Intestinal lesions in specific-pathogen-free lambs associated with a cryptosporidium from calves with diarrhea

Small and large intestines of seven specific pathogen-free lambs infected with cryptosporidia from calves with diarrhea were examined by scanning and transmission electron microscopy and by light microscopy. The small intestine was infected in all the lambs, and the cecum and colon in three. Small intestinal alterations were severe villous atrophy and dilatation of the crypts of Lieberkühn. Epithelial cross-bridging between contiguous villi caused much villous fusion. Epithelial cells constituting the bridges were connected by desmosomal junctions, and were continuous with the epithelial coverings of the associated villi. The lamina propria was heavily infiltrated with neutrophil leukocytes. Infected crypts in cecum and colon were dilated and devoid of mucus-secreting cells, while the ridges between crypts were hypertrophied, and the lamina propria was infiltrated by neutrophils. Cell vegetations with adherent bacteria were present in the surface intestinal epithelium of two lambs infected for 11 and 14 days, respectively. No adherent bacteria were seen in any site in lambs killed up to six days post-inoculation.     

Leukocyte numbers and intestinal mucosal morphometrics in horses with no clinical intestinal disease

Healthy horses and other animals have large numbers of resident leukocytes in the intestinal wall, but there is scant information regarding which and how many leukocytes are normally present in the equine intestinal wall. Our aim was to provide a reference range of leukocytes in the intestinal mucosal and submucosal propria of normal horses. We included in our study intestinal tissues from 22 Thoroughbred racehorses with no clinical intestinal disease, which had been euthanized because of catastrophic musculoskeletal injuries. Neutrophils, lymphocytes, eosinophils, macrophages, and plasma cells were counted in 5 random 17,600-µm² areas of villus lamina propria of the duodenum, jejunum, and ileum, and deep lamina propria of the duodenum, jejunum, ileum, right ventral colon, left ventral colon, left dorsal colon, right dorsal colon, and small colon. Other features investigated in the same intestinal segments included villus height and width (small intestine), presence of ciliated protozoa, Paneth cells number, subcryptal leukocyte layers (number of leukocyte layers between the bottom of the crypts and the muscularis mucosae), and submucosal leukocytes. Lymphocytes were the most numerous cells in all segments analyzed, followed by plasma cells, eosinophils, macrophages, and neutrophils. Eosinophil numbers were significantly higher in both lamina propria and submucosa of the large intestine than in the small intestine. The duodenum had shorter and thinner villi than either jejunum or ileum. The data provided from our study will be useful for diagnosticians examining inflammatory processes in the intestinal tract of horses.     

Gut-associated lymphoid tissue in the large intestine of calves. I. Distribution and histology

Gut-associated lymphoid tissue (GALT) in the large intestine was characterized in 12 calves (10 to 84 days old) obtained at necropsy (7, group A) or healthy animals (5, group B). Patches of mucosal lymphoid follicles were in all calves at ileocecal entrances (ICE), 23-42 cm distal to the ICE in the proximal loop of the ascending colon (proximal colon [PC] patch), and in the terminal rectum. PC patches varied from 8 to 30 cm in length. Solitary lymphoid follicles were found in the cecum of three calves, between the ileocecal entrances and the PC patch in four calves, adjacent to the PC patch in all calves, and in the ampulla recti. GALT occupied 7.8% of the large intestinal wall in animals of group A: 0.6% at the ileocecal entrance, 4.8% in the proximal colon, and 2.4% in the rectum. There were two different types of mucosal lymphoid follicles in group B: propria nodules with lymphoid follicles predominantly in the lamina propria, and lymphoglandular complexes with lymphoid follicles in the submucosa. In three 3-, 6-, and 7-day-old, germfree calves, distinct follicle-associated epithelium covered propria nodules and covering folds in depths of the lymphoglandular complexes; it was characterized by numerous intraepithelial cells and lack of goblet cells.     

Enterocecocolitis associated with intraepithelial Campylobacter-like bacteria in rabbits (Oryctolagus cuniculus)

