Ronny Lindberg

Dietary zinc oxide in weaned pigs — effects on performance, tissue concentrations, morphology, neutrophil functions and faecal microflora

The uptake and distribution of zinc in tissues and the effects of 2500 ppm dietary zinc oxide on health, faecal microflora, and the functions of circulating neutrophils were evaluated in weaned pigs. One group was fed a zinc supplement diet and another group was used as a control. All pigs remained healthy throughout the study, but the supplemented animals showed better performance than the controls. The serum zinc values rose rapidly. At autopsy, carried out at the age of 63 days, the zinc concentrations in liver tissue were 4.5 times higher, and in renal tissue two times higher in the supplemented group than in controls (P<0.001). Microscopic examination showed increased lipid accumulation in hepatocytes from supplemented pigs. No effect on the number of excreted Escherichia coli and enterococci per gram faeces or on the functions of circulating neutrophils was observed. Dietary supplementation with 2500 ppm ZnO for up to two weeks after weaning appears to be potentially beneficial in the prevention of postweaning diarrhoea in pigs.

A previously unidentified Chorioptes species infesting outer ear canals of moose (Alces alces): characterization of the mite and the pathology of infestation.

BackgroundDuring the past decade, Chorioptes mites occupying the outer ear canals have been a common finding at routine necropsies of moose (Alces alces) in Sweden, but neither the taxonomy of the mites nor lesions from the infestation have been investigated. In this study, the mites are characterized by morphological and molecular techniques, and the histopathology of the skin of the outer ear canal is described.MethodsExternal auditory meatuses from 53 necropsied moose were examined for the presence of Chorioptes, and samples from outer ear canals were taken for histopathological and microbiological examination. A proportion of the mites from each moose was identified to species. The DNA was extracted from mites from three moose, and their ITS-2 sequences were determined; these sequences were compared phylogenetically to sequences from other Chorioptes taxa.ResultsChorioptes mites were found in 43 (81%) of the 53 moose. The mites had morphological and genetic characteristics distinct from those of C. texanus and C. bovis, the two species generally accepted within the genus. Morphology also did not argue for a diagnosis as C. crewei, C. mydaus or C. panda. On histopathology, lesions were characterized by a hyperplastic perivascular to interstitial dermatitis with epidermal hyperkeratosis and crust formation. Dermal inflammatory infiltrates were composed of mixed T- and B-lymphocytes, plasma cells and macrophages, whereas eosinophils were notably uncommon. Staphylococcus aureus was grown from the infested epidermis of five of 14 examined moose.ConclusionChorioptes mite infestation was frequently detected in the outer ear canals of moose in Sweden. The mites were evidently pathogenic, being associated with inflammatory lesions of the external auditory meatus. Our studies indicate infestations with a previously undescribed Chorioptes species.

Experimental Contagious Caprine Pleuropneumonia: A Long Term Study on the Course of Infection and Pathology in a Flock of Goats Infected with Mycoplasma capricolum subsp. capripneumoniae

AbstractContagious caprine pleuropneumonia (CCPP) is a major threat to goat farming in parts of Africa and Asia. It classically causes acute high morbidity and mortality early in infection, but little is known of its long term epizootiology and course. In this study, 10 goats were inoculated with Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae) and then mixed with 15 goats for contact transmission. The disease course was monitored in each goat for 56–105 days, whereafter the goats were killed and necropsied. Varying features signifying infection occurred in altogether 17 goats (7 inoculated, 10 in-contact). Clinical signs were severe in 8 goats but no fatalities occurred. Only 6 goats had serum antibody titres against M. capripneumoniae in ELISA. Fourteen goats (5 inoculated, 9 in-contact) had chronic pleuropulmonary lesions compatible with CCPP at necropsy and 7 of those showed M. capripneumoniae antigen in the lung by immunohistochemistry. Neither cultivation nor PCR tests were positive for the agent in any goat. The results indicate that the clinical course of CCPP in a flock may be comparatively mild, M. capripneumoniae-associated lung lesions may be present at a late stage of infection, and chronic infection may occur without a significant serological response.SammanfattninExperimentell kontagiös pleuropneumoni hos get: Enlångtidsstudie över infektionsförlopp och patologi hos en flock getter infekterade med Mycoplasma capricolum subsp. capripneumoniae. Kontagiös kaprin pleuropneumoni (CCPP) utgör ett viktigt hot mot gethållningen i delar av Afrika och Asien. Sjukdomen är i sin typiska form förenad med hög akut morbiditet och mortalitet i tidig infektionsfas, men litet är känt om dess förlopp och epizootologi vid långvarig infektion. I denna studie inokulerades 10 getter med Mycoplasma capricolum subsp. capripneumoniae (M. capripneumoniae) och de blandades sedan med 15 getter för kontaktsmitta. Sjukdomsförloppet studerades hos varje get under 56 - 105 dagar, varefter getterna avlivades och obducerades. Varierande tecken på infektion uppträdde hos totalt 17 getter (7 inokulerade, 10 kontaktsmittade). Åtta visade markanta kliniska symptom men inga dödsfall uppträdde. Endast 6 getter hade antikroppstitrar i serum mot M. capripneumoniae i indirekt ELISA. Fjorton getter (5 inokulerade, 9 kontaktsmittade) hade kroniska pleuropulmonära lesioner förenliga med CCPP vid obduktion och 7 av dessa visade M. capripneumoniae-antigen i lungorna vid immunohistokemisk undersökning. Varken vid mykoplasmaodlingeller PCR-test kunde smittämnet påvisas. Resultaten visar att det kliniska förloppet vid CCPP kan vara jämförelsevis milt, att lunglesioner associerade med M. capripneumoniae kan förekomma i sent stadium av infektion i en flock, och att sjukdomen kan uppträda utan signifikant serologiskt antikroppssvar.

