The role of rodents and shrews in the transmission of Toxoplasma gondii to pigs     

Kijlstra A  Meerburg B  Cornelissen J  De Craeye S  Vereijken P  Jongert E 《Veterinary parasitology》2008,156(3-4):183-190

Inadequate rodent control is considered to play a role in Toxoplasma gondii infection of pigs. This issue was addressed in the current study by combining a 4-month rodent control campaign and a 7-month longitudinal analysis of T. gondii seroprevalence in slaughter pigs. Three organic pig farms with known rodent infestation were included in the study. On these farms, presence of T. gondii in trapped rodents was evaluated by real-time PCR. All rodent species and shrews investigated had T. gondii DNA in brain or heart tissue. Prevalence was 10.3% in Rattus norvegicus, 6.5% in Mus musculus, 14.3% in Apodemus sylvaticus and 13.6% in Crocidura russula. Initial T. gondii seroprevalence in the slaughter pigs ranged between 8% and 17% and dropped on the three farms during the rodent control campaign to 0-10%, respectively. After 4 months of rodent control, T. gondii infection was absent from pigs from two of the three farms investigated and appeared again in one of those two farms after the rodent control campaign had stopped. This study emphasizes the role of rodents and shrews in the transmission of T. gondii to pigs and the importance of rodent control towards production of T. gondii-free pig meat.  相似文献   

Freely dissolved PCDD/F concentrations in the Frierfjord,Norway: comparing equilibrium passive sampling with “active” water sampling     

Gerard Cornelissen  Dag Broman  Kristoffer Næs 《Journal of Soils and Sediments》2010,10(2):162-171

Introduction  

Equilibrium passive samplers consisting of 55-μm polyoxymethylene (POM) and 170-μm polydimethylsiloxane were tested for the analysis of polychlorinated dibenzodioxin/furan (PCDD/F) in the pore water and overlying water of the Frierfjord, a bay in southern Norway. This fjord is heavily polluted with PCDD/Fs due to emissions from a former Mg smelter.  相似文献   

Immune responses in Eimeria acervulina infected one-day-old broilers compared to amount of Eimeria in the duodenum, measured by real-time PCR     

Swinkels WJ  Post J  Cornelissen JB  Engel B  Boersma WJ  Rebel JM 《Veterinary parasitology》2006,138(3-4):223-233

T-cell responses are supposed to be the major immune reactions in broilers infected with Eimeria. The nature of such T-cell responses is influenced by the species of Eimeria involved, age of the host, amount of parasites and the preceding infection history. In young chicks the intestine is still developing in length while the lymphocyte populations in the gut develop and differentiate. In chicks infected at young age the immune response may be different in quality as compared to responses in adults. We investigated the (T-cell) immune responses of young broilers to a primary Eimeria acervulina infection in relation to the number of parasites used for infection. In our experiment we infected one-day-old broilers with a low (5 x 10(2) oocysts) and a high (5 x 10(4) oocysts) dose of E. acervulina. We used a newly developed species specific real-time PCR to quantify total amount of parasites in the duodenum as the number of oocysts in faeces may not be representative for the exposure of the gut immune system. We characterized T-cell subsets in the duodenum by means of FACS-analyses, lymphocyte proliferation assays with spleen lymphocytes and the mRNA profiles of different cytokines (TGF-beta2, -4, IFN-gamma, IL-2, -6, -8 and -18) in the duodenum by means of real-time PCR. From day 5 p.i. broilers with a high dose of E. acervulina had a significantly lower body weight than the control group. No increase in CD4(+) cells, but a strong increase in CD8(+) cells was observed at days 7 and 9 p.i. in the duodenum of broilers infected with a high dose E. acervulina. IL-8 mRNA responses were observed after infection with low and with high infection doses, but no IFN-gamma and TGF-beta mRNA responses were found in the duodenum. The specific proliferative T-cell responses to a low infectious dose were not significantly different as compared to the control group. In conclusion, based on the kinetics of observed responses a primary infection with a high dose of E. acervulina in one-day-old broilers seems to generate an immune response that shows a peak at the time of oocyst excretion, whereas the immune response to a low dose is less explicit.  相似文献   

Bacterial host interaction of GFP‐labelled Vibrio anguillarum HI‐610 with gnotobiotic sea bass,Dicentrarchus labrax (L.), larvae     

A Rekecki  R A Y S A Gunasekara  K Dierckens  S Laureau  N Boon  H Favoreel  M Cornelissen  P Sorgeloos  R Ducatelle  P Bossier  W Van den Broeck 《Journal of fish diseases》2012,35(4):265-273

The location and cell damage caused by Vibrio anguillarum, the causative agent of classical vibriosis, within the developing gut of the newly hatched sea bass, Dicentrarchus labrax (L.), is unknown. A gnotobiotic sea bass model was used to investigate the early interactions of V. anguillarum with sea bass larvae. In the present study, germ‐free sea bass larvae were orally exposed to a V. anguillarum HI‐610 pathogen labelled with the green fluorescent protein (GFP‐HI‐610) and sampled at regular intervals. Pathogenic colonization of gut enterocytes was observed 2 h post‐exposure (p.e.) and onwards, whereas bacteria within the swim bladder were visualized 48 h p.e and onwards. Ultrastructural findings demonstrated direct bacterial contact with the host cell in the oesophageal mucosa and putative attachment to microvilli of mid‐ and hindgut enterocytes. The present findings form a starting point for studies assessing the impact of potential candidates (probiotics, prebiotics, antimicrobial peptides) to mitigate bacterial virulence.  相似文献   

