Streptococcus R (Streptococcus suis type II) infection in pigs in Japan

Since the first outbreak of an epizootic disease on a pig farm in Shimane Prefecture in 1979, similar diseases have occurred continually on other 8 pig farms in the same prefecture until 1982. Main clinical symptoms of the disease were recumbency, convulsion, anorexia and paddling. The diseased pigs ranged mostly from 35 to 67 days of age. Monthly fatality on one pig farm for 1 year was 0.2 to 3.6%. Morbidities in affected litters were mostly at a level of 20 to 30% on 7 pig farms. The diseases were diagnosed as streptococcal meningitis and septicemia with each one of endocarditis and pneumonitis by pathological and bacteriological studies on 20 affected pigs. Distribution of piglets from a breeding farm to pig farms was considered as one of the causes of prevalence in the prefecture. Representative 20 strains of the isolates from diseased animals on 9 pig farms were identified as Streptococcus R (Streptococcus suis type II) by biological and serological examinations. For the latter examination, anti-Streptococcus R, S and T sera were prepared. It was also indicated that the disease had occurred in 8 prefectures in addition to Shimane, because positive results had been obtained from 41 strains submitted from those prefectures for serological diagnosis. The minimal inhibitory concentration was examined in 18 drugs to 19 isolates. It was the lowest in ampicillin and thiopeptin of all the drugs.     

A comparison of features and the microbial constitution of the fresh feces of pigs fed diets supplemented with or without dietary microbes

The features and the constitution of the microbial population of fresh feces were compared between pigs fed a diet supplemented with dietary microbes and pigs given nonsupplemented diets. The former were reared on farm C and the latter on farms A and B. The concentrations of ammonia-N, indole, and skatole of fresh feces were not significantly different between pigs reared on farm C and those raised on farms A and B, but the concentrations of ammonia-N and the skatole of fresh feces were significantly different between pigs reared on farms A and B. The total VFA (volatile fatty acids) concentration of fresh feces in pigs on farm C was slightly lower than in those on farms A and B. Moreover, the molar proportion of the acetic acid in feces in pigs on farm C was lower; inversely, that of propionic and butyric acids was higher in comparison with those on farms A and B. No differences were evident in the total viable counts of feces among pigs reared on the three different farms. Clostridium perfringens was abundant in feces of pigs raised on farms A and B, but it was not detected in pigs reared on farm C. Megasphaerae, bifidobacteria, and clostridia except for C. perfringens were more abundant in the feces of pigs fed a diet supplemented with dietary microbes on farm C, compared with pigs given the nonsupplemented diets on farms A and B.     

The epidemiology of clostridium perfringens type a on Ontario swine farms, with special reference to cpb2-positive isolates

ABSTRACT: BACKGROUND: There is poor understanding of most aspects of Clostridium perfringens type A as a possible cause of neonatal diarrhea in piglets, and the prevalence and types of C. perfringens present on Ontario swine farms is unknown. To study the prevalence of fecal C. perfringens and selected toxin genes, 48 Ontario swine farms were visited between August 2010 and May 2011, and 354 fecal samples were collected from suckling pigs, lactating sows, weanling pigs, grower-finisher pigs, and gestating sows, as well as from manure pits. The fecal samples were cultured quantitatively, and toxin genes were detected by real-time multiplex polymerase chain reaction (PCR). RESULTS: In mixed multivariable linear analysis, log10 C. perfringens in fecal samples from suckling pigs were higher than that of weanling pigs, grower-finisher pigs, and manure pit samples (P <0.05). In mixed multivariable logistic analysis, the C. perfringens isolates recovered from lactating sows (OR = 0.069, P <0.001), gestating sows (OR = 0.020, P <0.001), grower-finishers (OR = 0.017, P <0.001), and manure pits (OR = 0.11, P <0.001) were less likely to be positive for the consensus beta2 toxin gene cpb2 compared to the isolates from suckling pigs. The prevalence of cpb2 in the isolates recovered from weanlings did not differ significantly from suckling pigs. C. perfringens isolates that were positive for cpb2 were more likely to carry the atypical cpb2 gene (atyp-cpb2) (OR = 19, P <0.001) compared to isolates that were negative for cpb2. Multivariable analysis did not identify farm factors affecting the presence of consensus cpb2 and atyp-cpb2 genes. CONCLUSIONS: This study provides baseline data on the prevalence of C. perfringens and associated toxin genes in healthy pigs at different stages of production on Ontario swine farms. The study suggests that if C. perfringens type A are involved in neonatal enteritis, there may be strains with specific characteristics that cannot be identified by the existing genotyping system.     

