A Case of Feline Gastrointestinal Eosinophilic Sclerosing Fibroplasia

Feline gastrointestinal eosinophilic sclerosing fibroplasia was diagnosed in an 8-month-old Scottish fold that had a primary gastrointestinal mass involving the stomach, duodenum and mesenteric lymph nodes. Histopathologically, the most characteristic feature of this mass was granulation tissue with eosinophil infiltration and hyperplasia of sclerosing collagen fiber. Immunohistochemically, large spindle-shaped cells were positive for smooth muscle actin and vimentin. This case emphasizes the importance of feline gastrointestinal eosinophilic sclerosing fibroplasia as a differential diagnosis of gastrointestinal neoplastic lesions such as osteosarcoma and mast cell tumor in cats.     

Myelodysplastic changes in a cat with myelomonocytic leukemia

Submandibular and/or disseminated zygomycosis (mucormycosis) was diagnosed in 3 feeder pigs from 2 farrow-to-finish farms. Affected pigs were stunted and unthrifty. Each pig had a large unilateral submandibular granuloma replacing the mandibular lymph node on the affected side. Two pigs had disseminated lesions. One had an abscess on the serosa of the stomach; another had abscesses scattered throughout the liver and mesenteric lymph nodes. Impression smears were made of several masses and stained with blue-black ink. Examination of smears by light microscopy revealed coarse, infrequently septate, irregularly branching, mucoraceous fungi typical of a Zygomycete. Histologic examination of the submandibular masses revealed granulomas containing large numbers of mixed inflammatory cells, including giant cells. Mesenteric lymph nodes and liver abscesses had necrotic cores surrounded by fibrous capsules infiltrated by mixed inflammatory cells. Hyphae of a mucoraceous fungus were scattered throughout all masses. The 2 pigs submitted alive had marked serum hypoproteinemia, including hypoglobulinemia.     

A Disease Resembling Paratuberculosis (Johne’S Disease) in Roe Deer (Capreolus Capreolus L.) an Aetiological and Patho-Anatomical Study

A disease in wild living roe deer (Capreolus capreolus L.) caused by acid-fast bacteria is described.The morphological and cultural properties of these bacteria agree closely with corresponding properties of Mycobact. johnei.Enlarged lymph nodes, especially mesenteric lymph nodes with greyish-yellow necroses, were the most prominent macroscopic lesions. No intestinal lesions were present.The histopathological picture of the lymph nodes resembled mostly lesions which can occur in paratuberculous sheep and goats. The epithelioid cells contained masses of acid-fast bacteria. Such rods were also demonstrated in the intestinal villi.The acid-fast bacteria could be isolated from the mesenteric lymph nodes, spleens, bone marrow, mammary gland and also from the lymph nodes of other organs.The organism did not produce tuberculosis in guinea pigs. Intravenous injections into hens and rabbits resulted in miliary nodules resembling those of tuberculosis in the livers and spleens of the hens, and in joint and tendon sheath lesions in the rabbits. Microscopically the lesions mostly resembled those in paratuberculosis.One of the strains which was inoculated intravenously into two calves caused no lesions. The results of the allergy tests and serological blood tests in one animal indicate that infection with Mycobact. johnei cannot be excluded.A goat which was inoculated in the same manner and with the same strain as the calves died after six weeks. Miliary epithelioid cell granulomas in the liver, spleen, kidneys, bone marrow of long bones and in the submucosa of the ileum, as well as patchy infiltration of epithelioid cells in, among others, the mesenteric lymph nodes were observed on microscopic examinations.By intravenous infection the disease could be reproduced in a roe deer (fawn) (Gapreolus capreolus L.). The animal died nine weeks after the infection, and during the last two days before death it had a profuse diarrhoea. Masses of short acid-fast bacteria in clumps were present in the faeces. Nor in the experimental animal did macroscopic intestinal lesions occur. Enlarged villi infiltrated with epithelioid cells containing acid-fast bacteria were demonstrated by histological examination.The acid-fast bacteria could be recovered, but only on the Taylor/ Finlayson medium, from all experimental animals except the guinea pigs. Concerning the experimental calves, acid-fast bacteria were recovered from only one of them and then nearly three years after the infection.The acid-fast bacteria did not reduce nitrate. They showed positive neutral red reactions and were sensitive to isoniazid in a concentration of 2.5 µg per ml medium after three weeks’ incubation.The possibility that the isolated acid-fast bacteria and the lesions caused by them might be avian tubercle bacilli and avian tuberculosis has been discussed by the author. He does not, however, find any relevant reason for such an assumption. The author considers that the bacteria and the lesions exhibit the greatest similarity to Mycobact. johnei and paratuberculosis (Johne’s disease).On account of the organism’s pathogenicity for hens and rabbits, and necroses in the course of the disease, the author suggests that these bacteria possibly constitute a variety of the classic bovine Mycobact. johnei, different from the pigmented and the Icelandic varieties.     

