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The objectives of this study were to elucidate at which age tonsillar colonisation by Actinobacillus pleuropneumoniae occurs in pigs and relate this occurrence to the presence of colostral antibodies to A. pleuropneumoniae. The infection patterns were studied in an isolated cohort of pigs, which consisted of the offspring from five sows originating from a conventional pig herd. The sows were transferred to isolated research facilities before farrowing. A. pleuropneumoniae was detected on the tonsils of all sows. After a nursing period of 3 weeks, the pigs were weaned and reared isolated from other pigs until slaughter. The pigs were examined repeatedly for the presence of A. pleuropneumoniae on the tonsils and for antibodies to A. pleuropneumoniae using bacteriological and serological techniques, respectively.A. pleuropneumoniae was detected in the tonsils of one pig as early as 11 days after birth, showing that A. pleuropneumoniae can be transmitted from sow to offspring during a 3-week nursing period. The cumulative proportion of pigs carrying A. pleuropneumoniae in their tonsils increased significantly between the age of 4-12 weeks. This age period corresponded to the age at which the proportion of pigs with detectable levels of colostral antibodies to the different serotypes of A. pleuropneumoniae was declining. Since these two events take place in the same age period, we expect a possible biological association between the level of the passive immunity and the degree of tonsillar colonisation. The median duration of tonsillar colonisation was estimated to approximately 7-8 weeks. 相似文献
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Background
It has been shown that the prevalence of both clinical attachment loss (CAL) ≥1 mm and pocket probing depth (PPD) ≥4 mm is relatively high even in younger dogs, but also that only a minority of the dogs have such clinical signs of periodontal disease (PD) in more than a few teeth. Hence, a minority of dogs carry the major PD burden. These epidemiological features suggest that screening for PD in larger groups of dogs, allowing for rapid assessment of treatment planning, or for the selection of dogs with or without PD prior to be included in experimental trials, should be possible. CAL is the central variable in assessing PD extent and severity while PPD is the central variable used in treatment planning which make these two variables obvious in a screening protocol with the dual aim of disease identification and treatment planning. The main purpose of the present study in 98 laboratory Beagle dogs was to construct a fast, simple and accurate screening tool, which is highly sensitive for the identification of dogs with PD.Results
Examination of the maxillary P4, P3, P2, I1 and C would, in this population, result in the identification of 85.5% of all dogs and 96% of all teeth positive for CAL ≥1 mm, and 58.9% of all dogs and 82.1% of all teeth positive for PD ≥4 mm.Examination of tooth pairs, all C’s, maxillary I2, M2 and the mandibular P4 would, in this population result in identification of 92.9% of all dogs and 97.3% of all teeth positive for PD ≥4 mm, and 65.5% of all dogs and 83.2% of all teeth positive for CAL ≥1 mm. The results presented here only pertain to the present study population.Conclusions
This screening protocol is suitable for examination of larger groups of laboratory Beagle dogs for PD and our findings indicate that diseased dogs are identified with a high degree of sensitivity. Before this screening can be used in clinical practice, it has to be validated in breeds other than Beagle dogs and in populations with larger age variation. 相似文献3.
C. F. Ihler V. Rootwelt A. Heyeraas N. I. Dolvik 《Veterinary research communications》1995,19(6):487-494
The caecum and the adjacent 30 cm lengths of ileum and large colon of 201 horses from two different regions of Norway (Østlandet and Trøndelag) were examined for the presence ofAnoplocephala perfoliata. In all, 20% of the horses were infested with the cestode (27% in Østlandet and 7% in Trøndelag). The mean number of worms in infected horses from the two regions was 18 and 6, respectively.Information was obtained on the age, sex, breed, type of pasture and anthelmintic treatment after the grazing season for 183 of the 20 horses. The degree of infestation withA. perfoliata was not influenced by age, breed or sex. The odds ratio (confidence limits) for using permanent pastures that had been grazed by horses for at least the 5 last years in succession was 8.8 (3.2–24.4). There was a significantly higher prevalence ofA. perfoliata infestation in Østlandet (odds ratio 3.1 (1.1–9.1). The relatively low prevalence ofA. perfoliata infestation in Norwegian horses compared to the reported prevalences in other countries and the differences in the prevalence between Østlandet and Trøndelag are discussed. Gross pathological examination identified lesions such as mucosal thickening, hyperaemia and/or erosions. These lesions were found in all of the infected horses, compared with only 5% of the non-infected horses.Examination of faecal samples from 26 of the infected horses detected cestode eggs in only three cases. It was concluded that faecal examination is an inadequate method for the diagnosis ofA. perfoliata infestation. 相似文献
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Peer reviews of 84 organic farming grant applications from Sweden were analyzed to determine whether the reviewers’ affiliation to one of two types of agriculture (i.e., organic and conventional) influenced their reviews. Fifteen reviewers were divided into three groups: (1) scientists with experience in organic farming research; (2) scientists with no experience in organic farming research; and (3) users of organic farming research. The two groups of scientists assessed the societal relevance and scientific quality of the grant applications based on three criteria (i.e., presentation, methodology, qualifications), whereas the user group only assessed societal relevance. The analysis showed that the two groups of scientists provided very different reviews. Scientist reviewers with experience in organic farming research agreed more with the user group on research relevance than did scientist reviewers without such experience, and the assessment of relevance was closely correlated to the assessment of scientific quality within both scientific groups. As both scientific groups did not clearly distinguish between societal relevance and scientific quality, the idea of an objective science is challenged. The contextual values associated with the norms of good agriculture were not clearly distinguished from the constitutive values of science associated with the traditional norms of good science. This raises the question of whether organic and conventional grant applications should be mixed for review regardless of the reviewers. 相似文献
