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The therapeutic potential of infective pig whipworm eggs, Trichuris suis ova (TSO), is currently tested in several clinical trials on immune-mediated diseases. This paper studied the embryonic development of TSO in a medicinal raw product, where the parasite eggs were suspended in sulphuric acid (pH1). Unembryonated T. suis egg batches were stored at 5, 10, 15, 20, 25, 30, and 40°C (±1°C) and examined at 2, 4, 8, and 14 weeks. Subsequently, sub-batches from each temperature were allowed to embryonate for additional 14 weeks at 25°C, and selected samples were tested for infectivity in Göttingen minipigs. Both male and female pigs were used to evaluate eventual gender specific infectivity. Storage at 30°C up to 14 weeks and subsequent embryonation for 14 weeks at 25°C did not significantly reduce the overall larval establishment in minipigs, as compared to storage at 5°C and subsequent embryonation at 25°C. As marked impairment of egg development was observed during storage at 40°C, a second set of unembryonated egg batches were incubated at 30, 32, 34, 36, 38, and 40°C (±1°C) for 1-8 weeks. The development of the eggs was repeatedly examined by manual light microscopy, multispectral analysis (OvaSpec), and an egg hatching assay prior to the final testing in minipigs (Trial 1). These methods showed that the development started earlier at higher temperatures, but the long-term storage at higher temperature affected the egg development. The present study further documents tolerance of the TSO to storage at temperature 5-15°C, at which temperature development of larvae is not initiated.

Eggs of the pig whipworm, Trichuris suis ova (TSO), are currently tested in human clinical trials for their potential immunomodulatory capacity. The biological potency of TSO (egg viability and infectivity) is traditionally assessed in Göttingen minipigs as the establishment of intestinal larvae after inoculation with a known number of eggs. To minimize testing in animal models, development of an in vitro egg hatching assay is proposed as a reliable, cost-effective, and a faster alternative to test the egg viability. The present study aimed to investigate the influence of different chemical, physical, and biological factors on egg hatching. Thus, in a series of experiments and in different combinations, the eggs were stimulated with glass beads, artificial gastric juice, bile salt and trypsin solution, fermentation gut medium, or stimulated with mucosal scrapings from the ileum and the large intestine of the infected and uninfected Göttingen minipig. Mechanical stimulation with glass beads presented a simple and reproducible method for egg hatching. However, incubation of eggs with mucosal scrapings from the ileum, caecum, and colon for 24 h at 38 °C significantly increased hatching.

This histopathological study was carried out in order to investigate the cellular response in the jejunum to Ascaridia galli during the first 7 weeks of infection. Fourty-two ISA Brown chickens (7 weeks old) were infected orally with 500 embryonated A. galli eggs each while 28 chickens were left as uninfected controls. Six infected and four control chickens were necropsied at each time point 3, 7, 10, 14, 21, 28 and 42 days post-infection (dpi). Samples for histopathology were taken from three sites of the jejunoileum. Significantly higher eosinophil counts were seen in infected chickens compared to uninfected at 3, 7, 10, 14 and 28 dpi (P

The aim of the present study was to investigate the population dynamics and potential interactions between Trichuris suis and Oesophagostomum dentatum in experimentally co-infected pigs, by quantification of parasite parameters such as egg excretion, worm recovery and worm location. Forty-eight helminth naïve pigs were allocated into four groups. Group O was inoculated with 20 O. dentatum L3/kg/day and Group T with 10 T. suis eggs/kg/day. Group OT was inoculated with both 20 O. dentatum L3/kg/day and 10 T. suis eggs/kg/day, while Group C was kept as an uninfected control group. All inoculations were trickle infections administered twice weekly and were continued until slaughter. Faecal samples were collected from the rectum of all pigs at day 0, and twice weekly from 2 to 9 weeks post first infection (wpi). Six pigs from each group were necropsied 5 wpi and the remaining 6 pigs from each group were necropsied 10 wpi. The faecal egg counts (FEC) and total worm burdens of O. dentatum were dramatically influenced by the presence of T. suis, with significantly lower mean FECs and worm burdens at 5 and 10 wpi compared to single infected pigs. Furthermore, in the presence of T. suis we found that O. dentatum was located more posteriorly in the gut. The changes in the Trichuris population were less prominent, but faecal egg counts, worm counts 5 wpi (57% recovered vs. 39%) and the proportion of infected animals at 10 wpi were higher in Group OT compared to Group T. The location of T. suis was unaffected by the presence of O. dentatum. These results indicate an antagonistic interaction between T. suis and O. dentatum which is dominated by T. suis.

SUMMARYThe population dynamics of Ascaridia galli was studied in 70 ISA Brown layer pullets, 42 of them were each experimentally infected with 500 embryonated A. galli eggs and 28 chickens were kept as uninfected controls. Six chickens from the infected group and 4 from the control group were necropsied at 3, 7, 10, 14, 21, 28 and 42 days post-infection (d.p.i.). The mean worm recovery varied from 11–20% of the infection dose with the highest recovery at 3 d.p.i. and the lowest at 21 and 42 d.p.i. (P P P

Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this praxis may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seed of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37 °C) and thermophilic (55 °C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55 °C) were very clear as complete mortality, irrespective of weed species, was reached after less than two days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzincki amicranta still maintained low levels (~1%) of germination ability after one week. Chenopodium album was the only weed species which survived one week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55°C, no Ascaris eggs survived more than 3 h of incubation. Incubation at 37 °C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests.

SUMMARYSeparation of pig slurry into solid and liquid fractions is gaining importance as a way to manage increasing volumes of slurry. In contrast to solid manure and slurry, little is known about pathogen survival in separated liquid slurry. The viability of Ascaris suum eggs, a conservative indicator of fecal pollution, and its association with ammonia was investigated in separated liquid slurry in comparison with raw slurry. For this purpose nylon bags with 6000 eggs each were placed in 1 litre bottles containing one of the two fractions for 308 days at 5 °C or 25 °C. Initial analysis of helminth eggs in the separated liquid slurry revealed 47 Ascaris eggs per gramme. At 25 °C, egg viability declined to zero with a similar trend in both raw slurry and the separated liquid slurry by day 308, a time when at 5 °C 88% and 42% of the eggs were still viable in separated liquid slurry and raw slurry, respectively. The poorer survival at 25 °C was correlated with high ammonia contents in the range of 7·9–22·4 mm in raw slurry and 7·3–23·2 mm in liquid slurry compared to 3·2–9·5 mm in raw slurry and 2·6–9·5 mm in liquid slurry stored at 5 °C. The study demonstrates that at 5 °C, A. suum eggs have a higher viability in separated liquid slurry as compared to raw slurry. The hygiene aspect of this needs to be further investigated when separated liquid slurry is used to fertilize pastures or crops.

This study was conducted to observe the localization and to compare methods for isolation of minute Ascaridia galli larvae in chicken intestine. Firstly, six 7-week-old layer pullets were orally infected with 2,000 embryonated A. galli eggs and necropsied either at 3, 5 or 7 days post infection (dpi). More than 95 % of the recovered larvae were obtained from the anterior half of the jejunoileum, suggesting this part as the initial predilection site for A. galli larvae. Secondly, the intestinal wall of one layer pullet infected with 20,000 A. galli eggs 3 days earlier was digested in pepsin-HCl for 90 min. The initial 10 min of digestion released 51 % of the totally recovered larvae and the last 30 min of continuous digestion yielded only 5 %. This indicates that the majority of larvae were located superficially in the intestinal mucosa. Thirdly, 48 7-week-old layer pullets were infected with 500 A. galli eggs and necropsied at 3 dpi to compare three different larval isolation methods from the intestinal wall, viz., EDTA incubation, agar-gel incubation and pepsin-HCl digestion, resulting in mean percentages of the recovered larvae: 14.4, 18.2 and 20.0 %, respectively (P = 0.15). As conclusion, we recommended Pepsin-HCl digestion as the method of choice for larval recovery from the intestinal wall in future population dynamics study due to high efficiency and quick and simple detection. The agar-gel method was considered to be a prerequisite for molecular and immunological investigations as the larvae were more active and fully intact.

