Intestinal Strictures, Fibrous Adhesions and High Local Interleukin-10 Levels in Goats Infected Naturally with Mycobacterium avium subsp. paratuberculosis

Paratuberculosis in South American camelids: two independent cases in alpacas in Germany

BACKGROUND

Paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), is a chronic granulomatous enteritis that affects domestic and wild ruminants and camelids. The disease has rarely been reported in alpacas in Germany. This publication describes epidemiologically independent cases of paratuberculosis in two alpacas in Germany.

CASE PRESENTATION

Two alpacas, a 26-year-old female zoo animal (case 1) and a 2.5-year-old breeding stallion from a private owner (case 2), presented with progressive emaciation, leading to death (case 2) or euthanasia (case 1) because of deteriorating general condition. In both cases typical granulomatous lesions in the intestinal mucosa and mesenteric lymph nodes were found. In case 2, other lymph nodes were severely enlarged and MAP was detected in the mandibular lymph node, lung, and liver by qPCR. The MAP isolates differed between the alpacas, with two distinct phylogenetic clades (Clade 1 and 8) within Subgroup A of the MAP-C type group and two distinct INMV profiles (INMV 2 and 1) found. These genotypes have been identified in cattle and goats in different regions in Germany. The genotype isolated from case 1 has been detected in goats from the zoo since 2011, indicating transmission between these species.

CONCLUSIONS

MAP can cause severe clinical disease in alpacas of variable age and under different husbandry conditions. Therefore, paratuberculosis should be considered for differential diagnosis in alpacas with emaciation and poor general condition. Although not definitely shown, cross-species infection between ruminant species and camelids is exceedingly likely.

Using Omics Approaches in the Discovery of Biomarkers for Early Diagnosis of Johne's Disease in Sheep and Goats

Simple Summary

Johne’s disease (JD) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is an important and emerging problem in livestock. Most JD research has been carried out on cattle, but interest in the pathogenesis and diagnosis of this disease in sheep and goats is greatest in developing countries. Sheep and goats are also a relevant part of livestock production in Europe and Australia, and these species provide an excellent resource to study and better understand the mechanism of survival of MAP and gain insights into possible approaches to control this disease. This review gives an overview of the literature on paratuberculosis in sheep and goats, highlighting the immunological aspects and the potential for “omics” approaches to identify effective biomarkers for the early detection of infection.

Abstract

Johne’s disease (JD) is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is an important and emerging problem in livestock; therefore, its control and prevention is a priority to reduce economic losses and health risks. Most JD research has been carried out on cattle, but interest in the pathogenesis and diagnosis of this disease in sheep and goats is greatest in developing countries. Sheep and goats are also a relevant part of livestock production in Europe and Australia, and these species provide an excellent resource to study and better understand the mechanism of survival of MAP and gain insights into possible approaches to control this disease. This review gives an overview of the literature on paratuberculosis in sheep and goats, highlighting the immunological aspects and the potential for “omics” approaches to identify effective biomarkers for the early detection of infection. As JD has a long incubation period before the disease becomes evident, early diagnosis is important to control the spread of the disease.

Goat γδ T cells

Goats are important food animals and are disseminated globally because of their high adaptability to varying environmental conditions and feeding regimes that provide them with a comparative advantage. Productivity is impacted by infectious diseases; this then contributes to societal poverty, food insecurity, and international trade restrictions. Since γδ T cells have been shown to have vital roles in immune responses in other mammals we reviewed the literature regarding what is known about their functions, distribution in tissues and organs and their responses to a variety of infections in goats. It has been shown that caprine γδ T cells produce interferon-γ and IL-17, are found in a variety of lymphoid and nonlymphoid tissues and constitute a significant population of blood mononuclear cells. Their representation in tissues and their functional responses may be altered concomitant with infection. This review summarizes caprine γδ T cell responses to Brucella melitensis, Fasciola hepatica, Mycobacterium avium paratuberculosis, caprine arthritis encephalitis virus (CAEV), and Schistosoma bovis in infected or vaccinated goats. Caprine γδ T cells have also been evaluated in goats infected with M. caprae, Ehrilichia ruminantium, Haemonchus contortus and peste des petits ruminants (PPR) virus but found to have an unknown or limited response or role in either protective immunity or immunopathogenesis in those cases.

