Stomach gas analyses in canine acute gastric dilatation with volvulus.

BACKGROUND: The origin of the gas in the stomachs of dogs with acute gastric dilatation or gastric dilatation with volvulus (GDV) often is disputed. HYPOTHESIS: We tested the hypothesis that gaseous distention resulted from aerophagia. ANIMALS: Ten cases of GDV that were submitted to an emergency clinic were sampled intraoperatively. METHODS: With the abdomen open, the needle of a vacutainer blood collection set was inserted into the distended stomach, and gas was collected into 10 mL glass vacutainer vials with rubber stoppers. These were stored at room temperature for 1-7 days and then analyzed by gas chromatography and mass spectroscopy. RESULTS: CO2 composition ranged from 13 to 20%. One dog had an H2 concentration of 29%. CONCLUSIONS: Because the CO2 content of atmospheric air is less than 1%, these findings suggest that the gaseous gastric distention in GDV is not the result of aerophagia.

Lymphatics, tertiary lymphoid organs and the granulomas of Crohn's disease: an immunohistochemical study.

BACKGROUND: Case studies in the past repeatedly suggested that the fundamental alteration in Crohn's disease occurs in the regional lymphatics of the intestine. AIM: To evaluate the lymphatic inflammation in Crohn's disease, and to characterise lymphoid aggregates and granulomas in and surrounding lymphatics and blood vasculature. METHODS: Forty-eight tissue blocks from 24 Crohn's disease patients and 23 tissue blocks from 23 control patients were selected. Tissue sections were immunostained with a lymphatic endothelial cell marker (D2-40), a marker for blood vasculature (FVIII), and markers for T cells (CD3), B cells (CD20) and macrophages (CD68). RESULTS: Lymphangiectasia and lymphocytic perilymphangitis were demonstrated in all 24 patients, lymphocyte-obstructed lymphatics in seven patients, granuloma-obstructed lymphatics in nine patients and inflammatory lymphoid follicles in all 24 patients. Free-standing granulomas occurred in 19 patients, and in three further patients granulomas were in or attached to blood vascular units. CONCLUSIONS: This study, employing immunohistochemistry, revealed, better than standard microscopy, the association of inflammation, granulomas and tertiary lymphoid follicles or organs with the lymphatic vasculature in Crohn's disease. Disease in some patients was characterised by perilymphangitis and lymphoid follicular inflammation and in others by granulomas, some of which totally obstructed lymphatics. These findings have aetiological, therapeutic and prognostic implications.

Pathologic findings and liver elements in hibernating bats with white-nose syndrome.

Two groups of vespertilionid bats were collected from affected hibernacula. In group 1 (n, 14; pathology and microbiology), the average body weights of all species were at the lower limit of published ranges. Twelve bats (86%) had mycotic growth in the epidermis, hair follicles, and sebaceous glands. Geomyces destructans, with its characteristic curved conidia, was observed microscopically, cultured, and confirmed by polymerase chain reaction. Dermatitis and mural folliculitis was nil to mild. When focally coinfected with Gram-negative bacteria, there was necrosis and pustules. Fat stores were little to abundant in 12 bats (86%) and nil in 2. Thirteen bats (93%) had pulmonary congestion and 7 (50%) had bone marrow granulocytosis. In group 2 (n, 24; liver elements), 3 bats (13%) had potentially toxic lead levels and 1 (4%), potentially toxic arsenic level. There was no evidence of major organ failure or consistent element toxicity.

Herpetiform genital lesions in a heifer with mucosal disease.

A 14-month-old heifer with a 17-day history of unresponsive bloody diarrhea was necropsied. There were focal, pink-red erosions of the nares and hard palate; ulcers and fissures of the tongue; and multiple ulcerative lesions of the alimentary canal. Interdigital skin of both rear limbs was ulcerated and bleeding; and the margins of the vulva contained punctiform red ulcers. The gross lesions were consistent with mucosal disease. Histopathology and laboratory testing ruled out rinderpest, foot-and-mouth disease, and vesicular stomatitis, and identified bovine virus diarrhea virus to be the cause of this disease. Lesions of the vulva similar to those seen in some stages of infectious pustular vulvovaginitis were negative for bovine herpesvirus-1 and tested positive for bovine viral diarrhea virus antigen by immunohistochemistry.