The population dynamics of Ascaris suum was studied by long-term exposure of pigs to infective eggs. The pigs were experimentally inoculated with 25 A. suum eggs/kg/day, and 7, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 postinoculation (PI), respectively. Despite the fact that the pigs were continuously reinfected, dramatic reductions in numbers of liver lesions (white spots) and migrating lung larvae were observed as a function of time. However, even at the end of the study, a few larvae were able to complete migration, but these larvae seemed unable to mature in the small intestine. Thus, the adult worm population seemed to consist of worms from the first part of the exposure period. The noticeable decrease in number of white spots suggests that the level of exposure is not reflected in the number of white spots in the late phase of a continuous infection. The serum levels of A. suum L3-specific IgG1 and IgA were significantly elevated by week 4 PI, after which the antibody levels declined. The population dynamics and parasite regulating mechanisms are discussed for A. suum in pigs as well as for the closely related species A. lumbricoides in humans.

Three groups of Trichuris trichiura-infected school-age children were treated with one dose 400mg albendazole, 100mg mebendazole twice daily for 3 d, or 100mg mebendazole twice daily for 5 d. The albendazole study investigated cure and egg reduction rates and found that only 5 of 66 infected children were egg-negative 7 d post-treatment, giving a cure rate of 8% and a geometric mean egg reduction rate of 89%. However, at day 14 post-treatment, all children were again egg-positive with significantly higher egg counts than at day 7 (P0.001). The two mebendazole studies aimed for the recovery of adult T. trichiura worms. After the 3 d course of mebendazole treatment, only four worms were recovered on days 3-5 after start of treatment from 2 of 34 infected children. With the 5 d course of mebendazole treatment, 10 of 21 infected children expelled a total of 27 worms. In the last case the first worm appeared on day 4 post-treatment, and the highest number of worms was recovered when the study ended at day 7. In conclusion, even with the longest treatment regimen and collecting stool samples over seven consecutive days, only very few worms were recovered. The results of this study suggest that alternative drugs and/or alternative regimens in current control programmes against T. trichiura need renewed attention.

Aggregated distributions of macroparasites within their host populations are characteristic of most natural and experimental infections. We designed this study to measure the amount of variation that is attributable to host genetic factors in a pig-helminth system. In total, 195 piglets were produced after artificial insemination of 19 sows (Danish Landrace-Yorkshire crossbreds) with semen selected from 13 individual Duroc boars (1 or 2 sows per boar; mean litter size: 10.3; 5-14 piglets per litter). Starting at 10 weeks of age, piglets were repeatedly infected with the gastrointestinal helminths Trichuris suis and Ascaris suum by administering eggs in the feed for 14 weeks until necropsy. Faecal egg counts (FECs) were estimated regularly and A. suum worm burden was obtained at necropsy. Heritability calculations for log (FEC+1) at weeks 7-10 post-infection (p.i.) showed that 0.32-0.73 of the phenotypic variation for T. suis could be attributed to genetic factors. For A. suum, heritabilities of 0.29-0.31 were estimated for log (FEC+1) at weeks 7-14 p.i., whereas the heritability of log worm counts was 0.45. Strong positive genetic correlations (0.75-0.89) between T. suis and A. suum FECs suggest that resistance to both infections involves regulation by overlapping genes. Our data demonstrate that there is a strong genetic component in resistance to A. suum and T. suis infections in pigs. Identification of responsible genes would enhance our understanding of the host immune response to these common nematodes and for the closely related species (T. trichiura and A. lumbricoides) in man infecting more than a billion people.

A sensitive and inexpensive method for DNA isolation and amplification by polymerase chain reaction (PCR) from single unembryonated Ascaris sp. eggs is described. The resistant shell of single eggs was crushed mechanically and PCR applied to the crude egg contents without any further purification steps. The ITS1 region of the rDNA and three regions of the mtDNA could be successfully amplified. Using two primer sets, it was possible to amplify the rDNA and mtDNA simultaneously in one single reaction. The ability to perform PCR on single unembryonated eggs may result in better and more precise species identification of eggs recovered from faecal material, environmental samples and possibly archaeological samples. In addition, single egg PCR makes it possible to perform population genetic studies without having to recover adult worms by deworming or autopsy.

Isospora suis is a coccidian parasite infecting piglets soon after birth. While the gross epidemiology of I. suis is well known, little knowledge exists on the ecology of the oocysts. To study the development and survival of oocysts of I. suis under controlled laboratory conditions, known numbers of oocysts ( approximately 200 in each of 4 replicates) were exposed to all combinations of 4 relative humidities (53-100% RH) and 3 temperatures (20 degrees , 25 degrees , 30 degrees C). Determination of viability was based on morphological and fluorescent properties of the oocyst as well as on the permeability of the oocyst wall characterized by inclusion/exclusion of the fluorescent dye propidium iodide. The viability of the oocysts was studied over time by fluorescence and light microscopy until

In order to investigate immunological changes over time in pigs infected with Trichuris suis, we inoculated 40 pigs with 5000 infective T. suis eggs and left 40 pigs as uninfected controls. Equal numbers of pigs from both groups were sacrificed every other week from 1 to 11 weeks p.i. At necropsy tissue samples were collected from all pigs and their worm burdens were determined. In the proximal colon of T. suis-infected pigs infiltration of eosinophils peaked 5 weeks p.i. and mast cell infiltration developed from 5 to 11 weeks p.i. Histological evaluation of the proximal colon revealed that the presence of T. suis was closely associated with intestinal histopathological changes such as crypt hyperplasia, goblet cell hyperplasia and a general hypertrophy of mucosa. The crypt lengths were positively associated with worm burdens. Real-time PCR analysis of genes related to immune function indicate a local increased transcription of genes coding for CCR3, ARG1, MUC5AC, IL-4, IL-5, IL-13, FcepsilonR1alpha, and IL-13Ralpha2 and decreased expression of genes coding for iNOS, TNF-alpha, IL-10, CD3epsilon, CD80, CD86, IL-4Ralpha, IL-13Ralpha1 and CD40 in the proximal colon of pigs infected with T. suis. This local T-helper cell Type 2-like gene-expression pattern indicates that the Type 2 immune response characteristic of helminth infections in both mouse and humans also develops in pigs infected with T. suis. The results from this study expand our knowledge of the immunomodulatory effect of T. suis, a parasite that has proven effective in treating inflammatory bowel disease, when its eggs are administered regularly to patients.

Transmission ofOesophagostomum dentatumandTrichuris suiswas studied in outdoor reared pigs. Six farrowing paddocks were naturally contaminated in May to mid-June 2001 by experimentally infected seeder pigs. In early July 1 sow farrowed on each paddock and starting at week 3post-partum(p.p.) the offspring was slaughtered serially every 2 weeks for parasite recovery. Faeces were collected regularly for parasite egg counts and acid-insoluble ash (AIA) content as an indicator of geophagy. Weaning took place at week 7 p.p. by removing the sow. Paddock infection levels were estimated in mid-June (O. dentatum) and late November (O. dentatumandT. suis) using helminth-naïve tracer pigs. Soil and vegetation samples were collected regularly. Despite a high initial contamination by the seeder pigs,O. dentatumpaddock infectivity was negligible to low throughout the raising of the experimental piglets, which had a slow accumulation of nodular worms ending with a mean of 422 worms/pig at week 19 p.p. As only few eggs developed to infectivity overallT. suistransmission was minimal. The firstT. suiswere recovered at week 11 p.p. and the highest mean burden of 21 worms/pig was recorded at week 19 p.p. The experimental pigs initially had a high faecal level of AIA although it decreased over time. The results are discussed in relation to the biological characteristics of the 2 parasites and their occurrence in organic pig production.

