The pathology of goat paratuberculosis: gross and histopathological lesions in the intestines and mesenteric lymph nodes

From a pathological examination of the intestinal tracts of 1590 goats killed at slaughterhouses in the Fars Province of Iran, 59 cases (3.71%) were suspected, on gross examination, of having paratuberculosis. The diagnosis was confirmed by histopathological study and Ziehl-Neelsen staining of direct smears of rectal faeces. On the basis of severity of involvement of the terminal ileum and mesenteric lymph nodes, the microscopic lesions were classified to mild, moderate and severe forms. Caseous necrosis and calcification were observed only in the mesenteric lymph nodes. High numbers of acid-fast organisms were present in the epithelioid macrophages of the intestine but were inapparent or sparse in the mesenteric lymph nodes. On microscopic examination, 13.5% of the suspected animals were found to have paratuberculosis, in comparison with 3.38% by direct faecal smears. In addition, 30.5% and 15.3% of the animals were diagnosed as having eosinophilic enteritis and linguatulosis, respectively. These findings stress the importance of a careful histopathological examination of the intestines and mesenteric lymph nodes for the diagnosis of paratuberculosis in goats.     

The venous supply of the cecum, ileum, and the proximal loop of the ascending colon in the ox

The present study describes in detail the venous supply to the bovine cecum, ileum, and the proximal loop of the ascending colon. The cecum was supplied by branches from the cecal and accessory cecal veins. The accessory cecal vein was observed in the majority of the specimens examined. The cecal and accessory cecal veins were joined by 7–10 short oblique anastomoses. The ileum was supplied by the ileal branches of the cecal vein, and from the mesenteric ileal and first ileal (cranial mesenteric) veins. The ileal branches of the cecal vein formed a row of antimesenteric ileal arches in the ileal part of the ileocecal fold. The mesenteric ileal vein, in some cases, detached a collateral branch. The first ileal and the mesenteric ileal veins anastomosed on the ventral surface of the ileum. The initial loop of colon was supplied by branches from the ileocolic vein. In the majority of specimens, the common colic, a branch of the cranial mesenteric vein, supplied the first colic branch to the third part of the initial colon. In such cases, the ileocolic vein gave off only the second and third colic branches. However, in one case, the proximal loop of the ascending colon was supplied by three colic branches of the ileocolic vein and by the first colic branch of the common colic vein. In specimens in which the common colic vein was absent, the colic branches to the initial colon were all given off by the ileocolic vein. The third (or fourth) colic branch of the ileocolic vein and the first cecal branch of the cecal vein united on the lateral surface of the ileocecocolic junction to form an ileocecocolic arch. The veins on the medial surface of the ileocecocolic junction did not form an arch. The colic and ileal lymph nodes were supplied by twigs from the colic branches of the ileocolic vein and first ileal vein of the cranial mesenteric, respectively. The small cecal lymph nodes seen only in the specimen from the calf were supplied by fine branches from the cecal vein.     

Effect of vitamin E supplementation on lymphocyte distribution in gut-associated lymphoid tissues obtained from weaned piglets

Fifteen piglets were used to determine the effect of vitamin E supplementation on the number of CD4-immunoreactive (CD4+) T-lymphocytes, CD8-immunoreactive (CD8+) T-lymphocytes and IgA-immunoreactive (IgA+) B-lymphocytes per follicle in the Peyer's patch of distal ileum and the mesenteric lymph nodes of weaned piglets. Piglets, following a 3-day adaptation period after weaning, were assigned to one of three experimental groups: control (no vitamin E supplementation), vitamin E supplementation of 100 mg/kg of diet and vitamin E supplementation of 300 mg/kg of diet. Supplementation of vitamin E lasted for a period of 36 days. The basal diet contained 80 mg alpha-tocopherol/kg of diet. All piglets were killed at day 39 after weaning and samples of the distal ileum and adjacent mesenteric lymph nodes were collected. The number of cells for each lymphocyte subset was counted in the Peyer's patch and the mesenteric lymph nodes follicles, in cryostat sections processed for immunohistochemistry. Results showed that vitamin E supplementation (300 mg/kg diet) of piglets caused an increase (P < 0.05) in the number of IgA+ B-lymphocytes in the Peyer's patch, but not in the mesenteric lymph nodes, compared with the corresponding values in control animals. Vitamin E supplementation had no effect (P > 0.05) on the number of CD4+ and CD8+ T-lymphocytes in the follicles of the Peyer's patch and the adjacent mesenteric lymph nodes. Thus, vitamin E had relatively minor effects on distribution of the major immunocompetent cells in the gut. The numbers of CD4+ and CD8+ T-lymphocytes as well as IgA+ B-lymphocytes per follicle were higher by 26-77% (P < 0.05) in the mesenteric lymph nodes than the corresponding values in the Peyer's patch.     

