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1.
Fecal samples were collected from 724 horses admitted to, and 232 horses hospitalized at, a veterinary teaching hospital between October 2000 and June 2001, and cultured for Salmonella. Salmonella was isolated on 24 occasions from 12 horses. S. Newport was the most commonly isolated serotype. The estimated prevalence (95% confidence interval [CI]) of Salmonella shedding on admission was 0.5% (0.1, 2.0). The estimated incidence rate of Salmonella shedding during hospitalization was 4.3% (95% CI, 2.2-8.1). The highest incidence of Salmonella shedding during hospitalization occurred during June 2001, but no significant (P > .5) temporal clusters of horses shedding Salmonella were detected.Horses shed Salmonella in their feces at a low rate. Horses shedding Salmonella occurred only sporadically and no obvious serotype pattern was observed. The occurrence of fecal shedding probably reflected the prevalence of inapparent Salmonella infection in the hospital source population, providing a baseline against which future potential outbreaks can be identified.

Introduction

Infection of horses by Salmonella organisms is a serious health issue. It is particularly troubling when outbreaks occur in hospitalized patients because these outbreaks can result in substantial economic losses and have a major impact on the welfare of patients.[1] Establishments with a high-density of horses, including veterinary teaching hospitals (VTHs) and private veterinary clinics, [1 and 2] are most vulnerable to outbreaks of disease attributable to Salmonella infection. Host susceptibility and environmental persistence of Salmonella are also factors contributing to outbreaks.Estimates of the prevalence of Salmonella-shedding horses admitted to veterinary hospitals have generally been made under outbreak conditions.[1] For example, between 1971 and 1982, 245 hospitalized horses (1.7%) at the University of California were found to shed Salmonella.[3 and 4] Three major outbreaks occurred during the study period, with no apparent periodicity. Between 1996 and 1999, 35 hospitalized horses (5.5%) at the Michigan State University were found to shed Salmonella.[5] One major outbreak occurred during the study period. Only one national survey of nonhospitalized horses in the United States for Salmonella infection has been undertaken: the prevalence of fecal shedding of Salmonella was estimated to be 0.8%, and the farm prevalence of shedding was 1.8%.[6]Many factors have been associated with the risk of Salmonella isolation from hospitalized horses, including diarrhea, fever, change in diet, large colon impaction, colic, withholding feed, feeding bran mash, antibiotic treatment, intubation with nasogastric tubes, and average daily ambient temperature.[7, 8, 9 and 10] Many of theses factors are thought to operate primarily through the effect of stress, increasing the susceptibility of horses to infection. Also, if a horse is infected by Salmonella but not shedding the organisms in its feces, the presence of stressors may reactivate fecal shedding. Most studies that have been conducted on risk factors for Salmonella shedding in horses have included horses with clinical salmonellosis, with or without inclusion of horses inapparently infected by Salmonella.[7, 8 and 10] Risk factors for Salmonella fecal shedding versus clinical salmonellosis have not been clearly delineated.An outbreak (epidemic) of disease can be defined as “an occurrence of disease in excess of its anticipated frequency.”[11] To more effectively identify future outbreaks of Salmonella infection in hospitalized horses, it is necessary to have accurate estimates of the prevalence of endemic fecal shedding of Salmonella in horses admitted to VTHs, and the incidence of fecal shedding during hospitalization. The aims of this study were to estimate the prevalence of fecal shedding in horses admitted to a VTH, to estimate the incidence of fecal shedding during hospitalization, and to describe the seasonal distribution of fecal Salmonella-shedding prevalence and incidence.

Materials and Methods

Study Design

Fecal samples were collected from horses admitted to the Purdue University VTH between October 12, 2000 and June 30, 2001. Horses admitted as inpatients were sampled at least on the day of admission, the day after admission, the day of discharge, and once or more in between. All horses admitted to the VTH during the study period were eligible to be sampled. In the case of mares accompanying sick foals, samples were also collected from the mare. Fecal samples were collected generally from freshly voided fecal material in stalls. Samples were stored at 4°C for up to 24 hours before processing.

Data Collection

For all horses included in the study, date of examination (outpatients) or date of hospitalization (inpatients) was recorded. For inpatients, date of discharge or date of death was also recorded. Horse characteristics were recorded as part of each horse's medical record, and included date of birth, sex (mare, stallion, gelding), and specific breed. The outcome of each admission (discharged alive, died, euthanized) and whether a necropsy was performed were also recorded. The number of samples collected per horse was recorded in a laboratory-reporting system, but specific date of collection of each sample (except for the first and last samples collected) was not routinely recorded.

