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1.
Field studies on enzootic abortion of ewes in south east Scotland   总被引：6，自引：0，他引：6  
Statistical data were collected from 20 sheep flocks in which enzootic abortion of ewes (EAE) was diagnosed by examination of fetal material and maternal blood samples. The abortion rate in the 10,645 ewes in these flocks was 7.6 per cent. Thirteen of the flocks were fully vaccinated against EAE but the abortion rate in these was still in the order of 6.5 per cent. EAE was the major cause of the problem as ascertained from the laboratory examination of samples from a wide range of cases of abortion. There is therefore evidence that, in some flocks in south east Scotland, the efficacy of the vaccine against EAE is unsatisfactory. The reasons for this are discussed.  相似文献   

2.
Greco  G.  Totaro  M.  Madio  A.  Tarsitano  E.  Fasanella  A.  Lucifora  G.  Buonavoglia  D. 《Veterinary research communications》2005,29(1):107-115
An epidemiological survey was performed to detect the presence of Chlamydophila (C.) abortus and other members of the order Chlamydiales in ovine and caprine flocks with a history of abortion in southern Italy. Four pairs of primers were compared to evaluate their ability to detect Chlamydiales using purified DNA preparations and tissue samples from aborted foetuses with suspected chlamydial infections. As expected, amplification of DNA of the reference strain C. abortus using primer pairs U23F/23Sigr, 16SF2/23R, CTU/CTL and CpsiA/CpsiB produced fragments of about 600 bp, 585 bp, 1000 bp and 300 bp, respectively. The detection limits of the four PCR tests performed on serial DNA dilutions of the C. abortus reference strain were of 10 pg, 0.1 pg, 0.1 pg and 1 fg of DNA, respectively. The most sensitive amplification of DNA extracted from the organ tissues was obtained with primer pairs CpsiA/CpsiB, which detected Chlamydophila spp. DNA in all infected tissue samples. Only C. abortus was identified during the survey. The presence of this agent was confirmed in 3 out of 27 ovine and caprine flocks included in the survey suggesting that abortion due to C. abortus is uncommon in southern Italy.  相似文献   

3.
Enzootic abortion of ewes (EAE) caused by Chlamydia abortus is a disease of ruminants that results in serious economic losses in livestock industry. The zoonotic potential of the pathogen adds a public health concern on the efforts to control the disease. We report herein a cross-sectional study that was conducted during the lambing season (June and July) in Tunisia to estimate the seroprevalence of C. abortus infection in large sheep herds with abortion history. A total of 803 ewes were sampled and tested using indirect enzyme linked immunosorbent assay (iELISA). The overall apparent seroprevalence at herd and individual levels were 58 % (95 %CI = 39–74.5 %) and 6.6 % (95 %CI = 4.9–8.3 %), respectively. Significant risk factors investigated using univariate and multivariate analyses were history of infertility (OR = 5.7; 95 %CI = 3.05–10.66), the number of reproductive ewes (OR = 2.1; 95 %CI = 1.12–3.94), the control of new animals at introduction (OR = 4.35; 95 %CI = 2.46–7.68), the sharing of drinking water (OR = 2.18; 95 %CI = 1.22–3.9), the exchange of breeding males (OR = 2.56; 95 %CI = 1.003–6.54), the disposal of abortion materials without precaution (OR = 4.36; 95 %CI = 2.42–7.87), the lack of lambing barn (OR = 2.39; 95 %CI = 1.13–5.04), the non-application of hygienic post-abortion measures (OR = 10.35; 95 %CI = 5.28–20.26) and the manure management (OR = 11.35; 95 %CI = 3.26–39.48). To the best of our knowledge, this is the first sero-epidemiological survey conducted on an abortive disease in Tunisian ewes that investigated the risk factors of C. abortus infection.  相似文献   

