Occurrence of Lawsonia Intracellularis and Brachyspira spp. infection in swine suffering from diarrhoea

Principal aim of this study was to examine fecal samples from pigs suffering from diarrhea for the presence of Lawsonia intracellularis, Brachyspira hyodysenteriae and Brachyspira pilosicoli. The molecular techniques such as PCR and nested PCR were employed to detect the presence of p78 fragment of genomic DNA specific for Lawsonia intracellularis as well as fragment of tlyA gene specific for Brachyspira hyodysenteriae and 16S rDNA gene of Brachyspira pilosicoli. We assumed that about 25% of pigs were infected with Lawsonia intracellularis, about 10% with Brachyspira hyodysenteriae and only 0,8% with Brachyspira pilosicoli. In about 3% mixed infection with L. intracellularis and B. hyodysenteriae was observed. Results were comparable in herds that differed in quantity, breeding technology, hygienic standards and preventive treatment with different chemotherapeutics.     

Analysis of bacterial load and prevalence of mixed infections with Lawsonia intracellularis, Brachyspira hyodysenteriae and/or Brachyspira pilosicoli in German pigs with diarrhoea

Lawsonia (L.) intracellularis, Brachyspira (B.) hyodysenteriae and B. pilosicoli are important pathogens in domestic pig production world-wide, responsible for porcine intestinal adenomatosis, swine dysentery, and porcine intestinal spirochetosis, respectively. Conventional PCR is the major diagnostic tool in the detection of the three pathogens, but the sole detection of bacterial DNA might lead to misinterpretations of results with respect to their clinical relevance, especially with mixed infections. Thus, the present study targeted the detection and quantification of the three pathogens in samples from herds with a case history of diarrhoea. Herds and samples were selected by the practitioners on a voluntary basis. Results were based on 1176 individual samples from 95 herds from Southern Germany. The pathogens were detected simultaneously by multiplex real-time PCR. The overall prevalence for L. intracellularis, B. hyodysenteriae and B. pilosicoli was 12.6%, 8.4% and 3.2% in faecal samples and 48.4%, 24.2% and 31.6% in herds, respectively. Sixty one percent, 82.6%, and 73.4% of herds positive for L. intracellularis, B. hyodysenteriae, and B. pilosicoli, respectively, had mixed infections. Median log values of DNA equivalents/g of faeces for L. intracellularis, B. hyodysenteriae and B. pilosicoli were 3.3, 5.9 and 3.2, with maxima of 8.3, 8.0 and 6.3, respectively. Within herd prevalence of B. hyodysenteriae and B. pilosicoli as well as the load of B. hyodysenteriae were significantly associated with the severity of diarrhoea.     

Prevalence of selected enteropathogenic bacteria in Hungarian finishing pigs

The aim of this study was to obtain prevalence estimates about the most important enteropathogenic bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Brachyspira pilosicoli, Salmonella enterica and Clostridium perfringens A and C in Hungarian farrow-to-finish pig herds. A total of 31 herds were selected, from where six pooled faecal samples, each containing three individual rectal faecal samples were collected from fattening pigs of 5-6 months of age. All 186 samples were examined by polymerase chain reaction (PCR) for the presence of the pathogens mentioned above. Lawsonia intracellularis was found in 29 herds (93.55%) and in 108 samples (58.06%); B. hyodysenteriae in 14 herds (45.16%) and in 23 samples (12.37%); B. pilosicoli in 19 herds (61.29%) and in 53 samples (28.49%); S. enterica in 17 herds (54.83%) and in 40 samples (21.50%). We detected the presence of C. perfringens A in 19 herds (61.29%) and in 46 samples (24.73%), while C. perfringens C was found in 8 herds (25.81%) and in 11 samples (5.91%). All examined herds were infected with one or more of these agents. Herds with diarrhoea in the mid- to late finishing phase had almost 10 times higher prevalence of B. hyodysenteriae than herds without such a history.     

