Swine dysentery: protection against experimental challenge following single dose parenteral immunisation with inactivated Treponema hyodysenteriae

Groups of five pigs were vaccinated at three to four weeks old with either formolised Treponema hyodysenteriae in oil adjuvant alone, formolised T hyodysenteriae in oil adjuvant plus formolised Campylobacter coli in oil adjuvant, or sterile medium in oil adjuvant (as a control). Each group was challenged four weeks after vaccination by oral dosing on two consecutive occasions with pure cultures of the homologous strain of T hyodysenteriae plus direct contact with two pigs exhibiting severe swine dysentery. The disease was observed in two of five pigs immunised with T hyodysenteriae alone, three of five pigs immunised with T hyodysenteriae plus C coli and all five controls; haemorrhagic diarrhoea was exhibited only by the control group. Each pig immunised with T hyodysenteriae (alone or with C coli) recovered spontaneously, whereas four controls died. Vaccination with T hyodysenteriae also markedly reduced the severity and duration of clinical signs and of weight loss. No differences were observed in response to challenge between pigs immunised with T hyodysenteriae alone and pigs immunised with T hyodysenteriae plus C coli.     

Immunity to Swine dysentery in recovered pigs

The immune status of 29 pigs recovered from swine dysentery (SD) was evaluated after reexposure to Treponema hyodysenteriae. Pigs which had recovered from SD and remained asymptomatic for 4 to 6, 9 to 13, and 16 to 17 weeks after initial inoculation were reexposed to 1.5 X 10(9) viable cells of T hyodysenteriae per pig. Pigs which had recovered from SD were not shedding T hyodysenteriae, as determined by selective cultural examination of feces, before they were reexposed. Of 29 pigs reexposed to T hyodysenteriae, 27 were resistant to SD. In contrast, 23 of 28 control pigs developed signs of SD when exposed to T hyodysenteriae for the first time. Significant differences in immunity were not observed between pigs from the three convalescent periods. Serum agglutinins to T hyodysenteriae were present in recovered pigs for approximately 8 weeks after inoculation.     

Swine dysentery: studies of gnotobiotic pigs inoculated with Treponema hyodysenteriae, Bacteroides vulgatus, and Fusobacterium necrophorum

Transmission experiments were carried out in gnotobiotic pigs to determine whether lesions typical of swine dysentery could be produced by oral inoculation of Treponema hyodysenteriae in combination with Bacteroides vulgatus or Fusobacterium necrophorum, or both. Each of the organisms had been isolated from swine with early lesions of the disease. Lesions were not found in 6 pigs inoculated with T hyodysenteriae alone, in 4 pigs given F necrophorum and T hyodysenteriae, or in 4 pigs given B vulgatus and F necrophorum. Lesions typical of swine dysentery developed in 8 pigs given B vulgatus, F necrophorum, and T hyodysenteriae as well as in 3 of 4 pigs given B vulgatus and T hyodysenteriae. In both of these groups, the inoculated bacteria were recovered from the colon, and T hyodysenteriae was demonstrated in the colonic crypts, epithelium, and lamina propria. The pathogenicity of the T hyodysenteriae was shown by the development of characteristic signs and lesions of swine dysentery in 12 of 14 naturally farrowed pigs inoculated with T hyodysenteriae alone.     

Isolation of Treponema hyodysenteriae from sources other than swine

Fecal samples were collected from animals and environments on 3 swine farms and cultured for Treponema hyodysenteriae. Each farm was a farrow-to-finish operation and, at the time of sampling, swine dysentery was enzootic among 8- to 22-week-old pigs. Pathogenic T hyodysenteriae was isolated from pigs on all 3 farms. On farm A, nonpathogenic T hyodysenteriae was isolated from a sample of lagoon water. On farm B, pathogenic T hyodysenteriae was isolated from a waste-holding pit. On farm C, a dog was observed to be eating feces of pigs that had swine dysentery. The dog was diarrheic and a fecal sample yielded a pathogenic isolant of T hyodysenteriae. Further isolation attempts were unsuccessful after the dog was removed from the infected premises. Isolation of pathogenic and nonpathogenic organisms from waste-holding systems emphasizes the need for cultural techniques in detecting pathogenic T hyodysenteriae.     