The Arterial Supply to the Ileum, Cecum and Proximal Loop of the Ascending Colon in the Ox*

This study describes in detail the arteries supplying the ileum, cecum and proximal loop of the ascending colon in the ox important to the veterinary surgeon treating disorders of these segments of the intestinal tract. The ileum was vascularized by the mesenteric ileal artery (from the ileocolic), the first ileal artery (from the cranial mesenteric) and by the ileal branches of the cecal artery which, by means of their anastomoses, form a row of antimesenteric arches in the ileal part of the ileocecal fold. The termination of the ileum was also supplied by twigs from the ileocecocolic arch. The ileum appears to be the most vascular part of the small intestine. The cecum was supplied mainly by the cecal branches of the cecal artery. The proximal end of the cecum was also vascularized by branches from the ileocecocolic arch. The proximal loop of the colon was vascularized by the three colic branches of the ileocolic. The first colic branch supplied the third part of the loop, the second colic branch supplied the first and the second parts of the loop and the third colic branch supplied the first part and, together with the first cecal branch of the cecal artery, formed the ileocecocolic arch at the dorsolateral surface of the ileocecocolic junction. The terminal branches of the arteries to the ileum, cecum and proximal loop of the colon detached lateral branches in the tunica muscularis which anastomosed with similar branches from neighboring arteries in an arcuate manner in the tunica submucosa. The terminal branches from both sides terminated in the free border, releasing branches which anastomosed with each other in the tunica submucosa. The colic lymph nodes were supplied by the colic branches of the ileocolic artery, die two largest nodes being perforated by some of the branches of the first two colic branches. The ileal lymph nodes were supplied by the ileal arteries of the cranial mesenteric. They were also perforated by these arteries. Cecal lymph nodes were seen only in the specimen from the calf. They were much smaller than the colic and ileal nodes and were supplied by the first two or three cecal branches of the cecal artery and also by twigs arising directly from the cecal artery.     

Ultrastructural Studies of Paratuberculosis (Johne’s Disease) in Goats

Biopsy material of the ileum and corresponding mesenteric lymph nodes from 10 naturally infected goats was studied. In ileum a loss of epithelial cells and infiltration of epitheloid cells, macrophages and a low number of lymphocytes, plasma cells and occasional eosinophils were seen. Ultrastructurally, the epithelial cells showed degenerative changes. Epitheloid cells were characterized by a large nucleus and a wide cytoplasm rich in free ribosomes.Macrophages had been fixed in the process of engulfing bacteria or contained bacteria in phagosomes and phagolysosomes. Large phagolysosomes were common. In macrophages with many or large phagolysosomes, few or no lysosomes were observed. Degenerative changes were seen in macrophages containing many bacteria. Degenerative changes of capillary endothelium were observed. The intercellular spaces were distended by oedema and contained cell debris.The mesenteric lymph nodes were infiltrated with epitheloid cells and macrophages. The ultrastructural picture of these cells was almost identical to that of the ileum.The differences between the changes found in naturally infected and experimentally infected animals are discussed. It is concluded that the mode of infection, the number of bacteria to which the animal is exposed and the intervals between events of exposure may play a role.     