Detection of Brachyspira hyodysenteriae, Lawsonia intracellularis and Brachyspira pilosicoli in feral pigs

Feral pigs are recognized as being a potential reservoir of pathogenic microorganisms that can infect domestic pigs and other species. The aim of this study was to investigate whether feral pigs in Western Australia were colonized by the pathogenic enteric bacteria Lawsonia intracellularis, Brachyspira hyodysenteriae and/or Brachyspira pilosicoli. A total of 222 feral pigs from three study-populations were sampled. DNA was extracted from faeces or colonic contents and subjected to a previously described multiplex PCR for the three pathogenic bacterial species. A subset of 61 samples was cultured for Brachyspira species. A total of 42 (18.9%) of the 222 samples were PCR positive for L. intracellularis, 18 (8.1%) for B. hyodysenteriae and 1 (0.45%) for B. pilosicoli. Four samples were positive for both L. intracellularis and B. hyodysenteriae. Samples positive for the latter two pathogens were found in pigs from all three study-sites. A strongly haemolytic B. hyodysenteriae isolate was recovered from one of the 61 cultured samples. Comparison of a 1250-base pair region of the 16S rRNA gene amplified from DNA extracted from the isolate and five of the B. hyodysenteriae PCR positive faecal samples helped confirm these as being from B. hyodysenteriae. This is the first time that B. hyodysenteriae has been detected in feral pigs. As these animals range over considerable distances, they present a potential source of B. hyodysenteriae for any domesticated pigs with which they may come into contact.     

Diarrhoea in the growing pig - a comparison of clinical,morphological and microbial findings between animals from good and poor performance herds

Diarrhoea among growing pigs (8-13 weeks old) is a significant problem in many herds. Nine herds with poor performance and diarrhoea among growing pigs were selected on the basis of their piglet mean age at a body weight of 25 kg, compared to the overall mean age in Swedish herds. In addition, four herds with good average performance and no problems with diarrhoea were selected. Pigs were necropsied and samples for histology and microbiology were collected. Based on the necropsy findings, the pigs from the good performing herds were all judged to be healthy. The presence of Brachyspira pilosicoli and Lawsonia intracellularis was significantly correlated to poor performing herds and the results indicate that these microbes are main pathogens involved in enteric diseases among Swedish grower pigs. In addition, concomitant infections with other presumptive pathogens were commonly found.     

Simultaneous detection of Brachyspira hyodysenteriae, Brachyspira pilosicoli and Lawsonia intracellularis in porcine faeces and tissue samples by multiplex-PCR

Diarrhoea in growing and finishing pigs is usually caused by infectious agents and laboratory diagnosis is a prerequisite for efficient therapy. Cultivation of Brachyspira hyodysenteriae or Brachyspira pilosicoli and detection of Lawsonia intracellularis by means of immunofluorescence tests (IFT) are time-consuming and in some cases lack sensitivity. A multiplex-PCR was designed to detect simultaneously these three pathogens in faeces and tissue samples, allowing the differential diagnosis of dysentery, intestinal spirochaetosis and proliferative enteropathy. Detection limits for B. hyodysenteriae, B. pilosicoli and L. intracellularis were 10(4), 10(2) and 10(3) copies respectively. Agreement between multiplex-PCR and nested-PCR or cultivation was considered substantial to almost perfect. Agreement between multiplex-PCR and IFT in detecting L. intracellularis was only moderate, which was probably related to false-positive results given by IFT. The multiplex-PCR described herein is a valuable tool for the rapid and simultaneous detection of three different pathogens in porcine samples causing enteric diseases.     

Risk factors for intestinal pathogens in Danish finishing pig herds.

The objective of this investigation was to identify risk factors for infection with the intestinal bacteria: Lawsonia intracellularis, Brachyspira hyodysenteriae, Serpulina intermedia, Brachyspira innocens, Brachyspira pilosicoli and swine-pathogenic Escherichia coli (serogroups O138, O139, O141 and O149) in Danish finishing pig herds.A total of 79 herds was randomly selected and visited during 1998. From each herd, 20 faecal samples were collected from individual pigs weighing 30-50 kg. In total, 1580 faecal samples were collected and examined by polymerase chain reaction (L. intracellularis) or culture (all other agents). Information on feed and management procedures was collected by filling in questionnaires at the herd visits. The questionnaires included information on 29 dichotomous variables and three continuous variables. Variables with P<0.25 in a preliminary screening (chi2- or t-test) were selected for the statistical modelling.Our conclusions, based on the results of multifactorial logistic regression (cut-off: P=0.05), were the following: 1. Consistent batch production was associated with reduced prevalences of L. intracellularis and weakly -haemolytic spirochetes (S. intermedia, B. innocens, B. pilosicoli) (OR's=0.43 and 0.06, respectively). 2. Home-mixed (and/or non-pelleted) feed was associated with reduced prevalences of L. intracellularis and weakly -haemolytic spirochetes (OR's=0.6 and 0.4, respectively). 3. Providing straw to finishers was associated with a reduced prevalence of weakly -haemolytic spirochetes (OR=0.28-0.32). 4. Not using antimicrobial growth promoters for piglets was associated with an increased prevalence of S. intermedia (OR=11.11). 5. Rare occurrence of post-weaning diarrhoea (as opposed to common) was associated with an increased prevalence of weakly -haemolytic spirochetes (OR=8.3-13.7).     

