To describe the occurrence of fecal shedding, persistence of shedding over time, and serogroup classification of Salmonella spp on a large number of dairy farms of various sizes.
22,417 fecal samples from cattle and 4,570 samples from the farm environment on 110 organic and conventional dairy farms in Minnesota, Wisconsin, Michigan, and NewYork.
5 visits were made to each farm at 2-month intervals from August 2000 to October 2001. Fecal samples from healthy cows, calves, and other targeted cattle groups and samples from bulk tank milk, milk line filters, water, feed sources, and pen floors were collected at each visit. Bacterial culture was performed at 1 laboratory.
Salmonella spp were isolated from 4.8% of fecal samples and 5.9% of environmental samples; 92.7% of farms had at least 1 Salmonella-positive sample. The 75th percentile for median within-herd prevalence of Salmonella spp in cattle for 5 sampling visits to a given farm was 2.0% and for maximum within-herd prevalence of Salmonella spp was 13.6%. Farms with a median within-herd prevalence of Salmonella spp of > or = 2.0% accounted for 76.3% of Salmonella-positive samples. There was no significant difference in the prevalence of Salmonella spp between conventional and organic farms. Seasonal differences in Salmonella shedding were observed. More farms had at least 1 serogroup B isolate than any other serogroup, whereas serogroup E1 was the most common among all Salmonella-positive samples. More than 1 serogroup was isolated on 76.4% of Salmonella-positive farms.
Salmonella spp were isolated from > 90% of dairy farms; however, 25% of farms accounted for > 75% of Salmonella-positive samples. This information is critical for the direction of intervention strategies to decrease the prevalence of Salmonella spp on dairy farms.
"These results demonstrate the importance of diarrhea in calves within the first 2 weeks of age and that improved management practices during this time are necessary to reduce calf scours and its consequences. In Brazil, there is no longitudinal study for Salmonella infection in calves, and there are only few studies worldwide (Huston et al. 2002; Warnick et al. 2003; Fossler et al. 2004; Cummings et al. 2009a, b). Cummings et al. (2009a) found that 17 % (16/93) of positive herds were responsible for over 70 % of clinical cases of Salmonella which means most farms do not experience any clinical illness due to Salmonella infection and a subset of the positive properties had a very high incidence of salmonellosis. "
[Show abstract][Hide abstract] ABSTRACT: This prospective longitudinal study investigated the epidemiology of enteric disease associated with infections in calves aging up to 70 days. A total of 850 fecal samples were collected from 67 calves. Seventeen isolates of Salmonella spp. were recovered from feces of 11 calves (16.4 %), and statistical analysis revealed no association between the presence of Salmonella spp. and clinical signs of diarrhea or age. Virulence factors of Escherichia coli were identified in 103 strains: eae (7), K99/STa (7), Stx1 (7), Stx1/eae (36), Stx1/Stx2/eae (2), Stx2 (43), and Stx2/eae (1). There was statistical association between diarrheic animals carrying E. coli Stx1/eae
+ in their feces at 2 and 4 weeks of age (P = 0.003) and E. coli Stx2
+ at 5 weeks of age (P = 0.03). Rotavirus was detected in 49 (5.76 %) fecal samples collected from 33 calves (49.2 %). The presence of rotavirus was correlated with diarrheic feces (P < 0.0001) rather than feces with normal consistency. There was a significant relationship between age group and diarrhea (P = 0.001). Bovine coronavirus (BCoV) was detected in 93 fecal samples collected from 46 calves (68.6 %). There was an association (P < 0.0001) between diarrheic animals positive for BCoV and age groups. The results demonstrate the importance of the pathogens studied in the etiology of diarrhea in calves.
Tropical Animal Health and Production 09/2014; 47(1). DOI:10.1007/s11250-014-0675-5 · 0.82 Impact Factor
"The finding of cows excreting foodborne pathogens, such as Campylobacter sp., E. coli O157 and Salmonella sp. is not infrequent in Italy (Conedera et al., 1997; Bonardi et al., 1999; Bonardi et al., 2001; Ricci et al., 2006) as well as in other countries (Huston et al., 2002; Rugbjerg et al., 2003; Fossler et al., 2004; Hakkinen and Hanninen, 2009; Anon, 2010). According to the current European legislation (Reg. "
[Show abstract][Hide abstract] ABSTRACT: A pilot study was implemented in the Veneto Region of Italy, aimed at classifying dairy farms which produce milk to be commercialised unpasteurised on the basis of their risk of faecal contamination of milk, which is directly correlated to the probability of a foodborne pathogen, if present in the herd and eliminated through faecal excretion, to contaminate the raw product. Factors considered to be relevant in the definition of the risk of pathogens potentially present in animal faeces to be transmitted to milk, were hierarchically structured, weighted through the application of experts elicitation methods (Analytic Hierarchy Process, Delphi) and used to categorise farms through the application of a herd questionnaire. The probability of faecal contamination of milk, and thus the risk of pathogens transfer appears to be modulated more by farm management than by the structure of the farm or the health status of the herd. Such a method, combined with the microbiological evaluation of the prevalence of faecal excretion of such pathogens, can be used to implement a risk-based surveillance programme and to apply targeted control measures.
Research in Veterinary Science 02/2013; 95(1). DOI:10.1016/j.rvsc.2013.02.007 · 1.41 Impact Factor
"A number of studies have described the prevalence and/or risk factors for fecal Salmonella shedding among dairy cattle (Kabagambe, et al., 2000; Warnick, et al., 2001; Huston, et al., 2002; Fossler, et al., 2004), but few have examined the duration of shedding in either subclinical or clinical cases. This study had the particular advantage of involving a large number of clinically affected animals from multiple herds. "
[Show abstract][Hide abstract] ABSTRACT: The objectives of this study were to determine the duration of fecal Salmonella shedding among dairy cattle in the northeastern United States following laboratory-confirmed clinical disease and to evaluate whether age group or serotype was associated with either shedding period or mortality. Study farms included 22 dairy herds that had at least two previous salmonellosis cases confirmed by fecal culture. Veterinarians continued to submit culture samples from clinical suspects following herd enrollment, and fecal samples from positive cattle were collected monthly until three sequential negative results were obtained or until loss to follow-up. There were 357 culture-positive clinical cases that each involved a single serotype during the shedding period. The Kaplan-Meier median duration of fecal Salmonella shedding was 50 days, and the maximum was 391 days. S. Newport was the predominant serotype, accounting for 51% of the cases. Age group and serotype were not significant predictors of Salmonella shedding duration in a Cox proportional hazards model, when stratifying by herd. However, the proportion of adult cows shedding for at least two consecutive monthly samples was significantly greater than the proportion of female calves shedding for this duration (Fisher's exact test p-value<0.01). Age group was also associated with mortality in this study; calves with salmonellosis were more likely to die than cows as estimated by a logistic regression model which controlled for herd as a random effect (p-value=0.04).
Preventive Veterinary Medicine 09/2009; 92(1-2):134-9. DOI:10.1016/j.prevetmed.2009.07.002 · 2.17 Impact Factor
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