Histopathology of experimental plague in cats

Formalin-fixed paraffin-embedded archival tissues of seven adult cats of both sexes that died after being experimentally infected with Yersinia pestis were examined light microscopically to characterize the lesions. The cats were exposed in two groups using two routes of infection: ingestion of Y. pestis-infected rodent or a subcutaneous injection of Y. pestis to simulate a flea bite. Immunohistochemistry was performed on tissues from all organ systems from a representative cat from each group to determine the distribution of Y. pestis bacilli during infection. In all seven cats, bubonic plague lesions were seen. The lesions of pneumonic plague were present in two cats. Septicemic plague was confirmed in all seven cats by bacteriologic culture. Aggregations of bacteria were seen in lymphoid tissue in all cats and in lung tissues from the two cats with pneumonic plague. The most consistent histologic finding was necrosuppurative inflammation in the lymph nodes. Invariably, Y. pestis bacteria were present in large numbers at affected sites. Orally infected cats had more numerous lesions in the lymph nodes of the head and neck regions. These experimentally induced cases of feline plague document that cats are unique among carnivores in exhibiting bubonic, pneumonic, and septicemic plague following exposure to Y. pestis. The lesions of the orally infected cats were consistent with those previously described for naturally occurring Y. pestis infections in cats and corroborate the contention that cats most commonly contract plague by eating Y. pestis-infected rodents and not via flea bite. The histopathology of Y. pestis disease in these cats is comparable to that described for human plague.     

Rhodococcus equi infection of cats

Six cases of Rhodococcus equi infection in cats are described. One cat had pneumonia and died. The remaining five cats had cutaneous lesions affecting the feet in four of the cats and the metacarpus in one cat, and all these cats recovered with the aid of antibiotics. All the Rhodococcus equi isolates were sensitive to amoxycillin/clavulanic acid and, where used, at least 14–16 days of treatment was needed to help eliminate the infection. Histologically and cytologically the reaction was pyogranulomatous and many macrophages in the lesions contained large numbers of Gram-positive bacteria.     

Necrotizing enteritis in a calf infected with adenovirus

A three week old Holstein calf that died after a period of anorexia and diarrhea had a severe necrotizing ileitis. The lesions which were most severe above Peyer's patches contained numerous filamentous bacteria. Prominent intranuclear inclusion bodies in vascular endothelial cells in both the affected intestine and the mesenteric lymph nodes were accompanied by vasculitis and thrombosis. Adenovirus-like particles were demonstrated ultrastructurally in the inclusions.

This case demonstrates a preferential association of the intestinal necrosis with the gut associated lymphoid tissue. Also, the significance of viral infection of vascular endothelium versus intestinal epithelium in determining the type and severity of injury, is deduced from this and other previously reported cases.