The forgotten role of lymphangitis in Crohn's disease.

Research into Crohn's disease has recently been focused on the genetics of the patient, the gastrointestinal flora, the gut epithelium and mucosal immune responses. For over 60 years pathologists have reported that the fundamental alteration in Crohn's disease occurs in regional lymphatics of the intestine--the disease is a lymphocytic and granulomatous lymphangitis. At an earlier time, experimental sclerosis of regional intestinal lymphatics of the pig produced a chronic segmental enteritis with many features of Crohn's disease, including lymphocytic and granulomatous lymphangitis of the bowel wall and enteroenteric and enterocutaneous fistulas. In Crohn's disease, differences in the anatomic distribution of vasa recta appear to explain long-segment disease of the ileum and short-segment disease of the more proximal intestine. A variety of bacteria and viruses cause lymphangitis, suggesting that microorganisms may be at the centre of the basic changes in Crohn's disease. Dietary antigens and lipids are worthy of consideration as well. Now that antibodies to label lymphatics are available, attention should be directed at defining the initial damage to lymphatic endothelium and agents that might be responsible.

Extraintestinal pathogenic Escherichia coli-induced acute necrotizing pneumonia in cats.

Extraintestinal pathogenic Escherichia coli (ExPEC) are pathogens involved in several disease conditions, ranging from urinary tract infection to meningitis in humans and animals. They comprise epidemiologically and phylogenetically distinct strains, affecting most species and involving any organ or anatomical site. Here, we report fatal cases of necrotizing pneumonia in cats. Over a 1-week period, 13 cats from an animal shelter in Stamford, Connecticut were presented for necropsy. All had a clinical history of acute respiratory disease. The gross and microscopic findings for all the cats were consistent. Escherichia coli was uniformly isolated from the lungs of all the tested cats. All the isolates were haemolytic, genetically related as determined by enterobacterial repetitive intergenic consensus PCR, and harboured genes encoding for cytotoxic necrotizing factor-1 and fimbriae and adhesions that are characteristic of ExPEC, implying a point source clonal outbreak. As cats are common household pets, this report raises concerns regarding zoonotic potential (in either direction) for these ExPEC strains.

Fluorescent antibody test for rapid detection of West Nile virus antigen in avian tissues.

An indirect fluorescent antibody test (IFA) was developed to detect West Nile virus (WNV) antigens in tissues from avian species. The test samples used in the study consisted of 100 sets of tissues from dead crows that had been collected during the 2001 surveillance in Connecticut. The test tissues were punctured with a fine point Dacron cotton-tipped applicator and smeared in duplicate on 10-well diagnostic printed glass slides. Among several fixatives tested, 4% paraformaldehyde was the best. Reagent calibration for the IFA test was done in WNV-infected Vero cells and control uninfected Vero cells. Optimized antibody and fluorescent conjugate concentrations were then applied for the detection of WNV antigen on fixed tissue impression smears. Several tissues, including brain, heart, liver, kidney, and spleen were tested by the IFA test. The brain and heart seemed to be unsuitable for the test because of excessive background. Both virus isolation and reverse transcription-polymerase chain reaction (RT-PCR) were used for validation, with the latter technique having a higher sensitivity. Therefore, IFA results were compared with RT-PCR results. The diagnostic sensitivity was 96.8% for liver, 96.4% for kidney, and 100% for spleen. The diagnostic specificity was 69% for liver, 95.3% for kidney and 95.8 for spleen. The IFA test performed best with spleen and kidney. The IFA test described here is a useful, practical, and rapid test for screening for WNV.

The comparative importance of E. coli antigen in granulomatous colitis of Boxer dogs.

