A decision-support system for Salmonella in broiler-chicken flocks     

Rose N  Mariani JP  Drouin P  Toux JY  Rose V  Colin P 《Preventive veterinary medicine》2003,59(1-2):27-42

We built a decision-support system to assess the risk of contamination of chicken-broiler flocks by Salmonella at the end of the rearing period. This system was developed from the survey data from 85 chicken-broiler flocks located in western France. First, we estimated the probability of contamination of the house by Salmonella before placement of day-old chicks via a cleansing inspection using a visual-inspection grid, a decontamination evaluation using count-plates, and risk factors for Salmonella persistence in the barn after cleansing and disinfection. Second, we estimated (using a logistic model) the probability of prevalent contamination of the flock by Salmonella at the end of the rearing period. Validation was carried out on 60 flocks selected from seven production companies in western France. The risk estimated by the model was compared to the Salmonella status of the flock (gold standard) assessed by samples taken from the environment of the broilers and analysed with classical bacteriological methods. The sensitivity was 97.8% and the specificity 64.3%.  相似文献   

3-methylindole induces transient olfactory mucosal injury in ponies     

Miller MA  Kottler SJ  Ramos-Vara JA  Johnson PJ  Ganjam VK  Evans TJ 《Veterinary pathology》2003,40(4):363-370

Response to 3-methylindole (3MI) varies among species. Mice recover from 3MI-induced bronchiolar epithelial injury but sustain persistent olfactory mucosal injury with scarring and epithelial metaplasia. In contrast, 3MI induces obliterative bronchiolitis in horses and ponies, but olfactory mucosal injury has not been reported. To evaluate the effect of 3MI on equine olfactory mucosa, ponies were dosed orally with 100 mg 3MI/kg (n = 9) or corn oil vehicle (n = 6). All ponies treated with 3MI developed obliterative bronchiolitis with mild olfactory injury. By 3 days after 3MI dosing, olfactory epithelium appeared disorganized with decreased and uneven surface height and scalloping of the basement membrane zone. Epithelial cells of Bowman's glands were hypertrophic. Proliferation of olfactory epithelium and Bowman's glands was supported by an increased mitotic index and positive immunohistochemical staining for proliferating cell nuclear antigen as compared with controls. The activity of 11beta-hydroxysteroid dehydrogenase, an olfactory mucosal cytosolic enzyme localized to sustentacular and Bowman's glandular epithelial cells, was concurrently decreased. By 9 days postdosing, olfactory mucosal lesions had lessened. Results indicate that 3MI transiently injures equine olfactory mucosa without the extensive necrosis, scarring, or metaplasia seen in murine olfactory mucosa or in equine bronchiolar epithelium.  相似文献   

Pathogenicity of Cryptosporidium parvum--evaluation of an animal infection model   总被引：6，自引：0，他引：6  

Enemark HL  Bille-Hansen V  Lind P  Heegaard PM  Vigre H  Ahrens P  Thamsborg SM 《Veterinary parasitology》2003,113(1):35-57

With the intention of developing a standardised method for assessment of pathogenicity of Cryptosporidium parvum, the CPB-0 isolate was studied by propagation in 1-day-old calves followed by inoculation into specific pathogen free (SPF) piglets. The experiment was repeated. Diarrhoea and shedding of oocysts were seen in all animals infected with the CPB-0 isolate. Clinical signs included depression, inappetence, vomiting (exclusively in the piglets), and death. Histological examination at 17 and 19 days post-infection revealed parasitic stages and microscopic changes primarily restricted to colon and rectum.The unintended presence of rotavirus in some of the experimental animals revealed an additive or synergistic effect between rotavirus and C. parvum as indicated by prolonged diarrhoea, increased oocyst shedding, decreased weight gain and elevated levels of serum haptoglobin and serum amyloid A (SAA) in piglets infected simultaneously with both pathogens. The difference in daily weight gain between infected and control animals was significant only for piglets co-infected with rotavirus. The acute phase response of haptoglobin and SAA was characterised by a large individual variation. In piglets, co-infected with rotavirus, the levels of serum haptoglobin were 3.5 and 4.6 times higher in the infected versus the controls 6 and 9dpi, respectively (mean values: 2411microg/ml+/-S.D. 2023 and 1840 microg/ml+/-S.D. 1697). In the controls infected with rotavirus, peak haptoglobin concentration was seen 3dpi (mean: 1022 microg/ml+/-S.D. 425). Elevated levels of SAA were seen in 1 of 6 piglets infected with C. parvum, and in 5 of 6 piglets co-infected with rotavirus. Tumour necrosis factor alpha (TNFalpha) was undetectable in all serum samples from piglets.The obvious advantages of the SPF pig model are the naturally acquired intestinal microflora, the development of distinct clinical signs similar to cryptosporidiosis in humans and calves, the size of the animals, and the accessibility of individuals born within a short time span. This makes the model ideal for dose-response studies, evaluation of therapeutic agents as well as for assessment of differences in the clinical response to isolates of diverse genetic background. In conclusion, it was shown that the CPB-0 isolate was pathogenic to calves and piglets at a dose of 2.5 x 10(5) oocysts, and that the clinical signs could be replicated during separate experiments. Moreover, diarrhoea, oocyst shedding, body weight changes, histological alterations, and the acute phase response of haptoglobin and SAA were identified as useful parameters for discrimination of isolate-specific differences of pathogenicity.  相似文献   

