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1.
Rettigner C Lasri S De Meerschman F Focant C Beckers JF Losson B 《Veterinary parasitology》2004,122(4):261-271
The cellular and humoral responses as well as the antigen recognition during the acute stage of a Neospora caninum (NC) infection were investigated in non-pregnant ewes. The experimentally infected ewes developed specific lymphoproliferative and humoral responses within 2 weeks post-infection (PI). The magnitude of the cellular response showed large variations between animals. A significant decrease in the proliferative response to Con A mitogen and N. caninum, Toxoplasma gondii (TG) antigens was recorded on day 21 post-infection (PI). The humoral response and the pattern of antigen recognition were similar among infected ewes. Proteins of 44, 42, 40, 39 and 28 kDa were intensively recognized by the infected animals during the experiment. The 42 and 28 kDa antigens should be considered as useful for the diagnostic of N. caninum infection, as the intensity of recognition infection of the other antigens had decreased markedly 8 weeks post-infection. For some antigens a sequential recognition was recorded. The 59, 54 and 38-37 kDa proteins were frequently recognized by infected sera during the first weeks of the infection, but recognition of these antigens was absent or rare at the end of the experiment. These antigens could be related to the acute stage of the infection. 相似文献
2.
Mohammad Monirul Islam Eef Meerschman Timothy Saey Philippe De Smedt Ellen Van De Vijver Marc Van Meirvenne 《Precision Agriculture》2012,13(3):384-392
Every growing season, paddy fields are kept both flooded and drained for a significant period of time. As a consequence, these
soils develop distinct physico-chemical characteristics. For practical reasons, these soils are mostly sampled under dry conditions,
but the question arises how representative the results are for the wet growing conditions. Therefore, the apparent electrical
conductivity (ECa) of a 1.4 ha alluvial paddy field located in the Brahmaputra floodplain of Bangladesh was measured in both dry and wet conditions
by a sensing system using the electromagnetic induction sensor EM38, which does not require physical contact with the soil,
and compared both surveys. Due to the smooth water surface under wet conditions which ensured increased stability of the sensing
platform, the results of the survey showed considerably reduced micro-scale variability of ECa. Furthermore, the wet survey results more reliably furnished soil-related information mainly due to the absence of soil moisture
dynamics. The differences between ECa under wet and dry conditions were attributed to differences in soil texture, mainly the sand content variation having considerable
effect on soil moisture differences when flooded following drainage. Accordingly, the largest differences between ECa under wet and dry conditions were found in those parts of the field with a large sand content. Hence, the conclusion was
that an ECa survey on flooded fields has an added value to precision soil management. 相似文献
3.
An enzyme-linked immunosorbent assay (ELISA) was developed in our laboratory and used to determine the seroprevalence of Neospora caninum in three different dog populations in Belgium: healthy dogs from cattle farms and urban dogs with or without various neurological disorders. The test was validated and compared with two other tests: an indirect fluorescent antibody test (IFAT) and a commercially available competitive enzyme-linked immunosorbent assay (C-ELISA). The study showed a good correlation between the IFAT and the ELISA developed. When the two tests were compared with the C-ELISA, moderate positive and negative agreement indices were observed. Using our ELISA and the IFAT techniques, a high prevalence was found in farm dogs. This result showed that the neurological symptoms are not usually associated with the Neospora infection. In conclusion, the ELISA developed in our laboratory could replace the IFAT for the screening of a large number of dogs' sera. 相似文献
4.
The present work compared inbred (CBA/Ca) and outbred (Swiss white) strains of mice for their capacity to cope with a Neospora caninum infection and to consistently produce tissue cysts. In each experiment Swiss white and CBA/Ca mice were given three different doses of NC-1 tachyzoites. Lymphoproliferative and humoral responses as well as cytokine production were evaluated eight weeks after infection (PI) whereas tissue cyst production and histopathology were assessed 4, 6 and 10 weeks PI in immunosuppressed mice. Tissue cysts were observed 10 weeks after infection only in CBA/Ca mice receiving the two highest inoculum doses. Furthermore this strain showed the highest specific lymphoproliferative response. A mixed cytokine response with elevated IFN-gamma and fairly low IL-4 and IL-10 secretion was recorded. In both strains, no lesions were observed in the tissues of infected mice. This study indicates that CBA/Ca female mice infected with 5 x 10(6) NC-1 tachyzoites represent a useful model for the study of specific maternal immune responses in pregnant animals. 相似文献
5.