Granulomatous colitis of Boxer dogs is characterized by mucosal and submucosal infiltration by abundant large macrophages and lymphocytes and plasma cells. Involved intestine is thickened, corrugated and ulcerated. The macrophages that occur in colon, cecum and regional lymph nodes are PAS-positive, lipid-rich, contain cholesterol, and some of the time can be seen to hold bacteria. Paraffin tissue blocks of formalin-fixed colon and colic lymph nodes from 10 cases were cut at 5 microm and immunostained by a streptavidin-biotin immunoperoxidase technique, employing primary antibodies against Escherichia coli, E. coli 0157: 2, Campylobacter, C. jejuni-coli, Yersinia pseudotuberculosis, Salmonella, Shigella, Pseudomonas and Lawsonia intracellularis. The macrophages in the lamina propria and submucosa, as well as those in aggregates in regional lymph nodes, showed immunoreactivity with polyclonal E. coli antibody in all 10 cases. Tissues lacking granulomas were negative, as were those reacted with the other eight antibodies, with the exception that there was rare focal staining for Campylobacter, Lawsonia and Salmonella in a few dogs. We believe these results identify the causative agent of this granulomatous disease of Boxer dogs, a disease with great histologic and etiologic similarity to granulomatous leptomeningitis of Beagle dogs, and malacoplakia and xanthogranulomatous cholecystitis of man. Macrophages that are immunopositive for E. coli antigen occur in Crohn's disease as well, where their significance is less well understood.

The West Nile virus: its recent emergence in North America.

West Nile fever emerged in New York in the summer of 1999 when seven people, several horses and thousands of wild birds died. It was soon established that the human disease and the mortality of birds were related. Continued surveillance detected West Nile virus in mosquitoes, birds, horses, small mammals, bats and humans, and has shown its spread to several northeastern states. These events confirm the establishment of West Nile virus endemically in the United States.

A clustering of Crohn's disease in Mankato, Minnesota.

Infrequently, clusterings of Crohn's disease (CD) occur that suggest it is transmissible. We studied such a clustering. Graduates of the Mankato West High School Class of 1980 were contacted by mail and asked to respond, by self-addressed postcard, to a six-item questionnaire about inflammatory bowel disease and CD. Responses were followed-up by telephone contact and additional mailings. Two visits were made to Mankato, Minnesota, to interview individuals with CD, to obtain medical records, radiographs, and sera, and to study environmental risk factors. Of the 320 graduates of the class of 1980, 285 were contacted. Seven cases of CD were identified, the equivalent of a prevalence of 2,400/100,000. Concerns were discovered that CD may have emanated from recreational swimming. Fecal coliform counts in excess of 200/dL, the standard above which water is regarded as unsafe for recreational use, had been recorded year after year for the Blue Earth River at Mankato and for the Minnesota River. Recent fecal coliform counts (1993-1995) of Lake Washington, Lake German/Jefferson, and Lake Shetek were greater than 200/dL in 57%, 65%, and 62% of water samples. This clustering, in unrelated individuals, argues against a genetic cause for CD and suggests that environmental transmission occurred.

Recovery and identification of West Nile virus from a hawk in winter.

West Nile virus was recovered from the brain of a red-tailed hawk that died in Westchester County, N.Y., in February 2000. Multiple foci of glial cells, lymphocytes, and a few pyknotic nuclei were observed in the brain. Three to 4 days after inoculation of Vero cells with brain homogenates, cytopathic changes were detected. The presence of West Nile virus antigen in fixed cells or cell lysates was revealed by fluorescent antibody testing or enzyme-linked immunosorbent assay, respectively. Furthermore, Reverse transcriptase-PCR with primers specific for the NS3 gene of West Nile virus resulted in an amplicon of the expected size (470 bp). Electron microscopy of thin sections of infected Vero cells revealed the presence of viral particles approximately 40 nm in diameter, within cytoplasmic vesicles. The demonstration of infection with the West Nile virus in the dead of the winter, long after mosquitoes ceased to be active, is significant in that it testifies to the survival of the virus in the region beyond mosquito season and suggests another route of transmission: in this case, prey to predator.

Gastric intramural hematoma and hemoperitoneum in a captive northern fur seal.

A 16-yr-old adult male northern fur seal (Callorhinus ursinus) was found dead in its outdoor pool in November 1995. The animal was maintained at Mystic Aquarium (Mystic, Connecticut, USA) from March 1980 to November 1995. Gross necropsy findings included hemoperitoneum and locally extensive gastric intramural hemorrhage that involved the posterior fundic, antral, and pyloric regions and extended into the duodenum. The gastric mural thickening grossly resembled hemangioma, and the gastric serosa was ruptured at the site of maximal mural expansion. In histologic sections of the stomach, a cribiform network of fibrin, which encompassed numerous variably-sized aggregates of closely packed erythrocytes, markedly expanded the submucosa. No vascular endothelium was identified in serial histologic sections of the expanded gastric submucosa stained with hematoxylin and eosin or immunohistochemically with antibodies to vimentin and Factor VIII-related antigen, establishing an absence of hemangioma. Carstairs' and Weigert's histochemical stains confirmed that the framework expanding the submucosa was fibrin. Although the appearance of the gastric wall resembled hemangioma, a population of neoplastic endothelial cells was not identified within the submucosal expansion of hemorrhage and fibrin, and microscopic evidence was most consistent with the diagnosis of gastric intramural hematoma. This lesion is a rare pathologic event that has not been reported in marine mammals, but one that should be included in diagnostic considerations of hemoperitoneum and gastric mural expansion.