Lactating females Syrian hamster (Mesocricetus auratus) show protection against experimental Leishmania infantum infection     

Gomez-Ochoa P  Gascon FM  Lucientes J  Larraga V  Castillo JA 《Veterinary parasitology》2003,116(1):61-64

The Syrian hamster (Mesocricetus auratus) is the best animal model for human leishmaniosis, an emergent disease that causes 400,000 new cases every year. The main objective of this assay was to prove the relationship between female lactation, which implies hyperprolactinaemia (IFN-gamma, IL-12, IL-2 and TNF-alpha elevated), and leishmaniosis (IFN-gamma, IL-12, IL-2 and TNF-alpha diminished). The results demonstrate the clear implication of lactation in immune response. The infected lactating females did not show any symptoms of sickness, a 24 g mean increase was noticed, throughout the assay they were negative in the indirect diagnosis test (Direct Agglutination Test (DAT)), and in the direct diagnosis tests (N-N-N isolation, tissue impressions).  相似文献   

Effect of two thermal regimes on the muscle growth dynamics of sea bass larvae,Dicentrarchus labrax L     

Ayala MD  López Albors O  García Alcázar A  Abellán E  Latorre R  Vázquez JM  Ramírez Zarzosa G  Martínez F  Gil F 《Anatomia, histologia, embryologia》2003,32(5):271-275

Muscle growth was studied in larvae of sea bass, Dicentrarchus labrax L., reared at two temperatures: real ambient temperature ( congruent with 15 degrees C during vitelline phase and increased gradually) and 19 degrees C from fertilization until the end of larval development. Muscle cellularity, body length and body weight were measured. Early temperature influenced larval development and so, pre-larval phase finished earlier at 19 degrees C than at ambient temperature (4 and 6 days, respectively). Temperature also affected muscle growth such that at hatching and at mouth opening hypertrophy of muscle fibres was greater at 19 degrees C (P < 0.05), whereas hyperplasia was similar in both groups. After 25 days, the cross-sectional area of the white muscle was greater at 19 degrees C (P < 0.05), which was mainly associated with a higher proliferation of new white muscle fibres. At this stage the body length was also higher at 19 degrees C. Metamorphosis finished earlier in fish reared at 19 degrees C (52 days) than at natural temperature (82 days). At this developmental stage body length and cross-sectional area of the myotome were similar in both groups. However, muscle cellularity differed between groups. Thus, hypertrophy of muscle fibres was higher in fish reared at ambient temperature (P < 0.05), whereas proliferation of new muscle fibres was higher at 19 degrees C (P > 0.05).  相似文献   

Apoptosis and proliferation during seasonal testis regression in the brown hare (Lepus europaeus L.)     

Strbenc M  Fazarinc G  Bavdek SV  Pogacnik A 《Anatomia, histologia, embryologia》2003,32(1):48-53

Testes samples of 52 brown hares (Lepus europaeus L.), sacrificed between July and January, were subjected to immuno histochemical analysis. The terminal deoxynucleotidyl transferase-mediated d'UTP nick end labelling (TUNEL) method was applied to detect apoptosis; and antibodies to proliferating cell nuclear antigen (PCNA) were used to evaluate cell proliferation in the testes. In the seminiferous epithelium, the apoptotic processes were evident from August to early November with maximal values in September. Cell death in germ cells occurs predominantly during the prophase of the first meiotic division. In July, and from mid-November onwards, only the occasional TUNEL-positive cells can be seen. The proliferation of germ cells continues during the testis regression phase. The average number of PCNA-positive cells decreases slightly from September onwards and rises again in mid-November.  相似文献   

Strain specificity of the immune response of pigs following vaccination with various strains of porcine reproductive and respiratory syndrome virus   总被引：9，自引：0，他引：9  