4.
Chlamydophila (C.) abortus, responsible for chlamydial abortion (commonly known as Enzootic Abortion of Ewes [EAE]), causes major financial losses to the sheep industry worldwide. There remain many uncertainties surrounding the epidemiology of EAE. The aim of this study was to construct an epidemiological model to simulate EAE based on current knowledge of the disease, and in doing so, identify knowledge gaps that need to be addressed through further research. Key parameters that impact upon the development of the disease, such as the rate of contact between na?ve ewes and infected material, are defined. Sensitivity analysis was undertaken for parameter values that are unknown to explore their impact upon the pattern of disease. The simulated results show the importance of the transmission rate (i.e. contact) and the number of infected replacements introduced at the start of an outbreak. Depending upon the rate of transmission, the year in which the peak number of affected ewes occurs and the number of years over which a high number of animals are affected varies. This suggests that a better understanding of the underlying processes that drive transmission of C. abortus is needed. Furthermore, if infected ewes could be identified prior to parturition, when they shed the organism in large numbers, the impact of EAE on sheep flocks could be greatly reduced.  相似文献   

5.
We conducted a seroepidemiological survey to determine the prevalence of caseous lymphadenitis (CLA) in goat herds in Minas Gerais state, Brazil. Serum samples were collected from goats (n = 676) from 108 rural properties in 2001, covering most of the sub-regions of this ca. 586,500 square kilometer state. Antibodies against Corynebacterium pseudotuberculosis secreted proteins were detected by an indirect enzyme-linked immunosorbent assay (ELISA). Most of the animals (78.9%) tested positive for CLA; 98% of flocks presented at least one seropositive animal. Goats managed under an extensive production system had a significantly higher seroprevalence of CLA than those in intensive and semi-intensive operations. The age distribution of the animals in the flocks affected the prevalence of this disease; however, goat breed did not. We found seropositivity against C. pseudotuberculosis to be highly prevalent in these Brazilian goat herds; consequently, appropriate management practices for the control of CLA should be implemented.  相似文献   

6.
Chlamydophila abortus is one of the principal causes of late-term abortion (enzootic abortion of ewes or EAE) in sheep across Europe. Serological diagnosis of EAE is routinely carried out by the complement fixation test, although the interpretation of results can often be difficult because of cross reaction with Chlamydophila pecorum, which also commonly infects sheep. The purpose of this study was to evaluate and compare four ELISAs developed at Moredun Research Institute and based on whole C. abortus elementary bodies (EBs), an outer membrane preparation of the whole organism (SolPr) and two recombinant polymorphic outer membrane protein fragments (rOMP90-3 and rOMP90-4), with 3 commercial tests, the CHEKIT Chlamydophila Abortus, Pourquier ELISA Chlamydophila abortus and ImmunoComb Ovine Chlamydophila Antibody tests. The tests were evaluated using a panel of 202 sera from experimentally and naturally infected animals, as well as from EAE-free flocks. The EB, SolPr and CHEKIT ELISAs performed similarly to the CFT, all lacking in specificity by cross reacting with sera from C. pecorum infected animals. The ImmunoComb also lacked specificity with C. pecorum sera, but also badly cross reacted with sera from EAE-free flocks. The rOMP90-3, rOMP90-4 and Pourquier ELISAs were the most specific, although the Pourquier test appeared less sensitive with sera from naturally infected animals. Overall, the rOMP90-3 ELISA performed the best, with high sensitivity (96.8%) and no cross reaction with sera from C. pecorum infected animals or from EAE-free flocks (100% specificity) and so would be a suitable alternative to the CFT for the serological diagnosis of EAE.  相似文献   

7.
Enzootic abortion of ewes (EAE) caused by Chlamydophila abortus is an important disease resulting in significant lamb loss in most sheep producing countries. Ewes are considered to be naturally infected with C. abortus via the oral–nasal route and may become persistent carriers, shedding during subsequent oestrous cycles and at lambing. The aim of this study was to monitor the clinical outcomes, pathological changes and shedding of C. abortus in 18 periparturient orally infected sheep for two breeding seasons. In the first season, C. abortus was detected by real-time PCR (rt-PCR) in 13/18 conjunctival swabs at oestrus. Three out of the 15 pregnant ewes gave birth to 1 live and 1 dead lamb, and 2 of them aborted. Following parturition/abortion, C. abortus was detected in 12/15 vaginal swabs and in all the collected foetal membranes. However, only those membranes containing high copy numbers of the bacterium displayed the EAE typical lesions. In the second season, none of the 13 pregnant ewes aborted, and 5 of them gave birth to dead or weak lambs. C. abortus was not detected in conjunctival or vaginal swabs at oestrus or parturition. The bacterium was detected at low levels in 36% of the foetal membranes, but with no evidence of histopathological lesions. These results indicate that C. abortus can be detected in a large proportion of animals during the first pregnancy after oral infection. However, this proportion is reduced at the subsequent breeding season, confirming the occurrence of a chronic low level persistent infection in post-abortion/lambing ewes.  相似文献   