Comparison of two methods for detection of transmissible gastroenteritis virus in feces of pigs with experimentally induced infection     

A P van Nieuwstadt  J B Cornelissen  T Zetstra 《American journal of veterinary research》1988,49(11):1836-1843

An indirect, double-antibody sandwich-type ELISA for detection of transmissible gastroenteritis virus (TGEV) was developed, using a solid phase of rabbit hyperimmune serum and a pool of 3 antipeplomer monoclonal antibodies to trap and to detect the virus, respectively. The technique was used to detect viral antigen in feces of pigs that had been infected with the virulent Miller strain, the attenuated Purdue strain, or the Erica strain (a Dutch field isolate) of TGEV. The results were compared with those of a solid-phase immunosorbent electron microscopy (SPIEM) technique for virus detection. Both techniques detected shedding of virulent virus in feces obtained from pigs on the first or second day after infection, and virus excretion continued for 6 to 8 consecutive days. Virus shedding started later in pigs infected with the attenuated Purdue strain of TGEV and lasted only 2 to 4 days. In comparison with the 2 virulent strains, infection with the attenuated strain appeared to be limited to a smaller portion of the small intestine. Of 242 fecal specimens that were tested by use of ELISA and SPIEM, 119 had positive results in both tests. Additionally, virus could be detected by ELISA in 21 and by SPIEM in 16 specimens. Fecal specimens obtained from pigs before infection always reacted negatively by ELISA for TGEV antigen; there was no cross-reactivity with fecal specimens containing porcine rotavirus or porcine epidemic diarrhea virus. The ELISA and SPIEM were found to be specific and sensitive for the detection of TGEV in feces.  相似文献   

Editorial     

Cornelissen AW 《The Veterinary quarterly》1993,15(2):41-42

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Observations on the endo- and ectoparasites affecting dogs and cats in Aboriginal communities in the north-west of Western Australia   总被引：1，自引：1，他引：0  

RCA THOMPSON  BP MELONI  RM HOPKINS  P DEPLAZES  JA REYNOLDSON 《Australian veterinary journal》1993,70(7):268-270

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The effects of landscape patterns on ecosystem services: meta-analyses of landscape services     

Gabriela Teixeira Duarte  Paloma Marques Santos  Tatiana Garabini Cornelissen  Milton Cezar Ribeiro  Adriano Pereira Paglia 《Landscape Ecology》2018,33(8):1247-1257

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Molecular breeding for virus resistant potato plants     

Marianne J. Huisman  Erik Jongedijk  Dinie Posthumus-Lutke Willink  Frank Van Der Wilk  Ben J. C. Cornelissen 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(Z2):29-36

To engineer resistance against potato virus X (PVX), the viral coat protein (CP) gene has been introduced into two potato cultivars. Stable expression of the gene in transgenic clones throughout the growing season has been obtained and resulted in considerably increased virus resistance. With varying frequencies depending on the original cultivar used, true-to-type PVX resistant transgenic clones have been obtained. Since deviant light sprout characteristics were invariably associated with aberrations in plant phenotype, they can be used in procedures to early screen for deviations. Furthermore, it has been possible to unequivocally discriminate between the original untransformed and independent transgenic cultivars. Although no relation has been found between the presence, if any, of the CP of potato virus Y (PVY) or potato leafroll virus (PLRV) in CP gene transgenic potato, appreciable levels of resistance to these viruses has been obtained. This suggests that the mechanism by which a viral CP gene in the potato genome evokes resistance, differs amongst various viruses.  相似文献   

Loss of Avirulence and Reduced Pathogenicity of a Gamma-Irradiated Mutant of Fusarium oxysporum f. sp. lycopersici     

Mes JJ  Wit R  Testerink CS  de Groot F  Haring MA  Cornelissen BJ 《Phytopathology》1999,89(12):1131-1137

ABSTRACT The tomato Fusarium resistance gene I-2 confers resistance to F. oxy-sporum f. sp. lycopersici race 2, which expresses the corresponding aviru-lence gene avrI-2. To elucidate the molecular basis of this gene-for-gene interaction, we initiated a search for the avrI-2 gene. Gamma irradiation mutagenesis, using (137)Cs, was performed to generate an avrI-2 mutant of F. oxysporum f. sp. lycopersici. To this end, a race 2 isolate was first transformed with a phleomycine resistance gene and a GUS marker gene in order to distinguish mutants from contaminating isolates. A total of 21,712 mutagenized colonies was tested for loss of avirulence on I-2-containing tomato seedlings. One mutant was selected that showed the expected loss of avirulence but, surprisingly, also showed reduced pathogenicity toward susceptible tomato plants. DNA analysis was subsequently used to visualize genomic changes in the mutant. Southern analysis on contour-clamped homogeneous electrophoretic field blots demonstrated a translocation of a 3.75-Mb chromosome in the mutant. Random amplified polymorphic DNA and amplified fragment length polymorphism analysis identified at least nine polymorphisms between the wild-type and mutant isolates. Most of these polymorphisms appeared as extra fragments in the mutant and contained repetitive DNA sequences.  相似文献