Detection of gastric Helicobacter species in free-ranging lynx (Lynx lynx) and red foxes (Vulpes vulpes) in Sweden

Specimens of gastric mucosa and liver of 25 free-ranging Eurasian lynx (Lynx lynx), and four red foxes (Vulpes vulpes) shot in Sweden during 1999-2000, were investigated for the presence of Helicobacter species. Histopathology, bacteriologic culture and urease test, Helicobacter genus-specific 16S rDNA PCR analysis, and DNA sequence analysis were applied. Numerous Helicobacter-like organisms were observed histologically in the gastric mucosa of one fox. Helicobacter spp. were detected in the stomach by PCR analysis in 17 (68%) of the lynx and in three (75%) of the foxes. Seven of the positive lynx were also positive in the urease test. PCR fragments, amplified from lynx and foxes, were sequenced and compared with those of known Helicobacter species. PCR products from lynx were closely related (>or=98% homology) to H. heilmannii, and PCR fragments from foxes demonstrated close homology to H. heilmannii and H. salomonis. No Helicobacter spp. or Helicobacter-like organisms could be cultured. The PCR analysis of the liver was negative for all animals. The pathologic significance of the presence of Helicobacter spp. in the stomach of free-ranging lynx and foxes remains uncertain.     

Establishing a campylobacter-free pig population through a top-down approach

Fattening pigs are often infected with campylobacter. To eliminate campylobacter from the pig population, a top-down approach, involving the breeding and reproduction farms, seems appropriate. In order to investigate the effectiveness of a top-down approach, sows' faeces from the following farms were analysed for the presence of campylobacter: one specific pathogen free (SPF) farm, three top-breeding farms with no connection with SPF breeding, and a breeding farm repopulated with SPF sows after a period of vacancy (farm 5). The faeces samples from the SPF farm were free from campylobacter. The three top-breeding farms provided faeces samples which were 98% positive for campylobacter. However, only 22% of the faeces samples from farm 5 were positive for campylobacter. In a period of 20 months, the percentage of sows infected with campylobacter on farm 5 did not significantly increase. Genetic typing with ERIC-PCR and RFLP of campylobacter isolates from one of the top-breeding farms and from farm 5 showed a high diversity of campylobacter types. The results suggest that a campylobacter-free pig population can be established in breeding farms by combining a top-down approach (campylobacter-free top-breeding farms) with a strict regime of hygiene management.     

Persistent Spatial Clusters of Prescribed Antimicrobials among Danish Pig Farms – A Register-Based Study

The emergence of pathogens resistant to antimicrobials has prompted political initiatives targeting a reduction in the use of veterinary antimicrobials in Denmark, especially for pigs. This study elucidates the tendency of pig farms with a significantly higher antimicrobial use to remain in clusters in certain geographical regions of Denmark. Animal Daily Doses/100 pigs/day were calculated for all three age groups of pigs (weaners, finishers and sows) for each quarter during 2012–13 in 6,143 commercial indoor pig producing farms. The data were split into four time periods of six months. Repeated spatial cluster analyses were performed to identify persistent clusters, i.e. areas included in a significant cluster throughout all four time periods. Antimicrobials prescribed for weaners did not result in any persistent clusters. In contrast, antimicrobial use in finishers clustered persistently in two areas (157 farms), while those issued for sows clustered in one area (51 farms). A multivariate analysis including data on antimicrobial use for weaners, finishers and sows as three separate outcomes resulted in three persistent clusters (551 farms). Compared to farms outside the clusters during this period, weaners, finishers and sows on farms within these clusters had 19%, 104% and 4% higher use of antimicrobials, respectively. Production type, farm type and farm size seemed to have some bearing on the clustering effect. Adding these factors as categorical covariates one at a time in the multivariate analysis reduced the persistent clusters by 24.3%, 30.5% and 34.1%, respectively.     