Disseminated Mycobacterium avium complex infection following renal transplantation in a cat

An 11-year-old cat with a history of renal transplantation and treatment with cyclosporine and prednisolone was examined because of vomiting, diarrhea, inappetence, lethargy, and weight loss. Abdominal ultrasonography revealed 2 large heteroechoic masses thought to be mesenteric lymph nodes. Ultrasound-guided biopsy was performed, and histologic examination of biopsy specimens revealed granulomatous inflammation of presumptive lymph node tissue. Examination of sections stained with acid-fast stains revealed innumerable acid-fast bacilli within histiocytes, and a presumptive diagnosis of mycobacteriosis was made. The cat's clinical condition deteriorated, and euthanasia was elected. At necropsy, granulomatous inflammation was present within the mesenteric lymph nodes, spleen, liver, small and large intestines, lungs, and bone marrow. Bacterial culture yielded Mycobacterium avium, a slow-growing, opportunistic, saprophytic mycobacterium that can cause tuberculous lesions that are clinically indistinguishable from those associated with classic tuberculosis. It is a rare cause of disseminated mycobacteriosis in human transplant recipients. To our knowledge, this is the first report of disseminated M avium complex infection in a feline transplant recipient.     

Johne's Disease (Paratuberculosis) in Goats: A Report of Eight Cases in Quebec

Johne's disease (paratuberculosis) is reported in eight goats. Clinical signs were mainly those of a chronic wasting disease which lead to emaciation, severe weakness, prostration and death. Soft pasty stool and/or profuse diarrhea were observed only after several weeks of illness, in the terminal stages of the disease, in six of the eight goats. Gross lesions were characterized by emaciation and mesenteric lymphadenopathy with more or less extensive areas of caseous necrosis and calcification. Gross lesions in the intestinal tract were limited to a mild thickening and corrugation of the mucosa of the distal small intestine, cecum and proximal parts of the colon in three of the affected animals. Caseous necrosis of Peyer's patches and ulceration were observed in two goats when small tuberculoid nodules were present in the liver of another one. Histologically, the intestinal lesions were characterized by accumulations of large foamy or vacuolated macrophages in the intestinal mucosa. Lesions were usually mild and multifocal in the proximal and middle parts of the small intestine, more diffuse and severe in the distal jejunum, ileum and proximal parts of the colon. Several of the macrophages infiltrated in the intestinal mucosa and mesenteric lymph nodes were packed with acid fast bacilli. Observations made on these animals stress the importance of a careful histological examination of the intestines and mesenteric lymph nodes of adult goats submitted to necropsy because of a chronic wasting disease.     

Paratuberculosis in pigs. Experimental infection by oral administration of Mycobacterium paratuberculosis

Oral administration of Mycobacterium paratuberculosis to 61 pigs resulted in the development of caseous lesions of the mesenteric lymph nodes in 27.9 % of the animals. Positive results were found by bacterioscopy in 31.1 %, by culture in 60.7 % and by histological examination in 42.6 % of the animals.Histological changes typical of infection with M. paratuberculosis were found in the ileum in eight pigs. These changes, which consisted of infiltrations with epithelioid cells, were usually limited to the Peyer patches, but in one case such infiltrations were also present in the propria mucosae, similarly as in paratuberculosis in cattle.     

Paucibacillary paratuberculosis in a goat

A 5-year-old Saanen doe was presented with emaciation, good appetite, normal feces, and a dry flaky hair coat. Johne's disease was tentatively diagnosed. Gross postmortem findings were a thickened, corrugated ileum and enlarged edematous mesenteric lymph nodes. Histologically, there was extensive lymphocytic infiltration of the ileal lamina propria. Mycobacterium paratuberculosis could not be identified or cultured.     

Granulomatous lesions in lymph nodes of slaughter pigs bacteriologically negative for Mycobacterium avium subsp. avium and positive for Rhodococcus equi