Bacteriologic Cultures

All fecal samples were cultured for Salmonella species using standard techniques. Specimens were streaked onto brilliant green (BG) and xylose-lysine-tergitol (XLT-4) plates, and approximately 10 g of fecal material was put into 100 mL of tetrathionate Hajna broth. BG plates were incubated at 35° to 37°C for 18 to 24 hours and XLT-4 plates were incubated for 24 to 48 hours. Tetrathionate broth was incubated at 35° to 37°C for 24 to 48 hours, and then streaked to BG and XLT-4 plates. These plates were incubated as previously described. Suspect colonies on plates were subcultured and further identified by the Vitek GNI system. All Salmonella isolates were speciated and serotyped (National Veterinary Services Laboratory, Ames, Ia).

Data Analysis

The total number of horses examined (admissions), the total number of examinations (including admissions), the total number of horses hospitalized during the study period, and the number of samples collected per horse were calculated (Excel 2000, Microsoft Corp, Redmond, Wash) from recorded information. The frequency distributions of admissions (1-6) per horse, sex, breed, and patient outcome were calculated based on owner/horse identity and hospital record number, and the frequency distribution of number of samples collected per horse (nil to 8) was calculated from laboratory records and owner/horse identification and laboratory submission number. Length of hospitalization (days) was calculated from recorded date of hospitalization and date of discharge information, and was summarized by median and mean lengths of hospitalization and 95% confidence intervals (CIs), based on the Wilcoxon test (Minitab for Windows, Minitab Inc, State College, Penn) and the normal distribution (Statistix for Windows, Analytical Software, Tallahassee, Fla), respectively. Normality of the distributions of lengths of hospitalization and age were tested using the normal probability plot and Wilks-Shapiro statistic (Statistix).To estimate the incidence of Salmonella shedding, only hospitalized horses that were sampled on at least three occasions were included, because the sensitivity of culture is suboptimal and repeated attempts to culture Salmonella are necessary to increase the sensitivity of this technique.[12] The total number of days at-risk of shedding Salmonella was calculated as the sum of lengths of hospitalization. The incidence density rate (true incidence) of Salmonella shedding was calculated as
(No. horses detected shedding Salmonella)/(total No. horse-days at-risk)
and expressed as the number of horses shedding Salmonella per 1000 horse-days at-risk. For example, if 10, 10, and 30 horses were hospitalized for periods of 3, 6, and 9 days each, horse-days at-risk would be (10.3)+(10.6)+(30.9) = 360. If one case of Salmonella-shedding was detected in this group, the estimated incidence density rate would be one per (1000/360) 1000 horse-days AT-RISK = 2.8 per 1000 horse-days at-risk. Horses that were culture-positive on the first sampling were not considered incident cases of Salmonella-shedding, and therefore were not included in the numerator of the incidence density rate. Horses shedding Salmonella after hospitalization were assumed to have commenced shedding at the midpoint of their hospitalization, and therefore contributed half their length of hospitalization to the rate denominator. A 95% CI for the estimated incidence density rate was calculated assuming shedding Salmonella to be Poisson distributed.[13] Incidence-density rates were also calculated for each month of the study, the contribution of each horse to each month's horse-days at-risk being calculated on the basis of date of hospitalization and date of discharge information. Cumulative incidence (risk) rate (%) was calculated as described for the incidence density rate, except that the denominator used was the number of horses at-risk of Salmonella-shedding when hospitalized. For cumulative incidence rate, a 95% CI was calculated based on the binomial distribution.[14]The prevalence of Salmonella-shedding in horses admitted to the VTH was calculated as
(No. horses detected shedding Salmonella by culturewhen admitted)/(total No. horses admitted and sampled)
Ninety-five percent CIs for prevalence estimates were calculations based on the binomial distribution.[14]The temporal clustering of horses shedding Salmonella was investigated using the scan statistic.[15] For horses shedding Salmonella after hospitalization, the midpoint of their length of hospitalization was used as the date of first occurrence of Salmonella-shedding. The population at-risk used in these analyses was the monthly total number of horse-days at-risk. The occurrence of horses shedding Salmonella was assumed to be Poisson distributed, so the expected number of horses shedding Salmonella in any given time period was proportional to the incidence of Salmonella-shedding during the entire study period. The study period was scanned for clusters of horses shedding Salmonella using a scanning window of as much as 50% (130 days) of the time period (SatScan, Bethesda, Md).