Characterization of Multiple Helicobacter bizzozeronii Isolates From a Finnish Patient With Severe Dyspeptic Symptoms and Chronic Active Gastritis

Background:  Helicobacter pylori is the primary cause of gastritis and peptic ulceration in humans. In a minority of patients with upper gastrointestinal symptoms, long tightly coiled spiral bacteria, provisionally named " Helicobacter heilmannii, " are observed in gastric biopsies. These bacteria are extremely fastidious and only one previous study has succeeded in obtaining an isolate in vitro.
Materials and Methods:  We used two different selective media to isolate " H. heilmannii " from the gastric mucosa of a Finnish patient presenting with severe dyspeptic symptoms. The isolates were characterized by testing for urease and catalase activity, by using light and electron microscopy, and by sequencing of the partial 16S rRNA and ureAB genes. Single-enzyme amplified fragment length polymorphism (sAFLP) was used to analyze the genetic diversity among the isolates.
Results:  We obtained 15 isolates from different gastric biopsies prior and three after unsuccessful treatment of the patient. The isolates were identified as Helicobacter bizzozeronii . Eradication therapy was unsuccessful most probably due to high level of resistance to metronidazole. Persistent colonization by the same H. bizzozeronii clone was confirmed by sAFLP, however, small differences between the profiles suggested long-term colonization of the patient.
Conclusions:  Helicobacter bizzozeronii remains the only " H. heilmannii " species isolated from human gastric mucosa although it has been an infrequent observation among " H. heilmannii "-infected patients in PCR-based screening studies. The relevance of H. bizzozeronii and other potentially zoonotic gastric Helicobacter spp. in human disease remains to be determined.     

Longitudinal study of the persistence of antimicrobial-resistant campylobacter strains in distinct Swine production systems on farms, at slaughter, and in the environment

The objectives of this study were to compare and characterize the prevalence of antimicrobial-resistant (AR) Campylobacter in conventional and antimicrobial-free (ABF) production systems on farms, at slaughter, and in the environment. Fecal and environmental samples were collected from ABF farms (pigs, 1,239; environment, 797) and conventional farms (pigs, 1,650; environment, 1,325). At slaughter, we collected samples from carcasses, including postevisceration swabs, postchill swabs, and mesenteric lymph nodes from ABF systems (postevisceration swabs, 182; postchill swabs, 199; mesenteric lymph nodes, 184) and conventional systems (postevisceration swabs, 272; postchill swabs, 271; mesenteric lymph nodes, 255) at separate processing facilities. We also sampled the processing plant environment, including truck and lairage floor swab samples (ABF, 115; conventional, 90). Overall, a total of 2,908 Campylobacter isolates, including Campylobacter coli (farm, 2,557, 99.8%; slaughter, 341, 98.3%) and Campylobacter jejuni (farm, 4, 0.2%; slaughter, 6, 1.7%), were isolated in the study. There was no significant difference in the prevalence of Campylobacter between ABF and conventionally raised pigs (farrowing, P = 0.20; nursery, P = 0.06; finishing, P = 0.24) and the environment (P = 0.37). At slaughter, Campylobacter was isolated from all of the stages, including postchill. The highest frequencies of resistance were exhibited against tetracycline (ABF, 48.2%; conventional, 88.3%). Ciprofloxacin-resistant C. coli isolates were observed in conventionally raised (17.1%) and ABF (1.2%) pigs (P = 0.11). Antimicrobial use data from conventional farms indicated significant associations between oxytetracycline use and tetracycline resistance in the nursery pigs (P = 0.01), between tiamulin exposure and azithromycin and erythromycin resistance in nursery (P < 0.01) and finishing (P < 0.01) pigs, and between enrofloxacin exposure and ciprofloxacin and nalidixic acid resistance in farrowing (P < 0.01) and nursery (P < 0.01) pigs. Identical antimicrobial resistance profiles were observed in the pigs and their environments on farms and at slaughter. In summary, our results highlight the persistence and dissemination of AR Campylobacter from farm to slaughter in ABF and conventionally raised pigs and their environments.     

