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1.
This study evaluated the suitability of invA gene amplification by PCR as an effective means of detecting Salmonella species in pigs experimentally infected with S. Typhimurium DT104. A controlled infection study using 24 pigs was performed in order to compare efficacy, precision and detection rates of the invA-based PCR method originally described by Rahn, K. De Grandis, S.A., Clarke, R.C., McEwan, S.A., Galan, J.E., Ginocchio, C., Curtiss, R. 3rd, C.L. Gyles, (Mol. Cell. Probes 1992; 6: 271-279) as a new in-house invA-based PCR method for the specific detection of Salmonella spp. in pork and different tissue samples of slaughter pigs. Finally, PCR results were compared with culture detection rates obtained by isolation procedures following the ISO 6579:2000, the 'gold standard'. After slaughtering, 14 different tissue samples of each pig were investigated to verify the usefulness of the two invA-based PCR methods in different matrices of slaughter pigs. The results demonstrate that the application of the widely used invA-based primer pair (139 + 141) may result in questionable products if samples gained from selective enrichment in the Rappaport-Vassiliadis medium were investigated. These questionable products can lead to false-positive results, if no additional hybridization procedure is attached or if unspecialized persons use this method in routine laboratory practice. The newly developed in-house PCR method used is based on the 3'-prime region of invA, especially designed and harmonized for the detection of Salmonella in different matrices of slaughtered pigs after bacterial enriched broth culture. In this study, this PCR revealed no questionable products and, furthermore, the specificity of the amplificate could be tested by means of the restriction enzyme NdeI. In comparison with the culture detection procedure, the new PCR method has a sensitivity of 100% and a specificity of 96%. Thus, this method might be used as a meaningful tool in eliminating Salmonella-positive carcasses at slaughterhouse level and thus, keeping them out of the food chain.  相似文献   

2.
Most swine Salmonella national control programmes in Europe have been based on the categorization of herds according to risk levels based on serological results. However, none of the non‐Scandinavian countries have reported of any significant success on Salmonella infection reduction in fattening pigs or the number of human cases attributable to pigs or pork. The limited accuracy of the tests used, the small number of animals sampled and the likely lack of herd representativeness of the samples used could be major factors affecting the suitability of these programmes. Focusing on minimizing Salmonella shedding at slaughter appears more important to prevent human infections than focusing on detection of seropositive pigs/herds at this stage. This study assessed whether performing on‐farm serology may help to predict shedding at slaughter. Between 2010 and 2016, pigs from six cohorts from a Salmonella‐positive herd were bled at 30, 60 and 90 days on fattening and before slaughter, and faecal samples collected at slaughter. Serology on days 60, 90 and before slaughter predicted somewhat shedding at slaughter with no significant differences among them. Pigs with higher OD% values at these point times would have higher risk of shedding when arriving to slaughter. The probability of shedding for a pig sampled on day 90 and showing an OD% value of 10 was 43%, and the risk increased up to 65% if the OD% was 40. Concluding, on‐farm serology may help to determine to some extent the risk of Salmonella shedding at slaughter from seropositive fattening units, which would allow for prompt on‐farm and slaughter interventions to reduce the likelihood of slaughter contamination with Salmonella.  相似文献   

3.
Salmonella is one of the most common causes of human gastroenteritis often associated with pork consumption. The aims of this cross‐sectional study were to collect preliminary data on the presence of Salmonella enterica in pigs in Piedmont (Italy), through sampling on farm and at slaughter and to gather pilot data on serotypes and phagetypes present in the sampled area and distribution of anti‐microbial resistance among isolated strains. Salmonella was detected through culture and identified with Salmonella spp. and Salmonella Typhimurium PCR; positive samples were serotyped, phagetyped and tested for antibiotic susceptibility. Positive samples (from 9% of faeces up to 29% of tonsils) were found in 64% of the herds. Salmonella spp. was retrieved also from scalding water. Most of the isolates were Salmonella Derby, Salmonella Typhimurium and Salmonella 4,5,12:i:‐. The results of Salmonella Typhimurium specific PCR suggested that Salmonella 4,5,12:i:‐ might be unrecognized by serotyping. Anti‐microbial resistance was recorded in 75–100% of the isolates. Phagetyping allowed the identification of DT104B and DT46A strains. These results set the bases for further research studies that would aim to estimate the real herd prevalence in Piedmont and the diffusion of serotypes and anti‐microbial resistant strains within the same region.  相似文献   