The transmission ofAscaris suumwas studied in outdoor reared pigs. From May to June 2001, 6 farrowing paddocks were naturally contaminated withA. suumusing experimentally infected seeder pigs. Early July, 1 sow farrowed on each paddock. One piglet per litter was slaughtered every second week starting at week 3post-partum(p.p.) for registration of liver white spots and recovery ofA. suumfrom the lungs and the small intestine. The last pigs were slaughtered at week 19 p.p. Faeces was examined for parasite eggs and blood was analysed forA. suum-specific antibodies. Weaning took place at week 7 p.p. by removing the sow. Paddock infection levels were estimated by regular examination of soil samples and in late June and late November using parasite naïve tracer pigs. Paddock contamination was high but eggs developed slowly resulting in a low initial transmission to the experimental pigs. By week 5 p.p. transmission had increased and the numbers of infective eggs in the soil increased during the study. The results indicate a continuous uptake of infective eggs, but visceral larval migration was reduced with time, probably due to the development of a pre-hepatic barrier. Nevertheless, a rather large population of adult worms remained in the pigs throughout the study, and it may primarily have been eggs ingested in the early infection phase that gave rise to the patent infections. It is suggested that neonatal exposure may result in increased persistence and size of adult worm burden and that the higher ‘life-time worm burden’ may be of significant economic importance.

Trichuris suis population kinetics was studied by experimentally infecting 40 pigs with 5000 T. suis infective eggs. Six pigs were sacrificed every 2 weeks from 1 to 9 weeks post-inoculation (p.i.) and the remaining 10 pigs were sacrificed 11 weeks p.i. to estimate worm burdens. An equal number of uninfected control pigs were sacrificed at the same time points for comparison. Egg excretions from each pig were evaluated every week from 5 to 11 weeks p.i. Peripheral blood eosinophilia and basophilia were also evaluated every 2 weeks throughout the experimental period. After an initial almost 100% establishment of T. suis an expulsion phase followed approximately 9 weeks p.i., resulting in an aggregated distribution of the worms in the pig population, as it is characteristic for most helminth infections. By 11 weeks p.i. almost all worms had been expelled. Egg excretion peaked 7 weeks p.i. and a significant non-linear relationship between worm burdens and egg excretion was found. The predilection site for T. suis was the caecum and proximal colon and the relative distribution of worms in the large intestine did not change over time until expulsion. Peaking peripheral blood eosinophil and basophil levels were observed in the T. suis infected pigs 5 and 7 weeks p.i., respectively, reflecting the host activated immune response against the parasite. We here describe the course of a primary T. suis infection in pigs by detailed worm counts, demonstrating an effective expulsion that results in an almost 100% clearance of infection as previously indicated by monitoring faecal egg excretion.

Concomitant infections with helminths and bacteria may affect the course and the resulting disease outcome of the individual infections. Salmonella, Oesophagostomum, Trichuris and Ascaris coexist naturally in pig herds in Denmark, and possible interactions were studied. Pigs in one experiment were trickle infected with low or moderate dose levels of Oesophagostomum spp. and challenge infected with S. Typhimurium. In another experiment, pigs were inoculated with S. Typhimurium followed by a challenge exposure to either Oesophagostomum, Trichuris or Ascaris. Enhancement of the Salmonella infection was not demonstrated in either experiment. The helminth effect on the pigs was modest and may explain the lack of influence on the Salmonella infection. A previous experiment with a larger Oesophagostomum infection level resulted in enhancement of the S. Typhimurium infection. A dose dependency of the interaction is therefore suggested. However, the relatively high worm burdens in the present study suggest that infection with these common pig helminths does generally not influence the course of concurrent S. Typhimurium infections under natural conditions.

Two experiments (Exps 1 and 2) were carried out to study the effect of dietary carbohydrates on the establishment ofTrichuris suisin pigs. Two experimental diets based on barley flour were used; Diet 1 was supplemented with non-fermentable carbohydrates from oat hull meal, while Diet 2 was supplemented with fermentable carbohydrates from sugar beet fibre and inulin. In Exp. 1, thirty-two pigs were allocated randomly into 4 groups. Two groups were fed Diet 1 and 2 groups were fed Diet 2. Pigs from one of each diet group were inoculated with 2000 infectiveT. suiseggs each and the other two groups were uninfected controls. All pigs were slaughtered 8 weeks post-inoculation (p.i.). In Exp. 2, twenty-four pigs were allocated randomly into 2 groups and fed Diet 1 or Diet 2, respectively. All the pigs were inoculated with 2000 infectiveT. suiseggs. Six pigs from each group were slaughtered 8 weeks p.i. and the remaining 6 pigs from each group were slaughtered 12 weeks p.i. Infections were followed by faecal egg counts and worm burdens were assessed at necropsy. Pigs fed Diet 2 had lower egg counts in both experiments; in Exp. 2 the difference was significant (PPPT. suisin naïve pigs, but result in earlier expulsion and reduced growth of the established worms. Thus, diets with highly fermentable carbohydrates may be used in the control ofT. suis.

The direct influence of intracaecal infusion of short-chain fatty acids (SCFA) and lactic acids (LA) on already established Oesophagostomum dentatum infection in cannulated pigs was investigated. We tested the hypothesis that the previously discovered anti-parasitic effect of inulin is mediated through its metabolic products SCFA and LA by infusing into cannulated pigs these compounds in amounts approximating to those produced in the pigs large intestine and caecum during the metabolism of inulin. The experiment comprised of 18 pigs--2 groups of 9 pigs in each. The normal diet used in the experiment was based on barley flour with insoluble fibre from oat husk with added soybean meal, vitamins and minerals. After 2 weeks of adaptation to the diet all the pigs were inoculated with 6,000 infective larvae of O. dentatum. Six weeks later, surgery on all pigs was performed to install cannulas into caeci. At 7 weeks post-infection (p.i.) the SCFA and LA infusion was initiated in Group 1 (experimental) pigs; at the same time pigs in Group 2 (controls) were infused with saline. At week 10 p.i., all pigs were killed and their worm burdens determined. SCFA and LA infused pigs exhibited markedly reduced fecal egg counts and worm recoveries (98 and 92% reduction, respectively, compared to saline controls). The results from this study demonstrate that SCFA and LA have a significant negative influence on established O. dentatum infection in growing pigs. The results also show that the type of dietary carbohydrates fed and its intestinal degradation can yield metabolic by products that profoundly influence helminth survival.

Embryonated eggs of the pig whipworm Trichuris suis (TSOee) constitute the active pharmaceutical ingredient (API) in a medicinal product explored in human clinical trials against several immune-mediated diseases. The measurement of TSO biological potency (hatchability and infectivity) is a requirement for the assessment of TSO's pharmacological potency in human clinical trials. The present study aims to validate the dose-dependent establishment of T. suis larvae in Gottingen minipigs and eventual clinical implication of a dose range (1000-10,000 TSO). Four groups of 5 minipigs were inoculated with doses of 1000, 2500, 7500, and 10,000 TSOee, respectively, to evaluate a range of concentrations of TSOee in a minipig infectivity model. Unembryonated eggs (TSOue) were added to keep the total egg number in the inoculum constant at 10,000 eggs. Two groups received 2500 and 7500 TSOee per pig without the addition of TSOue as controls. The intestinal larval establishment at 21 days post inoculation (dpi) demonstrated a clear positive linear dose-response relationship between numbers of inoculated TSOee and recovered larvae. There was a low level of variation in larval counts in all study groups. Thus, the infectivity model in minipigs within the tested dose range offers a reliable, sensitive and accurate assay for testing biological potency of TSO.

Background: An observational study has suggested that relapsing–remitting multiple sclerosis patients with helminth infections have lower disease activity and progression than uninfected multiple sclerosis patients. Objective: To evaluate the safety and efficacy on MRI activity of treatment with TSO in relapsing MS. Methods: The study was an open-label, magnetic resonance imaging assessor-blinded, baseline-to-treatment study including ten patients with relapsing forms of multiple sclerosis. Median (range) age was 41 (24–55) years, disease duration 9 (4–34) years, Expanded Disability Status Scale score 2.5 (1–5.0), and number of relapses within the last two years 3 (2–5). Four patients received no disease modifying therapy, while six patients received IFN-β. After an observational period of 8 weeks, patients received 2500 ova from the helminth Trichuris suis orally every second week for 12 weeks. Patients were followed with serial magnetic resonance imaging, neurological examinations, laboratory safety tests and expression of immunological biomarker genes. Results: Treatment with Trichuris suis orally was well-tolerated apart from some gastrointestinal symptoms. Magnetic resonance imaging revealed 6 new or enlarged T2 lesions in the run-in period, 7 lesions in the early period and 21 lesions in the late treatment period. Two patients suffered a relapse before treatment and two during treatment. Eight patients developed eosinophilia. The expression of cytokines and transcription factors did not change. Conclusions: In a small group of relapsing multiple sclerosis patients, Trichuris suis oral therapy was well tolerated but without beneficial effect.

