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21.
A total of 595 faecal samples from raptorial birds, either captive or free‐living, residing in GREFA Wildlife Hospital were bacteriologically examined using various selective media and an Automated Diagnostic Assay System for Salmonella detection. Serotype and phage type of the strains identified as Salmonella was determined. In the captive group, of the 285 samples examined, 21 (7.36%) were positive for Salmonella. Serotyping revealed that most of the individuals were infected by Salmonella serotype Havana. This result suggested that there could be a source of contamination in the Hospital although it could not be established. In the wild free‐living group, over 310 samples examined (4.19%) were positive for Salmonella. The Salmonella isolates showed a major variety of serotypes: Enteritidis, Adelaide, Brandenburg, Newport, Typhimurium, Hadar, Saintpaul and Virchow. Most of them are similar to those commonly described in isolates from human and domestic animals. These results indicate that wild birds could be involved in the dissemination of Salmonella in humans or domestic animals or vice versa.  相似文献   
22.
Landscape-ecological mapping of the Netherlands   总被引:1,自引:0,他引:1  
The Landscape-ecological Mapping of the Netherlands project (LMN project) started in 1983 with the aim of establishing a landscape-ecological database for use in developing and evaluating national land-use plans. The project, working with grid cells of 1 km2, has four working objectives: a) development of mapping potential for basic landscape-ecological data, b) assessment of susceptibility to interventions, c) evaluation of significance for nature conservation and d) production of vulnerability maps, as a combination of susceptibility and significance. In addition to information on soil, groundwater, ecotopes, flora and fauna, the database also incorporates information on physiographical features and entire landscapes. The resulting database is a geographic information system (GIS). This article describes the second phase of the project (1985–1989), covering the Randstad area, and focusses on the methods and the applications potential of the database.  相似文献   
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Based on a simple model, the possible effects of certification of planting material on the occurrence of leek rust in a region can be derived from information on the proportion of infected fields (v) and the proportion of newly planted fields with infected planting material (i) in that region. Ifv i, certification of planting material will be highly effective.  相似文献   
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Summary An enzyme-linked immunosorbent assay (ELISA) is presented for the detection of the K99 antigen of Escherichia coli in calf faeces. False-positive reactions were not observed with K99-negative strains and with several viral antigens. Only bovine coronavirus caused slight positive reactions which could be eliminated by a blocking test. As compared with the conventional procedure for the detection of the K99 antigen, ELISA seemed to be at least as sensitive and had the advantage that samples could be stored at -20° C before testing. In addition many samples could be handled at the same time and the results became available quickly. By carrying out the assay as a blocking test, specific antibody against K99 in serum or colostrum could be detected and titrated.  相似文献   
26.
Summary The prevalence of antibodies to various viruses was investigated in a series of serum samples collected from horses in the Netherlands between 1963 and 1966 and from 1972 onwards. Neutralizing antibodies to equine rhinopneumonitis virus, equine arteritis virus and to equine rhinovirus types 1 and 2 were detected in respectively 76%, 14%, 66% and 59% of the equine serum samples tested. The observed incidence of serum samples positive to equine adenovirus in the complement fixation test was 39%. Precipitating antibodies to equine infectious anaemia virus were detected only in serum samples from two horses imported from abroad. Haemagglutination inhibiting antibodies to Myxovirus influenzae A / equi-1, M. Influenzae A / equi-2, and Reovirus types 1, 2, and 3 were present in respectively 82%, 50%, 10%, 33% and 3.6% of the serum samples tested. The most frequently observed incidence of antibodies to the various equine respiratory viruses occurred in the groups of horses having repeatedly contact with other horses.  相似文献   
27.
A mouse model system was used to study various aspects of host and parasite relationships in Trypanosoma vivax infections. These included the phenomenon of antigenic variation, the variable parasite antigens responsible for this phenomenon, parasite-host adaption, host immune responses and the role of genes in the major histocompatibility complex in the control of infection. While the mouse model system has allowed investigation of these aspects of host parasite relationships, it is clear that the system is much more limited than those generally used in T. brucei spp and T. congolense infections. This is indicated by the discovery that not all VATs of T. vivax were equally infective for mice, though in some cases infectivity could be improved by bovine serum supplementation and/or immunosuppression of the mouse host. In the case of rats, infection was even restricted to a smaller number of the VATs studied. It was, however, possible to biochemically characterize the variable surface antigen carried by T. vivax and show its similarity to those carried by T. brucei and T. congolense. The H-2 complex was found not to influence acquired resistance of inbred strains. Cyclic transmissions of T. vivax infections to goats combined with chemotherapy were carried out in an attempt to induce protection to subsequent infection as has been shown in T. brucei and T. congolense infections. Such protection could, however, not be obtained, The failure of the metacyclic VATs to induce immunity, was perhaps due to rapid decrease in antibody titres to bloodstream VATs found after treatment and prior to rechallenge. The usefulness of the mouse model system in elucidating the mechanisms responsible for the non-H-2 linked differences in susceptibility to T. vivax infections should be further explored and its relevance to mechanisms of trypanotolerance in domestic ruminants defined.  相似文献   
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The fungal pathogenPhytophthora infestans is the causal organism of late blight, one of the most devastating diseases of potato. In the past, various aspects of the potato-P. infestans interaction have been studied extensively. In this paper we briefly review the current knowledge of the molecular events associated with the interaction and in addition we discuss a new approach for analyzing the molecular basis of pathogenicity ofP. infestans.  相似文献   
30.