The prevalence of granulomatous lesions in lymph nodes of pigs was studied. From January till August 2004 in two slaughterhouses in The Netherlands 2,116,536 pigs were examined for the presence of granulomatous lesions in the sub-maxillary lymph nodes. In 15,900 (0.75%) of these pigs, lesions could be detected. Nine farms with the highest incidence of lesions were selected for a more detailed pathological and bacteriological examination. On these farms, the prevalence of lesions in sub-maxillary lymph nodes ranged from 2.3 to 5.7% with a mean of 3.0%. From 1276 pigs that were sampled, 98 (7.7%) displayed granulomatous lesions in the sub-maxillary lymph nodes and one (0.1%) pig showed lesions in its mesenteric lymph node. Mycobacterium avium subsp. avium (MAA) could not be isolated from the lymph nodes of the 99 pigs with lesions and from a selection of lymph nodes (n = 61) of pigs without lesions. Rhodococcus equi was isolated from 44 out of 98 (44.9%) of the sub-maxillary lymph nodes with granulomatous lesions and from two mesenteric lymph nodes without lesions. A comparison of former studies and the current results indicate that the prevalence of MAA infections in slaughter pigs has strongly decreased over the last decade, whereas R. equi is highly prevalent. The high incidence of granulomatous lesions associated with the bacteriological presence of R. equi could be considered as a serious cause of misdiagnosis of MAA infections in cases where meat inspection is carried out by inspection for granulomatous changes of lymph nodes only.     

Post-mortem examination in the diagnosis of Johne's disease in goats.

Post-mortem examinations play an important role in Johne’s disease programmes in Norway. The results of such examinations of samples of viscera from 2997 goats carried out during the 5-year period 1972–1976 are given. The investigations show that the demonstration of macroscopical changes in mesenteric lymph nodes and small intestine has only limited value as a guideline in the post-mortem diagnosis of Johne’s disease in goats. Often macroscopical changes were not seen or they were non-specific. Caseous and/or calcified foci in mesenteric lymph nodes in infected animals were demonstrated quite often whilst observed intestinal changes were strikingly few. Corrugation of the mucosa was rare. However, in sections of macroscopically unchanged intestine marked epithelioid cell infiltrations and abundant acid-fast bacilli were not uncommon. In sporadic cases productive inflammation with tubercle formation was seen in lymph nodes in infected animals.Bacteriological culture was by far the most reliable post-mortem diagnostic method. By this method 92% of the infected goats were detected. The corresponding figures for histological examination and microscopy were 54% and 47%, respectively.     

Intra-uterine transmission of paratuberculosis (Johne's disease) in farmed red deer

AIM: To determine whether intra-uterine transmission of paratuberculosis (Johne's disease) occurs in farmed red deer (Cervus elaphus) in New Zealand. METHODS: On four different farms, nine late-stage pregnant hinds with Johne's disease were slaughtered and samples were taken from them and their 10 fetuses. Samples of the hepatic, ileocaecal and mesenteric lymph nodes and the posterior ileum were collected from the hinds. The lung, liver, spleen, jejunum and ileum from the fetuses were sampled, as were the placentomes. Blood samples were tested using the 'Paralisa' test, a modified immunoglobulin G1 (IgG1) enzyme-linked immunosorbent assay (ELISA). Tissue samples were cultured using the BACTEC system, and fixed samples were sectioned and histological slides examined. RESULTS: All nine hinds and 9/10 fetuses (one hind had twins) were culture-positive for Mycobacterium avium subsp paratuberculosis (M. ptb). Six hinds had gross lesions of Johne's disease, while all hinds had characteristic histopathological lesions affecting the ileum, ileocaecal valve and associated lymph nodes. The only histopathological change observed in the fetuses was some mild inflammation in the lungs of one individual. Acid fast organisms (AFOs) were seen in histological sections of the lymph nodes and ileum of six hinds, and none were seen in tissues from the fetuses. These six hinds were Paralisa-positive, whereas the remaining hinds and fetuses were serologically-negative. CONCLUSIONS: These results confirm that there is a high risk of transmission of M. ptb from clinically affected hinds to their fetuses during pregnancy. CLINICAL RELEVANCE: Johne's disease is an increasingly important disease responsible for deaths in young red deer. Recognising the influence of intra-uterine transmission on the spread of this disease may be an important step towards improved control of Johne's disease.     

Isolation of Salmonella dublin from a sheep in New Zealand

Extract

On March 8, 1964, formalinized samples of liver, kidney and lung and fresh samples of mesenteric lymph nodes and lung from a ram hogget were submitted to the Wallaceville Animal Research Centre. The animal had died suddenly and post-mortem examination revealed intense reddening of the intestinal and abomasal mucosa and enlarged mesenteric lymph nodes, with some consolidation and pleural adhesions. Small red spots were observed on the liver surface. The possibility of salmonellosis was considered and appropriate cultures were made of the fresh material in addition to aerobic cultures on blood agar.     