4.
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   

5.
The seroprevalence of Salmonella spp., pathogenic Yersinia spp., Toxoplasma gondii and Trichinella spp. was studied in 1353 finishing pigs from 259 farms that were allocated according to farm types: large fattening farms (≥1000 pig places), small fattening farms (< 1000 pig places) and farrow‐to‐finish farms. The antibodies were analysed with commercial ELISA kits in meat juice samples that were collected at Finnish slaughterhouses. Salmonella antibodies were rare (3% of pigs, 14% of farms) when the cut‐off optical density (OD) value 0.2 was used. Antibodies to pathogenic Yersinia spp. and T. gondii were detected in 57% of pigs and 85% of farms (OD ≥0.3) and in 3% of pigs and 9% of farms (OD ≥0.15), respectively. No antibodies to Trichinella spp. were detected (OD ≥0.3). The European Food Safety Authority (EFSA) considers Salmonella spp., Yersinia enterocolitica, T. gondii and Trichinella spp. as the most relevant biological hazards in the context of meat inspection of pigs. The seroprevalence of these important zoonotic pathogens was low in Finland, except that of Yersinia. The seroprevalence of Toxoplasma was significantly higher in pigs originating from small‐scale fattening farms (P < 0.05). Strong positive correlation was observed at the animal level between Salmonella and Yersinia seropositivity and between Salmonella and Toxoplasma seropositivity (P < 0.05). We suggest that these results reflect the level and importance of biosecurity measures applied on the farms. Meat juice serology at slaughter is a useful tool for targeting measures to control these pathogens. The information obtained from analyses should be used as part of the food chain information (FCI).  相似文献   

6.
Salmonella is a major foodborne pathogen causing important zoonosis worldwide. Pigs asymptomatically infected in mesenteric lymph nodes (MLN) can be intermittent shedders of the pathogen through faeces, being considered a major source of human infections. European baseline studies of fattening pig salmonellosis are based on Salmonella detection in MLN. This work studies the relationship between Salmonella infection in MLN and intestinal content (IC) shedding at slaughter and the relationship between the presence of the pathogen and the serologic status at farm level. Mean Salmonella prevalence in the selected pigs (vertically integrated production system of Navarra, Spain) was 7.2% in MLN, 8.4% in IC and 9.6% in serum samples. In this low–moderate prevalence context, poor concordance was found between MLN infection and shedding at slaughter and between bacteriology and serology. In fact, most of shedders were found uninfected in MLN (83%) or carrying different Salmonella strains in MLN and in IC (90%). The most prevalent Salmonellae were Typhimurium resistant to ACSSuT ± Nx or ASSuT antibiotic families, more frequently found invading the MLN (70%) than in IC (33.9%). Multivariable analysis revealed that risk factors associated with the presence of Salmonella in MLN or in IC were different, mainly related either to good hygiene practices or to water and feed control, respectively. Overall, in this prevalence context, detection of Salmonella in MLN is an unreliable predictor of faecal shedding at abattoir, indicating that subclinical infections in fattening pigs MLN could have limited relevance in the IC shedding.  相似文献   

7.
The aim of the present study was to investigate the contamination sources and the transmission of Salmonella within a pig finishing herd in Italy. Nine sets of samples were collected during the fattening period from cleaned and disinfected pens, animals at different ages (4 days after arrival, 90, 150, 170 and 240 days of age) and at slaughter. Salmonella was isolated from cleaned pens, individual faecal samples, the truck used to transport the pigs to the abattoir and after slaughter (cecal contents, mesenteric lymph nodes and carcasses). Several serovars were isolated: Salmonella typhimurium and Salmonella derby on farm; Salmonella bovismorbificans, Salmonella bredeney, Salmonella blockley, Salmonella hadar and Salmonella corvallis from the truck; S. derby, S. hadar, S. bredeney, S. bovismorbificans and Salmonella infantis at slaughter. Antibiotic resistance of the strains was tested and PFGE was carried out to investigate the on-farm epidemiology of Salmonella. The results showed that the environmental contamination may have represented a major source of infection for the pigs both on farm and during transport to the abattoir.  相似文献   