Expression of cytokines following vaccination of goats with a recombinant capripoxvirus vaccine expressing Rift Valley fever virus proteins

The mosquito-borne Rift Valley fever virus (RVFV) causes severe diseases in domesticated animals including cattle, sheep, camels and goats. Capripoxviruses (CPV) are suitable vectors for multivalent vaccine development. A recombinant rKS1-based CPV expressing the gene encoding the viral glycoprotein Gn of RVFV has been shown to induce protection in mice and sheep. The aim of this study was to evaluate the immunogenicity induced by this candidate vaccine in goats, and the level of cytokines produced by RVFV-specific Th1 and Th2 lymphocytes. The results of this study suggest that Th2 mediates immunity mainly through the significant production of IL4, which, coupled with a decrease in IFN-γ, may be involved in the replication of the capripoxvirus expressing the G_N of RVFV. CD4+ cells may play the role of helper cells in B cell responses and neutralizing antibody production in the anti-CPV humoral response, leading to strong immunity against RVFV.

Macrophage Subsets Within Granulomatous Intestinal Lesions in Bovine Paratuberculosis

Animals infected with Mycobacterium avium subspecies paratuberculosis show a variety of granulomatous lesions that range from focal forms, seen in the subclinical stages, to diffuse lesions associated with clinical signs. The aim of this study was to phenotypically characterize the macrophages present in the different lesion types using immunohistochemical methods. Lesions from a total of 23 animals with bovine paratuberculosis, natural and experimental, were examined by immunohistochemistry. Antibodies against inducible nitric oxide synthase (iNOS), tumor necrosis factor α (TNF-α), CD163, interleukin 10 (IL-10), transforming growth factor β (TGF-β), major histocompatibility complex (MHC) class II, natural resistance-associated macrophage protein 1 (Nramp-1), calprotectin, Ki-67, CD68, lysozyme, and ionized calcium-binding adaptor molecule 1 (Iba-1) molecules were employed. Samples were scored semiquantitatively using a complete histological score (H-score), reflecting the staining intensity and the percentage of immunolabeled macrophages. Differences in the H-score were seen depending on the lesion type. In focal lesions, with none or few acid-fast bacilli (AFB), macrophages were polarized toward M1 phenotype, with high H-scores for iNOS and TNF-α. Diffuse multibacillary lesions showed M2 differentiation, with high expression of CD163, IL-10, and TGF-β as well as Nramp-1 and MHC class II antigens. Macrophages in diffuse paucibacillary forms showed high H-scores for iNOS but low ones for TNF-α. Diffuse lesions, either multibacillary or paucibacillary, showed high calprotectin and low Ki-67 expression, suggesting a progressive character, while focal forms, with low H-scores for these antigens, would be consistent with latency. Lysozyme and CD68 expression were related to the amount of AFB. H-score for Iba-1 antibody was similar among all types. The findings of this study provide insights into the polarization status of macrophages and lesion development in bovine paratuberculosis.

The relationship between the inflammatory response and cell adhesion on alginate-chitosan-alginate microcapsules after transplantation

Cell microencapsulation technology is a potential alternative therapy, but cell overgrowth and adhesion on the microcapsules after transplantation shortens their time of therapeutic efficacy. Inflammatory cells were the main cells that adhered to the microcapsules, so understanding the body's inflammatory processes would help to better identify the mechanisms of cell adhesion to the outer surface of the microcapsules. Our study measured the inflammatory cells and the cytokines and characterized the associated changes in the alginate-chitosan-alginate (ACA) microcapsules 1, 7, 14, and 28 days after implantation in the peritoneal cavity. Then the relationship between the inflammatory response and cell adhesion on the microcapsules was evaluated by multiple regression analysis. The results showed that the microcapsules did not evoke a systemic inflammatory response, but initiated a local inflammatory response in the peritoneal cavity. Furthermore, the correlation analysis showed that the level of cell adhesion on the microcapsules was related to the number of lymphocytes and macrophages, and the amount of IL-6, IL-10, and MCP-1 in the peritoneal cavity. Our results may provide a foundation for reducing the immune response to these microcapsules, prolonging graft survival and improving the efficacy of these treatments.

