M Desmidt

Ghent University, Gent, VLG, Belgium

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Publications (21)34.13 Total impact

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    ABSTRACT: This paper describes a case of mucormycosis combined with chlamydiosis in an African grey parrot (Psittacus erithacus erithacus). The clinical signs included diarrhoea, an unsteady gait and a twisted neck. Smears of the spleen, liver and contents of the cloaca stained strongly positive for Chlamydia species. Histologically, hyphae typical of Zygomycetes were observed invading through the walls of blood vessels of the spleen. Rhizomucor pusillus was isolated as a pure culture from the intestines, lungs and liver.
    The Veterinary record 11/1998; 143(16):447-8. · 1.80 Impact Factor
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    ABSTRACT: The role of avian humoral immunity in the clearance of S. enteritidis was evaluated through bursectomy. After oral inoculation of bursectomized and sham-treated chickens with S. enteritidis, faecal excretion of S. enteritidis was examined. Organs were collected weekly until six weeks post-inoculation (pi) for bacteriological enumeration. Antibody isotypes in serum and bile were quantified by ELISA. Faecal excretion of S. enteritidis was significantly lower in controls from 13 days pi. Numbers of S. enteritidis in caeca from controls were significantly decreased from three weeks pi. Numbers of S. enteritidis were significantly decreased at two weeks pi in the spleen and the liver and at six weeks pi in the liver. Antibodies to S. enteritidis peaked at two weeks pi in controls and were absent in bursectomized chickens. These findings indicate that elimination of S. enteritidis partly depends on humoral immunity. The intestinal humoral response appeared more effective than the systemic humoral response for elimination of S. enteritidis.
    Veterinary Immunology and Immunopathology 07/1998; 63(4):355-67. · 1.88 Impact Factor
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    ABSTRACT: Over the past 3 years the frequency of Salmonella hadar infections has increased in Belgium in both poultry and humans. Therefore, the course of infection with S. hadar in poultry was investigated. One day-old and 4 week-old specific pathogen-free chickens were orally infected with one of two S. hadar strains, SH1 or SH2. Mortality was 6% (SH1) and 17% (SH2) in birds infected at 1 day-old. Chickens infected at 1 day-old with SH2 showed a mild diarrhoea. The S. hadar faecal excretion in birds infected at 1 day-old remained high throughout the experiment until 12 weeks post-inoculation (pi). Faecal excretion was lower in older birds. Antibodies to S. hadar were observed from 2 weeks pi (SH2, infected at 1 day-old) or 4 weeks pi (SH1, both groups; SH2, chickens infected at 4 weeks of age). The percentage of chickens with antibodies was higher after infection at 1 day-old than after infection at 4 weeks of age. In a second experiment 1 day-old chicks were infected with SH1 and autopsied at regular intervals until 42 days pi. SH1 was isolated from the caeca from 3 h pi onwards and from the liver and spleen from 18 h until 14 days pi. Serous typhlitis and omphalitis were the main lesions. The number of macrophages in the lamina propria of the caecal tonsils was slightly increased from 18 h until 2 weeks pi. In the liver, inflammation was observed in the portal triads and in the sinusoids. This study indicates that infections with S. hadar lead to intense colonisation of the gut and extensive faecal shedding. It may also cause invasive infections in 1 day-old chickens.
    Veterinary Microbiology 03/1998; 60(2-4):259-69. · 3.13 Impact Factor
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    ABSTRACT: One-day-old specific-pathogen-free White Leghorn chicks were inoculated orally with Salmonella enteritidis phage type 4 to study adhesion and invasion of the ceca by immunohistochemistry. Positive staining bacilli were associated with the epithelial surface and were present in the lumen of the cecal crypts. They were observed in the interstitial tissue and in the cytoplasm of macrophage-like cells in the lamina propria. A granulomatous nodule containing positive staining bacilli was present in the submucosa of the cecum of one bird at 14 d after inoculation.