Experimental schistosomiasis japonica in the pig : immunohistology of the hepatic egg granuloma

Use of the pig as an animal model in schistosomiasis research is increasing, but knowledge of the porcine immune response to schistosome infection is still very limited. We investigated the immunohistology of different maturation stages of the Schistosoma japonicum egg granuloma in pigs. Liver sections from pigs experimentally infected with S.japonicum for 9, 12 or 21 weeks were examined by immunohistochemistry using a three‐step streptavidin‐biotin‐complex/immunoperoxidase method or a two‐step alkaline phosphatase‐mediated system. All granulomas showed marked expression of major histocompatibility complex (MHC) class II in epithelioid macrophages and were dominated by T lymphocytes, comprising both CD4+ and CD8+ phenotypes, with consistently higher proportions noted for CD8+ cells. B lymphocytes, as identified by expression of CD21, were confined to lymphoid nodular structures primarily associated with mature granulomas. Early and mature granulomas contained numerous immunoglobulin (Ig)G+ plasma cells. Significant differences in immunohistology related to duration of infection were not observed. The results indicate that all stages of the hepatic S.japonicum egg granuloma in the pig manifests MHC class II‐dependent CD4+ T cell activity concomitant with infiltration of CD8+ T cells. B cell activity preceding the effector cell stage appears to occur in granuloma‐associated lymphoid nodules, whereas antibody, mainly IgG, is produced within the granuloma.

Consecutive pathological and immunological alterations during experimentally induced swine dysentery – A study performed by repeated endoscopy and biopsy samplings through an intestinal cannula

Abstract The development of intestinal lesions after inoculation with Brachyspira hyodysenteriae was followed by repeated endoscopy and biopsy sampling through a caecal cannula. Seven eight-week-old pigs were cannulated and inoculated, two were cannulated but not inoculated, and two pigs were inoculated but not cannulated. Endoscopy, biopsy, and blood sampling to determine SAA (serum amyloid A), haptoglobin, cortisol, and WBC counts were performed at scheduled time-points. At the third day of disease, endoscopy showed a hyperaemic, perturbed mucosa and excessive amount of mucus. Histologically, crypt hyperplasia, depletion of goblet cell mucus, and erosions were noted. Simultaneously, elevated acute phase proteins and circulating monocytes, and decreased number of intraepithelial CD3+ cells were observed. After five days the pigs recovered. Intestinal lesions were demarcated and interspersed among apparently normal mucosa and blood parameters returned to initial values. Endoscopy through an intestinal cannula made it possible to follow the development of intestinal alterations in vivo and describe the sequential events during the course of swine dysentery. The number of animals used in a study could thus be minimised and the precision of the experiment increased.

Pathological and bacteriological characterization of neonatal porcine diarrhoea of uncertain aetiology

Neonatal porcine diarrhoea of uncertain aetiology has been reported from a number of countries. This study investigated 50 diarrhoeic and 19 healthy piglets from 10 affected Swedish herds. The piglets were blood-sampled for analysis of serum γ-globulin and necropsied, and the intestines were sampled for histopathology and cultured for Escherichia coli, Clostridium perfringens and Clostridium difficile. Escherichia coli isolates (n = 276) were examined by PCR for virulence genes encoding LT, STa, STb, EAST1, VT2e, F4, F5, F6, F18, F41, AIDA-I, intimin, and for the genes aaiC and aggR. Selected isolates were analysed for additional virulence genes by a microarray and subjected to O-typing. Clostridium perfringens isolates (n = 152) were examined by PCR for genes encoding major toxins, enterotoxin and beta2-toxin. There was no difference in serum γ-globulin concentration between diarrhoeic and non-diarrhoeic piglets, and pathological lesions in the intestines were generally mild. Porcine enterotoxigenic Escherichia coli, a common cause of piglet diarrhoea, was only found in two piglets. Further, the virulence gene profiling did not suggest involvement of other diarrhoeogenic pathotypes of Escherichia coli. Growth of Clostridium perfringens did not differ between diarrhoeic and non-diarrhoeic piglets. All isolates were type A, all were negative for enterotoxin, and 151 of 152 isolates were beta2-toxin positive. In pigs ≥ 2  days old, moderate to profuse growth of Clostridium difficile was more common in the controls. In conclusion, it was not possible to relate Escherichia coli, Clostridium perfringens type A and C or Clostridium difficile to neonatal porcine diarrhoea in any of the investigated herds.