Salmonella enterica in swine production: assessing the association between amplified fragment length polymorphism and epidemiological units of concern

The aims of this study were to determine the ability of amplified fragment length polymorphism (AFLP) to differentiate Salmonella isolates from different units of swine production and to demonstrate the relatedness of Salmonella between farms and abattoirs by AFLP. Twenty-four farms in the midwestern United States were visited four times from 2006 to 2009. At each farm or abattoir visit, 30 fecal samples or 30 mesenteric lymph nodes were collected, respectively. A total of 220 Salmonella isolates were obtained, serotyped, and genotyped by multilocus sequence typing (MLST) and AFLP. These 220 isolates clustered into 21 serotypes, 18 MLST types, and 14 predominant AFLP clusters based on a genetic similarity threshold level of 60%. To assess genetic differentiation between farms, harvest cohorts, and pigs, analysis of molecular variance was conducted using AFLP data. The results showed 65.62% of overall genetic variation was attributed to variance among pigs, 27.21% to farms, and 7.17% to harvest cohorts. Variance components at the farm (P = 0.003) and pig (P = 0.001) levels were significant, but not at the harvest cohort level (P = 0.079). A second analysis, a permutation test using AFLP data, indicated that on-farm and at-abattoir Salmonella from pigs of the same farms were more related than from different farms. Therefore, among the three subtyping methods, serotyping, MLST, and AFLP, AFLP was the method that was able to differentiate among Salmonella isolates from different farms and link contamination at the abattoir to the farm of origin.     

Animal-based measures on fattening heavy pigs at the slaughterhouse and the association with animal welfare at the farm level: a preliminary study

Monitoring animal welfare (AW) in pig farms requires both proper indicators and a feasible approach. Animal-based measures (ABMs) are well-established AW indicators. Furthermore, AW screening at the slaughterhouses could be useful for identifying problems on farm. The aim of this study was to evaluate ABMs at the slaughterhouse and, when possible, to compare these ABMs with those collected on the farm. The study was carried out in northern Italy in a commercial abattoir and in a sample of farms. Animal-based measures were recorded on pigs from 62 batches of 54 farms, during ante-mortem (n=10 085 pigs) and post-mortem (n=7952 pigs) inspections. Sixteen of 54 farms were selected to compare ABMs collected at the slaughterhouse with ABMs collected on the farm. Overall, 2295 pigs (mean pigs examined per farm 119±45) were inspected at the slaughterhouse (group S) and 420 pigs (mean pigs per farm 26±5) on the farm (group F). Non-animal-based measures were also collected at the 16 farms. Differences between groups S and F, at the animal level, were assessed by a two-tailed paired Wilcoxon–Mann–Whitney test. Differences at the site of observation level (farm and slaughterhouse) were assessed by Fisher’s exact test using a hierarchical log-linear modelling for contingency tables. The most frequent ABMs at the slaughterhouse were manure on the body (47.7%), followed by dermatitis (28.0%), white spot (25.4%) and bursitis (24.7%). Recording ABMs at the slaughterhouse and on the farm usually yielded similar results; however, there were some exceptions. In particular, significant differences were found for non-uniformity of size (P<0.05) and dermatitis (P<0.001), which were higher at the slaughterhouse than on the farm. Results of log-linear modelling underlined the effect of the farm of origin on the percentage of pigs with bursitis, manure on the body and ear injuries that were observed at the slaughterhouse. In group S, significant associations between manure on the body and insufficient presence of clean and dry areas in the corresponding farm were found (P<0.05). Although these results should be interpreted with care due to the limited sample of farms, the slaughterhouse could be a feasible site of observation of ABMs, which could then be integrated in monitoring of AW on farm. Considering the number of slaughtered batches per farm, it would be possible to repeat assessments several times throughout the year for each farm, which could help provide an index for the continuous monitoring of AW.     

Arcobacter population dynamics in pigs on farrow-to-finish farms

Healthy pigs are an important reservoir for the emerging human pathogen Arcobacter which can result in contamination of porcine carcasses and pork and the spread of arcobacters into the environment. Up to now, the excretion of arcobacters by pigs has been studied, but information about the transmission routes in fattening pigs is lacking. The present study aimed to elucidate the Arcobacter population dynamics in pigs during the fattening period on four farrow-to-finish farms. On each farm, 30 clinically healthy, 12-week-old piglets were selected. Fecal samples were collected on 10 sampling occasions until a slaughter age of 30 weeks was reached. Arcobacter spp. were isolated by a selective method and identified by multiplex PCR. The genetic diversity was examined by amplified fragment length polymorphism and enterobacterial repetitive intergenic consensus PCR. The Arcobacter presence in the fecal samples on the four farms ranged from 11.3 to 50.0%, with excretion levels of up to 10(4) CFU/g feces. The ratio in which Arcobacter species were isolated varied between the farms and over time. Characterization revealed a high degree of genotypic diversity among the isolates. Arcobacter strains persisted and spread within the finishing unit during the fattening period. The occurrence of both unique and shared genotypes in pigs in adjacent and nonadjacent pens demonstrates that transmission routes other than fecal-oral transmission occur.     