Swine dysentery: protection of pigs by oral and parenteral immunisation with attenuated Treponema hyodysenteriae.

An attenuated strain of Treponema hyodysenteriae was used to immunise 18 pigs in three experiments. Live attenuated spirochaetes were dosed orally and injected intra-peritoneally, and killed spirochaetes were injected intramuscularly with adjuvant. The vaccinated pigs, which developed high serum agglutination titres against T hyodysenteriae, and 18 unvaccinated litter-mates were repeatedly challenged with virulent T hyodysenteriae. Nine vaccinated pigs and 16 control pigs developed typical swine dysentery.     

Effect of levamisole on the clinical and immunologic responses to oral vaccine of Treponema hyodysenteriae

Conventionally raised crossbred Hampshire pigs were vaccinated orally with attenuated Treponema hyodysenteriae in combination with an anthelmintic, levamisole or dichlorvos. Pigs in group I (n = 9) were treated with levamisole and vaccinated with attenuated T hyodysenteriae and those in group II (n = 9) were treated with levamisole and permitted to commingle (contact exposure) with group I. Pigs in group III (n = 9) were vaccinated in a similar manner and were treated with dichlorvos. Pigs in group IV (n = 9) were treated with dichlorvos and permitted to commingle with group III. Control pigs (group V; n = 9) were not given any anthelmintic, nor were they vaccinated; they were housed separately. During the 8-week interval between vaccination and challenge inoculation, 4 total days and 8 total days of diarrhea were observed in pigs in groups I and II, respectively. Likewise, 5 total days and 10 total days of diarrhea were seen in groups III and IV, respectively. In all groups, the pigs tended to shed the organism in their feces after they were vaccinated or challenge inoculated, as determined by a fluorescent antibody technique (FAT) and culture procedure (CP). Overall mean shedding patterns of 5.5% and 24.5% identified by CP and FAT, respectively, were seen in the 2 levamisole-treated groups (I and II). In contrast, mean shedding patterns of 4% and 18% of the isolation attempts were detected by CP and FAT, respectively, in the 2 dichlorvos-treated groups. Diarrhea and shedding of T hyodysenteriae in the controls (group V) did not occur.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of fermentable carbohydrates on experimental swine dysentery and whip worm infections in pigs

An experiment was conducted to study the effect of diets with contrasting fermentability in the large intestine on experimental infections with Brachyspira hyodysenteriae, the causative agent of swine dysentery, and the whip worm, Trichuris suis, in pigs. Two diets with organically grown ingredients were composed. Both diets were based on triticale and barley and supplemented with either rape seed cake (Diet 1) or dried chicory root and sweet lupins (Diet 2). The study had a three-factorial design, with eight groups of pigs receiving Diet 1 or Diet 2, +/-B. hyodysenteriae, and +/-T. suis. Pigs fed Diet 2 and challenged with B. hyodysenteriae did not develop swine dysentery and B. hyodysenteriae was not demonstrated in any of the pigs during the study. In contrast, 94% of the B. hyodysenteriae challenged pigs fed Diet 1 showed clinical symptoms of swine dysentery and all the pigs were shedding B. hyodysenteriae in faeces at some points in time during the experiment. The number of T. suis was lower in pigs fed Diet 2 compared to pigs fed Diet 1, but the differences were not significant. Pigs on Diet 1 and challenged with both pathogens showed clinical symptoms of SD for a longer period than pigs inoculated with B. hyodysenteriae only. The study showed that diets supplemented with highly fermentable carbohydrates from dried chicory roots and sweet lupins can protect pigs against developing swine dysentery, but do not have any significant influence on T. suis.     