     

Yersinia enterocolitica infection in breeding colonies of ruffed lemurs

Two outbreaks of yersiniosis caused by Yersinia enterocolitica occurred in breeding colonies of red ruffed lemurs (Varecia variegata rubra) and black and white ruffed lemurs (Varecia variegata variegata) housed in outdoor enclosures during the winter breeding season and spring birth season, respectively. Seven of 11 animals at risk in the combined outbreaks became ill, and 3 died of acute to chronic infection. Clinical signs included anorexia, lethargy, diarrhea, abdominal pain, and hyperpyrexia. Necropsy findings included ulcerative enterocolitis and multifocal necrosis and abscess formation in mesenteric lymph nodes, liver, spleen, kidneys, and lungs. Histologically, lesions were characterized by necrotizing inflammation containing masses of basophilic bacteria. Yersinia enterocolitica serotype 0:2 was isolated from lesions. Neomycin sulfate given orally and chloramphenicol given intramuscularly were effective in treatment early in the course of the disease or in mild cases. In severe cases, lemurs did not respond to antibiotic and fluid therapy. Exposure to soil contaminated with infected rodent feces, stress, and behavioral factors in the ruffed lemur species are believed to have precipitated the infection.     

Enteritis associated with Yersinia pseudotuberculosis infection in a buffalo

SUMMARY: A week after transport a 4 month old buffalo calf developed diarrhoea. Its condition gradually deteriorated and it died. Necropsy revealed acute haemorrhagic enteritis and enlarged mesenteric lymph nodes. Haemorrhages and numerous microabscesses were detected in the lamina propria of the small intestine associated with colonies of Gram negative bacteria. Yersinia pseudotuberculosis was isolated from the small intestine and from mesenteric lymph node. Enteritis caused by Y pseudotuberculosis does not appear to have been reported previously in buffalo in Australia.     

Pathology of naturally occurring paratuberculosis in water buffaloes (Bubalus bubalis)

Gross and histologic lesions of paratuberculosis were studied in water buffaloes. Small intestines and associated mesenteric lymph nodes of 405 water buffaloes were examined. Of these, 20 animals having visible changes of intestinal thickening, mucosal corrugations, and enlargement of mesenteric lymph nodes exhibited histologic alteration characteristics of mild to moderate granulomatous inflammation. The histologic lesions observed in these animals were classified into 3 grades on the basis of type of cellular infiltration, granuloma formation, and presence of acid-fast bacilli. Grade-1 lesions observed in 8 animals were marked by the presence of scattered epithelioid macrophages amid large number of lymphocytes in the intestinal villi and in the paracortical regions of the associated mesenteric lymph nodes. Another 8 animals classified under grade-2 revealed microgranulomas, infiltration with a larger number of epithelioid macrophages besides lymphocytes in the intestinal villi, and granulomas in the mesenteric lymph nodes. Grade-3 lesions observed in 4 animals were characterized by the presence of epithelioid granulomas and giant cells in the intestines and the mesenteric lymph nodes. The Ziehl-Neelsen's stained tissue sections revealed acid-fast bacilli in grade-3 and -2 animals and acid-fast granular debris in grade-1 animals. Among these 20 buffaloes, 14 (70%) were positive in the IS900 specific polymerase chain reaction and 6 (30%) were positive in the bacterial culture.     

Prevalence and Identity of Translocating Bacteria in Healthy Dogs

Bacterial translocation is characterized by the passage of intestinally derived bacteria across the intestinal mucosa to local or regional tissues. This phenomenon is believed to be important in the pathogenesis of gram-negative bacteremia and septicemia; however, the pathway or route of translocation remains unclear. To define the route of translocation better, mesenteric lymph nodes from 50 apparently healthy dogs undergoing elective ovariohysterectomies were cultured aerobically and anaerobically. The aims of this study were to determine the prevalence of bacterial translocation and to quantify and identify types of organisms found in mesenteric lymph nodes. Peripheral blood and portal blood samples were similarly cultured to rule out hematogenous organisms as a source of lymph node contamination. Bacteria were isolated from mesenteric lymph nodes of 26 dogs (52%). The number of bacteria varied from 50 to > 10⁵ organ-isms/g of tissue. Bacteria isolated included Staphylococcus intermedius (n = 3), coagulase-negative Staphylococcus (n = 2), nonhemolytic Streptococcus (n = 4), Bacillus species (n = 5), Escherichia coli (n = 6), Salmonella species (n = 3), Pseudomonas species (n = 2), Enterococcus species (n = 2), Clostridium sordelli (n = 1), Micrococcus species (n = 1), Lactobacillus species (n = 1), and Propionibacterium acnes (n = 1). One of 50 peripheral blood samples yielded an unidentified gram-positive coccus and a coagulase-negative Staphylococcus. No bacteria were isolated from portal blood samples of any dog. Further studies of this type on sick dogs are warranted before clinical recommendations can be made to culture mesenteric lymph nodes routinely.     