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Thomsen VT Nielsen SS Thakur A Jungersen G 《Veterinary immunology and immunopathology》2012,145(1-2):316-322
Vaccination of cattle against Mycobacterium avium subsp. paratuberculosis (MAP) provides partial protection by delayed shedding of MAP and reduced numbers of clinically affected animals. The duration of vaccine induced immune response is not known. The primary objective of this study was therefore to characterize the long-term effect of whole-cell based vaccination against MAP on the immune response. A secondary objective was to evaluate whether immunodiagnosis of MAP and Mycobacterium bovis infections is affected by MAP vaccination. Two studies were performed: (1) A retrospective longitudinal study including 895 vaccinated and 2526 non-vaccinated dairy cows in 9 Danish dairy herds aiming at characterizing the long-term antibody-response to vaccination; and (2) a cross-sectional study of responses in the IFN-γ assay carried out in 140 vaccinated animals in two herds to evaluate the effect of vaccination on the cell-mediated immune response and to evaluate a possible interference with the diagnosis of M. bovis infections. The results showed that 37% of samples from vaccinated animals and 5% of samples from non-vaccinated animals, respectively, were test positive in the milk antibody ELISA. The prevalence of antibody responses of the vaccinated animals was relatively constant from 2 to 6 years of age, but decreased in older animals. Among the 140 vaccinated animals 88% tested positive with the IFN-γ test to johnin PPD and 50% responded to PPDb with IFN-γ production above a similar cut-off. Although Denmark is free of M. bovis, two of the vaccinated animals responded with higher IFN-γ levels when cultured with PPDb compared to PPDa. In conclusion, immunization with whole-cell MAP vaccines elicits both humoral and cell-mediated immune reactions, which may interfere with surveillance and diagnosis of both MAP and M. bovis infections using currently available tests. 相似文献
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Appetite,metabolism and growth regulation in Atlantic salmon (Salmo salar L.) exposed to hypoxia at elevated seawater temperature 
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下载免费PDF全文 High temperature combined with low dissolved oxygen (DO) is one of the most challenging environmental conditions farmed fish experience; thus, understanding their impact on growth regulation is of relevance to cultured and wild populations. This study examines appetite‐ and growth‐regulating mechanisms in Atlantic salmon postsmolt exposed to either high (HO) or low oxygen (LO) at a suboptimally high temperature (17°C). Additionally, the effects of high (HE) and low (LE) dietary energy (DE) were examined. After a month of treatment, analyses of hormones, regulating appetite (ghrelin) and growth (growth hormone receptor ghr1 and insulin‐like growth factor IGF‐1), and free amino acids (FAA) were measured pre‐ and postprandially at ?4, ?2, 0, 2, 4 and 6 h. No preprandial ghrelin peaks were detected despite a significant reduction in feed intake and growth under hypoxia compared to normoxia. LO treatment also had an overall negative effect on survival compared to HO, while nutrient retention efficiency, FCR and plasma FAA concentrations were unaffected (P > 0.05). Feeding HE diet resulted in increased growth (+17%) and improved FCR (?14%) and energy retention efficiency (+26%) independent of DO. Plasma FAA concentrations were unaffected by LO treatment and DE (P > 0.05). Growth regulatory gene expressions possibly reflect an overall lower growth at a high temperature overriding the impacts of DO and DE. This study also indicates that optimal adaptation time to environmental conditions and feeding regime is crucial for establishing a regular hormonal appetite signalling that reflects real feeding anticipation in salmon. 相似文献
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Grøndahl-Hansen J Barfod K Klausen J Andresen LO Heegaard PM Sørensen V 《Veterinary microbiology》2003,96(1):41-51
The objective was to develop an enzyme-linked immunosorbent assay (ELISA) for simultaneous detection of antibodies against Actinobacillus pleuropneumoniae (Ap) serotypes 2, 6 and 12. The assay was designated MIX-ELISA. Lipopolysaccharide (LPS) from Ap serotypes 2, 6 and 12 was purified using hot phenol-water extraction followed by fractionation by size-exclusion chromatography. A mixture of fractions containing molecules with molecular weight above 50 kDa from all three serotypes was used as antigen. The MIX-ELISA was evaluated with sera from pigs experimentally infected with the serotypes 1, 2, 5b, 6, 7, 8, 10 and 12 of Ap biotype 1. In addition to reaction with sera from pigs inoculated with Ap serotypes 2, 6 and 12, reaction was observed with sera from pigs inoculated with serotype 8. Furthermore, the sensitivity and specificity of the test on a herd level were evaluated with sera from herds naturally infected with serotypes 2, 6 or 12 and with sera from herds free of infection with any Ap serotype of biotype 1. The ELISA showed a high herd sensitivity (0.98; 95% confidence interval: 0.89-1.00) and specificity (0.95; 0.88-0.99). The high diagnostic sensitivity and specificity of the assay indicate that screening of herds for Ap infection can be performed using this ELISA. Efficient serological surveillance can be achieved by using such mixed antigen ELISAs coated with size-selected LPS-antigens from the most prevalent serotypes. 相似文献