Physiological properties and classification of strains of Treponema sp. isolated from pigs in poland

Fifty-one treponemas were isolated from pigs. Twenty-three isolates with typical morphology and growth characteristic were beta hemolytic, enteropathogenic, produced indole and with exception of three strains did not ferment fructose. These strains were classified as typical T. hyodysenteriae and were usually isolated from pigs with symptoms of mucohemorrhagic diarrhoea. The seventeen other isolates were weakly beta hemolytic after 48 h incubation, enteropathogenic, 12 out of 17 produced indole, 10 out 17 fermented fructose. These strains were usually isolated from pigs with symptoms of gray-green diarrhoea and classified as T. hyodysenteriae 2 biotype or intermediate type. They may be compared with Treponema sp. isolated by Taylor et al. Eleven non enteropathogenic strains showed typical characteristic for T. innocens. Gas chromatography analysis of the fatty acids production from glucose, showed that all isolated treponemas produced acetate and butyrate. Typical T. hyodysenteriae produced additionally propionate. Strains of T. hyodysenteriae biotype 2 produced propionate or isobutyrate as well.     

Swine dysentery: inoculation of gnotobiotic pigs with Treponema hyodysenteriae and Vibrio coli and a Peptostreptococcus.

Pure cultures of Treponema hyodysenteriae given orally to conventional pigs resulted in the development of swine dysentery, whereas identical cultures given to gnotobiotic pigs did not produce the disease. Oral inoculation of gnotobiotic pigs with Vibrio coli and/or a peptostreptococcus in addition to T. hyodysenteriae did not result in dysentery. Neutralization of gastric secretions with NaHCO3 immediately prior to inoculation with T. hyodysenteriae increased the period during which treponemes were evident in the feces, as did the inoculation of this organism via the intracecal route. None of the gnotobiotic pigs with a persistent fecal Treponema population developed signs of dysentery. Factors other than those investigated in this work must play a part in the etiology of swine dysentery.     

Use of a whole chromosomal probe for identification of Treponema hyodysenteriae

A whole chromosomal DNA probe labelled with photobiotin was used in a dot blot hybridisation to identify DNA from isolates of Treponema hyodysenteriae, the aetiological agent of swine dysentery. The probe was evaluated using DNA from 13 isolates of T hyodysenteriae and 13 isolates of non-T hyodysenteriae spirochaetes recovered from pigs. The initial test had both a sensitivity and specificity of 92.3 per cent, although when it was repeated the specificity fell to 84.6 per cent. The test was helpful in distinguishing between T hyodysenteriae and other morphologically similar treponemes that are part of the normal flora in the large intestine of pigs. The probe could also be used to detect as little as 10 ng of purified DNA from T hyodysenteriae, or DNA from 2 x 10(6) bacterial cells lysed directly onto nitrocellulose.     

A serological survey to determine the prevalence of infection with Treponema hyodysenteriae in Western Australia

A serological survey to detect antibody titres against Treponema hyodysenteriae was conducted on pigs from 106 herds in Western Australia. Titres indicating a positive result in the tests were determined by examining 400 sera from 4 herds known to be free of swine dysentery, and sera from immunised or experimentally infected pigs. Samples of serum from 40 bacon-weight pigs from each of the 106 herds were then collected at 2 abattoirs. Each serum was tested in enzyme-linked immunosorbent assays (ELISA) against the lipopolysaccharide of T hyodysenteriae of serogroups A, B and E, respectively. To assist in evaluating the test, 19 herds were resampled and retested, and faecal samples from 17 herds were cultured for T hyodysenteriae. Thirty-five of the 106 herds (33%) had serological evidence of infection when only one batch of sera from each herd was tested. The ELISA to detect T hyodysenteriae infection in herds using 40 sera was estimated as having a sensitivity of 77.3% and a specificity of 81.8% based on the owners' opinion of their herds disease status. Prevalence of infection within herds ranged from 2.5% to 47.5%, with a mean of 18%.     