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.     

Spontaneous lymphoma in a Japanese White rabbit

Lymphoma was observed in a 4-month-old female Japanese White rabbit. Grossly, the markedly enlarged mesenteric lymph nodes, prominent Peyer's patches of jejunum, splenomegaly, and enlargement of tracheobronchial lymph nodes, adrenal glands and ovaries were observed. Histologically, neoplastic lymphoid cells proliferated diffusely showing frequent mitotic figures and a characteristic 'starry sky' appearance. Their basophilic cytoplasm contained a few lipid droplets. The mesenteric lymph nodes, Peyer's patches of jejunum, and tracheobronchial lymph nodes were largely replaced by the tumor tissues. The stomach, small intestines, especially the jejunum, liver, spleen, ovaries, and adrenal glands were heavily infiltrated with neoplastic cells. These results suggest that the present lymphoma may have originated from the gastrointestinal lymphoid tissue.     

Mycobacterium bovis infection in a captive herd of Sika deer.

Infection with Mycobacterium bovis was diagnosed in a small privately owned herd of Sika deer. After postmortem examination of a deer with progressive pulmonary disease, diagnosis of infection with M bovis was confirmed by bacteriologic culture. The 2 remaining deer in this herd were euthanatized, necropsied, and confirmed to be infected with M bovis. Three cats in contact with the deer were also euthanatized and necropsied. One of these cats had lesions suggestive of mycobacterial infection in the colon and mesenteric lymph nodes. Infection of this cat with M bovis was not confirmed by bacterial culture. Mycobacteriosis, infrequently encountered in clinical veterinary practice, may be confused with disease caused by other infective agents or neoplasia. The zoonotic potential of these bacteria and a recent increase in human tuberculosis warrants continued surveillance of companion and food animal populations for mycobacterial infection.     

The emergence of Mycobacterium paratuberculosis in farmed deer in New Zealand - a review of 619 cases

AIM: To review cases in which Mycobacterium paratuberculosis was identified in farmed deer in New Zealand. METHODS: Case histories were reviewed where M. paratuberculosis was identified in deer by either culture or a polymerase chain reaction (PCR) test using primers from IS900. RESULTS: Between 1986 and 2000, M. paratuberculosis was identified by bacterial culture and/or PCR in 619 farmed deer from 299 herds, representing approximately 6% of deer herds in New Zealand. Over 85% of cases were identified during the last 6 years. In 60% of the infected herds, only one infected animal was identified. The maximum number of cases identified in a single deer herd was 47, and these were identified over a period of 8 years. Only 36 (5.8%) cases came from clinically affected animals identified on farms by veterinarians. The majority (89.7%) of the 619 cases were identified from lesions in mesenteric lymph nodes, including the ileocaecal lymph nodes, identified at meat inspection as being macroscopically either typical or equivocal of bovine tuberculosis (M. bovis). While the overwhelming majority of lesions were identified in mesenteric lymph nodes, M. paratuberculosis was also identified in 27 lesions in lymph nodes of the head, especially the retropharyngeal lymph node. CONCLUSIONS: The figures presented underestimate the true prevalence of infection with M. paratuberculosis, especially since not all suspect cases were submitted for culture or PCR. However, they do show that M. paratuberculosis appears to be spreading in farmed deer in New Zealand and highlight the possibility that Johne's disease is emerging as a potential major problem affecting this species. Identification of the organism by bacterial culture or PCR is required in many cases to distinguish lesions in mesenteric lymph nodes and lymph nodes of the head caused by M. paratuberculosis from those caused by M. bovis and M. avium.     