BackgroundOvaSpec is a new, fully automated, vision-based instrument for assessing the quantity (concentration) and quality (embryonation percentage) of Trichuris suis parasite eggs in liquid suspension. The eggs constitute the active pharmaceutical ingredient in a medicinal drug for the treatment of immune-mediated diseases such as Crohn?s disease, ulcerative colitis, and multiple sclerosis. MethodsThis paper describes the development of an automated microscopy technology, including methodological challenges and design decisions of relevance for the future development of comparable vision-based instruments. Morphological properties are used to distinguish eggs from impurities and two features of the egg contents under brightfield and darkfield illumination are used in a statistical classification to distinguish eggs with undifferentiated contents (non-embryonated eggs) from eggs with fully developed larvae inside (embryonated eggs). ResultsFor assessment of the instrument?s performance, six egg suspensions of varying quality were used to generate a dataset of unseen images. Subsequently, annotation of the detected eggs and impurities revealed a high agreement with the manual, image-based assessments for both concentration and embryonation percentage (both error rates

The study investigated the effect of gastrointestinal passage in pigs on free-living stages of bovine nematodes. Two Landrace x Yorkshire pigs, A and B, were fed fresh eggs of Ostertagia ostertagi and Cooperia oncophora while two other pigs, C and D, were fed third stage larvae (L3) of the same parasites. Faeces from the pigs were collected for 48 h after ingestion. In pigs A and B, 15 and 66% of the eggs were recovered after passage, respectively. However, only 0.003 and 0.002% of the ingested eggs developed into third stage larvae (L3) after subsequent culturing. In pigs C and D, 0.01 and 0.02% of the L3 survived the passage of the gastrointestinal tract. Fresh O. ostertagi and C. oncophora eggs were cultured in parasite free porcine and bovine faeces. Only 0.05% L3 developed in porcine faeces, whereas 21% of the eggs developed into L3 in the bovine culture. Our results demonstrate an extremely poor rate of development and survival of both bovine nematode eggs and infective larvae after passage in pigs. It may imply that pigs can play an important role in reducing transmission of cattle nematodes if the two species are grazed together or alternately.

A study was conducted to determine the distribution and transmission rate of Ascaris suum eggs and Oesophagostomum dentatum larvae in a pasture/pig house facility, which during the preceding summer was contaminated with helminth eggs by infected pigs. In May, four groups of 10 helminth naïve tracer pigs were exposed to fenced sections of the facility for 7 days and necropsied for parasite recovery 9-10 days later (trial 1). The highest rate of A. suum transmission (201 eggs per day) occurred in the pig house (A). On the pasture, egg transmission decreased with the distance from the house: 8 eggs per day in the feeding/dunging area (B); 1 egg per day on the nearest pasture (C);1 egg per day on the distant pasture (D). Only a few O. dentatum infections were detected, indicating a poor ability of the infective larvae to overwinter. Soil analyses revealed that the highest percentage (5.8%) of embryonated A. suum eggs were in the house (A). Subsequently, the facility was recontaminated with A. suum eggs by infected pigs. A replicate trial 2 was conducted in the following May. A major finding was the complete reversal of egg distribution between the 2 years (trials 1 and 2). In contrast to previous results, the highest rates of transmission (569 and 480 eggs per day) occurred in pasture sections C and D, and the lowest transmission rates (192 and 64 eggs per day) were associated with the feeding/dunging sections and the house (B and A). Soil analyses again supported the tracer pig results, as the pasture sections had the highest concentrations of embryonated eggs. Detailed soil analysis also revealed a non-random, aggregated egg distribution pattern. The different results of the two trials may be due to the seasonal timing of egg deposition and tracer pig exposure. Many eggs deposited during the summer prior to trial 1 may have died rapidly due to high temperatures and dessication, especially when they were not protected by the house, while deposition in the autumn may have favored egg survival through lower temperatures, more moisture, and greater sequestration of eggs in the soil by rain and earthworms. The latter eggs may, however, not have become embryonated until turnout the next year. The results demonstrate that yearly rotations may not be sufficient in the control of parasites with long-lived eggs, such as A. suum, and that a pasture rotation scheme must include all areas, including housing.

This study was made to elucidate the transmission of nematode infections in outdoor pigs at different stocking rates during two consecutive seasons. Five pigs (Group 1A) inoculated with low doses of Oesophagostomum dentatum, Ascaris suum, and Trichuris suis and five helminth-naïve pigs (Group 1B) were turned out together in June 1996 on each of four pastures at stocking rates of 100, 240 (two pastures) and 576m(2) per pig, respectively. The pigs were slaughtered in early October, and pasture infectivity was subsequently measured using helminth-naïve tracer pigs (Tracer). In 1997, 10 helminth-naïve pigs were turned out on each pasture in May (Group 2) and again in August (Group 3), and allowed to graze for 12 weeks. The percentage of grass cover was reduced considerably at the high stocking rate in comparison to the other stocking rates. Transmission of all three helminths was observed on all pastures. In 1996, the O. dentatum faecal egg counts and worm burdens were significantly higher in pigs at the high stocking rate compared to pigs at the other stocking rates. O. dentatum did not survive the winter and pigs of Group 2 were inoculated with 3000 larvae each to reintroduce this parasite. Ascaris suum ELISA values and worm counts were highest at the high stocking rate in 1997 (Group 3). Transmission of T. suis was not significantly influenced by stocking rate. The results indicate that transmission of O. dentatum, and to some extent A. suum is influenced by stocking rate. However, both A. suum and T. suis eggs are still expected to constitute a high risk of infection on intensively used pastures where eggs may accumulate for years. The relationship between host density and helminth transmission seems more complex for grazing/rooting pigs than for grazing ruminants. This may be due to the differences in behaviour of the animals and the resulting differences in microclimate of the developing eggs/larvae.

This study was carried out to examine the survival of infective Ostertagia ostertagi larvae (L(3)) on pasture under different simulated conditions of grazing, i.e. mixed grazing of cattle and nose-ringed sows, or grazing by cattle alone. Standardised pats of cattle faeces containing O. ostertagi eggs were deposited on three types of herbage plots, which were divided into zone 1: faecal pat; zone 2: a circle extending 25cm from the edge of the faecal pat; zone 3: a circle extending 25cm from the edge of zone 2. For "tall herbage" (TH) plots, the herbage in zone 2 was allowed to grow naturally, while the herbage in zone 3 was cut down to 5-7cm fortnightly, imitating a cattle-only pasture. For "short herbage" (SH) plots, the herbage in both zones 2 and 3 were cut down to 5-7cm fortnightly, imitating mixed grazing of cattle and sows. The grass in the "short herbage and scattered faeces" (SH/SF) plots were cut as for SH plots, and the faeces were broken down 3 weeks after deposition and scattered within zone 2, imitating the rooting behaviour of co-grazing sows. Five faecal pats from each plot group were collected on monthly basis, along with the herbage from zones 2 and 3 cut down to the ground. Infective larvae were then recovered from both faeces and herbage. The numbers of L(3) recovered from zone 1 were higher in the TH plots than in the other two groups and, furthermore, the larval counts from SH plots were always higher than from SH/SF plots. The three groups followed a similar pattern during the season regarding numbers of L(3) in zone 2, and no clear patterns between plot types were obtained. The presence of L(3) in zone 3 was almost negligible. Important differences were seen throughout the study from the biological point of view; more L(3) were able to survive in faeces on the TH plots, presumably reflecting a better protection from heat and desiccation compared to those in the other plots. The overall results support the idea that mixed grazing of cattle and pigs favour the reduction of O. ostertagi larval levels in pasture. This reduction is mainly due to the grazing behaviour of pigs, which by grazing up to the very edge of the cattle faeces, will either expose the larvae in faeces to adverse environmental summer conditions or ingest cattle parasite larvae, or both.