Detectability and prevalence of Brachyspira species in herds rearing health class feeder pigs in Finland

Faeces samples were taken three times at two-week intervals, from the farrowing units of four herds of known Brachyspira (formerly Serpulina) status and one of unknown Brachyspira status. Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira intermedia and Brachyspira group III were isolated from the faecal samples from the weaners in the herds using either a maximum of 50 ppm of olaquindox or no feed additives. The detection rates were relatively consistent. However, B hyodysenteriae was not detected at one sampling in a known positive herd. The prevalence of Brachyspira species was also studied in feeder pigs originating from LSO 2000 health class farrowing units, comparable with specific pathogen-free herds. These farms were free from swine dysentery, sarcoptic mange, swine enzootic pneumonia and progressive atrophic rhinitis. Fifty of 428 herds were sampled once. B hyodysenteriae was not isolated from any of them, but B intermedia, B pilosicoli and Brachyspira group III were isolated from five, 14 and 37 of the herds, respectively. The detection of Brachyspira species did not relate to the prevalence of diarrhoea in the herds, as judged by the farmers. The herds using carbadox (40 to 50 ppm) had a lower prevalence of Brachyspira species than those using olaquindox (40 to 50 ppm).     

Distribution of Brachyspira hyodysenteriae and Lawsonia intracellularis in healthy and diarrhoeic pigs

Although Brachyspira (B.) hyodysenteriae and Lawsonia (L.) intracellularis are widely distributed in pigs in Germany, there exists limited information on their clinical relevance.To get more insight into their potential role in swine diarrhoeal disease, in 2002 and 2003 faecal specimens from healthy pigs (n=1445) as well as from diarrhoeic pigs (n=2002) were tested by polymerase chain reaction (PCR) for the presence of both agents. Of the specimens from healthy pigs L. intracellularis and B. hyodysenteriae were detected in 7.3% and 6.7%, respectively. In contrast, of the diarrhoeic pigs the ratios of positive samples amounted to 19.4% for L. intracellularis and 17.9% for B. hyodysenteriae. Concerning the age of the diseased animals, in growing pigs the detection rates of L. intracellularis and B. hyodysenteriae were nearly identical (16.4% and 14.2%, respectively). In fattening pigs a significant higher number of animals were affected with B. hyodysenteriae (35.8%) than with L. intracellularis (28.2%). On the other hand, in sows L. intracellularis (35.6% positive samples) was dominant compared to B. hyodysenteriae (21.2% positive samples). Considering the nearly threefold higher percentage rates of L. intracellularis and B. hyodysenteriae in diarrhoeic pigs in comparison to healthy pigs, it is concluded that both agents play an important role in swine diarrhoeal disease. The results further indicated that in fattening pigs B. hyodysenteriae and in sows L. intracellularis have a dominant role, respectively.     

Neither hippurate-negative Brachyspira pilosicoli nor Brachyspira pilosicoli type strain caused diarrhoea in early-weaned pigs by experimental infection