8.
An observational study was conducted of chicken and turkey flocks slaughtered at federal processing plants in the province of Quebec, Canada. The objectives were to estimate prevalence of drug use at hatchery and on farm and to identify antimicrobial resistance (AMR) in cecal Escherichia coli and Enterococcus spp. isolates and factors associated with AMR. Eighty-two chicken flocks and 59 turkey flocks were sampled. At the hatchery, the most used antimicrobial was ceftiofur in chickens (76% of flocks) and spectinomycin in turkeys (42% of flocks). Virginiamycin was the antimicrobial most frequently added to the feed in both chicken and turkey flocks. At least 1 E. coli isolate resistant to third-generation cephalosporins was present in all chicken flocks and in a third of turkey flocks. Resistance to tetracycline, streptomycin, and sulfisoxazole was detected in > 90% of flocks for E. coli isolates. Antimicrobial resistance (AMR) was observed to bacitracin, erythromycin, lincomycin, quinupristin-dalfopristin, and tetracycline in both chicken and turkey flocks for Enterococcus spp. isolates. No resistance to vancomycin was observed. The use of ceftiofur at hatchery was significantly associated with the proportion of ceftiofur-resistant E. coli isolates in chicken flocks. In turkey flocks, ceftiofur resistance was more frequent when turkeys were placed on litter previously used by chickens. Associations between drug use and resistance were observed with tetracycline (turkey) in E. coli isolates and with bacitracin (chicken and turkey), gentamicin (turkey), and tylosin (chicken) in Enterococcus spp. isolates. Further studies are needed to provide producers and veterinarians with alternative management practices and tools in order to reduce the use of antimicrobial feed additives in poultry.  相似文献   

9.
Whirling disease (WD), a severe and widespread disease of salmonids, is caused by the myxosporean parasite Myxobolus cerebralis. It is further characterized by a unique two-host life cycle, utilizing the oligochaete Tubifex tubifex as an intermediate host. M. cerebralis is an invasive species that has been affecting populations in the United States including epidemics that killed in excess of 90% of populations in Colorado and Montana streams within the past 20 years. Currently, there is no known cure for WD, and the accepted method of control is removal of infected fish from the population. We have created a compartmental model of the WD system in order to assess more efficient means of control and management of the disease. Using data gathered from the literature, we used Bayesian model fitting to estimate model parameters and estimated that R0 ≈ 1.51 (95% CI: 1.39, 1.72), a value which implies that WD can be controlled using available strategies. To this end, we posit several parameters that we expect to be most influential to WD propagation, namely: release of triactinomyxons by T. tubifex, release of spores by salmonids, and infectious particle loads in each respective host. Based on currently available control strategies, approaches targeting the infectious particles and the oligochaete host appear the most effective alternative strategies for management and control of WD.  相似文献   

10.
Campylobacter is recognized as one of the leading cause of gastroenteritis worldwide, and is frequently isolated from the small intestines and ceca microflora of chickens. Twenty-one out of 81 Campylobacter-positive poultry flocks were selected to evaluate the genetic diversity of Campylobacter isolates and to study the distribution of genotypes among flocks. Campylobacter isolates recovered from chicken carcasses and ceca were analyzed by pulsed-field gel electrophoresis (PFGE). Little diversity was found among Campylobacter strains isolated from a given carcass, with a maximum of 2 different genotypes being present. However, at flock level, as many as 4 different profiles were observed. Typing of strains showed that most strains isolated from ceca were similar to those isolated from corresponding broiler carcasses. A total of 39 different macrorestriction profiles were observed, with evidence of Campylobacter cross-contamination among broiler flocks in Quebec slaughterhouses. Surprisingly, some flocks shared related genotypes both with and without sharing similar rearing practices. Existence of such cross-contamination must be considered to in developing strategies to control Campylobacter in chickens, and to avoid bacteria contamination of noncolonized flocks. Further typing studies of Campylobacter found in hatcheries, farm environment, and crates or trucks in Quebec might be helpful in elucidating the kinetics of broiler chicken Campylobacter contamination.  相似文献   