Ten chickens and 2 pigs were fed non-embryonated eggs ofAscaris suum,Trichuris suisandOesophagostomum dentatum. Each chicken was fed approximately 15000 eggs of each parasite species while approximately 300000 eggs were given to each of the pigs. After passage in chickens 8.3% ofO. dentatumeggs were recovered in faeces compared to 61.1% and 41.6% ofA. suumandT. suiseggs, respectively. After passage in pigs the percentages were 38.4%, 49.1% and 30.3%, respectively. After embryonation in the laboratory, 1000 eggs of each parasite species having passed through chickens or pigs or having been kept in the laboratory as controls were fed to groups of 6 pigs to check the infectivity. The number ofA. suumrecovered from pigs was similar in the 3 groups with 34.0, 52.8 and 41.8%, respectively. The recovery ofT. suisin the pig passage group was 54.0% which was significantly lower than the recovery in the chicken passage group (81.8%) and the laboratory group (88.0%). The number ofO. dentatumrecovered was not significantly different among the 3 experimental groups, the percentage recovery being 30.5, 9.2 and 28.5%, respectively. One explanation for the lower infectivity ofT. suisin the pig passage group may be that the eggs have been sublethally damaged through their passage. The results demonstrate that chickens and pigs can act as transport hosts forA. suum, T. suisandO. dentatum, and it is highly probable that these domestic animals are able to act also as transport hosts for the human parasite equivalents. This will have important consequences for the environmental and behavioural strategies in human helminth control programmes.

The helminth infections on 13 pig fattening farms with different management systems (complete or partial all-in-all-out system or continuous fattening) in North-Western Germany were investigated over at least three fattening periods. Pooled faecal samples were taken from pens once before and three times after anthelmintic treatment. At the beginning of fattening 34.9% of the samples contained helminth eggs, mainly from Oesophagostomum spp. (27.5%). Ascaris suum eggs were found in 10.5% of the samples, while other parasites were only rarely found. The number of pig-supplying farms was positively correlated with the helminth infection prevalence. Immediately after deworming, all pen samples were free of helminth eggs. However, the prevalences increased again, and by the end of fattening A. suum was found in 33.0% and strongylids in 6.0% of the samples. Pens harbouring A. suum-excreting pigs at the beginning of fattening had higher infection levels at the end, and this was also the case for nodular worms. The final prevalence of Ascaris was higher in partial exchange systems than in complete all-in-all-out systems and in old pig houses compared to new ones. Transmission of both Ascaris and Oesophagostomum was highest in autumn and winter. Thus, a single anthelmintic treatment at the beginning of fattening could not prevent infection during fattening, and the state of infection at the beginning was associated with the helminth burden at slaughter. Therefore, the purchase of parasite-free pigs in combination with appropriate hygiene management may minimise the initial infection pressure and keep subsequent infection of the herd at a minimum.

This paper reports on the influence of maternal exposure to Ascaris suum on worm burden distributions in experimentally infected piglets. In the first study, sows were inoculated before and during gestation (6 months, long-term exposure) with 10000 A. suum eggs twice weekly. In a second study, sows were inoculated during gestation only (3 months, short-term exposure) with increasing doses of eggs (10000–40000 eggs twice weekly). Helminth-naive sows served as controls in both studies. The third study used the same design as the short-term exposure study, but piglets from exposed and control sows were cross-suckled within 4 h of birth before colostrum uptake. All piglets were inoculated 2 or 3 times with 50 A. suum eggs on days 4 and 7 (and 14) after birth, and left with the sows. At 10 weeks of age all piglets were necropsied, and liver lesions and worm burdens were recorded. Surprisingly, in piglets born to long-term exposed sows, the prevalence of A. suum infection and the mean worm burden were significantly higher than those in piglets from control sows. In contrast, neither worm burdens nor prevalence were significantly different between piglets from short-term exposed sows compared with their controls. In the cross-suckling experiment, 67% of piglets suckling control sows harboured worms at slaughter, compared with 15%of piglets suckling exposed sows. Maximum likelihood analysis of worm burden distribution and the degree of parasite aggregation showed 3 distinctly different types of overdispersed distributions: worm counts in piglets from control sows, in piglets from short-term exposed sows and in piglets from long-term exposed sows. When the worm burden data were analysed including the cross-suckled piglets by biological mother, it appeared that the control and short-term distributions converged and that only the long-term exposure was significantly different. Overall, the degree of parasite aggregation in piglets infected with A. suum decreased with exposure of the sows. A non-linear relationship was observed between prevalence of infection and mean worm burden, which was different for piglets from exposed and control sows, and similar to relationships of this type that previously have been found in human A. lumbricoides infections. It was concluded that in porcine A. suum infections maternal exposure alters the distribution of worms in their offspring, in which the duration of exposure appeared to be an important influence. The results of the cross-suckling further suggest that maternal factors, e.g. antibodies, are transferred via colostrum.

Pig faeces were deposited on experimental plots in the spring, summer, autumn and winter to study development and survival of Ascaris suum and Trichuris suis eggs under outdoor conditions. Faeces were placed either in short grass or 2 cm below the surface of bare soil, imitating pastures used by nose-ringed, grazing pigs or normally rooting pigs, respectively. The numbers and developmental stages of the eggs were recorded in faeces and soil for up to 50 weeks post-deposition. Embryonation took place only during the summer months and seemingly was independent of the microclimate. The majority of A. suum and T. suis eggs, which are generally considered to be extremely resistant and long-lived, seems to disappear rather fast. The disappearance rate for A. suum eggs was higher than for T. suis eggs, and both egg types disappeared significantly faster in the summer months than in the winter months, and when placed in short grass than when buried in soil (less exposed). We discuss how knowledge on egg development and survival may be used in the planning of pasture strategies for control of helminth infections in outdoor pigs.

The aim of this study was to examine interactions between Ascaris suum and Oesophagostomum dentatum infections in pigs with regard to population dynamics of the worms such as recovery, location and length; and host reactions such as weight gain, pathological changes in the liver and immune response. Seventy-two helminth-naive pigs were allocated into four groups. Group A was inoculated twice weekly with 10 000 O. dentatum larvae for 8 weeks and subsequently challenge-infected with 1000 A. suum eggs, while Group B was infected with only 1000 A. suum eggs; Group C was inoculated twice weekly with 500 A. suum eggs for 8 weeks and subsequently challenge-infected with 5000 O. dentatum larvae, whereas Group D was given only 5000 O. dentatum larvae. All trickle infections continued until slaughter. Twelve pigs from Group A and B were slaughtered 10 days post challenge infection (p.c.i.) and the remaining 12 pigs from the each of the four groups were slaughtered 28 days p.c.i.. No clinical signs of parasitism were observed. The total worm burdens and the distributions of the challenge infection species were not influenced by previous primary trickle-infections with the heterologous species. Until day 10 p.c.i. the ELISA response between A. suum antigen and sera from the O. dentatum trickle infected pigs (Group A) pigs were significantly higher compared to the uninfected Group B. This was correlated with a significantly higher number of white spots on the liver surface both on Day 10 and 28 p.c.i. in Group A compared to Group B. The mean length of the adult O. dentatum worms was significantly reduced in the A. suum trickle infected group compared to the control group. These results indicate low level of interaction between the two parasite species investigated.