An immunohistological study of phenotypic characteristics of cells of the inflammatory response in the intestine of Schistosoma bovis -infected goats

The cellular inflammatory response in the small intestine of 21 goats infected with Schistosoma bovis was phenotypically characterized by immunohistochemistry between 6 and 32 weeks post-exposure, with particular reference to perioval granulomatous reactions. Macrophages of granulomas consistently expressed MHC class II molecules, whereas multi-nucleated giant cells in general did not. Most granulomas contained moderate infiltrates of CD2+ (CD4+ or CD8+) and gamma/delta (T19+) T cells, whereas B lymphocytes were sparse. Intact extravascular mucosal eggs, lacking appreciable cellular reactivity on plain histopathology, displayed surrounding collars of MHC class II+ macrophages. Gamma/delta T cells and MHC class II+ macrophages were the predominant cell types in perivascular inflammatory cell clusters in the submucosa. The phenotypic cellular composition of granulomas did not change appreciably with duration of infection. The results indicate the importance of MHC class II-restricted immune events in the caprine S. bovis egg granulomas and also suggest a role of gamma/delta T cells in their pathogenesis. It is hypothesized that the early appearance of perioval macrophage collars may serve to protect eggs from ovicidal host defence mechanisms, facilitating excretion and continuation of the life-cycle.

Acquired resistance against Schistosoma bovis after single or repeated low-level primary infections in goats

Experimental Schistosoma bovis infections were studied in groups of six goats for 32 weeks. Two types of primary infections, a single exposure to 400 cercariae per goat or repeated (trickle) exposure to 200 cercariae per goat weekly for 10 weeks, were followed by a challenge infection with 2000 cercariae per goat in week 16 of the experiment. Periods of high faecal egg excretion were associated with reduced weight gain, anaemia, hypoalbuminaemia and blood eosinophilia; these changes gradually diminished with decreasing faecal egg excretion but never disappeared completely. The pathogenic effects of the trickle exposure exceeded those of the single primary exposure. After the challenge, the goats excreted few or no additional eggs and no additional clinicopathological changes were observed in the group previously exposed to a trickle infection. However, the primary single infection did not provide full protection against the effects of the challenge infection.

Microarray and cytokine analyses of field cases of pigs with diarrhoea

This field study explored the cytokine expression in intestinal tissue and serum from 19 diarrhoeic and 9 healthy pigs in herds with a long-time history of Lawsonia intracellularis-infection. The disease, proliferative enteropathy (PE), is associated with diarrhoea and poor performance in growers and haemorrhagic diarrhoea and sudden death in finisher pigs, but the immunopathology is poorly understood. Histopathology, demonstration of L. intracellularis and porcine circovirus type 2 (PCV2) in intestinal tissue by PCR, and detection of serum antibodies to L. intracellularis, were performed. The presence of IL-1β, IL-6, IL-10, IFN-α, IFN-γ, TNF-α and TGF-β in sera was determined by immunoassays, and intestinal mRNA expression of these cytokines plus IL-12p40 was determined by qPCR. Intestinal specimens from pigs with intestinal adenomatosis (n=2), proliferative haemorrhagic enteropathy or swine dysentery (n=2), and controls (n=2) were analysed by a genome wide porcine microarray. The clinical signs of PE were not always supported by the subsequent analyses, and the presence of PCV2 may have contributed to an increased mRNA expression for IFN-γ in intestinal specimens from some pigs. The limited gene expression in the microarray analyses and the limited expression of cytokines in both sera and intestines, indicate that the immune response is poorly activated in the initial course of an infection with L. intracellularis. However, the gene encoding for insulin-like growth factor binding protein 3 (IGFBP-3) was up-regulated in two pigs with prominent mucosal proliferation.

Treatment efficacy and regulatory host responses in chronic experimental Schistosoma bovis infections in goats

The aim of this study was to elucidate the regulatory responses and the long-term effect of praziquantel treatment in chronically Schistosoma bovis-infected West African Dwarf goats. Forty-two goats were used and the design comprised a primary infection followed by treatment at week 13, challenge infection at week 36 and termination at week 52. Dependent variables included clinico-pathological data, worm numbers, faecal and tissue egg counts, and gross pathology of the liver. The results showed that primary infections remained suppressed for up to 52 weeks and, although challenge infections imposed on 36-week-old primary infections established fully, the impairment of their egg production capacity provided protection against clinico-pathological consequences measured by body weight and haemoglobin levels. The study also confirmed a high efficacy (97.7%) of praziquantel for treatment of S. bovis infection in goats and showed that anthelminthic removal of primary infections does not interfere with the ability of the goat to elicit a marked resistance to a subsequent challenge infection. Although treated goats had more fibrous scarring of livers than untreated goats, no negative effects of liver lesions were reflected in weight gains of treated goats. This study provides strong evidence for the beneficial effects of anthelminthic treatment of young domestic stock as an element of treatment and preventive programmes.