Results

Between October 12, 2000 and June 30, 2001, 724 horses were admitted to the VTH. Six hundred and thirty-two horses (87.3%) were admitted only once during the study period; 69 (9.5%), 15 (2.1%), 2 (0.3%), 5 (0.7%), and 1 (0.1%) horses were admitted on 2, 3, 4, 5, and 6 separate occasions, respectively. Length of hospitalization was not recorded for 2 horses. Three-hundred and sixty (42.3%) of the 854 admissions performed did not result in hospitalization of the horse. The distribution of length of hospitalization of all horses hospitalized during the study is shown in Figure 1. The median and mean lengths of hospitalization (95% CI) were 3.0 (2.5, 3.5) and 4.3 (3.8, 4.7) days, respectively. The minimum and maximum lengths of hospitalization were 1 and 57 days. The distribution of lengths of stay was nonnormally distributed (Wilks-Shapiro statistic, 0.7317).  相似文献   

2.
Aeromonas species have been isolated from the feces of diarrheic adult horses and foals. However, Aeromonas species have also been isolated from the feces of approximately 5% of clinically normal adult horses outside the United States. The objectives of this study were to determine whether Aeromonas species can be shed in the feces of nondiarrheic adult horses and identify any effects of season of year, transportation, and hospitalization on possible fecal shedding of Aeromonas species. Feces were cultured for Aeromonas and Salmonella species from 138 nondiarrheic adult horses examined in the hospital and by field services for complaints other than gastrointestinal disease. Fecal Aeromonas and Salmonella species were isolated from 6.5% and 2.2% of nondiarrheic horses, respectively. All Aeromonas isolates were identified as A caviae. There were no apparent effects on time of year, hospitalization, or transport on isolation of Aeromonas species from feces. Isolation of Aeromonas species from diarrheic horses in the absence of other possible enteric pathogens indicates intestinal disease as a result of Aeromonas infection, but Aeromonas species can also occur as copathogens with Salmonella infections.  相似文献   

3.
OBJECTIVE: To estimate prevalence of fecal shedding of Salmonella spp among horses in the US horse population and prevalence of Salmonella spp in grain or other concentrate used as horse feed on equine operations in the United States. DESIGN: Cross-sectional survey. SAMPLE POPULATION: Horses on 972 operations in 28 states. PROCEDURE: Fecal samples were collected from horses resident at each operation. Only a single sample was collected from any individual horse; number of horses from which samples were collected on each operation was determined on the basis of number of horses on the operation. A single sample of grain or concentrate was also collected from each operation. All samples were tested for Salmonella spp by means of bacterial culture. RESULTS: Overall, 0.8% (SE, 0.5) of resident horses shed Salmonella spp in their feces. The overall prevalence of operations positive for fecal shedding of Salmonella spp (i.e., operations with > or = 1 horse shedding Salmonella spp in its feces) was 1.8% (SE, 0.7). Prevalence of grain or other concentrate samples positive for Salmonella spp was 0.4%. Serotypes of Salmonella spp that were identified in grain or other concentrate were not those typically associated with clinical disease in horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the national prevalence of fecal shedding of Salmonella spp by horses in the United States was 0.8%, and that prevalence of Salmonella spp in grain or other concentrate used for horse feed was 0.4%.  相似文献   

4.
The purpose of this study was to determine pet‐related management factors that may be associated with the presence of Salmonella spp. in feces of pet dogs from volunteer households. From October 2005 until May 2006, 138 dogs from 84 households in Ontario were recruited to participate in a cross‐sectional study. Five consecutive daily fecal samples were collected from each dog and enrichment culture for Salmonella spp. was performed. A higher than expected number of the dogs (23.2%; 32/138) had at least one fecal sample positive for Salmonella, and 25% (21/84) of the households had at least one dog shedding Salmonella. Twelve serotypes of Salmonella enterica subsp. enterica were identified, with the predominant serotypes being Typhimurium (33.3%; 13/39), Kentucky (15.4%; 6/39), Brandenburg (15.4%; 6/39) and Heidelberg (12.8%; 5/39). Univariable logistic regression models were created with a random effect for household to account for clustering. Statistically significant risk factors for a dog testing positive included having contact with livestock, receiving a probiotic in the previous 30 days, feeding a commercial or homemade raw food diet, feeding raw meat and eggs, feeding a homemade cooked diet, and having more than one dog in the household. In two‐variable models that controlled for feeding raw food, the non‐dietary variables were no longer statistically significant. These results highlight the potential public health risk of including raw animal products in canine diets.  相似文献   