We examined 28 suckling, weanling, and young adult rabbits with lethargy, inappetence, and mucinous, semifluid feces. Sixteen of the rabbits had intestinal lesions. In eight of these rabbits, the primary changes were multifocal to diffuse epithelial proliferation and accumulation of lymphocytes, macrophages, or both in the lamina propria of the small intestine, cecum, and sacculated colon. In two of these rabbits, the accumulation of macrophages in the lamina propria was extensive. The other eight rabbits had erosive and suppurative cecocolitis, and four of the rabbits with proliferative lesions also had suppurative cecocolitis. In Warthin-Starry-stained sections of affected intestine, curved or spiral bacteria were visible within degenerated or hyperplastic epithelium, in luminal exudate, or in both. Such organisms were sparse or not found in the other 12 rabbits, which did not have intestinal lesions. The bacteria ultrastructurally resembled intraepithelial Campylobacter-like bacteria previously observed in proliferative enteritis in a variety of species and in acute typhlitis in young rabbits. In immunofluorescence tests, Campylobacter-like bacteria in epithelial cells, crypt lumina, and in luminal exudates in both proliferative and erosive lesions bound monoclonal antibodies and polyclonal antisera prepared against intracellular bacteria found in proliferative enteritis in pigs, hamsters, and ferrets. These observations indicate that a condition similar to proliferative enteritis of swine, hamsters, and other species also occurs in laboratory rabbits.     

An immunohistochemical study of S-100 protein in the intestinal tract of Chinese soft-shelled turtle, Pelodiscus sinensis

The present work describes the distribution of S-100 protein in the intestinal tract of a Chinese soft-shelled turtle specimen (Pelodiscus sinensis). S-100 protein positive cells were located in the intestinal tract, from the proximal small to distal large intestine. S-100 protein positive dendritic cells had irregular shape and were positive in both cytoplasm and nucleus. Most of them were located both lamina propria and submucosa in the small intestine, while few were found in the large intestine. S-100 protein, C-kit positive ICCs and Silver staining glial cells were predominantly observed in three locations: (1) in the interspace between the submucosa and circular muscle layer; (2) in the circular muscle layer; and (3) between the circular and longitudinal muscle layers of the intestine. Fewer were found in the large intestinal lamina propria and submucosa. Three types of positive cells (S-100 protein positive cells, C-kit positive ICCs and Silver staining glial cells) with 1–2 long or 2–3 short processes were distributed as lace-like or surrounding blood vessels in the different locations mentioned above. In the lamina propria, all the positive cells with irregular processes were connected with each other and formed a network. In the submucosa, all the positive cells were found surrounding the blood vessels.     

Myoelectric activity in the intestine of cows with strangulating obstruction of the distal small intestine

Myoelectric activity in 2 cows instrumented with permanent electrodes in the ileum, cecum, proximal loop of the ascending colon (PLAC), and spiral colon was analyzed after an obstruction developed in the distal small intestine. Results were compared with patterns from a group of 7 normal cows. Myoelectric activity in the ileum immediately orad to the occlusion was characterized by abolition of the migrating myoelectric complex (MMC) and a constant pattern of strong spike bursts of long duration. Cyclic activity was present in all parts of the large intestine, and propagation of phase III activity was evident from proximal to distal. A slight degree of disorganization in phase III propagation was restricted to the spiral colon. Activity cycles tended to be shorter in the cecum and PLAC of both cows with colic than in normal cows, and the intensity of spiking activity was generally lower. Changes in duration of the MMC in the spiral colon (bovine colonic MMC, bcMMC) were inconsistent, but the intensity of spiking activity tended to be lower in phases I and II of both cows compared to controls. The organization of phase III in several spindles typical of the bovine spiral colon was not disrupted, but phase IV of the bcMMC occurred only infrequently. Organized cyclic activity occurred in the large intestine of both cows despite complete disruption of the small intestinal MMC, indicating the presence of mechanisms able to initiate and regulate coordinated myoelectric patterns in the large intestine independent of the small intestine.     

An immunohistochemical study of S-100 protein in the intestinal tract of Chinese soft-shelled turtle,Pelodiscus sinensis

The present work describes the distribution of S-100 protein in the intestinal tract of a Chinese soft-shelled turtle specimen (Pelodiscus sinensis). S-100 protein positive cells were located in the intestinal tract, from the proximal small to distal large intestine. S-100 protein positive dendritic cells had irregular shape and were positive in both cytoplasm and nucleus. Most of them were located both lamina propria and submucosa in the small intestine, while few were found in the large intestine. S-100 protein, C-kit positive ICCs and Silver staining glial cells were predominantly observed in three locations: (1) in the interspace between the submucosa and circular muscle layer; (2) in the circular muscle layer; and (3) between the circular and longitudinal muscle layers of the intestine. Fewer were found in the large intestinal lamina propria and submucosa. Three types of positive cells (S-100 protein positive cells, C-kit positive ICCs and Silver staining glial cells) with 1–2 long or 2–3 short processes were distributed as lace-like or surrounding blood vessels in the different locations mentioned above. In the lamina propria, all the positive cells with irregular processes were connected with each other and formed a network. In the submucosa, all the positive cells were found surrounding the blood vessels.     