High prevalence of Cryptosporidium infection caused by C. scrofarum and C. suis among pigs in Thailand

Cryptosporidium spp. is an important intestinal protozoan causing diarrhea among both healthy and immunocompromised patients especially those with HIV/AIDS. Cryptosporidium spp. can be transmitted via foodborne, waterborne and person-to-person routes. In addition, several Cryptosporidium species are zoonotic. This study aimed to determine the prevalence of Cryptosporidium infection among pigs raised in both smallholder (<50 heads/farm) and large scale farms (50–500 heads/farm) in Chonburi Province, eastern Thailand using nested PCR amplifying the small subunit of the ribosomal RNA (SSU-rRNA) gene. DNA sequencing was also performed to identify the species of Cryptosporidium. A total of 245 fecal samples were collected from 11 pig farms. The overall prevalence of Cryptosporidium infection was 20.8% (51/245) which were found in both smallholder and small large scale pig farms. The prevalence of Cryptosporidium infection among pigs aged ≤6 months was significantly higher than those aged >6 months (p < .001). Among 51 Cryptosporidium positive samples, Cryptosporidium scrofarum (42/51, 82.4%) and Cryptosporidium suis (9/51, 17.6%) were identified. The prevalence of C. scrofarum infection observed among pigs aged ≤6 months was significantly higher when compared with those aged >6 months (20.7% and 2.1%, respectively, p < .001). The high prevalence of C. scrofarum and C. suis infections among pigs could be a potential source of infection to humans.     

Distinction of gastric Helicobacter spp. in humans and domestic pets by scanning electron microscopy

Background. A number of different Helicobacter spp. can colonize the stomach of humans and domestic pets. Difficulties encountered with primary isolation of these spiral microorganisms and their unusual inertia with respect to biochemical reactions still represent considerable obstacles to their characterization with classic tools. In addition, the high degree of similarity in the 16S rRNA sequence hampers differentiation of Helicobacter spp. using routine molecular biological assays.
Materials and Methods. Samples from experimentally monoinfected mice, of naturally infected hosts, and of cultured strains were examined by scanning electron microscopy (SEM). In parallel, all samples were analyzed by molecular techniques to ascertain the Helicobacter spp. involved.
Results. Using the mouse samples as a reference, microorganisms found in naturally infected hosts were identified by SEM as belonging to H. pylori , H. felis , or a group consisting of H. bizzozeronii and H. heilmannii. A further spiral microorganism with unique morphology was found in a dog that was positive for H. salomonis , but the organism could not be recovered from experimentally infected mice. In culture, most Helicobacter strains lost their ultrastructural characteristics.
Conclusions. When gastric Helicobacter spp. were collected from their natural habitat and examined by SEM, relevant differences could be detected between H. felis , H. bizzozeronii and H. heilmannii , and H. salomonis , respectively. SEM, therefore, seems to be a useful auxillary tool for the distinction of various gastric Helicobacter spp. as based on their ultrastructure.     

Effects of tylosin use on erythromycin resistance in enterococci isolated from swine

The effect of tylosin on erythromycin-resistant enterococci was examined on three farms; farm A used tylosin for growth promotion, farm B used tylosin for treatment of disease, and farm C did not use tylosin for either growth promotion or disease treatment. A total of 1,187 enterococci were isolated from gestation, farrowing, suckling, nursery, and finishing swine from the farms. From a subset of those isolates (n = 662), 59% (124 out of 208), 28% (80 out of 281), and 2% (4 out of 170) were resistant to erythromycin (MIC >/= 8 microg/ml) from farms A, B, and C, respectively. PCR analysis and Southern blotting revealed that 95% (65 out of 68) of isolates chosen from all three farms for further study were positive for ermB, but all were negative for ermA and ermC. By using Southern blotting, ermB was localized to the chromosome in 56 of the isolates while 9 isolates from farms A and B contained ermB on two similar-sized plasmid bands (12 to 16 kb). Pulsed-field gel electrophoresis revealed that the isolates were genetically diverse and represented a heterogeneous population of enterococci. This study suggests that although there was resistance to a greater number of enterococcal isolates on a farm where tylosin was used as a growth promotant, resistant enterococci also existed on a farm where no antimicrobial agents were used.     