5.
The aims of the present study were to determine (i) the profiles of phylogroup and (ii) the antimicrobial susceptibility of pathogenic Escherichia coli strains isolated from calves, and of Salmonella spp. strains isolated from calves and pigs in Minas Gerais State, Brazil. Sixty-one pathogenic E. coli strains and Salmonella spp. (n?=?24) strains isolated from fecal samples of calves and Salmonella spp. (n?=?39) strains previously isolated from fecal samples of growing/finishing pigs were tested. The minimum inhibitory concentration (MIC) using the agar dilution method was determined for nalidixic acid, amikacin, amoxicillin, ampicillin, cefoxitin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. All E. coli isolates were susceptible to amikacin. Tetracycline was the antimicrobial that presented the higher frequency of resistance among E. coli strains, followed by ampicillin, trimethoprim-sulfamethoxazole, amoxicillin, nalidixic acid, norfloxacin, gentamicin, and cefoxitin. E. coli (n?=?61) strains isolated from calves belonged to different phylogroup namely, phylogroup A (n?=?26), phylogroup B1 (n?=?31), phylogroup E (n?=?3), and phylogroup F (n?=?1). Phylogroups B2, C, and D were not identified among the E. coli in the present study. All Salmonella spp. (n?=?24) strains isolated from fecal samples of calves were susceptible to amikacin, amoxicillin, ampicillin, norfloxacin, gentamicin, tetracycline, and trimethoprim-sulfamethoxazole. Resistance to nalidixic acid and cefoxitin was detected in 16.66 and 8.33 % of the Salmonella spp. strains, respectively. Among the Salmonella spp. (n?=?39) strains isolated from fecal samples of pigs, the higher frequency of resistance was observed to tetracycline, followed by amoxicillin, gentamicin, ampicillin, trimethoprim-sulfamethoxazole, nalidixic acid, cefoxitin, and norfloxacin. All strains were susceptible to amikacin. Forty-eight (78.68 %) of the E. coli strains were classified as multidrug-resistant, whereas among Salmonella spp. strains, the percentage of multidrug resistance was 57.14 %, being all multidrug-resistant strains isolated from pigs (92.30 %). The results from the present study indicate a high frequency of antimicrobial resistance among pathogenic E. coli strains isolated from calves and Salmonella spp. strains isolated from pigs and a high rate of susceptibility to most antimicrobials tested among Salmonella spp. strains isolated from calves. Our study highlights the presence of multidrug-resistant strains of E. coli and Salmonella spp. isolated from food-producing animals in Minas Gerais, Brazil.  相似文献   

6.

Background

Colic has been associated with shedding of Salmonella. Horses with salmonellosis typically develop diarrhea, fever, and leukopenia. Overlooking additional predictors may result in failure to detect shedding horses and increase environmental contamination.

Objectives

Evaluate associations between signalment and clinicopathologic data during early hospitalization and Salmonella shedding in horses treated for acute colic.

Animals

Horses with acute colic admitted to a referral hospital. A total of 59 horses shedding Salmonella compared to 108 Salmonella‐negative horses.

Methods

Retrospective case‐control study evaluating patient and Salmonella culture data. Associations between variables and Salmonella shedding were identified using logistic regression. Two multivariable models were developed pertaining to (1) information available within 24 hours of admission and (2) clinical findings that developed later during hospitalization.

Results

Variables retained for multivariable model 1 indicated that Warmbloods and Arabians had increased odds for shedding Salmonella, as did horses requiring surgery (OR, 2.52; 95% CI, 1.10–5.75) or having more severe gastrointestinal disease (OR, 2.59; 95% CI, 1.08–6.20). Retained variables for model 2 demonstrated that horses that were treated surgically (OR, 1.60; 95% CI, 0.70–3.62), developed fever >103°F (OR, 2.70; 95% CI, 0.92–7.87), had abnormal leukocyte count (OR, 1.38; 95% CI, 0.61–3.09), or became inappetent and lethargic (OR, 16.69; 95% CI, 4.08–68.24) had increased odds for shedding Salmonella.

Conclusions and Clinical Importance

In horses with acute colic that present without signs of diarrhea, fever, or leukopenia, additional predictors associated with shedding Salmonella could be used to more promptly identify horses likely to shed organisms .  相似文献   

7.
Strongyle parasites are ubiquitous in grazing horses and constitute a potential threat to equine health. Feces were collected from six horses four times daily over a period of 5 days. Fecal egg counts (FECs) were performed to identify any diurnal rhythms in strongyle egg shedding and to quantify variability at the different levels: individual horses, repeated counts, repeated subsamples, different time points, and different days. No significant differences in FECs were found between the different time points (P = .11). The variables—horse, day, subsample, and egg count—accounted for a variance of 104.83, 0.10, 7.24, and 5.61, respectively. The apparent lack of additional variability between the four different time points suggests that time of the day chosen for collecting fecal samples does not constitute a source of error in field studies. The majority of variability exists between different subsamples and repeated egg counts on the same subsamples, whereas the variability of FECs between following days can be considered negligible. The findings of this study have implication for designing and performing field surveillance of strongyle FEC levels and applying the FEC reduction test for evaluating anthelmintic efficacy.  相似文献   