11.
Ovine footrot remains the most important cause of lameness in sheep flocks in the UK, despite the existence of proven methods for the control of the disease. Recent research suggests that sheep farmers may be unaware of these methods and may allocate greater resources to treatment of footrot rather than to its prevention. Foot paring, topical treatments, vaccination and parenteral antibiotic therapy all have a role in treating sheep with advanced footrot infections, but prevention of severe infections is best achieved by the timely implementation of control programmes. These are usually based on footbathing and vaccination. For control programmes to be effective it is essential that the pathogenesis and epidemiology of footrot is understood and that control methods are implemented at appropriate times in the season, depending on climatic and pasture conditions. This article reviews these strategies and makes recommendations for steps to reduce the spread of footrot between flocks and to reduce the incidence of footrot within UK flocks.  相似文献   

12.
Abortion due to Coxiella burnetii was confirmed in the 2007/08 season in two naturally-infected dairy sheep flocks. Proportion of C. burnetii shedders and bacterial loads in vaginal mucus were high among aborted or lambed ewes, as was within-flock seroprevalence. Before the next reproductive season (2008/09) 75% of ewes and 50% of replacement lambs were vaccinated (Coxevac, CEVA Santé Animale) keeping the remaining as untreated controls. Compared with the previous year results when abortion outbreak started, a great reduction in the percentage of abortions, in the number of shedders and in the bacterial burden excreted by the ewes was found in both flocks. However, seroconversion in non-vaccinated yearlings from both flocks and the presence of C. burnetii DNA in bioaerosols taken at sheep premises at lambing indicated that infection was still active. No differences were observed between vaccinated and control groups in terms of proportion of C. burnetii shedders. These results suggest that optimal results of vaccination in heavily infected flocks may not be obtained in a short-term period.  相似文献   

13.
Toxoplasma gondii seroprevalence was determined in 3333 sheep sera from 125 distinct sheep flocks in Scotland, with the majority of flocks being represented by 27 samples, which were collected between July 2006 and August 2008. The selected farms give a representative sample of 14 400 sheep holdings identified in the Scottish Government census data from 2004. Overall T. gondii seroprevalence, at individual sheep level, was determined to be 56.6%; each flock tested, had at least a single positive animal and in four flocks all ewes tested positive. The seroprevalence of sheep increased from 37.7% in one year old stock to 73.8% in ewes that were older than six years, showing that acquired infections during the life of the animals is frequent and that environmental contamination by T. gondii oocysts must be significant. The median within-flock seroprevalence varied significantly across Scotland, with the lowest seroprevalence of 42.3% in the South and the highest seroprevalence of 69.2% in the far North of Scotland and the Scottish Islands, while the central part of Scotland had a seroprevalence of 57.7%. This distribution disequilibrium may be due to the spread and survival of oocysts on pasture and lambing areas. A questionnaire accompanying sampling of flocks identified farms that used Toxovax®, a commercial vaccine that protects sheep from abortion due to T. gondii infection. Only 24.7% of farmers used the vaccine and the vaccine did not significantly affect the within flock seroprevalence for T. gondii. The implications for food safety and human infection are discussed.  相似文献   