Prevalence and genotypes of Cryptosporidium in livestock in Hualien Country,Eastern Taiwan

Cryptosporidium spp. is a group of protozoans that cause diarrheal disease in both humans and animals. In Taiwan, very little information is available about the epidemiology of Cryptosporidium spp. in domesticated animals, especially in Eastern Taiwan where agriculture is one of the main industries. Therefore, this study aimed to investigate the occurrence of Cryptosporidium spp. in livestock in Hualien Country of Eastern Taiwan and identify their genotypes. Excrements from dogs (n = 81), cattle (n = 156), and pigs (n = 142) were randomly collected from different pastures or farm in Hualien Country. Microscopic examination and nested PCR were performed on all samples and both showed identical results, with 4.94% (4/81) of dogs, 24.36% (38/156) of cattle, and 16.20% (23/142) of pigs being infected with Cryptosporidium species. Positive samples were then sequenced and analyzed. DNA sequencing revealed that all four positive samples isolated from dogs were Cryptosporidium canis (C. canis); 38 positive samples from cattle were identified as C. bovis (8/38), C. canis (1/38), C. ryanae (4/38), and C. scrofarum (25/38); and 22 positive samples isolated from pigs were identified as C. scrofarum while one was identified as C. suis. In addition, the infective rates of animals from indoor farms (57.14% of all positive samples) are much higher than the rates from pastures. This study provided evidence of the occurrence of Cryptosporidium spp. in Hualien country, and farming conditions largely affect their infection rates. Therefore, precautions should be made to control Cryptosporidium spp. transmission.     

Airborne Detection and Quantification of Swine Influenza A Virus in Air Samples Collected Inside,Outside and Downwind from Swine Barns

Airborne transmission of influenza A virus (IAV) in swine is speculated to be an important route of virus dissemination, but data are scarce. This study attempted to detect and quantify airborne IAV by virus isolation and RRT-PCR in air samples collected under field conditions. This was accomplished by collecting air samples from four acutely infected pig farms and locating air samplers inside the barns, at the external exhaust fans and downwind from the farms at distances up to 2.1 km. IAV was detected in air samples collected in 3 out of 4 farms included in the study. Isolation of IAV was possible from air samples collected inside the barn at two of the farms and in one farm from the exhausted air. Between 13% and 100% of samples collected inside the barns tested RRT-PCR positive with an average viral load of 3.20E+05 IAV RNA copies/m³ of air. Percentage of exhaust positive air samples also ranged between 13% and 100% with an average viral load of 1.79E+04 RNA copies/m³ of air. Influenza virus RNA was detected in air samples collected between 1.5 and 2.1 Km away from the farms with viral levels significantly lower at 4.65E+03 RNA copies/m³. H1N1, H1N2 and H3N2 subtypes were detected in the air samples and the hemagglutinin gene sequences identified in the swine samples matched those in aerosols providing evidence that the viruses detected in the aerosols originated from the pigs in the farms under study. Overall our results indicate that pigs can be a source of IAV infectious aerosols and that these aerosols can be exhausted from pig barns and be transported downwind. The results from this study provide evidence of the risk of aerosol transmission in pigs under field conditions.     