8.
Abrupt dietary transitions and feeding of rapidly fermentable diets are common practices in the horse industry and have been associated with digestive and metabolic disorders that can impair the performance of horses. The present study investigated the effect of dietary transition from pasture grazing to confinement with concentrate feeding, and back, on fecal pH and bacterial populations of Streptococcus spp and Lactobacillus spp. Six Thoroughbred fillies, previously grazing perennial ryegrass and white clover-based pasture, were housed in individual stalls and fed an increasing ratio of concentrate to conserved forages for 13 days (days 1-13), followed by an abrupt transition back to only pasture-grazing for 3 days (days 14-16). The concentrate was initially offered at 0.83 kg dry matter (DM)/d and increased to 5 kg DM/d, whereas ensiled alfalfa was initially offered at 0.61 kg DM/d, increasing to 1.22 kg DM/d. Meadow hay was initially offered at 6.73 kg DM/d, decreasing to 1.6 kg DM/d. Fecal specimens were collected daily for determination of pH, and every 2 days for quantitative analysis of Streptococcus spp and Lactobacillus spp. Mean fecal pH increased significantly from pasture baseline values (pH 6.18) during the initial confinement and supplementation on day 1 (6.37), day 2 (6.52), day 3 (6.58), and day 4 (6.43) (standard error of mean [SEM]: 0.056; P < .001). By day 5, mean fecal pH values had decreased to, and remained at, baseline values until the horses returned to pasture, when another increase occurred at day 15 (6.45). Fecal colony forming units (cfu) of Streptococcus spp and Lactobacillus spp increased linearly (r = 0.94; P < .001) from 6.0 and 6.1 log10 cfu/g on day -4, to 7.8 log10 cfu/g on day 14 (SEM: 0.2 P < .001), respectively. Fecal cfu decreased on return to a pasture-only diet (P < .001). In this study, the increment of bacterial populations was associated with a relatively stable fecal pH and highlights the difficulty in identifying the effects of dietary transition on the equine hindgut health, without microbial culture.  相似文献   

9.
The purpose of this study was to evaluate the effects of probiotic administration on the prevalence of fecal shedding of Salmonella , the prevalence of postoperative diarrhea, the length of antimicrobial therapy, and the length of the hospitalization stay during the postoperative period in horses with colic. Two commercially available probiotics for horses were used in a double-blind prospective study of 200 horses undergoing surgery for colic. Probiotic or placebo was administered PO once a day for 7 days postoperatively, and fecal cultures for Salmonella were obtained daily for 10 days. After selection of 186 patients completing the treatment protocol, the results indicated that the commercial probiotic formulations had no effect on Salmonella shedding, prevalence of diarrhea, length of antimicrobial therapy, or length of hospitalization ( P > .05). Twenty percent of the horses yielded 1 or more positive fecal cultures for Salmonella; of these horses, 74% were classified as asymptomatic shed-ders. Twenty-six percent of all horses had fluid diarrhea postoperatively, with only 12% of these horses having positive fecal cultures for Salmonella , The most common isolate was Salmonella krefeld (24 of 39 isolates). Among the different gastrointestinal disorders, horses with feed and sand impactions appeared to be more prone to shed Salmonella .  相似文献   

10.

Background

The primary aims of this study were to determine the incidence of Giardia infections in dairy herds on farms in the New York City Watershed region and to evaluate risk factors associated with infections. Because co-infections of Giardia and Cryptosporidium spp. are common in this population, we also evaluated the effect of herd infection status on Giardia infections.

Methods

Farms were grouped into three cohorts based on their prior infection status with Giardia and/or Cryptosporidium spp. The sampling plan included collecting fecal samples from all calves below 30 days of age and proportional sampling of calves, young stock, and adults. A total of 10,672 fecal samples were collected and analyzed for the presence of Giardia cysts using zinc sulfate flotation. Herds enrolled in the study were sampled seasonally for a study period of two years. The probability of shedding cysts past a certain age and the factors that influenced the likelihood of shedding were evaluated using survival analysis. Linear regression was used to evaluate factors that were associated with the intensity of shedding.