14.
A survey of sheep diseases in Canada.   总被引：2，自引：1，他引：1       下载免费PDF全文
A mail survey of disease occurrence in Canadian sheep flocks was conducted. The survey, which covered the period from September 1982 to August 1983, utilized flocks on the Record of Performance (ROP) sheep program and relatively complete data were available from 116 flocks. Data about lambing rates, incidence of a variety of lamb and ewe diseases and reasons for culling were obtained. At the same time a retrospective evaluation of records of diagnoses of sheep diseases recorded at diagnostic laboratories across the country was performed. Data from the years 1978 to 1982 were obtained and summarized. A lambing percentage of 153% (1.53 lambs live born per ewe lambing) was observed and an additional 0.05 lambs were stillborn. The major identified causes of mortality amongst lambs were starvation, pneumonia, scours and accidents. Pasteurella spp. were the etiological agents most commonly associated with pneumonia in lambs and Escherichia coli had the same predominant position with regards to nonparasitic scours. A large discrepancy existed between the proportional mortality rates for internal parasites and coccidiosis as determined from the farm survey data compared to diagnostic laboratory data. This suggests that clinical parasitism may not be adequately recognized at the farm level. Abortions in ewes occurred in approximately half the flocks, but generally at a low level and no severe abortion storms occurred. Pneumonia was the most commonly identified cause of mortality in ewes and although Pasteurella spp. appear to be the most important etiological agents, regional differences were apparent.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
Twenty-two flocks of turkeys affected by enteric problems, with ages between 10 and 104 days and located in the Southern region of Brazil, were surveyed for turkey by PCR for turkey astrovirus type 2 (TAstV-2), turkey coronavirus (TCoV), hemorrhagic enteritis virus (HEV), rotavirus, reovirus, Salmonella spp., and Lawsonia intracellularis (Li) infections. Eleven profiles of pathogen combination were observed. The most frequently encountered pathogen combinations were TCoV-Li, followed by TCoV-TAstV-2-Li, TCoV-TastV-2. Only TCoV was detected as the sole pathogen in three flocks. Eight and 19 flocks of the 22 were positive for TAstV-2 and TCoV, respectively. Six were positive for Salmonella spp. and L. intracellularis was detected in 12 turkey flocks. Reovirus and HEV were not detected in this survey. These results throw new light on the multiple etiology of enteritis in turkeys. The implications of these findings and their correlation with the clinical signs are comprehensively discussed, illustrating the complexity of the enteric diseases.  相似文献   

16.
The present study was carried out to investigate the presence of Chlamydophila abortus, the causative agent of ovine enzootic abortion, in milk samples collected from sheep flocks with and without the history of abortion in Eastern Turkey by means of immunomagnetic separation (IMS) in conjunction with the polymerase chain reaction (PCR). A total number of 201 milk samples collected from 10 flocks with abortion and four flocks without abortion were tested. In the analysis of the milk samples by IMS–PCR, correct amplification was obtained with three (1.5%) samples originating from one flock with abortion. In the digestion of PCR positive products by AluI, restriction profiles observed in all three samples were determined to be the same as C. abortus S26/3.  相似文献   

17.
A cross-sectional survey was carried out to investigate the seroprevalence of ovine and bovine brucellosis in the livestock–wildlife interface area of Nechisar National Park, Ethiopia. Furthermore, producer’s knowledge about brucellosis and its zoonotic potential was assessed using a structured questionnaire. A total of 268 cattle and 246 goat sera were collected from 50 herds and 46 flocks and subjected to Rose Bengal test (RBT) and enzyme-linked immunosorbent assay (ELISA) in parallel to detect anti-Brucella species antibodies. Positive reactions were further confirmed with compliment fixation test (CFT). Flock and herd level seroprevalence rate was 12.8% (95% CI 4.8–25.7) and 32.0% (95% CI 19.5–46.7) in goats and cattle, respectively. An overall animal-level seroprevalence of 4.5% (95% CI 2.25–7.86) and 9.7% (95% CI 6.44–13.89) was recorded for goats and cattle, respectively. Seroprevalence showed an increasing trend with age, where adult cattle >?2 years. Goats (>?1 year) recorded relatively higher seroprevalence, but the differences were not statistically significant. Similarly, female cattle and goats recorded a relatively higher seroprevalence, 11 and 5.6%, respectively, compared to males but the difference was not significant. However, a significant (P <?0.01) variation of seroprevalence was noted for parity (bovine), higher in animals in second parity, and abortion history, in both species, higher in animals that experienced abortion. Interviews revealed lack of awareness about brucellosis and food safety related to the zoonotic potential from consuming raw animal products (milk and meat). Ninety-eight percent of respondents did not consider handling abortion material is risky, and only a very low proportion (8%, n?=?50) was able to mention limited zoonotic diseases (anthrax and Taenia cysticercosis) could be transmissible to people. The study indicated that brucellosis is endemic in domestic animals in the interface area and calls for further broad epidemiological investigation of the disease in livestock, human and wildlife following ‘one health’ unified research approaches beside enhancing public awareness.  相似文献   