Localization of astrovirus in experimentally infected turkeys as determined by in situ hybridization

Twenty-one 3-day-old turkey poults from British United Turkeys of America were orally inoculated with a recently characterized astrovirus, TAstV-2, isolated from turkeys with poult enteritis and mortality syndrome. At 1, 2, 3, 4, 5, 7, and 9 days postinfection (dpi), three inoculated birds were euthanatized, and tissues (intestines, spleen, bursa, and thymus) were collected immediately into 10% neutral buffered formalin. Inoculated birds were diarrheic by 3 dpi, and frothy feces persisted throughout the experimental period. Histologically, there was only slight evidence of enteric damage, which was characterized by mild epithelial necrosis, lamina propria infiltrates, minimal villus atrophy, and mild crypt hyperplasia. In situ hybridization, using a negative sense digoxigenin-labeled riboprobe to the capsid gene of TAstV-2, revealed viral RNA in intestinal epithelial cells at the basal margins of the villi, in distal small intestine, and in cecum at 2 dpi, with subsequent extension to epithelium of the large intestine and proximal small intestine (3-5 dpi). Minimal virus remained by 9 dpi.     

Cryptosporidiosis in young artiodactyls

Cryptosporidium was found in the intestinal tract of 10 blackbuck, 2 scimitar-horned oryx, 2 fringe-eared oryx, 2 addax, and 1 sable antelope that had diarrhea. Cryptosporidia were most numerous in the small intestine, but also were found in the cecum, spiral colon, and colon. The small intestine had minimal inflammation in association with the cryptosporidia. Salmonella typhimurium was isolated from 10 of the 51 animals evaluated, with extensive inflammation of the cecum, spiral colon, and colon observed in these animals.     

Histological Study of Lymphatic Nodules and their Distributions Throughout the Cecum of the Caspian Miniature Horse

The cecum is a great cul-de sac intercalated between the small intestine and the colon. It has a remarkable size in the equine and digestion of more than 30% of total cellulose and production of volatile fatty acids by anaerobic metabolism of cellulose by its micro flora were made on it. It has also a substantial number of lymphatic nodules, which in horses are located near the apex. Topographically, cecum is situated chiefly to the right of the median plane and occupies around the whole volume of there in the abdominal cavity. The histological structure of the lymphatic follicles and their distributions pattern throughout the cecum in five healthy mature miniature horses (an special species of horses lives only in north of Iran) were studied (Fig. 1a). Each cecum was divided into three parts, namely, the base, body and apex, and samples were taken from each part immediately after slaughter and fixed with 10% buffered formalin. Routine histological laboratory techniques were made and 6 μm ?sections were cut and stained with haematoxylin and eosin staining and studied under light microscope. Lymphatic nodules were mostly found in the submucosa, but they disrupted the muscularis mucosa and merged into the lamina propria (Fig. 1c). The thickness of the mucosa and submucosa at these sites was smaller, and the epithelium that covered the mucosa was here modified into simple squamous or low cuboidal epithelia with dark and flattened nuclei (Figs 1b,d). The large and small lymphatic nodules were extensively accumulated in the apex, forming a nearly continuous layer in lamina propria and submucosa. However, they were less prominent at the base and least in the body of the cecum.
 

     

Effect of feed particle size and feed processing on morphological characteristics in the small and large intestine of pigs and on adhesion of Salmonella enterica serovar Typhimurium DT12 in the ileum in vitro

A 2 x 2 factorial experiment with pigs was undertaken to investigate the effect of particle size (fine and coarse) and feed processing (pelleted and nonpelleted) on morphological characteristics in the small intestine, cecum, and colon of pigs and on the adhesion of Salmonella enterica serovar Typhimurium DT12 to the ileum in vitro. Ninety-six pigs (average BW = 33 +/- 7 kg) were fed the experimental diets. After 4 wk, 24 pigs were selected (six pigs per diet) and euthanized, and tissue samples were taken from the mid and distal small intestine, cecum, and distal colon. The effects of particle size and feed processing on villus height and crypt depth in the small intestine were minor. Feeding coarse diets increased (P = 0.05) the crypt depth in the colon. The crypt depth was 420 +/- 12 and 449 +/- 12 microm in pigs fed finely and coarsely ground feed, respectively. Pigs fed pelleted diets had a larger (P = 0.01) staining area for neutral mucins, as well as for acidic and sulfomucins on the villi of the distal small intestine than pigs fed nonpelleted diets. The area was 41, 46, and 33% larger for neutral, acidic, and sulfomucins, respectively. The mucin-staining areas of the crypts in the cecum and the colon were not affected by the experimental diets. Examination of lectin binding characteristics of the distal small intestine and the cecum did not reveal any differences between the experimental diets. Using a pig intestine organ culture model, Salmonella adhered less (P < 0.05) to the ileal tissue of pigs fed the nonpelleted diets than to those fed pelleted diets; the adherence was 60% less in these pigs. Results of this study suggest that pigs fed pelleted diets secrete mucins that are capable of binding Salmonella enterica serovar Typhimurium DT12 and thereby allowing for colonization. Therefore, pigs fed a nonpelleted diet are better protected against Salmonella infections than pigs fed a pelleted diet.     