Results

The majority of Giardia infections occurred in calves within their first 180 days of age, with the most number of calves shedding Giardia cysts between 11 and 20 days of age. The incidence of shedding of Giardia cysts ranged from 0.0004 per animal day for cattle in the low risk cohort to 0.0011 per animal day for cattle in the high risk cohort. The likelihood of shedding was influenced by the prior infection status of the herd and the season of collection. Infected animals shed on average 9,658 cysts/gram and the intensity of shedding Giardia cysts varied significantly with the age (p < 0.0001) and the season of collection (p = 0.0151 for Spring).

Conclusion

Giardia infections are common in dairy herds in the New York City watershed, particularly in calves less than 6 months of age. Seasonality may be an important factor in the perpetuation of infections based on changes in management practices corresponding to weather patterns of a particular season. A dairy herd''s prior infection status with Cryptosporidium influences the likelihood of infection with Giardia.  相似文献   

11.
The efficacy of topical ivermectin (IVM) on foals naturally infected by parasitic nematodes was evaluated. Two dosages of IVM were applied pour-on (F-Nor0.5; 0.5 mg/kg body weight [BW] and F-Nor1; 1 mg/kg BW) and results compared with the oral administration (F-Eq0.2; 0.2 mg/kg BW of IVM). The efficacy was measured by estimating the reduction in the fecal egg counts (fecal egg count reduction) and in the numbers of horses shedding parasite eggs (positive horse reduction). Several biochemical and enzymatic serum parameters were measured in the groups F-Eq0.2 and F-Nor1. Before the deworming of the horses, eggs of Parascaris equorum, Cyathostomum, Gyalocephalus spp, and Oxyuris equi were identified. In all the treated groups, the excretion of ascarid eggs ended 4 days after the treatment. The orally administered IVM suppressed the egg output of strongyles and pinworms 4 days after the treatment, whereas for the F-Nor1 group this occurred 8 days after the treatment. Eggs of strongyles were detected in the F-Nor0.5 group throughout the study. The levels of blood urea nitrogen, creatinine, total proteins, albumin, globulins, and lactate dehydrogenase (LDH) reduced significantly after the administration of IVM, but values not within the normal range were only achieved for LDH. A significant positive correlation between the fecal egg output of cyathostomins and the LDH was investigated. Clinically, no adverse reactions in the horses receiving the topical IVM were observed. It was concluded that the pour-on administration of 1 mg/kg BW IVM provides similar results to the oral administration, and offers a very useful tool to control infestation by the intestinal nematodes affecting wild grazing horses.  相似文献   

12.
The diagnostic accuracy of a PCR used to identify horses shedding Salmonella spp. in their feces during hospitalization was estimated, relative to bacterial culture of serially collected fecal samples, using longitudinal data. Five or more fecal samples were collected from each of 116 horses admitted as inpatients, for reasons other than gastrointestinal disease, between July 26, 2001 and October 25, 2002. All 873 fecal samples collected were tested with a PCR based on oligonucleotide primers defining a highly conserved segment of the histidine transport operon gene of Salmonella typhimurium, and each sample was cultured for Salmonella spp. One or more samples from 87 (75%) horses were PCR positive, and Salmonella was cultured from 1 or more samples from 11 (9.5%) horses. All culture-positive horses had at least 1 PCR-positive result, whereas only 29 (28%) culture-negative horses were PCR negative on all fecal samples tested. The PCR was most specific, relative to bacterial culture of serially collected fecal samples, when used to test samples from Quarterhorse or breeds other than Thoroughbred or Standardbred, or from clinical (vs. healthy, accompanying horses) cases. Overall, the PCR had the greatest agreement (70%), compared with bacterial culture of serially collected fecal samples, using a cutoff of 2 or more positive PCR test results to define a Salmonella-positive horse. The reasons why some fecal samples, from which Salmonella organisms cannot be isolated, are PCR positive need to be determined before the PCR can be incorporated into Salmonella surveillance programs for hospitalized equine populations.  相似文献   

13.
Bacteriologic cultures of 65 rectal mucosal samples and 335 fecal samples from 53 horses and 5 cattle shedding Salmonella were performed. Salmonella spp were isolated from 34 (52%) rectal mucosal samples, 21 (32%) concurrent fecal samples, and 150 (45%) total fecal samples. The use of rectal mucosal samples when compared with concurrently obtained fecal samples significantly (P less than 0.025) improved the ability to isolate Salmonella spp. Concurrent bacteriologic culture of rectal mucosal samples and fecal samples resulted in 39 (60%) isolations. Compared with a series of fecal samples, Salmonella was isolated significantly more often when rectal mucosa and feces were cultured concurrently. Salmonella was isolated from rectal mucosal samples when it was not isolated from feces.  相似文献   