18.
Salmonella Enteritidis is a leading food-borne pathogen in the United States, with many outbreaks in humans traced back to shell eggs. As a result, the implementation of effective strategies for reducing Salmonella Enteritidis in commercial layer flocks has become a critical public health and economic objective. In this paper, we share the findings of 2 multistate USDA-National Integrated Food Safety Initiative grant teams and their work aimed at Salmonella Enteritidis reduction in shell eggs. One project, led by K. Venkitanarayanan, is using plant-derived antimicrobial molecules as dietary supplements to reduce Salmonella Enteritidis colonization of the digestive and reproductive tract of chickens. The same molecules are being evaluated for their effect on Salmonella Enteritidis in egg wash solutions. The project led by S. Kariyawasam used on-farm investigation and novel bacterial typing methods to study Salmonella Enteritidis transmission in diverse layer environments to update and optimize Egg Quality Assurance Programs that will significantly reduce Salmonella Enteritidis contamination of shell eggs. The current US Food and Drug Administration Egg Safety Rule and Egg Quality Assurance Programs are based on critical control points and best management practices developed from studies of large flocks (>50,000 hens) conducted in the 1990s, indicating that opportunities exist to improve preharvest programs to reduce Salmonella Enteritidis contamination. This paper will share the findings of these 2 projects.  相似文献   

19.
Nineteen flocks of four poultry species were monitored at a veterinary field station to investigate the distribution and spread of Campylobacter genotypes between sequential and adjacent flocks. Caecal and liver samples were obtained at frequent intervals from birds of all flocks and examined for Campylobacter. Amplified fragment length polymorphism (AFLP) analysis was performed to genotype Campylobacter isolates. Of the 1643 caecal and liver samples investigated, 452 (27.5%) caecal samples and 11 (0.7%) liver samples contained Campylobacter. Of the caecal isolates 76.3% were identified as Campylobacter jejuni and 23.7% were identified as Campylobacter coli. Poultry flocks were largely colonized by more than one AFLP type and an intense exchange of Campylobacter genotypes between different poultry flocks occurred. These findings indicate that multiple genotypes can constitute the Campylobacter population within single poultry flocks, hinting to different sources of exposure and/or genetic drifts within the Campylobacter population. Nevertheless, in most flocks single Campylobacter genotypes predominated. Some strains superseded others resulting in colonization by successive Campylobacter genotypes during the observation period. In conclusion, the data demonstrate that the large genetic diversity of Campylobacter must be considered in epidemiological evaluations and microbial risk assessments of Campylobacter in poultry.  相似文献   

20.
A Canada-wide flock management survey of 294 randomly selected commercial broiler chicken flocks was conducted during 1989-1990. The prevalence of flocks that yielded Salmonella from cultures of floor litter or drinking water, and the prevalence of floor litter samples that yielded Salmonella, were significantly associated (p < 0.05) with the age of the flock and the region of Canda in which the flock was located. Culture of Salmonella from the drinking water was significantly associated (p < 0.05) with the type of drinker used, the dead bird disposal method, and the region of Canada in which the flock was located. There was a significantly greater risk (p < 0.05) of contamination of drinking water with Salmonella from trough drinkers (odds ratio = 7.99) and plastic bell drinkers (odds ratio = 6.10) than from nipple drinkers. No significant associations were found between pest control, restrictions on visitors, clean-out methods, or water sanitization and the culture of salmonellae from floor litter or drinking water.  相似文献   

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