Lymphocyte recirculation in cattle: patterns of localization by mammary and mesenteric lymph node lymphocytes

We examined patterns of lymphocyte localization in female dairy cattle following infusion of 51Cr-labeled autologous lymphocytes prepared from surgically excised mammary or ileal mesenteric lymph nodes. Labeled lymphocytes prepared from mammary lymph nodes were recovered in proportionally high numbers from mammary and prescapular lymph nodes, and in low numbers from intestinal mesenteric nodes. This pattern was observed in both heifers and lactating cows. In contrast, labeled lymphocytes prepared from ileal mesenteric lymph nodes of lactating cows were recovered in proportionally high numbers from intestinal mesenteric nodes, and in low numbers from mammary and prescapular nodes. These findings, when compared with previous results in sheep and swine, support the hypothesis that lymphocytes do not migrate efficiently between the gut and mammary gland of ruminants.     

Morphology of the lymph nodes in bottlenose dolphin (Tursiops truncatus) and striped dolphin (Stenella coeruleoalba) from the Adriatic Sea

Morphology of the lymph nodes was examined in six bottlenose dolphins (Tursiops truncatus) and three striped dolphins (Stenella coeruleoalba) from the Adriatic Sea. All animals had been found dead in nature. One group of the nodes was taken from the tracheal branching area and was marked as bifurcational lymph node, and the other group was taken from the mesenteric root and was marked as mesenteric lymph node. Microscopic analysis showed that the lymph nodes in both dolphin species were surrounded by a connective tissue capsule comprising smooth muscle cells. The parenchyma of the mesenteric and bifurcational lymph nodes in bottlenose dolphin was divided into the peripherally situated cortex with the lymphatic nodules and diffuse lymphatic tissue, and the centrally situated medulla structured of the medullary cords separated by the medullary sinuses. These lymph nodes structurally correspond to the lymph nodes in the majority of terrestrial mammals. The mesenteric lymph node of striped dolphin also had a peripherally situated cortex and a centrally positioned medulla as the majority of terrestrial mammals. In the bifurcational lymph nodes of striped dolphin, there was a central dense lymphatic tissue with the lymphatic nodules and a peripheral less dense lymphatic tissue structured of the cell cords and sinuses. The bifurcational lymph node in striped dolphin resembled porcine lymph nodes and belonged to the inverse lymph nodes.     

Hypereosinophilic paraneoplastic syndrome in a cat with intestinal T cell lymphosarcoma

A 10-year-old, neutered female, domestic shorthair cat was presented with a recent history of weight loss, polydipsia, diarrhoea and vomiting. On physical examination, intestinal thickening and mesenteric lymph node enlargement were apparent. Clinical investigations revealed peripheral blood eosinophilia, eosinophilic abdominal effusion and eosinophilic mesenteric lymphadenitis. There was a temporary response to treatment with glucocorticoids but signs progressed and the cat was euthanased. On histology, there was eosinophilic infiltration and fibroplasia of intestine and mesenteric lymph nodes. Large aggregates of neoplastic round cells in the intestine and lymph nodes were identified as T lymphocytes using immunohistochemistry. A diagnosis of intestinal T cell lymphosarcoma was made. This case demonstrates that hypereosinophilic paraneoplastic syndrome may occur in cats with lymphosarcoma. Eosinophil chemotaxis may be a response to the production of interleukin-5 by neoplastic lymphocytes.     