In Denmark (DK), Finland (FIN), Iceland (I), Norway (N), and Sweden (S), 516 swine herds were randomly selected in 1986-1988. Individual faecal analyses (mean: 27.9 per herd) from eight age categories of swine showed that Ascaris suum, Oesophagostomum spp., Isospora suis, and Eimeria spp. were common, while Trichuris suis and Strongyloides ransomi-like eggs occurred sporadically. Large fatteners and gilts were most frequently infected with A. suum with maximum prevalences of 25-35% in DK, N and S, 13% in I and 5% in FIN. With the exception of the remarkably low A. suum prevalence rates in FIN, no clear national differences were observed. Oesophagostomum spp. were most prevalent in adult pigs in the southern regions (21-43% in DK and southern S), less common in the northern regions (4-17% adult pigs infected), and not recorded in I. I. suis was common in piglets in DK, I, and S (20-32%), while1% and 5% were infected in N and FIN, respectively. Eimeria spp. had the highest prevalences in adult pigs (max. 9%) without clear geographical differences. I. suis and Eimeria spp. were recorded for the first time in I, and I. suis for the first time in N.

To study population kinetics during primary Ascaris suum infections, 3 groups of 52 pigs each were inoculated with 100, 1000, or 10000 infective eggs. In all groups, the majority of larvae was found in the liver on day 3 post inoculation (p.i.) and in the lungs on day 7 p.i. Liver white spots, caused by migrating larvae, were most numerous at day 7 p.i., whereafter they gradually healed, and only low numbers of granulation-tissue type white spots and lymphonodular white spots persisted at days 21–56 p.i. Independent of dose level, 47–58% of the inoculated eggs were recovered as larvae in the small intestine on day 10 p.i., but most larvae were eliminated at days 17–21 p.i. This elimination started earlier and removed a higher percentage of the worms with increasing inoculation dose, resulting in small strongly aggregated worm populations by day 28 p.i. ( k of the negative binomial distribution was low: 0·2–0·4) without significant differences between groups. Thus, overdispersion, which is a characteristic of both porcine and human ascarosis, is found here under experimental conditions where aggregation factors like host behaviour, transmission rate, host status etc have been partly or totally controlled.

To define prepatent periods of different Oesophagostomum spp. isolates we carried out two separate experiments, one using two monospecific laboratory isolates and another using laboratory isolates as well as isolates obtained from pig herds having different management systems and with different anthelmintic treatment histories. Pigs were inoculated with 1,000-2,000 infective larvae. Fecal samples were collected daily beginning on days 15 and 16 postinoculation (p.i.). Fecal cultures were set up at different times to yield larvae that could be identified by DNA analyses. All pigs started to excrete eggs on days 18-24 p.i. The mean prepatent period was 20.2 +/- 1.4 days, with no significant difference being observed between species and isolates. Prepatent periods of 17-19 days were found for the monospecific laboratory isolates of O. dentatum and O. quadrispinulatum. These findings conflict with parasitology textbooks; therefore, suggestions as to the possible reasons for the observed short prepatent periods are given.

In Denmark, alternative outdoor production systems for pigs are becoming more frequent, and information on the transmission of Ascaris suum and Trichuris suis under continuously grazed pasture conditions is needed. A group of pigs was turned out on a pasture in May 1993 (Year 1 of the study), inoculated with 200 eggs of A. suum and 1000 eggs of T. suis , and followed parasitologically. A non-experimentally infected group of pigs was similarly turned out on the same pasture the following year (Year 2) and again followed parasitologically. Pasture infectivity was measured using helminth-naive tracer pigs. During the summer of Year 1, A. suum eggs became infective within 4–6 weeks on the pasture. However, transmission was moderate until August of Year 2, when a pronounced increase in transmission occurred. After 2 months on the pasture, the continuously exposed pigs in summer seasons of both Years 1 and 2 harboured small overdispersed populations of adult A. suum , moderate numbers of liver white spots, and high specific IgG responses. These parasitological measures on chronically exposed pigs did not, however, correlate well with pasture infectivity or with each other. In contrast, the liver inflammation and specific IgG responses (but not the intestinal A. suum burdens) of the tracer pigs were highly correlated ( P = 0.0001) and appeared to better reflect pasture infectivity. The inoculated pigs excreted T. suis eggs by the late summer of Year 1, but no transmission took place before August of Year 2. Thus, the T. suis population of infective eggs built up very slowly. The results indicate that T. suis eggs may survive for a considerable time, however. The study results reveal that A. suum and T. suis eggs are much more resistant to environmental factors than free-living infective larvae of pig parasites such as Oesophagostomum dentatum and Hyostrongylus rubidus . Control of these parasites in outdoor systems will present more difficult challenges than that for parasites transmitted by free-living larvae.

A questionnaire survey on the use of anthelmintics and presence of other potential risk factors for the development of anthelmintic resistance of nematodes in 136 Danish sow herds was carried out between November 1992-February 1993. Twenty one veterinarians who specialize in diseases of pigs administered the questionnaire in personal interviews during their regular visits to the respective pig farmers. In the study population, 91% of the farmers currently treated their sows with anthelmintics, while only 38% and 14% treated their weaners and fatteners, respectively. Most respondents treated their sows either before or after farrowing (40%) or once every 6 months (27%). Benzimidazole and pro-benzimidazole (Class I) anthelmintics were the most used in sows by the farmers (39%, 47%, 49%, 50%, 46%, and 47% during the years 1987, 1988, 1989, 1990, 1991 and 1992, respectively). When sows were treated, fenbendazole was the most frequently used anthelmintic during the period 1987-1992 (30%-39%). The proportion of farmers that used Class II (pyrantel and levamisole) or Class III (ivermectin and piperazine) anthelmintics during the year 1992 were 25% and 13%, respectively. Of the 70 farmers who used anthelmintics from either Class I, II or III during the study period, 44 farmers always used the same class of drugs. Eight herd owners among those 44, had changed the pharmaceutical product within the same class. Sixty nine percent of the farmers did not weight the sows, but used visual appraisal of average body.

Four groups with three pigs in each group were inoculated with Oesophagostomum dentatum larvae (L3 larvae). Groups 1 and 3 were inoculated with 20,000 larvae, and Groups 2 and 4 with 200,000 larvae. On Days 11 and 34, respectively, Groups 1 and 2 and Groups 3 and 4 were slaughtered, and the contents from the large intestines collected. Subsamples of intestinal contents were mixed with agar to a final concentration of 1% agar and allowed to set. The worms were allowed to migrate from the agar-gel into 38 degrees C 0.9% saline overnight. Then the worms were collected on a sieve (38 microns mesh) and counted. The worms retained in the agar-gel were counted after pouring the melted agar through a sieve (38 microns mesh). The results showed that more than 95% of the worms migrated out of the agar-gel, and subsequently were available for counting in an almost clean suspension. Additionally the method yielded a high worm recovery; all stages were recovered. The recovery percentage was not significantly affected by either the dose of parasites or the time interval from slaughtering to start of incubation (37-128 min).

Two groups of 20 pigs weighing approx. 26 kg were offered either ground barley plus protein supplement (GBP) or commercial pelleted feed (CPF), two diets consisting of nearly the same amounts of carbohydrates, proteins and micronutrients. All pigs were experimentally infected with 600 infective Ascaris suum eggs and 6000 infective Oesophagostomum spp. larvae and followed coprologically for approx. 12 weeks post infection, whereafter they were slaughtered. The number of Oesophagostomum spp. and A. suum eggs was significantly higher in the GBP-fed pigs compared with the CPF-fed pigs (P < 0.0001). The mean worm burden of adult Oesophagostomum spp. was higher in the GBP-pigs than in the CPF-pigs (P < 0.05), while the mean worm burden of adult A. suum in the two groups was not significantly different. The results indicate that two diets, both fulfilling the requirements of modern pig raising, may result in different establishment rates of natural adult gastrointestinal helminths in swine.