A hippurate-negative biovariant of Brachyspira pilosicoli (B. pilosicolihipp-) is occasionally isolated in diarrhoeic pigs in Finland, often concomitantly with hippurate-positive B. pilosicoli or Lawsonia intracellularis. We studied pathogenicity of B. pilosicolihipp- with special attention paid to avoiding co-infection with other enteric pathogens. Pigs were weaned and moved to barrier facilities at the age of 11 days. At 46 days, 8 pigs were inoculated with B. pilosicolihipp- strain Br1622, 8 pigs were inoculated with B. pilosicoli type strain P43/6/78 and 7 pigs were sham-inoculated. No signs of spirochaetal diarrhoea were detected; only one pig, inoculated with P43/6/78, had soft faeces from day 9 to 10 post inoculation. The pigs were necropsied between days 7 and 23 after inoculation. Live pigs were culture-negative for Brachyspira spp., but B. pilosicolihipp- was reisolated from necropsy samples of two pigs. The lesions on large colons were minor and did not significantly differ between the three trial groups. In silver-stained sections, invasive spirochaetes were detected in colonic mucosae of several pigs in all groups. Fluorescent in situ hybridisation for genus Brachyspira, B. pilosicoli and strain Br1622 was negative. However, in situ detection for members of the genus Leptospira was positive for spirochaete-like bacteria in the colonic epithelium of several pigs in both infected groups as well as in the control group. L. intracellularis, Salmonella spp., Yersinia spp. and intestinal parasites were not detected. The failure of B. pilosicoli strains to cause diarrhoea is discussed with respect to infectivity of the challenge strains, absence of certain intestinal pathogens and feed and management factors.     

Amplification and sequencing of Brachyspira spp. specific portions of nox using paraffin-embedded tissue samples from clinical colitis in Austrian pigs shows frequent solitary presence of Brachyspiramurdochii

Brachyspira infections are significant causes of enterocolitis in pigs. In order to differentiate pathogenic species (Brachyspira (Br.) hyodysenteriae, Brachyspira pilosicoli) from less pathogenic or non-pathogenic species (Brachyspira intermedia, Brachyspira innocens, Brachyspira murdochii) in paraffin-embedded tissue samples a polymerase chain reaction (PCR) protocol allowing identification of Brachyspira at species level in archival material was developed. This approach was complemented by sequencing of the PCR amplification products. All seven cases presented with clinical and morphological Brachyspira-associated enterocolitis. Br. hyodysenteriae was not identified in any of the cases, while Br. pilosicoli was identified in a single case in conjunction with Br. murdochii. One case each was found positive for Br. innocens and Br. intermedia. Interestingly, the majority of cases presented as single or double infections with Br. murdochii. In some of the pigs other pathogens, like porcine circovirus-2 or Lawsonia intracellularis were present. These observations point at the possibility that under certain conditions even Brachyspira species of low pathogenicity can multiplicate extensively and lead to Brachyspira-associated enterocolitis.     

An investigation of the etiology of a mild diarrhea observed in a group of grower/finisher pigs

An investigation into a mild diarrhea in a group of grower/finisher pigs was carried out in order to determine the etiology. A tiamulin injection and a carbadox-medicated ration were given to pens of pigs in a 2 x 2 factorial experimental design. Pens of pigs were assessed a score, based on the consistency of the feces in the pen, each week. The clinical investigation looked for the intestinal pathogens Brachyspira pilosicoli, B. hyodysenteriae, Lawsonia intracellularis, Salmonella spp., Yersinia spp., transmissible gastroenteritis virus, and rotavirus. Despite a rigorous investigation, the diarrhea was not attributed to any pathogen. A mild colitis was noted among pigs necropsied while affected with diarrhea. Improved diagnostic tools may allow a more effective response to an outbreak of mild disease, while at the same time reducing the amount of antimicrobials used in swine production.     

Detection of Lawsonia intracellularis in wild boar and fallow deer bred in one game enclosure in the Czech Republic

The prevalence of Lawsonia intracellularis between wild boar (Sus scrofa) and fallow deer (Dama dama) bred in one game reserve was investigated using the nested PCR method. In the study, 88 clinically healthy wild boars of different age categories and two fallow deer bagged in the game reserve were examined. Lawsonia intracellularis was demonstrated in the mucous membrane of the intestine of eight (9.1%) wild boars and one fallow deer. Of the nine wild boar whose tissues of corresponding lymph nodes were examined in addition to the mucous membrane of the ileum, one tested positive for the microorganism. A relationship between the occurrence of L. intracellularis and age of wild boar was demonstrated. Because wild boar and fallow deer are bred together in one game reserve, the possibility of inter-species transfer of L. intracellularis should be borne in mind.     

