Comparison of the complement-fixation and agar gel immunodiffusion tests for diagnosis of subclinical bovine paratuberculosis

The performance of the serum complement fixation (CF) test was compared with that of a serum agar gel immunodiffusion (AGID) test on 74 subclinically infected and 154 uninfected cattle in 6 commercial midwestern dairy herds with Mycobacterium paratuberculosis infection and on 30 cattle in a herd that was free of infection. Infection status of cattle within herds was established by performance of a series of 3 or more fecal cultures and of ileocecal lymph node cultures of culled cattle. In cattle with subclinical infection detected by culturing, the sensitivity estimates of the CF and AGID tests were 10.8% (3.6% SE) and 18.9% (4.5% SE), respectively. In the cattle classified as disease free, the specificity estimates of the CF and AGID tests were 97.4% (1.3% SE) and 99.4% (0.6% SE), respectively. Neither set of estimates was significantly different. Negative test results obtained with the use of either test in apparently normal cattle from suspect herds should be interpreted with caution because both tests suffer from low sensitivities in subclinically infected animals. However, the AGID test may be more useful in regulatory situations in which the CF test is currently used because the AGID test is easier to perform and to interpret.     

Epidemiology of feline leukaemia and feline immunodeficiency virus infections in the Czech Republic

Commercial serological sets were used for the examination of 727 cats kept in larger towns of the Czech Republic. FeLV antigen and antibodies to FIV were demonstrated in 96 (13.2%) and 42 (5.8%) of the animals, respectively. Seven (0.96%) animals were positive for both FeLV and FIV. Most of the FeLV and/or FIV positive patients were intact rambling males aged 1-4 years. Chronic gastrointestinal and respiratory diseases were found in 54.2% and 43.8% of the FeLV-positive patients, respectively. Chronic urinary tract diseases and generalized lymphadenopathy were found in 47.6% and 45.2% of the FIV-positive patients, respectively. The results of this first survey in the Czech Republic have shown prevalence values and clinical patterns similar to those reported formerly from other European countries.     

Presence of cervical vertebral malformation in Dobermann puppies and the effects of diet and growth rate

OBJECTIVE: To investigate the relationship between diet, growth rate and the presence of caudal cervical malformation in Doberman puppies. DESIGN: A prospective study of 15 Dobermann puppies from three unrelated litters, aged from 0 to 16 weeks. PROCEDURE: The growth rate in terms of body weight gain and increase in ulna length were measured weekly for all puppies. In addition the nutritional quality of the diets was assessed. Radiographs of the cervical spine were taken at 6 and between 12 and 16 weeks of age and examined for the presence of caudal cervical vertebral malformation. A mixed model for repeated measures data was used to investigate the relationship between the growth rate of the puppies and the fixed effects age, dam, diet, gender and presence of caudal cervical malformation. RESULTS: Five of the puppies had changes consistent with caudal cervical malformation. The diets fed were either balanced or transiently deficient in protein, calcium, phosphorus and/or magnesium. There was no significant association between growth rate and the variables dam, gender and the presence of caudal cervical vertebral malformation. There was no significant association between diet and increase in ulna length, but a trend existed between body weight gain and the feeding of a balanced diet (P = 0.0672). CONCLUSION: Caudal cervical vertebral changes can be detected radiographically as early as 6 weeks of age in some Dobermann puppies. A balanced diet and growth rate are not significant factors in its initial development.     

Mycobacterium paratuberculosis detection in bovine feces is improved by coupling agar culture enrichment to an IS900-specific polymerase chain reaction assay.

The feasibility of coupling an agar culture enrichment step with gene amplification (ACE-PCR) as a means to improve turnaround time and detect Mycobacterium paratuberculosis (Mpt) in the presence of contaminants was investigated. Fecal samples from 463 Pennsylvania dairy cows were cultured in duplicate sets. One replicate from each set was processed and interpreted according to standard culture (SC) protocol, whereas cultures from the second replicate were harvested at 6 weeks postinoculation; DNA extracts from the harvested material were evaluated by a polymerase chain reaction (PCR) test for the Mpt-specific IS900 gene. One hundred seventy-six of 463 culture sets were positive by either method. One hundred sixty-five of these (94%) were ACE-PCR positive, and 151 (86%) were positive by SC. Eleven SC-positive samples were ACE-PCR negative, and 9 ACE-PCR-positive samples were negative by SC; these discrepancies could be a consequence of a low organism burden (< or = 5 organisms/g) or slow growth rate of Mpt in cultures of these samples. One hundred thirty-nine of 463 culture sets (30%) were reported as inconclusive because of culture contamination according to SC protocol; 16 of these (11.5%) were ACE-PCR positive. Seventy-four ACE-PCR-positive sets (42% of all positives) were negative or inconclusive by SC at 6 weeks postinoculation. Agar culture enrichment prior to IS900 PCR testing significantly improves Mpt culture turnaround time and sensitivity.     