8.
Non-typhoid Salmonella serovars remain a potential threat to human health, and beef cattle and broiler chickens are possible sources of these organisms on Prince Edward Island (PEI). In this study, the ceca of beef cattle belonging to fasted and non-fasted groups, and broiler chickens were examined for Salmonella at the time of slaughter. The characteristics of the isolates, including antimicrobial resistance patterns and virulence genes, were studied along with the isolates obtained from cases of human salmonellosis on PEI during the study period (1996–97). The prevalence of Salmonella in beef cattle was 4.6% (11/240). The rate was significantly higher in fasted cattle (7.46%), than in non-fasted cattle (0.94%). The prevalence rate in chickens was 32.5% (39/120). In beef cattle, Salmonella typhimurium phage type (PT) or definitive type (DT) 104 which was resistant to ampicillin, chloramphenicol, streptomycin, sulfisoxazole and tetracycline, was the most predominant type (64%). In chickens, S. heidelberg, with resistance to gentamicin, streptomycin and sulfisoxazole, predominated. Of 26 isolates from humans, the most common serovar was S. typhimurium, including a multidrug-resistant strain of DT104. Examination by PCR revealed presence of the virulence gene invA in all serovars, and the spvC gene in all S. typhimurium isolates, of both beef cattle and human origin. Among the other serovars the latter gene was found in 7 human isolates, but in none of the chicken or beef isolates. All but 3 of the spvC-positive isolates possessed a 90 kilobasepair (kbp) plasmid suggesting that the 3 isolates had the spvC gene on their chromosome. These findings were confirmed by plasmid DNA isolation using 3 different protocols and by sequence analysis of the spvC-PCR product.  相似文献   

9.
Feral pigs are one of the most abundant free‐roaming ungulates in the United States, yet their role in the ecology and transmission of foodborne pathogens is poorly understood. Our objectives were to estimate the prevalence of Salmonella shedding among feral pigs throughout Texas, to identify risk factors for infection, and to characterize the isolates. Faecal samples were collected from feral pigs in Texas from June 2013 through May 2015. Standard bacteriologic culture methods were used to isolate Salmonella from samples, and isolates were characterized via serotyping and anti‐microbial susceptibility testing. The prevalence of faecal Salmonella shedding among sampled pigs was 43.9% (194/442), with positive pigs originating from 50 counties. Pigs sampled during fall and summer were significantly more likely to be shedding Salmonella than pigs sampled during winter. High serovar diversity was evident among the isolates, and many of the detected serovars are leading causes of human salmonellosis. The most common serovars were Montevideo (10.0%), Newport (9.1%), and Give (8.2%). Resistance to anti‐microbial agents was rare. The burgeoning feral pig population in the United States may represent an emerging threat to food safety.  相似文献   

10.
A study was carried out to establish the prevalence of extra-intestinal porcine helminth infections and to assess the pig slaughter slab sanitary conditions in Dar es Salaam city, Tanzania. A total of 24 privately owned pig slaughter slabs were assessed. All slaughter slabs were sub-standard; wrongly located, poorly designed and constructed and lacked most basic requirements for a slaughter house. Because of inadequate slaughtering, disposal and cleaning facilities, the slaughter slabs were under unhygienic condition with questionable safety, soundness and wholesomeness of the pork produced. Routine meat inspection procedures were used to detect extra-intestinal porcine helminth infections. Of the 731 examined pigs; 8.1%, 5.9% and 0.4% were infected with ascariosis, porcine cysticercosis and hydatidosis, respectively. It was noted that almost all slaughter pigs in Dar es Salaam originated from different regions. Based on the region of origin, the status of porcine cysticercosis was 8.2% for Dodoma (n = 98), 8.2% for Manyara (n = 260) and 6.9% for Mbeya (n = 116). This study disclosed the unhygienic sanitary condition prevailing in Dar es Salaam pig slaughter slabs and recommends that strategies should be devised to improve the situation. Porcine ascariosis and cysticercosis were widely prevalent and caused economic losses due to condemnations. Because of their zoonotic nature, the observed extra-intestinal porcine helminth infections in pig pose a public health risk among consumers. Thus, there is a need to introduce appropriate control measures of parasitic infections in pigs.  相似文献   