Application of real-time PCR for detection of Lawsonia intracellularis and Brachyspira hyodysenteriae in fecal samples from pigs

The aim of the study was to develop and validate real-time PCR method for the quantification of Lawsonia intracellularis and Brachyspira hyodysenteriae in porcine feces. Before the optimization process was performed two different extraction methods were compared to select the more efficient one. Based on the results achieved at this stage the boiling procedure was rejected and a commercially available silica-membrane based method was chosen for further analysis. The primers and the Taqman probe for B. hyodysenteriae and L. intracellularis were based on the sequence of NADH oxidase gene and 16S rDNA gene, respectively. The detection limit of the real-time PCR for suspension of feces inoculated with B. hyodysenteriae and L. intracellularis was determined to be 1.5x10(3) CFU/ml and 6.5x10(1) CFU/ml, respectively. The results of this study demonstrate that our real-time PCR is able to detect low number of B. hyodysenteriae and L. intracellularis cells which is satisfying in routine diagnosis of swine dysentery and proliferative enteropathy. Therefore, it is possible to identify both subclinically infected pigs and those representing an acute form of mentioned diseases. In summary, the quantitative real-time PCR is useful for routine diagnosis of L. intracellularis and B. hyodysenteriae. Compared to conventional PCR, the new validated quantification method based on real-time PCR is fast and with reduced risk of laboratory contamination. The novel technique is specific and even more sensitive than the previously used one. Furthermore, the new real-time PCR enables quick detection and quantification of both pathogens in fecal samples, which helps to estimate the health status of a pig herd.     

Diagnosis of swine dysentery and spirochaetal diarrhea. III. Results of cultural and biochemical differentiation of intestinal Brachyspira species by routine culture from 1997 to 1999

A survey is given on the occurrence and distribution of different Brachyspira species in pigs, in the northwest of Germany. In total 2975 specimen (feces, fecal swabs, colon) were taken and sent for laboratory analysis during the years 1997 to 1999. 1218 Brachyspira (B.) strains were found by cultural analysis. 1757 samples (59%) were negative. The cultural and biochemical differentiation revealed 720 (59.1%) strains B. hyodysenteriae (77.5% were indole negative), 22 (1.8%) B. pilosicoli, 29 (2.4%) B. intermedia, 167 (3.7%) B. innocens and 114 (9.4%) B. murdochii. 166 (13.6%) strains could not be identified. These strains could either not be compared with any of the described species by the methods used or it was impossible to achieve a pure culture from these isolates. The results demonstrate the wide spread of B. hyodysenteriae in pig herds in the northwest of Germany with a very high prevalence of indole negative strains. The most frequent strain was B. hyodysenteriae. B. pilosicoli which causes spirochaetal diarrhoea was rarely isolated and seems not to play an important role in Germany. Experience from routine cultures for Brachyspira give evidence that it is more useful to examine faeces from single pigs instead of pooled samples from a herd. It is recommended to use special transport media for the transport of the specimen.     

The use of a mimic to detect polymerase chain reaction-inhibitory factors in feces examined for the presence of Lawsonia intracellularis.

Lawsonia intracellularis is an intracellular organism that causes proliferative enteritis in pigs. This bacterium is difficult to culture, and antemortem demonstration of the microbe is therefore often performed on fecal samples by polymerase chain reaction (PCR). Polymerase chain reaction is sensitive and specific, but inhibitory factors in feces might cause false-negative results. This article describes the construction and use of an internal standard, a mimic. The mimic is amplified by the same primers as those used for L. intracellularis DNA and thus could indicate false-negative results in clinical samples. The amplicon was clearly visible when as few as 10 mimic molecules were added per amplification reaction and when no inhibitors werepresent. When fecal samples were spiked with the mimic, the detection limit was 10(2) molecules per PCR. Sixty clinical samples, 20 from wild boars, 20 from growing pigs with diarrhea, and 20 from pigs without diarrhea, were prepared by a boiling procedure and subjected to PCR together with 10(3) mimic molecules. Nine samples were positive, of which 7 originated from pigs with diarrhea and 2 from pigs without diarrhea. In 14 samples from wild boars, in 8 samples from pigs without diarrhea, and in 3 samples from pigs with diarrhea, neither the mimic nor the target DNA was visible. This indicated the presence of inhibitors in these samples. It is concluded that the mimic can be used as an internal control in the diagnosis of L. intracellularis to indicate inhibition of PCR.     