Effect of levamisole on parenteral vaccines for swine dysentery

Leucocyte migration-inhibition and humoral antibody responses (HAR) were demonstrated in swine immunized with particulate or soluble antigen of Treponema hyodysenteriae. Levamisole (at the recommended deworming level), given simultaneously with particulate vaccine did not significantly (P greater than 0.05) enhance nor suppress the leucocyte migration-inhibition response. However, an enhancing leucocyte migration-inhibition of the drug was seen in pigs given soluble vaccine in combination with levamisole compared with those receiving soluble antigen alone. Levamisole generally suppressed the HAR throughout the immunization schedule of pigs given soluble or particulate vaccine. There was no significant suppression (P greater than 0.05) of clinical signs of swine dysentery (SD) in animals given particulate vaccine nor in those receiving this vaccine plus levamisole. However, pigs receiving soluble vaccine plus levamisole had fewer clinical signs of SD as well as significantly (P less than 0.05) fewer shedding episodes of T. hyodysenteriae than those given soluble antigen alone. When compared with the control pigs, swine vaccinated with soluble antigen had fewer days of total diarrhoea and shedding episodes of T. hyodysenteriae. However, the diarrhoea of vaccinated pigs was not significantly (P greater than 0.05) delayed when compared to the unvaccinated swine.     

Induction of swine dysentery in swine by the intravenous injection of filtered Treponema hyodysenteriae.

Swine dysentery was induced in 18 swine exposed by intravenous injection of a filtrate which contained Treponema hyodysenteriae and was obtained from macerated colonic scrapings of swine dysentery. However, swine dysentery did not develop in swine injected intravenously with a pure culture of T. hyodysenteriae or when combined with a colonic filtrate from normal swine. Diarrheal feces from the swine injected intravenously with the filtered T. hyodysenteriae contained more mucus, and fecal smears contained more T. hyodysenteriae and fewer other bacteria than did swine exposed orally to colon infected with swine dysentery or filtered T. hyodysenteriae. In the colons of the 12 swine injected intravenously with filtered T. hyodysenteriae that died, there was a minimum amount of croupous membrane and, microscopically, the T. hyodysenteriae were located deep in the colonic crypts. Five of the six surviving swine injected intravenously with filtered T. hyodysenteriae developed serum anti-T. hyodysenteriae antibodies using the indirect fluorescent antibody test and four of these swine developed diarrhea when reexposed with swine dysentery infected colon six weeks after initial exposure. None of the swine injected intravenously with cultured T. hyodysenteriae developed serum anti-T. hyodysenteriae antibodies and all were highly susceptible to swine dysentery.     

3-Acetyl-4'-isovaleryl tylosin for prevention of swine dysentery

The 21 field isolates of Treponema hyodysenteriae which were tested were sensitive to 3-acetyl-4'-isovaleryl tylosin (AIV); the minimal inhibitory concentration was 0.25 to 16 micrograms/ml. 3-Acetyl-4'-isovaleryl tylosin administered prophylactically to pigs at concentrations of 5 to 100 mg/kg of feed and tylosin at 110 mg/kg of feed for 28 or 31 days prevented swine dysentery induced by tylosin-sensitive T hyodysenteriae strain SQ2; 15 nonmedicated, inoculated control pigs had bloody diarrhea, and 9 pigs died. In 2 additional trials, AIV administered prophylactically for 28 days at 55 or 110 mg/kg of feed prevented swine dysentery induced by tylosin-insensitive T hyodysenteriae strain B204. All of the inoculated principal pigs medicated with AIV at 55 or 110 mg/kg of feed or carbadox at 55 mg/kg of feed and the noninoculated sentinel pigs for each group had solid feces throughout the 56-day trial. In the nonmedicated, inoculated control groups, bloody diarrhea began at 4 to 5 days after inoculation was done, and 9 of 10 principal pigs and 6 of 9 sentinel pigs had dysentery; 2 pigs died. In the groups medicated with AIV at 27.5 or 5.5 mg/kg of feed, all 5 principal pigs and 3 or 4 sentinel pigs in each group had dysentery; 3 or 4 pigs in each group died. In the group medicated with tylosin at 110 mg/kg of feed, 7 of 10 principal pigs and all 9 sentinel pigs had dysentery; 1 pig died.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of selective culture and serologic agglutination of Treponema hyodysenteriae for diagnosis of swine dysentery