E. Meerschman M. Van Meirvenne E. Van De Vijver P. De Smedt M. M. Islam T. Saey 《European Journal of Soil Science》2013,64(2):183-191
The commonly used variogram function is incapable of modelling complex spatial patterns associated with repetitive, connected or curvilinear features, because it is a two‐point statistic. Because this was strongly limiting to petroleum‐ and hydrogeologists, they developed multiple‐point geostatistics (MPG), an approach that replaces the variogram by a training image (TI). However, soil scientists also face complex spatial patterns and MPG might be of use to them as well. Therefore, this paper aims to introduce MPG to soil science and demonstrate its potential with a case study of polygonal subsoil patterns caused by Weichselian periglacial frost cracks in Belgium. A high‐resolution proximal soil sensing survey provided a reference image from which a continuous (655 sensor data) and a categorical (100 point observations) dataset were extracted. As a continuous TI, we used the geophysical data of another part of the field, and as categorical TI we used a classified photograph of an ice‐wedge network in Alaska. The resulting MPG maps reconstructed the polygonal patterns very well and corresponded closely to the reference image. Consequently, we identify MPG as a promising technique to map complex soil patterns and suggest that it should be added to the pedometrician's toolbox. 相似文献
6.
Chiers K Donné E Van Overbeke I Ducatelle R Haesebrouck F 《Veterinary microbiology》2002,85(4):343-352
Many farrow-to-finish herds are endemically infected with Actinobacillus pleuropneumoniae. In order to control the disease efficiently, a better knowledge of the ages at which pigs become infected is necessary. Furthermore, no information is available concerning the influence of maternally derived antibodies on the colonization of the upper respiratory tract. Therefore, A. pleuropneumoniae infection patterns were studied in five farrow-to-finish pig herds (A-E) with a history of pleuropneumonia. A longitudinal study was carried out in herds A and B. In these herds, piglets from sows carrying A. pleuropneumoniae in their noses or tonsils were sampled. Nasal and tonsillar swabs as well as sera, were collected from these animals at the age of 4, 8, 12, 16 (herds A and B) and 23 weeks (herd B). At these ages other pigs from the same sows were euthanized. The lungs were macroscopically examined and samples from nose, tonsils and lungs were collected at necropsy. A cross-sectional study was performed in herds C-E. In these herds nasal and tonsillar swabs, as well as sera, were taken from 10 animals of 4, 8, 12 and 16 weeks of age. Lung, nasal and tonsillar samples were tested for the presence of A. pleuropneumoniae by routine bacteriology and PCR with mixed bacterial cultures. The sera were examined for the presence of Apx toxin neutralizing antibodies. In herd A, A. pleuropneumoniae serotype 2 and 10 strains were isolated, whereas serotype 2, 3, 5b and 8 strains were demonstrated in herd B. In most herds, A. pleuropneumoniae was detected in mixed bacterial cultures of tonsillar and/or nasal samples by PCR from the age of 4 weeks onwards. Colonization of the lungs and development of lung lesions was observed in 12- and 16-week-old animals of herd A and 23-week-old animals of herd B. In most herds, high antibody titres were detected in 4-week-old piglets. These titres decreased during the first 12 weeks of age, but thereafter, increased. It was concluded that PCR with mixed bacterial cultures from tonsillar swabs is a valuable tool for the detection of infected animals. It was also concluded that colonization of tonsils and nasal mucosae can occur in the presence of maternally derived antibodies. Infection of the upper respiratory tract without lung involvement did not result in development of Apx toxin neutralizing antibodies. Therefore, such serological assays cannot be used for the detection of subclinically infected animals. 相似文献
7.
Mohammad Monirul Islam Timothy Saey Eef Meerschman Philippe De Smedt Fun Meeuws Ellen Van De Vijver Marc Van Meirvenne 《Agricultural Water Management》2011,102(1):8
Paddy rice fields are kept inundated during most of the growing period. This requirement is challenging to achieve because of the lack of suitable technologies to detect rapidly percolation prone zones within these fields. The objective of this study was to evaluate a methodology to identify water leakage areas to support precision soil–water management at a within-field level. Therefore, a Floating Sensing System (FloSSy) was designed to record the soil apparent electrical conductivity (ECa) of a paddy field both under dry and inundated conditions using the electromagnetic induction sensor EM38. Comparison of ECa data sets obtained under inundated and dry conditions showed that the ECa measurements under inundated condition (ECa-i) were more strongly related to soil properties due to the absence of variability in soil moisture and the increased stability of the floating sensing platform. Therefore, we proceeded with the ECa-i measurements and grouped them into two classes using a fuzzy k-means classification method. These classes showed significant differences in water infiltration: lower ECa values represented a higher infiltration rate and vice versa. This effect was attributed to differences in soil texture, more specifically the sand content, and its effect on water retention. It was concluded that an ECa-i survey with FloSSy allowed the detection of soil heterogeneity linked to downward water fluxes which has a potential to support precision soil–water management in inundated fields. 相似文献
8.