The microbiota of pigs influenced by diet texture and severity of Lawsonia intracellularis infection

Pigs with and without naturally occurring Lawsonia intracellularis infection were fed diets with different texture. In a previous study from 79 pig herds using a similar feeding on pelleted or non-pelleted form showed that the non-pelleted diet was associated with a reduced prevalence of L. intracellularis. In this study a mechanistic approach was taken for explaining and testing this observation by studying the microbiota and the occurrence of L. intracellularis in the distal ileum of 54 pigs by terminal restriction fragment length polymorphism (T-RFLP) analysis, Real-Time PCR and in situ hybridization. The texture of the diet influenced the microbiota, and from a quantitative discriminative analysis of the terminal restriction fragments (T-RFs) of ileum samples it was deduced that Clostridium spp. and Lactobacillus spp. were associated with the non-pelleted diet and Streptococcus spp. with the pelleted diet. In experimentally infected pigs it was verified that 89bp and 90bp sized T-RFs (HhaI) from ileum represented L. intracellularis. The non-pelleted diet seemed to reduce the relative amount of L. intracellularis in the total microbiota of the ileum, but the number of pigs detected positive with L. intracellularis by Real-Time PCR was not influenced. The five pigs with highest L. intracellularis content showed T-RFs that were not present in profiles from less or non-infected pigs, which may indicate that some bacterial species were associated with L. intracellularis infection.     

Assessment of diagnostics and antimicrobial susceptibility testing of Brachyspira species using a ring test

There is no ring test for quality assessment available in Europe for diagnostics and antimicrobial susceptibility testing of the fastidious, anaerobic bacteria of the genus Brachyspira. Therefore, an international ring test for Brachyspira spp. was performed once a year during 2002-2004. Two sets of coded samples were prepared and distributed on each occasion. One set comprised six swabs dipped in pig faeces spiked with Brachyspira spp. intended for diagnostics. The other set comprised two pure strains intended only for susceptibility testing. All methods used were in-house methods. The species used were Brachyspira hyodysenteriae, Brachyspira pilosicoli, Brachyspira innocens, Brachyspira murdochii and Brachyspira intermedia. In most cases, the correct Brachyspira spp. were detected. However, the results showed that Brachyspira spp. could be difficult to identify, especially if two Brachyspira spp. were mixed or if the concentration of Brachyspira in faeces was low. Additionally, some laboratories reported Brachyspira growth in control samples that were not seeded with any spirochaetes. The lowest detection level was 10(2) bacteria/ml faeces for both B. hyodysenteriae and B. pilosicoli. The susceptibility tests performed showed that disc diffusion was not recommendable for Brachyspira spp. Extended antimicrobial dilution series gave most congruent results. The diversity of the results highlights the importance of ring tests for a high quality of diagnostics and antimicrobial susceptibility tests for Brachyspira spp. This is the first ring test described for Brachyspira spp.     

Observations of variable inter-observer agreement for clinical evaluation of faecal consistency in grow-finishing pigs

Inter-observer agreement for assessment of faecal consistency in pigs was evaluated using a scoring system with 3 categories. In a pilot study, 3 observers performed an examination of faecal samples post-collection. The samples were obtained from pigs (12-13 weeks old) in 4 herds with a history of diarrhoea associated with Lawsonia intracellularis, Brachyspira spp. and/or Porcine Circovirus Type 2. Observer 1 examined all the faecal samples from the 4 herds. Observer 2 only examined the faecal samples from herds 1 and 2. Observer 3 only examined the faecal samples from herds 3 and 4. We observed a substantial agreement in faecal consistency scores between Observers 1 and 3 (kappa=0.64, 95% CI: 0.51-0.78). In contrast, only a fair agreement was observed between Observers 1 and 2 (kappa=0.24, 95% CI: 0.14-0.34). The variations in inter-observer agreement detected in the current study suggest that misclassification error can be a problem in studies assessing faecal consistency. Solutions may include developing a standardized system for scoring the consistency of pig faeces, calibration when more than one observer is involved in clinical studies and using a more objective measure of faecal consistency.     

The organic acid profiles in the feces of pigs at Brachyspira hyodysenteriae- or B. pilosicoli-positive farms

We observed a significant difference in the organic acid profile of diarrheal feces between pigs infected with and free from pathogenic spirochetes. Diarrhea and loose feces were collected from growing pigs, held at 15 different commercial farms. A total of 106 samples were measured for organic acid concentration by HPLC and were checked for the presence of B. hyodysenteriae and B. pilosicoli by PCR. B. hyodysenteriae was detected in 3 samples collected from one farm. B. pilosicoli was detected in 5 samples collected from another farm. Lower concentrations of iso-butyrate and iso-valerate were likely associated with development of pathogenic spirochete infection.