Morphology of the intestinal tract in the white rhinoceros (Ceratotherium simum)

The intestinal tract of the white rhinoceros (Ceratotherium simun) was dissected. We observed a simple structure for the small intestine, duodenum, jejunum and ileum, and a well-developed large intestine, cecum, colon and rectus. The cecum consisted of a small chamber, whereas the colon was much enlarged; notably larger than that of the domesticated horse, which belongs to the same order, Perissodactyla. This suggests that in the white rhinoceros the cecum may be functionally replaced by the well-developed colon which may act as the main fermentation tank in this animal.     

Mycotoxicosis caused by aerosolized T-2 toxin administered to female mice

Thymus, spleen, adrenal glands, and small intestine of female mice exposed to aerosolized T-2 mycotoxin were examined at postexposure hours (PEH) 0.25, 1, 2, 4, 6, 9, 12, and 24. Lymphocyte necrosis was observed at PEH 1 in the thymus, spleen, and lamina propria and Peyer patches of the small intestine. Necrosis of small intestinal crypt epithelial cells was observed at PEH 2, and necrosis of parenchymal cells and increased number of neutrophils were seen in sinusoids of the adrenal cortex at PEH 4. These results indicated that the earliest microscopic evidence of T-2 mycotoxicosis after aerosol exposure was necrosis of lymphocytes in the thymus, spleen, and lamina propria and Peyer patches of the small intestine.     

Studies on the pathogenesis of Salmonella heidelberg infection in weanling pigs

Experiments were conducted to define the pathogenic potential of Salmonella heidelberg in weanling pigs. Oral inoculation with S heidelberg resulted in severe catarrhal enterocolitis with accumulation of large amounts of fluid in the small intestine and colon. Salmonella heidelberg was demonstrated, with fluorescence microscopy and bacteriologic cultural techniques, to colonize the ileum, to invade ileal mucosal enterocytes, and to reach mesenteric lymph nodes and extraintestinal tissues by 8 hours. In 5 pigs, intestinal loops were surgically prepared and inoculated with S heidelberg (to determine its invasiveness). Microscopically, there were atrophy of villi, erosion of enterocytes, and neutrophilic infiltration in the lamina propria. Ultrastructurally, intracellular bacteria were demonstrated in villous and cryptal enterocytes, as well as in macrophages of the lamina propria. Bacteria were morphologically intact, occurred free and membrane-bound and caused no detectable cytotoxic effect to the cell.     

The distribution of immunoglobulin-containing cells in canine small intestine.

Peroxidase conjugated antisera to canine immunoglobulins G and A and to human immunoglobulin M, have been used to study the distribution of immunoglobulin-containing cells in the small intestine of the young and adult dog. At all levels of the small bowel of the adult dog, IgA:IgM:IgG cells have a 2:1:1 ratio while the greatest number of immunocytes is found in the duodenum and decreases towards the distal portion of the small intestine. The young puppy shows a predominance of IgM-containing cells in the small intestinal lamina propria during early life but the adult pattern of immunocyte distribution has been achieved by weaning.     

Microscopic structure of the large intestinal mucosa in piglets during an antibiotic-associated diarrhea

Antibiotic-associated diarrhea (AAD) is caused by the treatments of broad-spectrum antimicrobials that seriously affect the activity and composition of the large intestinal microflora. The pathogenic bacteria or low concentration of short-chain fatty acids (SCFAs) has been repeatedly discussed in relation to AAD. Recently, we reported the detection of a large amount of succinate and lactate in the diarrheal feces in AAD-induced piglets. In this study, we investigated histologically the large intestinal mucosa in AAD-induced piglets, in which succinate and lactate were accumulated. AAD was induced in the piglets by an oral dose of polymyxin B sulfate (PL) or by an intra-muscular injection of enrofloxacin (ERFX). When the piglets were defecating diarrheal feces with a high concentration of succinate and/or lactate, the large intestine was removed and separated into four segments (cecum, gyri centripetales, gyri centrifugales, and rectum). Healthy piglets were used as the control. In the AAD-induced piglets, the lamina propria was edematous in the gyri centripetales. Piglets treated with ERFX were also edematous in gyri centrifugales. These edematous lamina propria contained larger amounts of inflammatory cells than observed in control tissues. ERFX-treated piglets had a more shallow crypt than PL-treated and control piglets. The mucosal tissue of the large intestine was more seriously damaged in the ERFX- than in the PL-treated piglets, which might have been caused by the high succinate and low SCFAs concentration in the digesta.     