Samples of faeces and of serum were collected from pigs of various ages on 21 farms. Faecal samples were cultured on trypticase soy agar containing 5 per cent citrated bovine blood and 400 micrograms per ml spectinomycin, incubated at 42 degrees C in Gaspak jars under an atmosphere of 80 per cent hydrogen: 20 per cent carbon dioxide. Antibody titres to Treponema hyodysenteriae were determined by a microtitration agglutination method using merthiolate-inactivated whole cell antigen prepared from a beta-haemolytic isolate. Results indicated that mean titres in pigs from which beta-haemolytic T hyodysenteriae was isolated were significantly higher than in pigs which yielded isolates of weak beta-haemolytic T innocens or in culturally negative pigs (P less than 0.0225). Mean titres of herds where beta-haemolytic T hyodysenteriae was isolated were significantly higher (P less than 0.005) than the mean titres of either of the other two groups. However, mean titres of herds where no isolates were obtained were not significantly different from mean titres of herds where weak beta-haemolytic T innocens was isolated.     

Studies on the pathogenesis of swine dysentery. II. Search for a cytotoxin in spirochetal broth cultures and colon content.

Broth cultures of Treponema hyodysenteriae and colonic content from pigs with swine dysentery were tested for cytotoxicity in cell cultures, erythrocyte suspensions and in ligated segments of pig colon. Live cells of T. hyodysenteriae attached to the surface of cells in all cultures tested but did not penetrate them nor cause morphologic change detectable by light microscopy. Only live T. hyodysenteriae caused erythrolysis. Broth cultures or colonic content sterilized by filtration or by disruption with ultrasound had no visible effect on the cell cultures, erythrocyte suspensions or the mucosa of ligated colonic segments.     

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.     

A study of swine dysentery by immunofluorescence and histology.

Twenty-six specific-pathogen-free pigs were fed pure cultures of Treponema hyodysenteriae. Five untreated pigs were controls. Distribution of this large spirochete in pigs with swine dysentery was shown by the indirect fluorescent antibody technique. Findings by this method were compared with those from dark-field examination of colonic mucosal scrapings and from tissue sections. The cultures caused mucohemorrhagic colitis which by 10 days after inoculation was indistinguishable from the colitis of swine dysentery. Control pigs remained normal. Pigs killed when spirochetes were first seen in the feces had normal colonic mucosa with only a few spirochetes. At the first sign of diarrhea, however, the colonic mucosa was thicker than normal and had many spirochetes. T. hyodysenteriae was confined to regions of hypertrophy and exudation of the large intestine mucosa throughout the course of disease.     

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.     

Experiences with a vaccine being developed for the control of swine dysentery

SUMMARY A prototype vaccine that is being developed for the control of swine dysentery (SD) was tested in two groups of experimental pigs. Vaccination induced high circulating antibody titres against the aetiological agent, Serpulina (Treponema) hyodysenteriae .
Pigs in the first trial were vaccinated twice before being challenged orally with the bacteria. Five of 6 unvaccinated animals developed dysentery within a fortnight of challenge, but only 1 of 6 vaccinated pigs showed signs of disease at this time. Unexpectedly, 1 mo after challenge, the surviving unvaccinated pig and 2 remaining healthy vaccinated animals succumbed to the disease. The reason for the development of this late-onset form of dysentery was not clear.
In the second trial, 8 pigs were vaccinated 3 times. Only 2 of these animals (25%) developed severe dysentery after being mixed with infected pigs, whereas 7 of 8 (88%) unvaccinated control pigs in the same pen became diseased. The late-onset form of dysentery was not observed.
The prototype vaccine for SD provided a useful level of protection, and could be used in programs to control the disease in Australia.