Summary Sixty dairy buffaloes (second to fourth lactation) from a large buffalo farm were used to compare the effects of single intramuscular injections of 100 µg gondadotrophin releasing hormone (GnRH), 250 µg GnRH or saline given on day 14post partum. The buffaloes had calved at the end of the breeding season (December). Milk samples for progesterone determination were taken at the time of injection and then three times a week either until first insemination or until around day 90post partum. GnRH given at 14 dayspost partum resulted in quicker completion of uterine involution, earlier resumption of ovarian activity, shorter intervals between calving and conception and a better first service conception rate in non-suckled dairy buffaloes. Differences between the results obtained by a GnRH dose level of 100 µg and 250 µg were non-significant. In the post-treatment period cases of prolonged luteal activity were common in all groups of buffaloes. Therefore the sequential administration of GnRH and prostaglandin is suggested for the management of post-partum reproductive activity in problem herds.
Desempeno Reproductivo De Bufalos Nili-Ravi Despues De Una Sola Inyeccion De GnRH Temprano Despues Del Post-Parto
Resumen Sesenta búfalos lecheros (segunda a cuarta lactancia) pertenecientes a un hato grande fueron utilizados para comparar los efectos de inyecciones intramusculares de 100 µg de GnRH, 250 µg y de solución salina, aplicadas 14 días después del parto. Los búfalos habian parido al final de la estación de pariciones (diciembre). Se tomaron muestras de leche para medir progesterona, en el momento de la inyección y después tres veces por semana hasta la primera inseminación, o hasta cerca de los 90 días post-parto. La GnRH administrada 14 días post-parto, dio como resultado una rápida involución uterina, más rápido retorno a la actividad ovárica, más cortos intervalos entre partos y concepción, y un mejor índice servicio-concepción en búfalos lecheros que no estaban amamantando. Los resultados de dosis de 100 µg y 250 µg no fueron significativos. En el período post-tratamiento, los casos de actividad luteal prolongada fueron comunes en todos los grupos de búfalos. Se sugiere entonces, la administración secuencial de GnRH y prostaglandina, parar el manejo de la actividad reproductiva post-parto en hatos problema.

Performances De Reproduction Du Buffle Nili-Ravi Apres Une Injection Unique PrecocePost Partum De Gonadotrophine (GnRH)
Résumé Soixante bufflesses laitières (de la seconde à la quatrième lactation), appartenant à une grande ferme d'élevage de buffles, ont été utilisées pour comparer les effets d'une injection unique intramusculaire de 100 µg de gonadotrophine, ou de 250 µg du même produit ou d'une solution de sérum physiologique. Les bufflesses avaient mis bas à la fin de la saison de reproduction soit en décembre. Des prélèvements de lait ont été effectués pour déterminer le taux de progestérone au moment de l'injection d'une part, puis trois fois par semaine d'autre part jusqu'à la première insémination ou aux alentours d'une période de 90 jours après le part. La gonadotrophine, libérée sous forme d'hormone (GnRH), injectée 14 jours après la mise bas a eu pour effet un retour complet plus rapide de l'involution utérine et des intervalles plus courts entre la mise bas et la conception ainsi qu'un meilleur taux de conception à la première monte chez les femelles laitières non allaitantes. Les différences entre les résultats obtenus par une dose de 100/µg ou de 250/µg de gonadotrophine (GnRH) n'étaient pas significatives. Pendant la période post-thérapeutique, des cas d'activité lutéale prolongée ont été courants dans tous les groupes de bufflesses. En conséquence, l'administration séquentielle de GnRH et de prostaglandine est conseillée pour contrôler l'activité post-partum de reproduction dans les troupeaux qui présentent des problèmes de cet ordre.
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