    Poultry Science 02/1998; 77(1):73-4. · 1.52 Impact Factor
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    ABSTRACT: Monocytes from 10 week-old specific pathogen-free turkeys were isolated from peripheral blood by density centrifugation and assayed for their oxidative activity by means of a luminometer. Chemiluminescence (CL) properties after stimulation with different soluble and particulate stimuli were compared in lucigenin- and luminol-enhanced assays. A distinct response could be measured with 12-phorbol 13-myristate acetate (PMA) and Zymosan A, but only a weak signal was obtained with calcium ionophore A23187. No oxidative activity could be induced with N-formyl-methionyl-phenylalanine. Peak maxima for both lucigenin- and luminol-enhanced CL were ranked: PMA > Zymosan A > calcium ionophore. The velocity of the lucigenin- and luminol-enhanced responses induced by calcium ionophore were of similar magnitude, but the lucigenin-enhanced responses of Zymosan A and PMA-stimulated monocytes were respectively about 5 and 10 times higher than those obtained in luminol-enhanced assays. No peroxidase activity could be detected in the purified turkey monocytes. As luminol-enhanced CL primarily results from the peroxidase activity, this lack of myeloperoxidase may explain the observed lower responses to the different stimuli, in the presence of a luminol. In contrast, lucigenin-enhanced CL is not related to peroxidase activity, but is a selective probe of oxidase activity. Irrespective of the myeloperoxidase deficiency, different soluble and particulate stimuli induced a significant and reproducible CL response in turkey monocytes, in the presence of both chemiluminigenic probes, lucigenin and luminol. The possibility of measuring the phagocyte oxygenation activity of turkey monocytes represents a useful tool for the study of monocyte mediated host defence in the turkey.
    Journal of Bioluminescence and Chemiluminescence 07/1997; 12(4):207-14.
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    ABSTRACT: White leghorn specific-pathogen-free chickens were inoculated orally with Salmonella enteritidis phage type 4 at the age of one day (group 1) and four weeks (group 2). From 3 h until 4 weeks post inoculation (pi), birds were sacrificed. Gross lesions were recorded and different sites of the intestine and visceral organs were collected for bacteriological and histopathological examination. Clinical disease and mortality were only observed in group 1. Mortality was 8%. The birds were depressed, had diarrhoea and an indurated yolk sac. Infection of the liver and the heart was present within 12 h pi in both groups. The percentage of infected organs was very high and similar in both groups during the first week pi. Thereafter the isolation rate of Salmonella was declining faster in group 2. The crop, the proventriculus, the lower intestinal tract and the bursa of Fabricius were the predilective sites of isolation in both groups. Most prevalent lesions were serous typhlitis, omphalitis and polyserositis. Histopathology revealed inflammation in the intestines and visceral organs. In some birds granulomatous nodules were present in the caeca. Antibodies were detected from 18 and 5 days pi in group 1 and 2, respectively. Granulomatous nodules were typical of infection with this strain of S. enteritidis phage type 4. These granulomatous nodules together with the retained yolk sac possibly are a source of Salmonella organisms that may account for intermittent faecal shedding by carrier birds.
    Veterinary Microbiology 06/1997; 56(1-2):99-109. · 3.13 Impact Factor
  • Veterinary Microbiology - VET MICROBIOL. 01/1997; 56:99-109.
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    ABSTRACT: Luminol- and lucigenin-dependent chemiluminescence (CL) was used to compare activation of the respiratory burst of chicken peripheral blood monocytes and heterophils after stimulation with various agents. Monocytes and heterophils were obtained from the blood of three specific-pathogen-free chickens at 14 months of age and purified by a two-step discontinuous Percoll gradient. All cells responded to phorbol 12-myristate 13-acetate (PMA), zymosan A and calcium ionophore A23187 producing CL. The time course of luminol- and lucigenin-dependent CL was similar for both monocytes and heterophils after stimulation with PMA or zymosan A. Heterophils at lower cell number than monocytes responded with similar or higher peak maximum (PM) values. At the concentrations of stimuli used, the order of mean PM values was: zymosan A > PMA > A23187. Addition of 4 x 10(-6) M N-formyl-1-L-methionyl-L-leucyl-L-phenylalanine (fMLP) showed weak but significant CL activity at 1 x 10(6) monocytes per tube with luminol and at 5 x 10(6) monocytes per tube with lucigenin. No significant response to fMLP was observed with heterophils. The results indicate that the respiratory burst of chicken monocytes and heterophils can be measured by CL.
