Detection of pathogenic Listeria spp. in zoo animal faeces: use of immunomagnetic separation and a chromogenic isolation medium

Faecal samples, collected from 200 healthy animals in Antwerp Zoo, were examined for the presence of pathogenic Listeria spp. A two-stage standard isolation (ISO) method was combined with immunomagnetic separation (IMS). ALOA agar, a chromogenic isolation medium, differentiating Listeria spp. on the basis of beta-glucosidase and phosphatidylinositol-specific phospholipase C (PIPLC) activity, was compared with PALCAM agar. Confirmation of the isolates was based on conventional biochemical tests and a disc test, which detects a specific aminopeptidase produced by all Listeria spp. except Listeria monocytogenes. Listeria spp. were isolated from 42 (21.0%), L. monocytogenes from 14 (7.0%), and Listeria ivanovii from two (1.0%) faecal samples. The application of IMS after primary enrichment detected pathogenic Listeria spp. in 12 (6.0%) samples. The ISO method, combining primary and secondary enrichment, detected pathogenic Listeria spp. in 15 (7.5%) samples. The sensitivity of IMS compared to the ISO method was 73.3% and the specificity was 99.5%. ALOA agar was superior to PALCAM agar for isolation of Listeria spp. The disc test identified all L. monocytogenes isolates. IMS after primary enrichment was a suitable screening method, but secondary enrichment increased the number of positive samples.     

Seroprevalence of Toxoplasma gondii and Neospora caninum infection of cats in Hungary

Blood samples were collected from 330 cats in Hungary in order to evaluate their seroconversion to Toxoplasma gondii and Neospora caninum using the indirect fluorescent antibody test (IFAT). The overall prevalence of toxoplasmosis was 47.6%, the prevalence being 22.4% among urban, 50% among suburban and 61.3% among rural animals. Significantly more cats had high IFAT titres (1:640 to 1:5120) in the countryside. Female cats were more frequently infected with T. gondii than males (53.3% vs. 39.3%), and seropositivity increased with the age of animals. The prevalence (0.6%) and titre (1:40) of antibodies to N. caninum was low. Sixty-two cats were also screened for seroconversion to feline infectious peritonitis (FIP) virus. Higher titres to T. gondii were more frequently detected among FIP-positive cats, but this difference was non-significant due to the small number of cats with concurrent infection.     

Towards the construction of a resistance risk evaluation scheme

Pesticide resistance management needs an indication of the risk of resistance developing in pests against pesticide applications. This paper describes an evaluation system for the ranking of these risks. The term pests includes all organisms which are causing economic damage in agriculture, including weeds and plant pathogens. The system distinguishes six broad risk categories. It is based on expert judgement of answers to a maximum of ten questions on crop husbandry, pest biology and pest control. The system has been developed for registration purposes in The Netherlands, and is currently being discussed within the European and Mediterranean Plant Protection Organisation (EPPO). ©1997 SCI     

Biochar application to sandy soil: effects of different biochars and N fertilization on crop yields in a 3-year field experiment

During the past years, most biochar studies were carried out on tropical soils whereas perennial field experiments on temperate soils are rare. This study presents a 3-year field experiment regarding the effects of differently produced biochars (pyrolyzed wood, pyrolyzed maize silage, hydrothermal carbonized maize silage) in interaction with digestate incorporation and mineral N fertilizer application on soil C and N, crop yields of winter wheat, winter rye and maize and the quality of winter wheat. Soil C and plant available potassium were found to be significantly positive affected by pyrolyzed wood biochar whereas the latter only in combination with N fertilization. Crop yields of winter wheat, winter rye and maize were not affected by biochar and showed no interaction effects with N fertilizer supply. Wheat grain quality and nutrition contents were significantly affected by biochar application, for example, highest amounts of phosphorus, potassium and magnesium were determined in treatments amended with pyrolyzed maize silage biochar. Biochar induced an improved availability of plant nutrients, which apparently were not yield limiting in our case. These results limit the potentials of biochar for sustainable intensification in agriculture by increasing crop yields for the temperate zones. However, detection of other environmental benefits requires further investigations.     

Potential of acrylamide formation,sugars, and free asparagine in potatoes: a comparison of cultivars and farming systems

Glucose, fructose, sucrose, free asparagine, and free glutamine were analyzed in 74 potato samples from 17 potato cultivars grown in 2002 at various locations in Switzerland and different farming systems. The potential of these potatoes for acrylamide formation was measured with a standardized heat treatment. These potentials correlated well with the product of the concentrations of reducing sugars and asparagine. Glucose and fructose were found to determine acrylamide formation. The cultivars showed large differences in their potential of acrylamide formation which was primarily related to their sugar contents. Agricultural practice neither influenced sugars and free asparagine nor the potential of acrylamide formation. It is concluded that acrylamide contents in potato products can be substantially reduced primarily by selecting cultivars with low concentrations of reducing sugars.     