14.
The primary objectives of this study were to describe the prevalence and risk factors for Cryptosporidium spp. and Giardia spp. infection in cows and calves during the calving season in western Canadian cow-calf herds. Through the calving season of 2002, fresh fecal samples were collected from 560 beef cows and 605 calves in western Canada. Feces were examined for the presence of Cryptosporidium spp. and Giardia spp. using a quantitative sucrose gradient immunoflourescent antibody test. Samples were collected from mature cows on 59 farms and from calves on 100 farms. Only 1.1% (5/560) of the cows were positive for Cryptosporidium spp. whereas 3.1% (19/605) of the calves were positive. Prevalence for Giardia spp. was much higher; Giardia spp. was detected in 17.0% (95/560) of the cow and 22.6% (137/605) of calf fecal samples. Data describing herd management practices, treatment and disease history, age, gender, breed and fecal consistency were gathered to assess potential risk factors associated with shedding. The association between the risk of shedding and average precipitation from December to June and ecological region were also evaluated. Risk factors for infection with Cryptosporidium spp. in either cows or calves could not be evaluated because the multilevel model would not converge due to the relatively low prevalence of the organism in this sample. The prevalence for Giardia spp. was sufficient to explore potential risk factors in both cows and calves. No risk factors were identified for Giardia spp. in beef cows following calving. After the construction of a multivariable model, the only significant predictors for Giardia spp. presence in beef calves was dam age and calf age. Calves born to 2-year-old heifers were 2.3 (95% CI, 1.09-5.06; P = 0.031) times more likely to be shedding Giardia spp. then calves born to cows that were 4-10 years of age. Calves that were 9-18 days of age and calves that were > 18 days of age were 22.4 (95% CI, 5.88-88.18; P < 0.001) and 150 (95% CI, 39.72-603.19; P < 0.001) times more likely, respectively, to be shedding Giardia spp. than calves < or = 4 days of age.  相似文献   

15.
OBJECTIVE: To estimate prevalence of Salmonella spp in Ohio dairy farms and to identify potential risk factors for fecal shedding of salmonellae. DESIGN: Cross-sectional study. SAMPLE POPULATION: 105 Ohio dairy farms. PROCEDURE: Individual fecal samples from all mature cows in study herds were tested for Salmonella spp by use of standard bacteriologic culture procedures. Herds were identified as infected if at least 1 cow was shedding Salmonella spp. Information regarding herd characteristics, management practices, and health history were collected. Potential risk factors for herd-level Salmonella infection were identified. RESULTS: In 31% of the study herds (95% confidence interval, 22 to 40%), at least 1 cow was shedding Salmonella spp. Six percent of 7,776 fecal samples contained Salmonella organisms; prevalence within infected herds ranged from < 1 to 97%. Herd size, use of free stalls for lactating and nonlactating cows, and use of straw bedding in nonlactating cows were significantly associated with fecal shedding of Salmonella spp, as determined by use of univariate analysis. By use of multivariate analysis, large herds were more likely to be infected than smaller herds; however, no other factors were associated with Salmonella infection after adjustment for herd size. CONCLUSIONS AND CLINICAL RELEVANCE: Subclinical shedding of Salmonella spp is common in Ohio dairy herds, although we could not identify specific interventions that may influence the prevalence of Salmonella spp on dairy farms. It appears that large herd size and intensive management may provide an environment conducive to Salmonella shedding and chronic dairy herd infection.  相似文献   

16.
Cryptosporidium spp. and Giardia duodenalis are common protozoal parasites in livestock including beef cattle on rangeland and irrigated pasture. A statewide cross-sectional study was conducted to determine the prevalence, species or genotype, and risk factors for fecal shedding of Cryptosporidium and Giardia by cattle from California cow-calf operations. Species and genotypes of Cryptosporidium and Giardia were determined by molecular fingerprinting. Prevalence of Cryptosporidium (19.8%) and Giardia (41.7%) in fecal samples from calves were approximately twice as high as fecal samples from cows (9.2% and 23.1%, respectively). In addition to age, multivariable logistic regression showed that higher stocking density and a higher number of replacement heifers were positively associated with fecal shedding of Cryptosporidium while longer calving interval, a winter/spring calving season, and higher numbers of replacement heifers were positively associated with shedding of Giardia. The dominant species and genotypes of Cryptosporidium and Giardia in feces from these cow-calf herds were Cryptosporidium ryanae (75%) and assemblage E for Giardia duodenalis (90%), which have low impact on public health compared with other zoonotic species/genotypes of these two parasites. We identified host and potential management practices that can be used to protect cattle health and reduce the risk of surface water contamination with protozoal parasites from cow-calf operations. In addition, this work updated the scientific data regarding the predominance of low zoonotic genotypes of Cryptosporidium and Giardia shed in the feces of commercial cow-calf herds on California rangeland and irrigated pasture.  相似文献   