    Veterinary Immunology and Immunopathology 10/1996; 53(3-4):303-11. · 1.88 Impact Factor
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    ABSTRACT: A collaborative exercise, supervised by the World Health Organisation, was set up to compare ELISAs used for the serological detection of Salmonella enteritica serotype Enteritidis in chickens. The aim was to ascertain how far agreement could be reached on the interpretation of optical density readings for high titre, intermediate titre and low titre sera. Two sets of sera were sent to 14 participants. The first set compared high, medium and low titre sera raised in specified-pathogen-free and commercial broiler breeder chickens. The second set comprised 20 sera of different antibody titres raised in commercial birds reared under laboratory conditions and sent blind. Both indirect and double-antibody sandwich blocking ELISAs were used with a number of different detecting antigens. With a few exceptions good agreement was reached on the interpretation of results obtained from high and low titre sera from the optical density obtained with a single serum dilution. Differences were observed in the interpretation of medium titre sera. The results suggested that most ELISAs produce reasonably comparable results and that practical problems may arise from interpretation of the results mainly as a result of the choice of the criteria used for differentiating sera obtained from infected and uninfected chickens. These problems are discussed.
    Epidemiology and Infection 09/1996; 117(1):69-77. · 2.87 Impact Factor
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    ABSTRACT: An indirect enzyme-linked immunosorbent assay (ELISA) based on the lipopolysaccharide (LPS) of Salmonella enteritidis phage type 4, was developed for the detection of antibodies to salmonella. Sera and yolks from chickens infected experimentally with S enteritidis showed strong positive reactions. Cross-reactions occurred with sera from chickens inoculated with S typhimurium or S gallinarum. Cross-reactions were weak with sera from chickens infected with five strains of other Enterobacteriaceae. The ELISA was tested with sera and yolks from commercial poultry flocks which were bacteriologically negative for salmonella or infected with salmonella serotypes belonging to serogroup D or to other serogroups. The serological reactions were strong in most flocks infected with S enteritidis and were weaker in flocks infected with S typhimurium. In some flocks infected with these serotypes no antibodies were detected. The correct setting of the cut-off value of the optical density in the ELISA makes it possible to discriminate between chickens which are infected with S enteritidis and chickens which are not infected with S enteritidis.
    The Veterinary record 04/1996; 138(10):223-6. · 1.80 Impact Factor
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    ABSTRACT: Cases of Enterococcus hirae septicaemia are described in 10 different species of psittacine birds. In most of the cases other disease causes were not detected, and cytological examination confirmed the aetiological role of the bacteria isolated. Despite these findings, attempts to reproduce the disease in young budgerigars failed. The bacterium was isolated frequently from the faeces of healthy psittacine birds belonging to a wide range of species, and appeared to be member of the normal intestinal flora of these birds. The bacteriological diagnosis of E. hirae, and especially its differentiation from Enterococcus durons, is discussed.
    Avian Pathology 09/1995; 24(3):523-31. · 1.73 Impact Factor
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    ABSTRACT: Four cases of Streptococcus suis infection were diagnosed in psittacine birds and four others in zebrafinches, bullfinches, canaries and a duck. The main clinical and pathological manifestation was septicaemia with multiple sudden deaths in nestlings, young and adults. Other cases were solitary, with evidence for secondary involvement of S. suis. Four serotypable strains all belonged to serotype 9.
