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Three screening tests {(newly developed, six recombinant secretory proteins based 'cocktail ELISA', in-house robust 'indigenous ELISA' based on semi-purified protoplasmic antigens and tissue microscopy were evaluated with 'Gold standard', histo-pathology for the diagnosis of Johne's disease in goats and buffaloes. Serum and tissues {mesenteric lymph nodes and intestines) were driven from farmer's goats (n = 77) and buffaloes (n = 40) slaughtered for harvesting meat and farm goats (n = 77), died and necropsied. Twenty seven (35%) goats and 23 (57.5%) buffaloes were positive in all the four tests. Of 134 tissues screened by histo-pathology, 79.8% MLN and 76.8%, intestines, were positive for MAP infection. In tissue microscopy, 55.2 and 52.3%, goats and buffaloes were positive, respectively. Of 117 sera screened by i_ELISA, 58.4 and 70.0%, goats and buffaloes were positive, respectively. Whereas, c_ELISA detected 55.8 and 62.5%, goats and buffaloes, positives, respectively. Twelve tissues (70.5%) of goats necropsied were positive, both in tissue microscopy and histo-pathology. Most significant gross findings were serous atrophy of the fat and mild to moderate, diffuse thickening of terminal ileum, especially at ileo-caecal junction with or without transverse / longitudinal corrugations. In histo-pathology grade III and IV lesions were significantly low as compared to grade I and II. Of the four tests used for screening 268 samples, histo-pathology was most sensitive (78.3%), followed by i_ELISA (62.3%), c_ELISA (58.9%) and tissue microscopy (58.9%). Between two ELISA tests, c_ELISA using six recombinants secretory proteins, had higher specificity as compared to i_ELISA., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Vaccination of goat kids against paratuberculosis protects against lesions and clinical disease. The systemic cellular response was studied in goat kids 3-9 weeks after vaccination. Peripheral blood cells showed increased interferon-gamma production and expression of interleukin-2 receptor (CD25) after stimulation with Mycobacterium avium subsp. paratuberculosis antigens. The lymph node draining the vaccination granuloma was studied three weeks after vaccination in a parallel group of goat kids. In deep cortex, MHCII+ cells were observed surrounded by CD4+ T-cells, while follicular hypertrophy and hyperplasia were prominent in the subcapsular region and along connective tissue trabecula. Comparison of the local and systemic immune responses revealed an inverse relationship between CD25+ T-cells in the lymph node deep cortex and cells in peripheral blood that up-regulate CD25 upon in vitro stimulation, suggesting that activated and regulatory T-cells in the local lymph node influence the level of circulating antigen-specific T-cells following vaccination against paratuberculosis in goats.

The organized gut-associated lymphoid tissue (the Peyer's patches [PPs] of domestic ruminants) is an important site of lesions caused by Mycobacterium avium subsp. paratuberculosis. To investigate the association between PP morphology and the lesions of paratuberculosis in goats, two experiments were performed. Five healthy kids aged 4-5 weeks were examined and the morphology of organized lymphoid tissue in the small intestine was described. Morphological similarities were observed between the ileocaecal-valve PP (ICVPP) and the jejunal PPs (JPPs), with pear-shaped follicles, large submucosal interfollicular T-cell areas, and many intraepithelial leucocytes in the follicle-associated epithelium. The ileal PP (IPP) consisted of elongated follicles, small T-cell areas and few intraepithelial leucocytes. The association between these three locations of PPs and lesions of paratuberculosis was then studied in seven goats inoculated with M. a. paratuberculosis at 5-8 weeks of age and killed 2 years later, while in the subclinical phase of infection. Gross lesions were recorded in five animals and microscopic lesions were observed in the intestine and mesenteric lymph nodes of six animals. The lesions in the small intestine were mainly located in the PPs of the mid-jejunum (JPPs) and ICVPP. Lesions were not present in the intestinal segments that had contained IPP, which had undergone involution during the first 12-18 months of life. These observations indicate that the persistent organized lymphoid tissue in the JPPs and ICVPP, but not the involuted IPP, sustains the development of granulomatous inflammation due to paratuberculosis during the subclinical phase of infection.

Mycobacterium paratuberculosis infection was detected in 2 goats in 1974 and in 5 goats in 1975; 5 of which were from a single herd. The magnitude of the subsequent epizootic in the goat herd was not recognized until 1977, when results of bacteriologic culture of fecal and tissue specimens, antibody determinations (agar-gel immuno-diffusion test), and histopathologic studies became available. By 1984, paratuberculosis had been diagnosed in 124 goats. Nearly all the goats were being used in antiserum production and had been given Freund complete adjuvant and human antigens. From 1974 to 1986, herd size varied from 100 to 300. The yearly incidence of paratuberculosis decreased from 13.2% (27 of 204 goats) in 1977 to 0% in 108 goats in 1985. The prevalence was higher in does. In goats that arrived on the farm in 1975 and before, 49 of 121 (40.5%) does developed paratuberculosis vs 41 of 120 (34.2%) wethers. In goats arriving on the farm in 1976 and after, 25 of 274 (8.5%) does and 9 of 216 (4.1%) wethers developed paratuberculosis. The average incubation period was approximately 4 years from arrival on the farm in every year except 1978, regardless of whether the goat was born on the farm or was purchased elsewhere.(ABSTRACT TRUNCATED AT 250 WORDS)

Between May, 1972 and February, 1978, six cases of paratuberculosis (Johne's Disease) caused by Mycobacterium paratuberculosis were diagnosed in free-ranging Rocky Mountain bighorn sheep (Ovis canadensis) and one Rocky Mountain goat (Oreamnos americanus) on or near Mt. Evans in Colorado. Diagnosis of paratuberculosis was based on gross and histopathologic examination of the animals and by isolation of M. paratuberculosis from three sheep and the goat. The clinical signs and pathologic changes seen in the bighorn sheep resembled those described in cattle, while the lesions in the goat were similar to those described for domestic sheep and goats.

Spontaneous paratuberculosis was studied in free-ranging and captive bighorn sheep (Ovis canadensis), and Rocky Mountain goats (Oreamnos americanus). Lesions of paratuberculosis in these species resembled the disease in domestic sheep and goats. Mycobacterium paratuberculosis cultured from bighorn sheep was used to orally infect bighorn x mouflon (Ovis musimon) hybrid sheep, elk (Cervus elaphus nelsoni), mule deer (Odocoileus hemionus), and white-tailed deer (Odocoileus virginianus). Clinical paratuberculosis developed only in mule deer and was characterized by poor growth and diarrhea. Gross lesions were mild in all species. Enlargement of mesenteric lymph nodes was mild to moderate; the wall of the distal small intestine was affected minimally. Focal to diffuse infiltrates of epithelioid macrophages and giant cells occurred in the cortex of mesenteric lymph nodes, around mesenteric lymphatics, and in the intestinal mucosa. Extraintestinal lymph nodes, spleen, liver, and lung were involved in some animals; focal necrosis and mineralization was present in all species but was severe and widespread in the cervids.