Virus serology in familial Crohn disease.

BACKGROUND: Recent findings that early-in-life virus infections represent a risk factor for Crohn disease, that exacerbations of disease sometimes appear associated with common viral infections, and, in particular, suggestions that Crohn disease may be the result of persistent infection with measles virus prompted serologic studies for antibody to 19 common viruses, Chlamydia psittaci, and Mycoplasma pneumoniae. METHODS: Sera from 14 affected members of 2 French families with a high frequency of Crohn disease and from age- and sex-matched controls, taken in 1990 and 1992, and from unaffected family members were tested. Complement fixation, enzyme immunoassay, and indirect immunofluorescent tests were used. RESULTS: There were no significant differences between patients and controls or between affected and unaffected family members of family 2, with the exception that affected siblings carried higher antibody titers for mycoplasma one year and for varicella another year. There were no differences in measles IgM and IgG or mumps IgG antibody levels between patients and controls, or between patients and unaffected family members. CONCLUSIONS: Serology failed to find evidence of participation by 19 common viruses, C. psittaci, and M. pneumoniae in Crohn disease. The data do not support the hypothesis that persistent measles virus infection causes Crohn disease.

Isolation of West Nile virus from mosquitoes, crows, and a Cooper's hawk in Connecticut.

West Nile (WN) virus, a mosquito-transmitted virus native to Africa, Asia, and Europe, was isolated from two species of mosquitoes, Culex pipiens and Aedes vexans, and from brain tissues of 28 American crows, Corvus brachyrhynchos, and one Cooper's hawk, Accipiter cooperii, in Connecticut. A portion of the genome of virus isolates from four different hosts was sequenced and analyzed by comparative phylogenetic analysis. Our isolates from Connecticut were similar to one another and most closely related to two WN isolates from Romania (2.8 and 3.6 percent difference). If established in North America, WN virus will likely have severe effects on human health and on the health of populations of birds.

Reporting of vancomycin-resistant enterococci in Connecticut: implementation and validation of a state-based surveillance system.

OBJECTIVE: To assess state-based surveillance for isolation from a sterile site of vancomycin-resistant enterococci (VRE) in Connecticut. DESIGN: Clinical laboratory reporting (passive surveillance) of VRE isolates to the Connecticut Department of Public Health (CDPH) was followed by state-initiated validation, laboratory proficiency testing, and review of hospital demographic characteristics. SETTINGS: All 45 clinical laboratories and all 37 (36 for 1995 and 1996) acute-care hospitals in Connecticut were included in the study. MAIN OUTCOME MEASURES: The outcome measures included determination of the statewide incidence of VRE and the accuracy of passive reporting, determination of clinical laboratory proficiency in detecting VRE, and analysis of hospital characteristics that might be associated with an increased incidence of VRE. RESULTS: During 1994 through 1996, 29 (78%) of 37 hospital-affiliated clinical laboratories and 1 (11%) of 9 commercial or other laboratories in Connecticut reported to the CDPH the isolation of VRE from sterile sites; 158 isolates were reported for these 3 years. Based on verification, we discovered that these laboratories actually detected 58 VRE isolates in 1994, 104 in 1995, and 104 in 1996 (total, 266). The age-standardized incidence rate of VRE was 14.1 cases per million population in 1994 and 26.8 cases per million population for both 1995 and 1996. Laboratory proficiency testing revealed that high-level vancomycin resistance was identified accurately and that low- and moderate-level resistance was not detected. The incidence of VRE isolates was three times greater in hospitals with over 300 beds compared with categories of hospitals with fewer beds. Increases in the number of VRE isolates were at least twice as likely in hospitals located in areas with a higher population density, or with a residency program or trauma center in the hospital. CONCLUSIONS: Passive reporting of VRE isolates from sterile sites markedly underestimated the actual number of iso lates, as determined in a statewide reporting system. Statewide passive surveillance systems for routine or emerging pathogens must be validated and laboratory proficiency ensured if results are to be accurate and substantial underreporting is to be corrected.