This report describes the effect of different dose levels of infection upon worm burdens and development and fecundity of the parasites. Three groups each of 40, 9-week-old, helminth naive pigs were inoculated once with either 2000 (group A), 20,000 (group B), or 200,000 (group C) infective third stage larvae of Oesophagostomum dentatum . Subgroups of 5 pigs from each major group were killed 3, 6, 11, 14, 18, 25, 34 and 47 days post inoculation (p.i.) and the large intestinal worm burdens were determined. Faecal egg counts were determined at frequent intervals after day 13 p.i. There were no overt clinical signs of gastrointestinal helminthosis during the experiment. Faecal egg counts became positive in groups A and B at around day 19 p.i., whereas most pigs in the high dose group C did not have positive egg counts until day 27–33 p.i. and some pigs remained with zero egg counts until the end of the study. Throughout the experiment the worm populations in group C consisted mainly of immature larval stages, while those in groups A and B were predominantly adult stages after days 14–18. Adult worms from the low dose group A were significantly longer than those from group C. At high population densities, stunted development of worms and reduced fecundity among female worms were found. Furthermore, there was a tendency for the distribution of the worms within the intestine to be altered with increasing population size.

Background Parasitic helminths have been shown to reduce inflammation in most experimental models of allergic disease, and this effect is mediated via cytokine responses. However, in humans, the effects of controlled helminth infection on cytokine responses during allergy have not been studied. Objective The aim was to investigate whether infection with the nematode parasite Trichuris suis alters systemic cytokine levels, cellular cytokine responses to parasite antigens and pollen allergens and/or the cytokine profile of allergic individuals. Methods In a randomized double-blinded placebo-controlled clinical trial (UMIN trial registry, Registration no. R000001298, Trial ID UMIN000001070, URL: http://www.umin.ac.jp/map/english), adults with grass pollen-induced allergic rhinitis received three weekly doses of 2500 Trichuris suis ova (n = 45) or placebo (n = 44) over 6 months. IFN-γ, TNF-α, IL-4, IL-5, IL-10 and IL-13 were quantified via cytometric bead array in plasma. Cytokines, including active TGF-β, were also quantified in supernatants from peripheral blood mononuclear cells cultured with parasite antigens or pollen allergens before, during and after the grass pollen season for a sub-cohort of randomized participants (T. suis ova-treated, n = 12, Placebo-treated, n = 10). Results Helminth infection induced a Th2-polarized cytokine response comprising elevated plasma IL-5 and parasite-specific IL-4, IL-5 and IL-13, and a global shift in the profile of systemic cytokine responses. Infection also elicited high levels of the regulatory cytokine IL-10 in response to T. suis antigens. Despite increased production of T. suis-specific cytokines in T. suis ova-treated participants, allergen-specific cytokine responses during the grass pollen season and the global profile of PBMC cytokine responses were not affected by T. suis ova treatment. Conclusions and clinical relevance This study suggests that cytokines induced by Trichuris suis ova treatment do not alter allergic reactivity to pollen during the peak of allergic rhinitis symptoms.

Swine production systems are characterised by a high diversity with regard to management type and the level of intensity of management. The number of helminth species and their infection levels are strongly influenced by the different systems. The present paper focuses on the situation in northern Europe, with examples from Denmark, and describes a decrease in both the number of helminth species and in their infection levels as a result of a shift from non-intensive to highly intensive production systems. Differences in the basic biological requirements of the pre-infective larvae, and in the transmission characteristics and immunogenicity of the various helminth species, explain why some species are more vulnerable to manage mental changes than others. Finally, control measures for the different production systems are discussed. Even though it is well documented that proper hygiene and management may prevent transmission of helminths, use of anthelmintics is still the single most important action taken by pig farmers to control worm infections. It is emphasised that anthelmintics should not be used uncritically, but should be integrated with management practices and the production system to achieve optimum effect and to avoid development of anthelmintic resistance.

The normal habitat of the parasitic stages of Ascaridia galli is in the small intestine of poultry but the exact localization is poorly understood. Therefore, a histological study was conducted in order to localize the larvae during the early phase of infection. Six layer pullets seven-week old were infected orally with 20,000 embryonated A. galli eggs each, whereas four chickens were left as un-infected controls. At necropsy 3 days after infection the first half of jejunum/ileum was divided into two equally sized sections (J1 and J2). After taking samples for histology from the middle of J1 and J2 and the junction between these determined JX, the two sections were subjected to parasitological examination. A higher number of A. galli larvae were recovered from section J2 than J1 and the majority of larvae were recovered from the most profound layers. Based on histology 144 larvae were identified and their location was noted. The highest number of larvae was observed in the JX sample as compared to J1 and J2 (P0.001). Most of them were located in the profound crypt zone of the mucosa (51%) as compared to the other zones (P0.05). The number of larvae was higher in the lumen (63%) compared to the epithelium (32%) and lamina propria (5%) (P0.001). A significantly higher number of eosinophils were found in lamina propria of the infected group compared to the control group (P0.001). This experiment clearly showed that only few larvae had penetrated the epithelium and were positioned in the lamina propria at 3 days post infection. It was far more common that the larvae were localized within the epithelium or in the lumen of the crypts. It is therefore suggested that at least in this early phase "mucosal phase" is a more appropriate term to be used for the A. galli larval localization as compared to the term "histotrophic phase" currently used in many textbooks.

Helminths in pigs have generally received little attention from veterinary parasitologists, despite Ascaris suum, Trichuris suis, and Oesophagostomum sp. being common worldwide. The present paper presents challenges and current research highlights connected with these parasites. In Danish swine herds, new indoor production systems may favour helminth transmission and growing knowledge on pasture survival and infectivity of A. suum and T. suis eggs indicates that they may constitute a serious threat to outdoor pig production. Furthermore, it is now evident that A. suum is zoonotic and the same may be true for T. suis. With these 'new' challenges and the economic impact of the infections, further research is warranted. Better understanding of host-parasite relationships and A. suum and T. suis egg ecology may also improve the understanding and control of human A. lumbricoides and T. trichiura infections. The population dynamics of the three parasites are well documented and may be used to study phenomena, such as predisposition and worm aggregation. Furthermore, better methods to recover larvae have provided tools for quantifying parasite transmission. Thus, an on-going study using helminth naive tracer pigs has surprisingly demonstrated that soil infectivity with A. suum and T. suis increases during the first 2-3 years after pasture contamination. Though all three helminth species stimulate the Th2 arm of the immune system, Oesophagostomum seems weakly immunogenic, perhaps via specific modulation of the host immune system. A. suum and T. suis potently modulate the host immune response, up-regulating Th2 and down-regulating Th1. As a consequence, A. suum may compromise the efficacy of certain bacterial vaccines, whereas T. suis, which establish only short-term in humans, is a favourite candidate for down-regulating autoimmune Th1-related diseases in man. Some basic research findings have offered new possibilities for future sustainable control measures. For example, the heredity of host resistance to A. suum and T. suis is so high that breeding for resistant pigs may be a possibility. Experimental studies have demonstrated that fermentable dietary carbohydrates have an antagonistic effect on Oesophagostomum and to a lesser extent on T. suis and A. suum, whereas egg-destroying microfungi may be used to inactivate the hard-shelled A. suum and T. suis eggs in the environment. Helminth control in Denmark has previously relied solely on anthelmintic treatment in herds with low helminth transmission. When indoor transmission rates increase, or in outdoor herds with high pasture contamination levels, medication may advantageously be combined with sustainable control measures, such as selected pig genomes, bioactive forages, and egg-destroying microfungi.