11.
四川省部分地区山羊沙门氏菌健康带菌率及耐药性调查   总被引：2，自引：1，他引：1  
为了解四川省山羊沙门氏菌带菌情况,本试验采集了四川省部分地区5个规模化山羊养殖场表观健康山羊粪便196份,经BPW预增菌、TTB选择性增菌后,采用靶向invA基因的PCR方法检测沙门氏菌的带菌率;对阳性样本进行细菌分离鉴定,随机选择25株沙门氏菌分离株测定其对15种抗菌药物的敏感性。结果显示,山羊沙门氏菌的平均带菌率为54.59%。药敏试验结果显示,分离株均对丁胺卡那敏感,而对其余14种抗菌药物呈不同程度的耐药,多重耐药菌株占88%,其中耐2~7种药物的占52%,耐9~13种药物的占36%。结果表明,四川省部分地区山羊的沙门氏菌健康带菌率较高,且多重耐药性普遍,其公共卫生意义值得进一步研究。  相似文献   

12.
New molecular diagnostic techniques often rely on hybridization or amplification of specific DNA regions to detect pathogenic bacteria. The choice of genes to be used as probes or as the targets of amplification techniques is critical to the success of these procedures. The genes so used might best be those associated with virulent isolates and having a wide distribution among such isolates. In this study three genes,invA, pagC andspvC, thought to be associated with the virulence of salmonellae, were labelled and used to probe the total DNA from 103Salmonella isolates from animals in an attempt to determine whether these genes might be useful in diagnostic procedures.pagC was detected in 99% of theSalmonella tested, andinvA was detected in 94.2% of the isolates. BothpagC andinvA were detected with a significantly higher frequency thanspvC in isolates from chickens and swine, but no significant difference in detection of these three genes occurred when bovine isolates were examined. Failure to detect any of these genes occurred in only one isolate. Isolates from apparently healthy or from clinically ill chickens and swine could not be distinguished by detecting these three genes. The genes were not detected in the non-Salmonella strains tested. These results suggest that, of these three genes,pagC may be the best choice for use as a probe or polymerase chain reaction target in future detection protocols.Abbreviations df degrees of freedom - H apparently healthy animal - I animal diagnosed clinically as having salmonellosis - LB Luria-Bertani - NDSU North Dakota State University in Fargo, North Dakota - NS not significantly different - NVSL National Veterinary Services Laboratory in Ames, Iowa - PCR polymerase chain reaction - SDS sodium dodecylsulphate - UGA University of Georgia in Athens, Georgia  相似文献   

13.
Ankamali pigs, the domesticated native pigs of Kerala province of India were genetically characterized using 23 FAO recommended microsatellite markers and were compared with other native Indian pig types and Large White pigs. Twenty‐six blood samples were collected from genetically unrelated animals from their breeding tract and DNA was isolated by standard procedure of phenol/chloroform. The genomic DNA was amplified by polymerase chain reaction (PCR) at these 23 microsatellite loci, which were also used earlier to characterize Desi (North Indian) and Gahuri (North‐East Indian) pigs, the other two native domesticated pig types of India. The PCR products were resolved by denaturing urea‐polyacrylamide gel electrophoresis and alleles were visualized after silver nitrate staining. The data were analysed for allele size range, number of alleles, allelic frequencies, heterozygosity and polymorphism information content for each locus. The allele size range varied between 92–108 bp at locus S0026 and 280–296 bp at locus IGF‐1. The total number of alleles varied between five (S0178 and S0386) and 11 (S0355). The mean observed and expected heterozygosities were found to be 0.74 ± 0.09 and 0.83 ± 0.03 respectively. In the neighbour‐joining dendrogram based on DA genetic distances developed after 1000 bootstraps, the Ankamali pigs did not show genetic closeness either with other native Indian pig types or exotic Large White pigs with high bootstrap values indicating genetic distinctness of Ankamali pigs.  相似文献   