Impacts of Fair Trade certification on coffee farmers,cooperatives, and laborers in Nicaragua

This paper analyzes the possibilities and challenges of Fair Trade certification as a movement seeking to improve the well-being of small-scale coffee growers and coffee laborers in the global South. Six months of fieldwork was conducted in 2005–2006 to study the roles of a wide range of farmers, laborers, cooperative administrators, and export companies in Fair Trade coffee production and trade in Nicaragua. The results of our evaluation of the ability of Fair Trade to meet its objectives indicate that Fair Trade’s opportunities to provide a significant price premium for participating farmers largely depend on world coffee prices in mainstream markets. While Fair Trade has promoted premiums for social development for participating producers and strengthened the institutional capacities of the cooperatives involved, its ability to enhance significantly the working conditions of hired coffee laborers remains limited.     

Transendoscopic injection of poly-L-lactic acid into the soft palate in horses: A new therapy for dorsal displacement of the soft palate?

The purpose of this study was to establish a minimal invasive, transendoscopic technique for injection of poly-L-lactic acid into the free edge of the soft palate that can be performed on the standing sedated horse. Furthermore, whether the implant material induces an increase in fibrous tissue at the injection site, resulting in a greater rigidity of the soft palate, was determined.In 4 horses, the injection was performed bilaterally along the caudal margin of the soft palate, and the influence of the treatment on the soft palate function was determined. Clinical, radiographic and endoscopic examinations at rest were performed before and up to 168 days after injection according to a standardized examination protocol.In 6 horses, the implant material was injected unilaterally into the right half of the caudal margin of the soft palate. After clinical and endoscopic follow-up examinations, 2 horses each were killed 28, 84, and 168 days after the implantation procedure. At necropsy, macroscopic comparison of the treated and the untreated halves of the soft palate showed the influence on the size of the ostium intrapharyngeum and on the soft palate thickness. The localization of the implant material in the soft palate and the tissue response to the poly-L-lactic acid were evaluated histologically.Transendoscopic injection into the soft palate requires neither general anesthesia nor wound management, and it is noted for minimal tissue trauma. After injection, no alteration of the soft palate function was observed in horses with normal upper airway mechanics. One horse with intermittent dorsal displacement of the soft palate showed an improvement of the soft palate function for 112 days after implantation. No significant alteration in the size of the ostium intrapharyngeum was evident in any horse. Histologic assessment indicated the presence of implant material during the entire observation period of 168 days. The implant was accompanied by a granulomatous inflammation, and it was encapsulated by fibrous tissue. This may result in an increase in stiffness, and subsequent a greater rigidity of the soft palate, preventing it from displacement. The injection may therefore be considered an alternative to established therapies in horses showing dorsal displacement of the soft palate because of its unstable free edge.     

Immunization with Eimeria ninakohlyakimovae-live attenuated oocysts protect goat kids from clinical coccidiosis

Caprine coccidiosis, affecting mainly young goat kids around the weaning period, is worldwide the most important disease in the goat industry. Control of caprine coccidiosis is increasingly hampered by resistances developed against coccidiostatic drugs leading to an enhanced need for anticoccidial vaccines. In the current study we conducted an oral immunization trial with live attenuated sporulated Eimeria ninakohlyakimovae oocysts. Sporulated E. ninakohlyakimovae oocysts were attenuated by X-irradiation technique. The experimental design included a total of 18 goat kids divided into the following groups: (i) animals immunized with attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-irradiated homologous oocysts (group 1); (ii) animals infected with non-attenuated E. ninakohlyakimovae oocysts at 5 weeks of age and challenged 3 weeks later with non-attenuated homologous oocysts (group 2); (iii) animals primary-infected with untreated E. ninakohlyakimovae oocysts at 8 weeks of age (control of the challenge infection, group 3); (iv) non-infected control animals (group 4). Goat kids immunized with live attenuated E. ninakohlyakimovae oocysts (group 1) excreted significantly less oocysts in the faeces (95.3% reduction) than kids infected with non-attenuated ones (group 2). Furthermore, immunization with live but attenuated oocysts resulted in ameliorated clinical coccidiosis compared to goat kids infected with untreated oocysts (group 2) and resulted in equally reduced signs of coccidiosis after challenge infection compared to acquired immunity driven by non-attenuated oocysts. Overall, the present study demonstrates for the first time that live attenuated E. ninakohlyakimovae oocysts orally administered showed almost no pathogenicity but enough immunogenicity in terms of immunoprotection. Importantly, vaccinated animals still shed low amounts of oocysts, guaranteeing environmental contamination and consecutive booster infections to sustain ongoing immunity.