Lack of support for a common etiology in Johne's disease of animals and Crohn's disease in humans.

The superficial similarity of Johne's disease to Crohn's disease led to the hypothesis that, like the former. Crohn's disease was caused by Mycobacterium paratuberculosis. Detailed pathologic comparisons, however, reveal little similarity between these two entities, including the lack of important extraintestinal manifestations. Attempts to recover M. paratuberculosis by culture have only rarely succeeded and the significance of spheroplasts that appear more frequently on culture is seriously in question. Five immunocytochemistry studies have failed to find mycobacterial antigens in diseased tissues and the five most recent polymerase chain reaction (PCR) attempts to find genomic evidence of M. paratuberculosis were uniformly negative. Numerous serologic studies failed to demonstrate antibody to M. paratuberculosis and attempts to show cell-mediated immunity were also unrewarding. Inoculation of numerous experimental animals with Crohn's disease tissue has failed to induce Johne's disease, and inoculation of various animal species with M. paratuberculosis has equally failed to result in Crohn's disease. Controlled studies of the treatment of Crohn's disease with antimycobacterial agents have generally resulted in no improvement, and most studies that have shown a positive response are either uncontrolled or include broad-spectrum antibiotics that may be acting on pathogens other than mycobacteria. Finally, although Johne's disease is common in farm animals, and infected animals shed M. paratuberculosis in large numbers, no record of zoonotic transmission has been recorded.

Molecular characterization of the myxosporean associated with parasitic encephalitis of farmed Atlantic salmon Salmo salar in Ireland.

During seasonal epizootics of neurologic disease and mass mortality in the summers of 1992, 1993 and 1994 on a sea-farm in Ireland, Atlantic salmon Salmo salar smolts suffered from encephalitis associated with infection by a neurotropic parasite. Based on ultrastructural studies, this neurotropic parasite was identified as an intercellular presporogonic multicellular developmental stage of a histozoic myxosporean, possibly a Myxobolus species. In order to generate sequence data for phylogenetic comparisons to substantiate the present morphological identification of this myxosporean in the absence of detectable sporogony, polymerase chain reaction (PCR), Southern blot hybridization, dideoxynucleotide chain-termination DNA sequencing, and in situ hybridization (ISH) were used in concert to characterize segments of the small subunit ribosomal RNA (SSU rRNA) gene. Oligonucleotide primers were created from sequences of the SSU rRNA gene of M. cerebralis and were employed in PCR experiments using DNA extracted from formalin-fixed paraffin-embedded tissue sections of brains from Atlantic salmon smolts in which the myxosporean had been detected by light microscopy. Five segments of the SSU rRNA gene of the myxosporean, ranging in length from 187 to 287 base pairs, were amplified, detected by hybridization with sequence-specific probes, and sequenced. Consensus sequences from these segments were aligned to create a partial sequence of the SSU rRNA gene of the myxosporean. Assessments of sequence identity were made between this partial sequence and sequences of SSU rRNA genes from 7 myxosporeans, including Ceratomyxa shasta, Henneguya doori, M. arcticus, M. cerebralis, M. insidiosus, M. neurobius, and M. squamalis. The partial SSU rRNA gene sequence from the myxosporean had more sequence identity with SSU rRNA gene sequences from neurotropic and myotropic species of Myxobolus than to those from epitheliotropic species of Myxobolus or Henneguya, or the enterotropic species of Ceratomyxa, and was identical to regions of the SSU rRNA gene of M. cerebralis. Digoxigenin-labeled oligonucleotide DNA probes complementary to multiple segments of the SSU rRNA gene of M. cerebralis hybridized with DNA of the parasite in histologic sections of brain in ISH experiments, demonstrating definitively that the segments of genome amplified were from the organisms identified by histology and ultrastructural analysis. Based on sequence data derived entirely from genetic material of extrasporogonic stages, the SSU rDNA sequence identity discovered in this study supports the hypothesis that the myxosporean associated with encephalitis of farmed Atlantic salmon smolts is a neurotropic species of the genus Myxobolus, with sequences identical to those of M. cerebralis.