ULTRASOUND‐GUIDED MESENTERIC LYMPH NODE IOHEXOL INJECTION FOR THORACIC DUCT COMPUTED TOMOGRAPHIC LYMPHOGRAPHY IN CATS

Computed tomographic (CT) lymphography was performed in cats using percutaneous ultrasound‐guided injection of contrast medium into a mesenteric lymph node. The thoracic duct and its branches were clearly delineated in CT images of seven cats studied. The thoracic duct was characterized by anatomic variation and appeared as single or multiple branches. The thoracic duct and the cisterna chyli were identified along the ventral or left ventral aspect of the vertebrae from the level of the cranial lumbar to the caudal cervical vertebrae. The thoracic duct was identified in the central caudal mediastinum, deviated to the left in the cranial mediastinum, and finally moved toward the venous system. Small volumes of extranodal contrast medium leakage were identified in all cats. After injection, the mesenteric lymph nodes were cytologically normal. Ultrasound‐guided CT lymphography via percutaneous mesenteric lymph node injection appears safe and effective in cats.     

High viral loads despite absence of clinical and pathological findings in cats experimentally infected with feline coronavirus (FCoV) type I and in naturally FCoV-infected cats

Specified pathogen-free cats were naturally infected with FCoV or experimentally infected with FCoV type I. Seroconversion was determined and the course of infection was monitored by measuring the FCoV loads in faeces, whole blood, plasma and/or monocytes. Tissue samples collected at necropsy were examined for viral load and histopathological changes. Experimentally infected animals started shedding virus as soon as 2 days after infection. They generally displayed the highest viral loads in colon, ileum and mesenteric lymph nodes. Seroconversion occurred 3-4 weeks post infection. Naturally infected cats were positive for FCoV antibodies and monocyte-associated FCoV viraemia prior to death. At necropsy, most animals tested positive for viral shedding and FCoV RNA was found in spleen, mesenteric lymph nodes and bone marrow. Both experimentally and naturally infected cats remained clinically healthy. Pathological findings were restricted to generalized lymphatic hyperplasia. These findings demonstrate the presence of systemic FCoV infection with high viral loads in the absence of clinical and pathological signs.     

Clinical sarcocystosis in calves fed Sarcocystis hirsuta sporocysts from cats

Lesions of sarcocystosis were studied in 14 calves necropsied between seven and 110 days after inoculation with 5000 to 25 million sporocysts of Sarcocystis hirsuta from cats. Calves developed fever, anemia, and diarrhea between 11 and 30 days after inoculation. The development of first generation meronts in arteries of small intestine, mesentery, and mesenteric lymph nodes seven to 25 days after inoculation was associated with vascular occlusion and necrosis of associated tissues. The development of second generation meronts in capillaries of striated muscles 15 to 23 days after inoculation was associated with necrosis, edema, and nonsuppurative myositis in heart and other muscles. Sixty-two days after inoculation lesions were reduced to focal areas of granulomatous inflammation around degenerating sarcocysts in striated muscles, but not in the heart.     

Ultrasonographic anatomy of abdominal lymph nodes in the normal cat.

Lymph nodes are essential structures to be evaluated in an ultrasonographic examination of the feline abdomen. It was hypothesized that current technical proficiency would allow all feline abdominal lymph nodes to be identified ultrasonographically. Ten clinically normal, adult, domestic shorthair cats were examined using real-time compound ultrasonographic imaging. The medial iliac lymph nodes were visible in 100% of the cats, the jejunal lymph nodes in 90%, the hepatic lymph nodes in 70%, the aortic lumbar, the splenic, and the pancreaticoduodenal lymph nodes in 60% each, the ileocecal and the colic lymph nodes in 50% each, and the renal, the gastric, the sacral and the caudal mesenteric lymph nodes in 40%, 30%, 20%, and 10% of the cats, respectively. The inconsistent presence of lymph nodes, their poor echocontrast and interposed gas of the gastrointestinal tract explain the lower percentages of identification. The ultrasonographic length and diameter of the lymph nodes were determined. The majority of these measurements corresponded to those in the literature. We conclude that ultrasonography is a valuable tool for the identification and evaluation of most abdominal lymph nodes in the normal cat. Average ultrasonographic measurements are presented as a preliminary guideline for normal feline abdominal lymph nodes. ete