14.
The aim of this study was to examine whether and to what extent the addition of potassium diformate (pdf) or free organic acids (fpa) to the diet and the grinding intensity might affect the course of infection and the passage of orally applied Salmonella and Escherichia coli in pigs. Experiments were carried out using 80 reared piglets allotted to four groups. Pigs were fed pelleted diets ad libitum (except during a 15 h feed‐withholding‐period before infection). The control diet contained finely ground cereals (2 mm screen). To two test diets (also finely ground) 1.2% pdf, 0.9% organic acids (75% formic and 25% propionic acid, fpa) respectively were added. The fourth diet (without acids) was based on coarsely ground cereals (6‐mm screen). After experimental infection alternately with S. Derby or E. coli, the course of infection was examined (rectal swab technique). Pigs were sacrificed 4–5 h after a further oral application of ～109–1010 CFU S. Derby or E. coli to determine the counts of Salmonella or E. coli in chyme (classical culture methods). Adding pdf or fpa to the diet led to reduced Salmonella shedding and resulted in significantly lower counts of Salmonella and E. coli in the stomach content indicating an improved efficacy of the stomach barrier. In the distal parts of the digestive tract, the effect was less obvious concerning counts of E. coli, whereas counts of Salmonella were reduced markedly as well. The diet based on coarsely ground cereals failed to demonstrate positive effects concerning infection and passage of orally applied bacteria as well, but this diet was also pelleted and showed unintentionally, comparable amounts of fine particles. Results obtained in this study allow the recommendation of using pdf or organic acids as additives when dietary measures against Salmonella or E. coli in pigs are required.  相似文献   

15.
A total of 64 5‐month‐old Pietrain pigs were randomly allocated to four treatments with four replicates per treatment according to body weight. The pigs were fed either a standard corn‐soybean meal based control diet (treatments 1 and 2), the standard diet with 1% Lycium barbarum (LB) (treatment 3), or the standard diet with 1% Polygala tenuifolia Willd (PT) (treatment 4). Serum lactic acid and glucose concentrations were increased in stressed pigs (P < 0.05). Addition of the herbs in the diet had no effect on the serum lactic acid concentration, but 1% LB decreased (P < 0.05) serum glucose concentration in the stressed pigs. Pre‐slaughter stress also decreased (P < 0.01) liver glycogen concentration and the decrease could be inhibited by addition of 1% LB in the diet (P > 0.05). Pre‐slaughter stress increased the concentration of maleic dialdehyde (MDA) (P < 0.05) and decreased glutathione peroxidase (GSH‐Px) activity in serum, while dietary 1% LB increased (P < 0.05) the activity of GSH‐Px and decreased the concentration of MDA in the serum. In conclusion, pre‐slaughter stress induces oxidative stress in pigs and dietary supplementation with 1% LB improves antioxidant capacity in stressed pigs before slaughtering.  相似文献   

16.

  1. The onset and progression of Salmonella infections was investigated in commercial turkey flocks from placement at 1 d old until slaughter in “brood and move” systems using a longitudinal observational approach based on faeces and environmental sampling with subsequent culture of Salmonella.

  2. Persistent Salmonella Newport contamination was found within rearing houses and on their external concrete aprons after cleaning and disinfection between crops of heavily shedding young birds.

  3. Salmonella shedding was often detected by 5 d of age and the frequency of positive samples peaked at 14–35 d. Thereafter Salmonella isolations declined, especially in the later (fattening) stages. Samples were still Salmonella-positive at low prevalence in half of the intensively sampled houses at slaughter age.

  4. A number of management interventions to combat Salmonella infection of flocks, including sourcing policy, competitive exclusion cultures and cleaning and disinfection, were inadequate to prevent flock infection, although improved disinfection on one unit was associated with a delay in the onset of flock infection.