Colonic microbiome profiles for improved feed efficiency can be identified despite major effects of farm of origin and contemporary group in pigs

While feed efficiency (FE) is a trait of great economic importance to the pig industry, the influence of the intestinal microbiome in determining FE is not well understood. The objective of this experiment was to determine the relative influence of FE and farm of birth on the pig colonic microbiome. Animals divergent in residual feed intake (RFI) were sourced from two geographically distinct locations (farms A + B) in Ireland. The 8 most efficient (low RFI (LRFI)) and 8 least efficient (high RFI, (HRFI)) pigs from farm A and 12 LRFI and 12 HRFI pigs from farm B were sacrificed. Colonic digesta was collected for microbial analysis using 16S ribosomal RNA gene sequencing and also for volatile fatty acid analysis. The α-diversity differed between the farms in this study, with pigs from farm A having greater diversity based on Shannon and InvSimpson measures compared to pigs from farm B (P < 0.05), with no difference identified in either Chao1 or observed measures of diversity (P > 0.05). In the analysis of β-diversity, pigs clustered based on farm of birth rather than RFI. Variation in the management of piglets, weight of the piglets, season of the year, sanitary status and dam dietary influence could potentially be causative factors in this large variation between farms. However, despite significant variation in the microbial profile between farms, consistent taxonomic differences were identified between RFI groups. Within the phylum Bacteroidetes, the LRFI pigs had increased abundance of BS11 (P < 0.05) and a tendency toward increased Bacteroidaceae (P < 0.10) relative to the HRFI group. At genus level, the LRFI pigs had increased abundance of Colinsella (P < 0.05), a tendency toward increased Bacteroides and CF231 (P < 0.10). At species level, Ruminococcus flavefaciens had increased abundance in the LRFI compared to the HRFI animals. In conclusion, while farm of birth has a substantial influence on microbial diversity in the pig colon, a microbial signature indicative of FE status was apparent.     

Seroprevalence of Toxoplasma gondii infection in pigs, in Zhejiang Province, China

Seroprevalence of Toxoplasma gondii infection in pigs in 10 regions of Zhejiang Province, China, was obtained by enzyme-linked immunosorbent assay (ELISA). Anti- T. gondii antibodies were found in 53.4% (434/813) of pigs. Results were analyzed by a chi-square (χ(2)) test. Differences were observed according to farm size, animal age, and sampling regions. Seroprevalences in pigs raised on small farms (71.4%) were significantly higher than that (42.7%) on large farms (P < 0.05), and seroprevalence increased progressively with age. The seroprevalence ranged from 28.1% to 66.0% in different regions, with Jiaxing having the lowest level (28.1%), followed by Hangzhou (36.0%) and Taizhou (42.0%). This is the first study on seroprevalence of T. gondii infection in pigs in Zhejiang Province.     

Prevalence and clonal nature of Escherichia coli O157:H7 on dairy farms in Wisconsin.

A survey was conducted between March and October of 1994 to determine the prevalence and identify the sources of serotype O157:H7 isolates of Escherichia coli in Wisconsin dairy herds. A stratified sample of 400 farms was identified, and 70 farms with weaned calves less than 4 months old were included in the study. During the prevalence study, 5 of the 70 farms (herd prevalence, 7.1 +/- 4.5%) and fecal samples from 10 of 560 calves (animal prevalence, 1.8%) tested positive for serotype O157:H7. In a follow-up study, the five O157:H7-positive farms and seven of the O157:H7-negative farms identified in the prevalence study were visited again. An additional 517 fecal samples from cattle of various ages were tested, and a total of 15 animals from four of the five herds that were previously positive and 4 animals from two of seven herds that were previously negative tested positive for E. coli O157:H7. Observations made during the follow-up study suggested that horizontal transmission was an important means of E. coli O157:H7 dissemination on the farms. A total of 302 environmental samples, were examined, and 2 animal drinking water samples from one previously negative farm and 1 animal drinking water sample from a previously positive farm contained E. coli O157:H7. Analyses by the pulsed-field gel electrophoresis technique of contour-clamped homogeneous electric field electrophoresis revealed that isolates from the same farm displayed identical or very similar XbaI restriction endonuclease digestion profiles (REDP), whereas isolates from different farms typically displayed different REDP. However, more than one REDP was usually observed for a given herd over the 8-month sampling period. Analyses of multiple isolates from an animal revealed that some animals harbored O157:H7 strains that had different REDP, although the REDP of isolates obtained from the same fecal sample were very similar. Collectively, 160 bovine isolates obtained from 29 different animals and three water isolates displayed 20 distinct XbaI REDP. Our data revealed that there are several clonal types of serotype O157:H7 isolates in Wisconsin and indicated that there is probably more than one source of this pathogen on the dairy farms studied. However, animal drinking water was identified as one source of E. coli O157:H7 on one farm.