Laminectomy for 34 dogs with thoracolumbar intervertebral disc disease and loss of deep pain perception

The case details and the results of treatment of 34 dogs with thoracolumbar intervertebral disc disease, without deep pain perception, that had been treated by laminectomy and fenestration, are presented. The association of a number of potential prognostic factors with the neurological outcome is examined. Twenty-one dogs (62 per cent) recovered neurological function, seven (21 per cent) failed to recover neurological function and three (9 per cent) developed progressive myelomalacia postoperatively, while three dogs (9 per cent) were euthanized intraoperatively because of diffuse myelomalacia. Twenty of the dogs that recovered neurological function showed a return of deep pain perception within two weeks of decompressive surgery. Statistical analysis showed significant differences in the outcome between dogs that took less than one hour to lose the ability to ambulate and dogs with a longer duration of onset of inability to ambulate. The extent of spinal cord swelling determined by myelography was not found to be a useful prognostic indicator.     

Mesenchymal chondrosarcoma in a young German shepherd dog

An 18-month-old, entire male German shepherd dog was presented with signs indicative of a caudal abdominal space-occupying mass. A needle-core biopsy of this mass failed to establish a definitive diagnosis, but identified a prominent round-cell component. The dog's condition worsened and euthanasia was performed on humane grounds. Histopathology of the mass revealed a mesenchymal chondrosarcoma.     

Dynamics in the membrane organization of the mammalian sperm cell and functionality in fertilization

The capacitation process of sperm cells involves complex changes in the composition and orientation of molecules at the surface of the sperm cell. Here we focus on the lipid architecture in the sperm plasma membrane and demonstrate that the sperm plasma membrane is not static but is an extremely dynamic structure. Advanced fluoroscopic techniques enabled continuous monitoring of lipid organization in living cells and extremely rapid lipid movements were observed. The orientation of lipids in the sperm plasma membrane changed under capacitative treatments, was found to be sensitive for temperature and also changed upon binding of sperm cells to the zona pellucida. The changes in membrane properties coincided with an activation of protein kinases resulting in tyrosine phosphorylation of specific plasma membrane proteins. The detected membrane changes relate to intrinsic membrane properties such as fluidity, permeability, adhesiveness and fusibility. We think that these results may provide a physiological basis for new assays, able to discriminate between functional and non-physiological sperm cells.     

Attaching and effacing lesions in the large intestine of an eight-month-old heifer associated with Escherichia coli O26 infection in a group of animals with dysentery

Escherichia coli O26:K60, with genetic attributes consistent with a potentially human enterohaemorrhagic E. coli was isolated from the faeces of an eight-month-old heifer with dysentery. Attaching and effacing lesions were identified in the colon of a similarly affected heifer examined postmortem, and shown to be associated with E. coli O26 by specific immunolabelling.     

A new isolate of the nematophagous fungus Duddingtonia flagrans a biological control agent against free-living larvae of horse strongyles

An experiment was carried out in 1997 to test the efficacy of an isolate of the microfungus Duddingtonia flagrans against free-living stages of horse strongyles under conditions in the field and to assess the eventual effect of the fungus on the normal degradation of faeces. Faecal pats were made from faeces of a naturally strongyle infected horse, which had been fed fungal material at a dose level of 106 fungal unit/kg bwt. Control pats without fungi were made from faeces collected from the same animal just before being fed fungi. Faecal cultures set up for both groups of faeces to monitor the activity of the fungus under laboratory conditions showed that the fungus significantly reduced the number of infective third-stage larvae (L3) by an average of 98.4%. Five faecal pats from each batch of faeces were deposited on pasture plots at 3 times during spring-summer. The herbage around each pat was sampled fortnightly to recover L3 transmitted from faeces. The results showed that the herbage infectivity around fungus-treated pats was reduced by 85.8-99.4%. The remaining faecal material at the end of each sampling period was collected, and the surviving L3 were extracted. Significantly fewer larvae were recovered from the fungus-treated pats. Analysis of wet and dry weight of the collected pats, as well as their organic matter content, were performed to compare the degradation of faeces of both groups. The results indicated that the presence of the fungus did not alter the degradation of the faeces.