Mengeling WL  Lager KM  Vorwald AC  Koehler KJ 《Veterinary microbiology》2003,93(1):13-24

The primary objective of the study was to determine strain specificity of the immune response of pigs following vaccination with selected strains of porcine reproductive and respiratory syndrome virus (PRRSV). The experimental design included five groups (I through V, six pigs per group) free of antibody for PRRSV at the beginning of the experiment (day 0). On day 0, groups III, IV, and V were vaccinated with attenuated versions of PRRSV strains 8, 9, and 14, respectively. On day 21, the immunity of group II (non-vaccinated/challenged controls) and groups III, IV, and V was challenged by exposing each pig to a composite of the virulent versions of these same three strains. On day 35, all pigs, including non-vaccinated/non-challenged pigs of group I, were necropsied. Lungs and selected lymph nodes were examined for lesions. Serum samples obtained at weekly intervals throughout the study and lung lavage fluids obtained at necropsy were tested for the presence of PRRSV and its strain identity. Before challenge the strain of PRRSV identified in the sera of vaccinated pigs was always that with which the particular pig had been vaccinated (i.e. homologous strain), whereas, with one exception, only heterologous strains were identified after challenge. This apparent strain exclusion as a result of vaccination was statistically significant (P = 0.004). The tendency for heterologous strains to predominate after challenge suggests that a pig's immune response to PRRSV has some degree of strain specificity. Whether this finding has any clinical relevance in regard to immunoprophylaxis remains to be determined.  相似文献   

Equine infectious anemia in mules: virus isolation and pathogenicity studies     

Spyrou V  Papanastassopoulou M  Psychas V  Billinis Ch  Koumbati M  Vlemmas J  Koptopoulos G 《Veterinary microbiology》2003,95(1-2):49-59

There appears to be a lack of information concerning responses of mules to natural infection or experimental inoculation with equine infectious anemia virus (EIAV). In the present study EIAV was isolated from mules, for the first time, and its pathogenicity in naturally infected and experimentally inoculated animals was investigated. Two naturally infected (A and B) and three EIAV free mules (C, D and E) were used for this purpose. Mule A developed clinical signs, whereas mule B remained asymptomatic until the end of the study. Mules C and D were each inoculated with 10ml of blood from mule A and developed signs of the disease; they were euthanatized or died at day 22 and 25 post-inoculation, respectively. Mule E served as a negative control. The virus was isolated from the plasma samples of mules with clinical signs of the disease (A, C and D), but not from the asymptomatic mule B. Both proviral DNA and viral RNA were amplified from blood and tissues of the infected animals by nested polymerase chain reaction (nPCR). Antibodies were not detected in the two experimentally infected mules until their natural death or euthanasia. Clinicopathological and laboratory findings showed that, in mules, EIAV produced clinical signs similar to those observed in horses and ponies. Nested PCR proved to be a rapid, sensitive and specific diagnostic method for the detection of EIAV, regardless of the disease stage.  相似文献   

Characterization of an avianpox virus isolated from an Andean condor (Vultur gryphus)     

Kim TJ  Schnitzlein WM  McAloose D  Pessier AP  Tripathy DN 《Veterinary microbiology》2003,96(3):237-246

A novel pox virus, condorpox virus (CPV) isolated from the spleen of an Andean condor (Vultur gryphus) by inoculation of chorioallantoic membranes (CAM) of specific pathogen free (SPF) chicken embryos was compared biologically, antigenically and genetically with fowlpox virus (FPV), the type species of the genus Avipoxvirus. Susceptible chickens inoculated with CPV developed only mild localized lesions but were not protected against subsequent challenge with FPV. Based on Western blotting, in addition to the presence of cross-reacting antigens, distinct differences in antigenic profiles of CPV and FPV were observed. Sequence analysis of a 4.5 kb HindIII fragment of CPV genomic DNA revealed the presence of eight co-linear genes corresponding to FPV open reading frame (ORF)193-198, 201 and 203. Interestingly, reticuloendotheliosis virus (REV) sequences present in the genome of all FPV were absent in CPV. Although, the results of a phylogenic analysis suggested that CPV is a member of the genus Avipoxvirus, its unique antigenic, biologic and genetic characteristics distinguish it from FPV to be considered as a new member of this genus.  相似文献   

Analytical sensitivity of assays used for detection of bovine viral diarrhea virus in semen samples from the Southeastern United States     

Givens MD  Heath AM  Carson RL  Brock KV  Edens MS  Wenzel JG  Stringfellow DA 《Veterinary microbiology》2003,96(2):145-155

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