UnlabelledSymptoms after human infection with the helminth Trichuris suis have not previously been described. Exposure to helminths has been suggested as immune therapy against allergy and autoimmune diseases. We randomized adults with allergic rhinitis to ingest a dose of 2500 T. suis eggs or placebo every 21 days for 168 days (total 8 doses) in a double-blind clinical trial. In a previous publication, we reported a lack of efficacy and a high prevalence of adverse gastrointestinal reactions. The aim of the present study was to present a detailed description of the adverse event data and post-hoc analyses of gastrointestinal reactions. Adverse events and severity (mild, moderate, severe) were recorded daily by subjects, classified by organ using MedDRA 10.0, and event rates compared between subjects on T. suis treatment vs. subjects on placebo. T. suis-specific serum IgG antibodies were measured by a fluoroenzymeimmunoassay (Phadia ApS). During 163 days complete follow-up, subjects ingesting T. suis eggs (N = 49) had a three to 19-fold higher rate of events (median duration, 2 days) with gastrointestinal reactions (moderate to severe flatulence, diarrhea, and upper abdominal pain) compared with placebo subjects (N = 47). The highest incidence of affected subjects was seen from the first few days and until day 42 (3(rd) dose): 63% vs. 29% for placebo; day 163: 76% vs. 49% for placebo. Seroprevalences increased concurrently in the T. suis group: Day 59, 50%; day 90, 91%; day 170, 93%. The combined duration of episodes with onset before day 42 was ≤ 14 days in 80% of affected subjects. Age, gender, total IgE, and recent intestinal symptoms at baseline did not predict gastrointestinal side effects. In conclusion, during the first 2 months, repeated ingestions of 2500 T. suis eggs caused frequent gastrointestinal reactions lasting up to 14 days, whereas 4 months further treatment mainly provoked a subclinical stimulation.Trial registrationUniversity hospital Medical Information Network trial registry Reg. no. R000001298, Trial ID UMIN000001070.

During the last 30 years, pig production in Uganda and neighbouring counties has increased markedly. Pigs are mainly kept as a source of income for small-scale farmers; however, the pig production is subject to several constraints, one of them being worm infections. A study was carried out in rural communities in Kabale District in the South Western part of Uganda in September and October 2007 in order to estimate the prevalence of gastrointestinal nematode parasites in pigs based on coprological examination. Fifty-six households were randomly selected and visited. Housing system and deworming history were recorded. Faeces was sampled from rectum of one to five pigs (age, 3–12 months) per household. A total of 106 pigs were examined coprologically of which 91% excreted nematode eggs. The following prevalences of nematode eggs were recorded: strongyles (89%), Ascaris suum (40%), Trichuris suis (17%) and spiruroid eggs (48%). On household level, rearing pigs on slatted floors in pens significantly reduced the faecal egg excretion of strongyle eggs with almost 80% (p = 0.010) and a significant interaction between floor type and anthelmintic treatment was found for spiruroids (p = 0.037). Fifteen T. suis egg positive pigs were selected for post-mortem examination of the gastrointestinal tract. The post-mortem examinations revealed that 93% pigs were infected with Oesophagostomum spp. (worm burden, min–max 10–2,180), 73% with A. suum (1–36), 67% with T. suis (6–58), and 20% with Hyostrongylus rubidus (worms not quantified). In general, nematode infections were widespread and polyparasitism common in pigs in Uganda. However, worm burdens were moderate which may be related to recent deworming or to the practice of rearing pigs on slatted floors in wooden elevated pens.

Commercially reared growers, finishers, and sows of Danish Landrace x Yorkshire crossbred were inoculated orally with Ascaris suum at 50 eggs kg-1 body weight. White spots on the serosal surface of livers and total larval recoveries from lungs were recorded 7 days later. The response in pigs originating from a specific pathogen free and parasite free herd (parasite naïve) was observed in the three different age groups and compared with age-matched pigs from a herd maintained in a facility contaminated with A. suum (naturally exposed). The pre-inoculation immune status of the various groups was characterized serologically using antigen preparations derived from various stages of A. suum. Inoculation of all age groups of parasite naïve pigs with A. suum eggs produced relatively high liver white spots and lung larvae, although expression of these counts as a percentage of the inoculum showed a moderate age-related resistance from growers to finishers to sows. In contrast, pigs naturally exposed to A. suum expressed strong immunity to a challenge infection as few or no larvae were detected in the lungs. In addition, growers, finishers, and sows from the naturally exposed herd had significantly higher levels of serum IgG/IgA to several different A. suum antigens compared with pigs from the parasite nave herd. Liver white spots, expressed as a percentage of the inoculum, were highest in growers from the naturally exposed herd but were markedly reduced in finishers and sows from that herd. In fact, few or no white spots were observed in naturally exposed sows, while sows from the parasite-naïve herd had in excess of 300 liver white spots following challenge. These results indicate that commercially raised pigs that are exposed to A. suum develop a strong protective immunity that ultimately produces a complete pre-hepatic barrier to larval migration, while pigs raised parasite free remain susceptible to infection.

SUMMARYThe population dynamics ofTrichuris suisin pigs was studied during long-term experimental infections. Twenty-three 10-week-old pigs were inoculated with 5T. suiseggs/kg/day. Seven, 8, and 8 pigs were necropsied at weeks 4, 8, and 14 post-start of infection (p.i.), respectively. The median numbers of worms in the colon were 538 (min–max: 277–618), 332 (14–1140) and 0 (0–4) at 4, 8, and 14 weeks p.i. respectively, suggesting an increased aggregation of the worms with time and acquisition of nearly sterile immunity. The serum levels ofT. suisspecific antibodies (IgG1, IgG2 and IgA) peaked at week 8 p.i. By week 14 p.i. the IgG2 and IgA antibody levels remained significantly elevated above the level of week 0. The population dynamics ofT. suistrickle infections in pigs is discussed with focus on interpretation of diagnostic and epidemiological data of pigs, the use of pigs as a model for humanTrichuris trichiurainfections and the novel approach of usingT. suiseggs in the treatment of patients with inflammatory bowel disease.

Since their first introduction more than a century ago, vaccines have become one of the most cost-effective tools to prevent and manage infectious diseases in human and animal populations. It is vital to understand the possible mechanisms that may impair optimal vaccine efficacy. The hypothesis posed in this study was that a concurrent Ascaris suum infection of pigs vaccinated with a Mycoplasma hyopneumoniae (Mh) vaccine would modulate the protective immune response to a subsequent challenge infection. Four groups of pigs were either (1) untreated (group C), (2) vaccinated against Mh 3 weeks after the start of the study (group V), (3) given a trickle infection with A. suum throughout the study (group A), or (4) given a trickle infection with A. suum and vaccinated against Mh (group AV). All pigs were subsequently inoculated with live Mh bacteria 4 weeks after the Mh vaccination and necropsied after another 4 weeks. All pigs in group V sero-converted 3 weeks after vaccination (100%), as opposed to only 33% of group AV pigs that were Mh-vaccinated and given A. suum. At the end of the study, only 78% of pigs in group AV had sero-converted. Pigs in group AV had a higher mean percentage of lung pathology and the variation was significantly higher in these pigs compared to pigs in group V. The pattern of gene expression in the lungs and draining lymph nodes indicated a local Th2-skewed response induced by A. suum. Our study indicated that A. suum significantly compromised the effect of Mh vaccination. The impact of reduced vaccine efficacy caused by a common gastrointestinal helminth emphasises the importance of parasite control. More focus should be put into this area of research to outline the practical consequences of this interaction, and to be able to predict, prevent and correct negative interactions.

SUMMARYThe aim of this study was to investigate the intra-litter infection dynamics ofIsospora suisunder natural conditions, and to study any association between parasite transmission and the contamination level of the farrowing pen by applying different interventions in order to reduce the transmission ofI. suisinfection within the litter. The study was divided in 2 trials including in total 22 litters (254 piglets). The first trial included 4 litters (where standard procedures practiced routinely on the farm piglets were applied) and the piglets were followed coprologically from farrowing until 2 weeks after weaning. The sows of those litters were also examined at various intervals before and after farrowing. The second trial included the application of 3 different management procedures: (A) standard farm hygiene and management procedures, (B) standard farm hygiene and management procedures+the first piglets found to excreteI. suisoocysts in each pen were removed from the pen, and (C) reduced cleaning. Each procedure was studied in 2 litters. This was replicated 3 times to yield a total of 18 litters. The results suggested that (i) the sow does not play an important role in transmission ofI. suisin the farrowing pen; (ii) in natural infections, both the age of the piglet age at onset of oocyst excretion and the oocyst excretion patterns may vary considerably; (iii) the course of oocyst excretion or development of diarrhoea is related to the time of initial infection and (iii) piglets, which are heavy at birth, are more prone to acquireI. suisinfection. Moreover, it was demonstrated that cleaning could be an effective means of restricting the spread of the parasite within the litter and thus the development of diarrhoea.