limiting, campylobacteriosis represents a significant public health burden. Human illness caused by infection with campylobacters has been reported across Canada since the early 1970s. Many studies have shown that dietary sources, including food, particularly raw poultry and other meat products, raw milk, and contaminated water, have contributed to outbreaks of campylobacteriosis in Canada. Campylobacter spp. have also been detected in a wide range of animal and environmental sources, including water, in Canada. The purpose of this article is to review (i) the prevalence of Campylobacter spp. in animals, food, and the environment, and (ii) the relevant testing programs in Canada with a focus on the potential links between campylobacters and human health in Canada.
Asunto(s)
Enfermedades de los Animales/epidemiología , Infecciones por Campylobacter/epidemiología , Campylobacter/aislamiento & purificación , Microbiología de Alimentos , Salud Pública , Enfermedades de los Animales/microbiología , Animales , Animales Salvajes , Infecciones por Campylobacter/microbiología , Canadá/epidemiología , Ambiente , Heces/microbiología , Humanos , Mascotas , PrevalenciaRESUMEN
BACKGROUND: The concurrent rise in consumption of fresh chicken meat and human campylobacteriosis in the late 1990's in Iceland led to a longitudinal study of the poultry industry to identify the means to decrease the frequency of broiler flock colonization with Campylobacter. Because horizontal transmission from the environment is thought to be the most likely source of Campylobacter to broilers, we aimed to identify broiler house characteristics and management practices associated with flock colonization. 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. Logistic regression models with a farm random effect were used to analyse the association between flock Campylobacter status and house-level risk factors. A two-stage process was carried out. Variables were initially screened within major subsets: ventilation; roof and floor drainage; building quality, materials and repair; house structure; pest proofing; biosecurity; sanitation; and house size. Variables with p < or = 0.15 were then offered to a comprehensive model. Multivariable analyses were used in both the screening stage (i.e. within each subset) and in the comprehensive model. RESULTS: 217 out of 792 flocks (27.4%) tested positive. Four significant risk factors were identified. Campylobacter colonization was predicted to increase when the flock was raised in a house with vertical (OR = 2.7), or vertical and horizontal (OR = 3.2) ventilation shafts, when the producer's boots were cleaned and disinfected prior to entering the broiler house (OR = 2.2), and when the house was cleaned with geothermal water (OR = 3.3). CONCLUSION: The increased risk associated with vertical ventilation shafts might be related to the height of the vents and the potential for vectors such as flies to gain access to the house, or, increased difficulty in accessing the vents for proper cleaning and disinfection. For newly constructed houses, horizontal ventilation systems could be considered. Boot dipping procedures should be examined on farms experiencing a high prevalence of Campylobacter. Although it remains unclear how geothermal water increases risk, further research is warranted to determine if it is a surrogate for environmental pressures or the microclimate of the farm and surrounding region.
Asunto(s)
Infecciones por Campylobacter/veterinaria , Campylobacter/crecimiento & desarrollo , Pollos , Vivienda para Animales , Enfermedades Intestinales/veterinaria , Enfermedades de las Aves de Corral/microbiología , Animales , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/microbiología , Infecciones por Campylobacter/transmisión , Islandia/epidemiología , Enfermedades Intestinales/epidemiología , Enfermedades Intestinales/microbiología , Estudios Longitudinales , Análisis Multivariante , Enfermedades de las Aves de Corral/epidemiología , Enfermedades de las Aves de Corral/transmisión , Factores de Riesgo , Estaciones del Año , Encuestas y CuestionariosRESUMEN
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
Asunto(s)
Infecciones por Campylobacter/veterinaria , Campylobacter/aislamiento & purificación , Pollos , Enfermedades de las Aves de Corral/epidemiología , Crianza de Animales Domésticos/métodos , Animales , Infecciones por Campylobacter/epidemiología , Infecciones por Campylobacter/etiología , Infecciones por Campylobacter/prevención & control , Contaminación de Alimentos/prevención & control , Humanos , Islandia/epidemiología , Modelos Logísticos , Estiércol/microbiología , Densidad de Población , Enfermedades de las Aves de Corral/etiología , Enfermedades de las Aves de Corral/prevención & control , Prevalencia , Factores de Riesgo , Estaciones del Año , ZoonosisRESUMEN
Campylobacter jejuni is a major cause of bacterial food-borne infection in the industrial world. There is evidence that C. jejuni is present in eggs and hatchery fluff, opening the possibility for vertical transmission from hens to progeny. Poultry operations in Iceland provide an excellent opportunity to study this possibility, since breeding flocks are established solely from eggs imported from grandparent flocks in Sweden. This leaves limited opportunity for grandparents and their progeny to share isolates through horizontal transmission. While Campylobacter was not detected in all grandparent flocks, 13 of the 16 egg import lots consisted of eggs gathered from one or more Campylobacter-positive grandparent flocks. No evidence of Campylobacter was found by PCR in any of the 10 relevant quarantine hatchery fluff samples examined, and no Campylobacter was isolated from the parent birds through 8 weeks, while they were still in quarantine rearing facilities. After the birds were moved to less biosecure rearing facilities, Campylobacter was isolated, and 29 alleles were observed among the 224 isolates studied. While three alleles were found in both Sweden and Iceland, in no case was the same allele found both in a particular grandparent flock and in its progeny. We could find no evidence for vertical transmission of Campylobacter to the approximately 60,000 progeny parent breeders that were hatched from eggs coming from Campylobacter-positive grandparent flocks. If vertical transmission is occurring, it is not a significant source for the contamination of chicken flocks with Campylobacter spp.
Asunto(s)
Infecciones por Campylobacter/veterinaria , Campylobacter/aislamiento & purificación , Pollos/microbiología , Enfermedades de las Aves de Corral/transmisión , Alelos , Animales , Secuencia de Bases , Campylobacter/genética , Campylobacter/patogenicidad , Infecciones por Campylobacter/microbiología , Infecciones por Campylobacter/transmisión , ADN Bacteriano/genética , Huevos/microbiología , Femenino , Microbiología de Alimentos , Humanos , Islandia , Transmisión Vertical de Enfermedad Infecciosa , Masculino , Datos de Secuencia Molecular , Filogenia , Enfermedades de las Aves de Corral/microbiología , SueciaRESUMEN
We sampled 1,091 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 (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.