Induction of apoptotic lesions in liver and lymphoid tissues and modulation of cytokine mRNA expression by acute exposure to deoxynivalenol in piglets

Six 1-month-old piglets were intravenously injected with deoxynivalenol (DON) at the concentration of 1 mg/kg body weight, with three pigs each necropsied at 6 and 24 h post-injection (PI) for investigation of hepatotoxicity and immunotoxicity with special attention to apoptotic changes and cytokine mRNA expression. Histopathological examination of the DON-injected pigs revealed systemic apoptosis of lymphocytes in lymphoid tissues and hepatocytes. Apoptosis of lymphocytes and hepatocytes was confirmed by the TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method and immunohistochemical staining against single-stranded DNA and cleaved caspase-3. The number of TUNEL-positive cells in the thymus and Peyer''s patches of the ileum was increased at 24 h PI compared to 6 h PI, but the peak was at 6 h PI in the liver. The mRNA expression of interleukin (IL)-1β, IL-6, IL-18, and tumor necrosis factor (TNF)-α in the spleen, thymus and mesenteric lymph nodes were determined by semi-quantitative RT-PCR, and elevated expression of IL-1β mRNA at 6 h PI and a decrease of IL-18 mRNA at 24 h PI were observed in the spleen. IL-1β and IL-6 mRNA expressions increased significantly at 6 h PI in the thymus, but TNF-α decreased at 6 h PI in the mesenteric lymph nodes. These results show the apoptosis of hepatocytes suggesting the hepatotoxic potential of DON, in addition to an immunotoxic effect on the modulation of proinflammatory cytokine genes in lymphoid organs with extensive apoptosis of lymphocytes induced by acute exposure to DON in pigs.     

Morphologic changes in the intestine of swine after infection with verotoxin-producing Escherichia coli

Spontaneous morphologic lesions are described in 12 of 66 pigs submitted for necropsy. All 12 pigs were culture positive for Verotoxin-producing E. coli (VTEC). 10 of them were weaned pigs, one a suckling piglet and one a fattening hog. In 6 cases E. coli serovar 0139:H1 and in one case each the serovars 0139:H40; 0138:H-; 0125ac:H27 and 0154:H- were isolated. From the fecal samples of 2 animals E. coli ONT (O-group non typable):H- were cultured. Macroscopically there were cyanosis, edema of the eye lids, catarrhal enteritis and/or colitis as well as edema of the mesentery, swelling of the mesenteric lymph nodes and congestion of the lung to varying degrees. Histopathologic examination of 5 animals was carried out. In 3 animals atrophy and edema of the villi in the jejunum and ileum were discovered. In one animal an additional infection with corona virus was confirmed electron microscopically. Furthermore there was disseminated necrosis of lymphocytes in Peyer's patches of the small intestine and in secondary follicles of the mesenteric lymph nodes. In one of the animals a hemorrhagic-necrotising ileitis, occurred characterized by necrosis of villi and thrombosis of blood vessels in the mucosa. The highest number of VTEC with seven out of twelve animals was found in weaned pigs in association with the E. coli serovar 0139.     

Bacterial isolation, immunological response, and histopathological lesions during the early subclinical phase of experimental infection of goat kids with Mycobacterium avium subsp. paratuberculosis

The diagnosis of Mycobacterium avium subsp. paratuberculosis infection is difficult, especially in the early stages of disease. This is due to the long incubation period, the variable lag phase associated with bacterial proliferation, and the multifocal distribution of slowly developing lesions. There are few previous studies of the early stages of experimental paratuberculosis in goats. In the present study, the ability of conventional diagnostic methods to detect M. a. paratuberculosis infection during the early stages of infection was assessed. Eight goat kids were experimentally infected with M. a. paratuberculosis and subjected to a series of immunological and bacteriological tests before being euthanatized at various times postinfection. At postmortem examination, the ages of the kids ranged from 1 1/2 to 12 months. Of the eight goats infected, three had histopathological evidence of paratuberculosis. Two of these goats were positive with bacteriology, but only one was also positive with all immunological tests. One animal had a positive immunological response, but infection could not be demonstrated by bacteriologic or histopathologic examination. Histopathologic lesions were found in the jejunum, in the ileum, and in one mesenteric lymph node, but only the mesenteric lymph nodes and one retropharyngeal lymph node gave positive results following bacteriologic culture. The disparity between the localization of histopathologic lesions and bacteriologic results emphasizes the need for exhaustive sampling to confirm a diagnosis during the early phase of an infection. It also highlights the need for a better understanding of the biology of M. a. paratuberculosis and its interaction with the immune system of the host.