  相似文献   

17.
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   

18.
为建立猪伪狂犬病病毒(PRV)gE基因缺失疫苗和野毒感染的快速鉴别诊断方法,本研究根据猪伪狂犬病野毒具有gD表面抗原基因和gE毒力基因,而基因缺失疫苗只有gD基因无gE基因的特性,针对gD/gE基因的5'端核苷酸序列自行设计引物,建立鉴别PRV gE基因缺失疫苗和野毒感染的二重PCR诊断方法,并进行了特异性、敏感性和重复性试验;利用所建立的检测方法对临床疑似样品进行了检测.结果表明,成功建立了鉴别PRV gE基因缺失疫苗和野毒感染的二重PCR诊断方法,该方法灵敏度高,最低检出限为100拷贝/μL;重复性好;特异性强,可特异性地扩增出PRV细胞毒中的gD和gE基因及gE基因缺失疫苗毒中的gD基因,但对PK-15细胞和猪流行性腹泻病毒等其他8种病原扩增不出任何条带;自835份临床疑似PRV感染病料中共检测出PRV gD和gE基因双阳性样品即野毒感染阳性样品267份,PRV gD基因单阳性样品28份,选取该方法检测出的26份PRV野毒感染阳性样品用于病原分离培养,两种方法的符合率为96.1%.说明本试验建立的二重PCR鉴别诊断方法快速、灵敏、特异,对于临床上疫苗毒和野毒感染的快速鉴别诊断具有重要意义.  相似文献   

19.
Various methods have been described in the literature for the detection of virulent Yersinia enterocolitica in pigs. The risk factors for pig herd contamination have yet to be determined. The objective of this study was to validate a sensitive method for the detection of Y. enterocolitica and to describe the distribution of the bacteria in pigs at slaughter from conventional and alternative ("organic") housing systems. First, samples were collected from tonsils, caecum with caecal contents, and the caecal lymph nodes of 60 slaughter pigs. These samples were used to compare the sensitivity of six different laboratory culture methods either in common use or described in the literature with that of a polymerase chain reaction with two primer pairs (multiplex PCR). Then, only PCR was used to examine tonsils, caecum and caecal lymph nodes from two groups of slaughter pigs: 210 from six conventional fattening farms and 200 from three with alternative housing. The results of the multiplex PCR were positive in 28 cases. All culture methods proved inferior to PCR in sensitivity. In the second part of the study, PCR detected 36 (18%) positive pigs from alternative housing and 60 (29%) from conventional housing (p<0.05). The highest rate of Y. enterocolitica contamination was found in tonsils (11% alternative, 22% conventional; p<0.05), followed by caecum (5%, 11%) and lymph nodes (2%, 7%). The housing system appears to be one important factor in the prevalence of this common pathogen in pig herds, as we found important differences between the two systems studied here. In the conventional system, the main risk factors appeared to be sourcing pigs from different pig suppliers, use of commercial feed and transportation to slaughter.  相似文献   

20.
A total of 1401 German and 226 Croatian pigs raised either indoors or outdoors were tested for Trichinella infection by direct and indirect detection methods. A 10 g sample of diaphragm were examined for muscle larvae by the artificial digestion method; the species was determined by multiplex polymerase chain reaction (PCR). For detection of anti‐Trichinella IgG, serum samples diluted 1:100, and meat juice samples diluted 1:10, were tested by enzyme‐linked immunosorbent assay. All German pigs and those Croatian pigs raised indoors proved to be Trichinella‐negative by all methods. Muscle larvae were detected in a total of eleven of the Croatian pigs, which were raised on small outdoor farms. For eight isolates, PCR results demonstrated that recovered larvae were Trichinella spiralis. Anti‐Trichinella‐IgG was detected in serum and meat juice of digestion positive animals when the worm burdens exceeded 0.38 larvae per gram of muscle. Positive results in Croatian pigs indicate a higher risk of infection for outdoor farming in areas where Trichinella is endemic. Results of direct and indirect detection were compared and are discussed with special regard to specificity and sensitivity of methods.  相似文献   

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