17.
The risk of Salmonella shedding among pigs at slaughter with regard to their previous on‐farm Salmonella status was assessed in a group of pigs from a farm from NE of Spain. A total of 202 pigs that had been serologically monitored monthly during the fattening period and from which mesenteric lymph nodes (MLN) and faecal (SFEC) samples were collected at slaughter for Salmonella isolation were included. A repeated‐measures anova was used to assess the relationship between mean OD% values during the fattening period and sampling time and bacteriology on MLN and SFEC. Pigs were also grouped into four groups, that is pigs seronegative during the fattening period and Salmonella negative in MLN (group A; n = 69); pigs seronegative during the fattening period but Salmonella positive in MLN (B; n = 36); pigs seropositive at least once and Salmonella positive in MLN (C; n = 50); and pigs seropositive at least once but Salmonella negative in (D; n = 47). Pigs shedding at slaughter seroconverted much earlier and showed much higher mean OD% values than non‐shedders pigs. The proportion of Salmonella shedders in groups A and D was high and similar (26.1% and 29.8%, respectively), but significantly lower than that for groups B and C. The odds of shedding Salmonella for groups B and C were 4.8 (95% CI = 1.5–15.5) and 20.9 (3.7–118) times higher, respectively, when compared to A. It was concluded that a large proportion of Salmonella seronegative pigs may shed Salmonella at slaughter, which would be likely associated to previous exposure with contaminated environments (i.e. transport and lairage). For pigs already infected at farm, the likelihood of shedding Salmonella was much higher and may depend on whether the bacterium has colonized the MLN or not. The odds of shedding Salmonella spp. were always much higher for pigs in which Salmonella was isolated from MLN.  相似文献   

18.
Foodborne salmonellosis is one of the most important bacterial zoonotic diseases worldwide. Salmonella Typhimurium is the serovar most frequently isolated from persistently infected slaughter pigs in Europe. Salmonella Typhimurium pathogenesis is host species specific. In addition, differences in in vitro behaviour of Salmonella Typhimurium strains have also been described, which may be reflected by a different course of infection within a host species. We compared the course of a Salmonella Typhimurium infection in pigs, using two Salmonella Typhimurium strains that were able to interfere with MHC II expression on porcine macrophages to a different extent in vitro. After experimental inoculation, blood and faecal samples from all pigs were collected at regular time points. At 40 days post inoculation (pi), animals were euthanized and tissue samples were bacteriologically analysed. The proportion of serologically positive piglets at 33 days pi was significantly higher in pigs that were inoculated with the strain that did not downregulate MHC II expression in vitro. Furthermore, this strain was less frequently shed and isolated in lower numbers from tonsils and ileocaecal lymph nodes than the strain that was able to markedly downregulate MHC II expression in vitro. We thus found that the delayed onset of seroconversion after oral inoculation of piglets with a particular Salmonella Typhimurium strain coincided with higher faecal shedding and increased persistence. Strain specific differences in Salmonella pathogenesis might thus have repercussions on the serological detection of Salmonella Typhimurium infections in pigs.  相似文献   

19.
Muscle samples from the neck and diaphragm and fecal samples were collected from five hogs from each of 50 lots of market hogs at three Manitoba abattoirs. Environmental samples were also collected. Each sample was tested for Salmonella contamination, and tissue and fecal samples were tested for Campylobacter.

Salmonella was isolated from 34 (4.1%) of 821 samples, with 17 of the isolates coming from one lot of hogs and their concurrent environment. Campylobacter was isolated from 175 (26.3%) of 666 samples. Fifty-five percent were Campylobacter coli and 45% were Campylobacter jejuni.

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20.
The purpose of this study was to characterize the fecal microbiota of horses with acute and chronic diarrhea before and after fecal microbiota transplantation (FMT). Six client-owned horses with acute and chronic diarrhea received FMT from 2 healthy donor horses. Microbiota analysis using next-generation sequencing was performed on fecal samples collected before and 2 and 7 d after FMT. Signs of diarrhea improved in 4 horses, whereas the remaining 2 horses did not survive. There was a significant difference in the number of bacterial species between donors and recipients (P < 0.05). The Order Lactobacillales and the genera Lactobacillus, Intestinimonas, and Streptococcus were increased in the microbiota of diarrheic horses, and Saccharofermentans genus increased in healthy donors. The results suggest that FMT from the healthy donors was not effective over a 7-day period as it did not change the fecal microbiota of the diarrheic horses. Further research to improve the efficacy of FMT in horses is needed.  相似文献   

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