Cellular composition of granulomatous lesions in gut-associated lymphoid tissues of goats during the first year after experimental infection with Mycobacterium avium subsp. paratuberculosis

Mycobacterium avium subsp. paratuberculosis (MAP) causes lesions in naturally and experimentally infected ruminants which greatly differ in severity, cellular composition and number of mycobacteria. Morphologically distinct lesions are already found during the clinically inapparent phase of infection. The complex local host response and number of MAP were characterized at the initial sites of lesions, organized gut-associated lymphoid tissue, in experimentally infected goats. Tissues were collected at 3, 6, 9 and 12 month post-inoculation (mpi) from goat kids that had orally received 10 times 10mg of bacterial wet mass of MAP (JII-1961). The cellular composition of lesions in Peyer's patches in the jejunum and next to the ileocecal valve was evaluated in 21 MAP-inoculated goats, where lesions were compared with unaltered tissue of six control goats. CD68+, CD4+, CD8+, γδ T lymphocytes, B lymphocytes and plasma cells, MHC class II+ and CD25+ cells were demonstrated by immunohistochemistry in serial cryostat sections. At 3 mpi, extensive granulomatous infiltrates predominated, consisting of numerous epitheloid cells admixed with many CD4 and γδ T lymphocytes. Only single MAP were detected. This indicates a strong cellular immune reaction able to control MAP infection. γδ T lymphocytes were markedly increased in this type of lesion which may reflect their important role early in the pathogenesis of paratuberculosis. At 9 and 12 mpi, divergent lesions were observed which may reflect different outcomes of host-pathogen interactions. In five goats, minimal granulomatous lesions were surrounded by extensive lymphoplasmacytic infiltrates and no MAP were detected by immunohistochemistry. This was interpreted as effective host response that was able to eliminate MAP locally. In three goats, decreased numbers of lymphocytes, but extensive granulomatous infiltrates with numerous epitheloid cells containing increased numbers of mycobacteria were seen. This shift of the immune response resulted in uncontrolled mycobacterial multiplication. Focal and multifocal circumscribed granulomatous infiltrates of mainly epitheloid cells may represent sites of new infection, since they were observed in goats at all times after inoculation. Their presence in goats with minimal granulomatous lesions surrounded by extensive lymphoplasmacytic infiltrates may indicate that despite the local clearance, the infection may be perpetuated. The complex cellular immune reactions postulated for the pathogenesis of paratuberculosis were demonstrated at the local sites of infection. These early host-pathogen interactions are most likely essential for the eventual outcome of the MAP infection.

Sequential development of lesions 3, 6, 9, and 12 months after experimental infection of goat kids with Mycobacterium avium subsp paratuberculosis

The development of lesions after infection with Mycobacterium avium subsp paratuberculosis (MAP) was examined in an experimental infection model. Goat kids were orally inoculated 10 times with 10 mg bacterial wet mass of MAP (total dose 2.6 × 10(8) colony-forming units). Six to 7 inoculated goats and 3 controls were autopsied 3, 6, 9, and 12 months postinoculation (mpi), lesions were documented, and samples were collected for histology, immunohistochemistry (IHC), and bacterial culture. Twenty-five of the 26 inoculated goats did not develop clinical signs. Macroscopic lesions were detected in 3 of the 7 inoculated goats as soon as 3 mpi. Jejunal Peyer's patches (JPPs) were thickened and had ulcerated surfaces and circumscribed serositis. Characteristic granulomatous infiltrates were seen in all goats in gut-associated lymphoid tissues (GALTs), especially JPPs and lymphoid tissue at the ileocecal valve and in intestinal lymph nodes. Granulomatous intestinal infiltrates not associated with GALT were seen beginning at 6 mpi and with increasing frequency thereafter. Interindividual differences in lesions were most pronounced at 12 mpi, varying from mild focal paucibacillary to severe diffuse multibacillary patterns. Bacterial culture of MAP confirmed the IHC findings but was more sensitive and revealed widespread dissemination at 3 and 12 mpi. Granulomatous arteritis was found in intestinal submucosa of several goats. This may contribute to the spreading of MAP to the intestinal wall and possibly systemically. The different lesions observed during the clinically inapparent period of paratuberculosis are most likely indicators for the later progression of infection and development of clinical disease.