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.     

Variability in the localization of cryptosporidia in the intestines of spontaneously infected calves

31 to 37 localities were examined in the small and large intestines of 48 calves spontaneously infected with cryptosporidiosis. It was found that cryptosporidia occurred the most frequently in the distal part of small intestine, within the range of six metres of small intestine, in front of the ostium ileocecale (OIC); at the ileocecal valve the incidence of cryptosporidia dropped rapidly. In none case were the protozoans revealed in duodenum and in the adjacent four to six metres of proximal jejunum. The small intestine was invaded by cryptosporidia in a variable manner, in some cases a major part was continuously invaded, in other cases only one or two metres of distal jejunum without any changes in the ileum and vice versa. Approximately half the calves had cryptosporidia in the cecum, fewer cryptosporidia were found in the transverse colon. Cryptosporidia in the rectum were found in about 25% of cases. Some calves had cryptosporidia only in the large intestine. The intensity of the mucous membrane invasion varied: mass incidence of cryptosporidia was found only in caudal parts of small intestine, with high variability of the extent and with sudden cases of negative findings. In the large intestine only the cecum was invaded more intensively and in a diffusive manner, in the transverse colon and in the rectum the groups of parasites were usually found at the openings and in the wall of Lieberk uhn 's crypts.     

野生黄鼬消化管组织结构的观察

通过组织学观察,探讨野生黄鼬消化管的组织结构特点.将8只野生黄鼬经乙醚麻醉后处死,解剖取食管、胃、小肠、大肠,制作石蜡切片,观察其组织结构.结果显示野生黄鼬食管的黏膜为复层扁平上皮,食管腺发达,肌层以骨骼肌为主.胃贲门部有发达的皱襞和贲门腺;胃底腺有大量的主细胞和壁细胞;胃大弯部的腺体以壁细胞为主,仅有少量主细胞;胃幽门部有发达的幽门腺和大量壁细胞.十二指肠黏膜层有小肠腺,内有潘氏细胞存在,黏膜下层含有十二指肠腺;空肠可见孤立淋巴小结、弥散淋巴组织及集合淋巴小结.结肠无皱襞和肠绒毛,大肠腺排列紧密,其中杯状细胞特别多;直肠固有膜内有发达的大肠腺.所以野生黄鼬消化管的特点是胃各部胃腺发达,壁细胞特别多.     

Morphologic and physiologic changes induced by Clostridium perfringens type A alpha toxin in the intestine of sheep

OBJECTIVE: To evaluate the morphologic and physiologic changes induced by Clostridium perfringens type A (alpha toxin in the ileum and colon of sheep. SAMPLE POPULATION: 16 ligated intestinal loops in 4 Merino lambs and 18 explants of ileum and colon from slaughtered lambs. PROCEDURE: alpha Toxin-induced fluid accumulation was evaluated in ligated ileal and colonic loops of sheep. Tissues were evaluated morphologically by use of gross and histologic examination. Effects of toxin on in vitro intestinal net water transport were tested in modified Ussing chambers. RESULTS: Ovine ileal and colonic loops incubated with C perfringens type A alpha toxin retained more fluid than control loops. Histologically, in the ileum of lambs inoculated with 300 LD50 of alpha toxin/mL, there was a mild to moderate multifocal infiltration of neutrophils in the lamina propria and submucosa. The colonic loops of lambs inoculated with 30 or 300 LD50 of alpha toxin/mL had excessive mucus in the lumen, a moderate amount of neutrophils mixed with mucus in the intestinal lumen, and moderate multifocal infiltration of the lamina propria and submucosa with neutrophils; the blood vessels of these layers were engorged with neutrophils. In vitro measurements of water transport also revealed inhibition of net epithelial water absorption in ileum and colon incubated with alpha toxin on the mucosal side. CONCLUSIONS AND CLINICAL RELEVANCE: These results indicate that alpha toxin induces alterations in sheep intestine. Clostridium perfringens type A organisms that produce alpha toxin could be responsible for diseases of intestinal origin in some ruminants.