Chiers K Donné E Van Overbeke I Ducatelle R Haesebrouck F 《Veterinary microbiology》2002,88(4):385-392
Pigs, asymptomatically infected with Actinobacillus pleuropneumoniae in their upper respiratory tract, can transmit the infection. Detection of such animals is indispensable to prevent the intake of the disease in a herd. This study was conducted to evaluate bacteriology, polymerase chain reaction (PCR) and serology for the detection of subclinically infected pigs. Pigs were inoculated onto the tonsils with an A. pleuropneumoniae serotype 9 strain (n=12, group 1) or phosphate buffered saline solution (PBSS) (n=5, group 2). To prevent infection of the lungs, pigs of group 1 were treated three times with sodium ceftiofur as an aerosol. A third group (n=5) was inoculated intranasally with the same strain. All animals were euthanized 30 days post-inoculation (dpi). In pigs of group 1, clinical signs were not observed. A small lung lesion was found in only one pig and A. pleuropneumoniae was isolated from this lesion. The bacterium was not isolated from the lungs of animals that did not develop lung lesions. A. pleuropneumoniae was demonstrated in tonsils of 9/12 animals using bacteriological isolation, whereas it was demonstrated in mixed bacterial cultures from tonsils of all 12 animals by PCR. In non-infected animals (group 2), clinical signs were not observed and A. pleuropneumoniae was not demonstrated in any sample. All intranasally infected animals (group 3) developed disease signs and lung lesions. High antibody titers against ApxI, ApxII and heat-stable antigens were detected in animals that developed lung lesions. Antibody titers against these antigens were low or absent in all other pigs. It was concluded that pigs carrying A. pleuropneumoniae in the upper respiratory tract generally do not show measurable antibodies in serum. Therefore, sensitive methods for the detection of the etiological agent such as PCR are required to identify carrier animals, while serological methods are not suitable. 相似文献
9.
De Meerschman F Rettigner C Focant C Boreux R Pinset C Leclipteux T Losson B 《Veterinary research》2002,33(2):159-168
Neospora caninum and Toxoplasma gondii are cyst-forming coccidian parasites of human and veterinary clinical relevance. In vitro cultivation of the protozoans using Vero cells is usually performed in order to produce antigenic materials. Quantitative and qualitative comparisons of Vero cells grown in RPMI medium supplemented either with foetal calf serum (FCS), horse serum (HS) or a specific serum-free additive (DefCell) were performed. A serum-free cell culture system used to propagate N. caninum (NC-1 isolate) and T. gondii tachyzoites (Rh stain) were compared with the other two cell culture systems. FCS supplemented media was found to be more effective than the others in promoting Vero cells and N. caninum tachyzoites. However, it was found unable to support adequate T. gondii tachyzoite proliferation. Vero cells, T. gondii and N. caninum tachyzoite production gave similar growth patterns with either HS or DefCell supplemented media. Defcell was considered as a good alternative to supplement culture medium. 相似文献
10.
Mohammad Monirul Islam Liesbet Cockx Eef Meerschman Philippe De Smedt Fun Meeuws Marc Van Meirvenne 《Precision Agriculture》2011,12(6):850-859
Continuous paddy rice cultivation requires fields to be flooded most of the time limiting seriously the collection of detailed
soil information. So far, no appropriate soil sensor technology for identifying soil variability of flooded fields has been
reported. Therefore, the primary objective was the development of a sensing system that can float, acquire and process detailed
geo-referenced soil information within flooded fields. An additional objective was to determine whether the collected apparent
electrical conductivity (ECa) information could be used to support soil management at a within-field level. A floating sensing system (FloSSy) was built
to record ECa using the electromagnetic induction sensor EM38, which does not require physical contact with the soil. Its feasibility was
tested in an alluvial paddy field of 2.7 ha located in the Brahmaputra floodplain of Bangladesh. The high-resolution (1 × 1 m)
ECa data were classified into three classes using the fuzzy k-means classification method. The variation among the classes could be attributed to differences in subsoil (0.15–0.30 m below
soil surface) bulk density, with the smallest ECa values representing the lowest bulk density. This effect was attributed to differences in compaction of the plough pan due
to differential puddling. There was also a significant difference in rice yield among the ECa classes, with the smallest ECa values representing the lowest yield. It was concluded that the floating sensing system allowed the collection of relevant
soil information, opening potential for precision agriculture practices in flooded crop fields. 相似文献