    Avian Pathology 01/1995; 23(4):721-4. · 1.73 Impact Factor
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    ABSTRACT: An enzyme-linked immunosorbent assay (ELISA), using the Salmonella-Tek ELISA test system, was compared with bacteriological isolation for detection of Salmonella enteritidis phage type 4 in litter and cloacal swabs of poultry. Before ELISA, samples were enriched in tetrathionate broth for 18-24 h or in tetrathionate broth (18-24 h), followed by M-broth/novobiocine (4-6 h). The bacteriological isolation procedure included incubation in buffered peptone water and inoculation on modified semisolid Rappaport-Vassiliadis. For detection of S. enteritidis in litter samples, ELISA was more sensitive than bacteriological examination. For cloacal swabs, both techniques were equally sensitive. The two enrichment procedures gave no significant differences in ELISA results. It was concluded that the Salmonella-Tek ELISA test might be a promising test for detection of Salmonella infected poultry flocks, providing that further studies are performed to determine the cut-off value for litter and cloacal swabs of commercial flocks.
    Zentralblatt für Veterinärmedizin. Reihe B. Journal of veterinary medicine. Series B 11/1994; 41(7-8):523-8.
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    ABSTRACT: Staphylococcus aureus was isolated from six cases of bacterial infection in canaries, Staphylococcus hyicus from three and Staphylococcus intermedius from one case. Staphylococcus aureus was most often involved in outbreaks of septicaemia, with or without 'Megabacterium' proventriculitis. The other coccal species were mainly complicating disease caused by Atoxoplasma (Lankesterella), Chlamydia psittaci and canary pox.
    Avian Pathology 04/1994; 23(1):159-62. · 1.73 Impact Factor
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    ABSTRACT: A central axonopathy in 2 male and 1 female Scottish Terrier puppies from 3 different but related litters is reported. Clinical signs consisting of severe whole-body tremors and ataxia were first detected at the age of 10 to 12 weeks. They worsened with activity and excitement and diminished during rest or sleep. Two dogs also had paraparesis. In 1 dog the neurological deficits progressed over several months. Neuropathological examination revealed widespread axonal changes, vacuolation, and gliosis in the white matter of the central nervous system.
    Journal of Veterinary Internal Medicine 01/1994; 8(4):290-2. · 2.06 Impact Factor
  • The Veterinary record 04/1993; 132(11):283. · 1.80 Impact Factor
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    ABSTRACT: Thirty pigeons were experimentally infected with Streptococcus bovis using an intravenous infection model. Ninety percent of the inoculated pigeons developed clinical disease. Disease signs included acute death, inability to fly, lameness, inappetence, emaciation, polyuria, and the production of slimy, green droppings. At necropsy, the septicemic character of the disease was evident. Typical lesions included extensive well-circumscribed areas of necrosis in the pectoral muscle, tenosynovitis of the tendon of the Musculus pectoralis profundus, and arthritis of the stifle, tibiotarsal, or shoulder joints. Focal myocardial necrosis also was seen. Meningitis and encephalitis occurred in the cerebrum and the cerebellum. Disease signs and lesions described here after experimental infection were similar to those in naturally occurring cases of S. bovis septicemia.
    Avian Diseases 10/1992; 36(4):916-25. · 1.73 Impact Factor
  • The Veterinary record 07/1992; 130(25):558-9. · 1.80 Impact Factor
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    ABSTRACT: Intranuclear inclusions were observed under light microscopy in the bronchial epithelial cells of a recently purchased female rose-ringed parakeet that died of chlamydiosis. Transmission electron microscopy revealed the presence of numerous particles of adenovirus morphology. A latent adenovirus infection may have become more severe following chlamydiosis and the stress of handling.
    Avian Diseases 10/1991; 35(4):1001-6. · 1.73 Impact Factor
  • The Veterinary record 07/1991; 128(22):524-5. · 1.80 Impact Factor