Studies on food selection behaviour of the Norway rat (Rattus norvegicus) on farms

Measures used to control Norway rats (Rattus norvegicus Berk.) on farms are frequently unsuccessful due to poor bait uptake. In pest-control operations, rats always have the choice between the farms own food resources and the bait. In this study we analysed the individual selection behaviour in two rat colonies when the rats were offered a familiar bait which matched the food on the farm and a bait which was unknown. Bait stations equipped with video and transponder technology were installed in two differently structured areas on a farm. In four experiments, a familiar foodstuff (rolled oats) was put out for 3 days, and then at one of the stations, a test bait was put out for 4 days. The relative palatability of the test baits was known from laboratory experiments. The visits of marked individuals were registered, and the amounts consumed were estimated in the video evaluation. Location preference was determined by offering identical food in two neighbouring bait stations. Social interaction was evaluated using the video recordings. The bait stations were visited on a daily basis irrespective of the supply. Food selection patterns (and bait acceptance) observed in the two differently structured areas on the farm were different. However, the relative palatability among the four test baits was stable and agreed with the ranking in laboratory experiments. Over the days of the experiment there was no significant difference in bait acceptance. Location preference and social interaction influenced the choice of bait station. The results show that it is possible to predict bait palatability in the laboratory, which is an important prerequisite for good bait uptake. However, the bait acceptance level is ultimately determined by the prevailing living conditions in the respective area. For optimising bait uptake, the structure of the areas on the farm must be considered just as much as findings about location preferences and social interaction.     

Infections artificielles de jeunes plants ?Hevea brasiliensis par Rigidoporus lignosus (Kl.) Imaz. et Phellinus noxius (Corner) G. H. Cunn.1

Inoculations of young plants of Hevea brasiliensis by Rigidoporus lignosus (Kl.) Imaz. and Phellinus noxius (Corner) G. H. Cunn. Inoculations of young Rubber plants by two root rotting fungi, Rigidoporuslignosus and Phellinus noxius were performed under greenhouse conditions. For each parasite, parameters such as method of inoculation and level of soil moisture, were investigate. The results are discussed in relation to the fungal biology.     

Crown condition as a function of soil,site and tree characteristics

One of the aims of this work is to describe how the target variable “tree vitality” in terms of needle loss is affected by other explanatory variables. To describe such a relationship in a realistic way, we use generalized additive mixed models (GAMMs) which allow to take spatial correlation of the data into account and in addition allow the inclusion of explanatory variables as predictors with the possibility of having non-linear effects. The GAMMs are fitted in a Bayesian framework using Markov chain Monte Carlo techniques. Data are available for two years 1988 and 1994. We select a set of best explanatory variables from a large set of variables including tree-specific variables, such as species, age, nutrients in the needles and site-specific variables such as altitude, relief type, soil depth and content of different nutrients in the top soil. In the two models for 1988 and 1994, different sets of explanatory variables were selected as best predictors. In both models, the effects of explanatory variables allowed a plausible interpretation. For example, the site-specific variables such as relief and soil depth were significant predictors, since these factors determine how well water and nutrient supply is balanced at a specific site. The selected sets of explanatory variables differed between 1988 and 1994, giving an indication of a possible change in the main causes of forest deterioration between 1988 and 1994. From the set of nutrient variables measured in the soil and in the needles, in 1988 altitude a.s.l. and magnesium supply were among the explanatory variables, in 1994 a combination of Al in the soil and the N/K-ratio (in the needles) was selected in the model. In 1988 altitude a.s.l. was among the most important predictors in the model. This is in contrast to 1994 where altitude was not selected. This may have to do with the fact that in the early phase of forest health monitoring (1988) one of the main causes of forest deterioration was magnesium deficiency. Later on this may have changed to a combination of soil acidification and nitrogen eutrophication. Thus by using an adequate model such as the GAMM, sets of explanatory variables for needle loss may be identified. By fitting two GAMMs, with different sets of “best” predictors, at two time points 1988 and 1994, we can detect changes in these sets of “best” predictors over time. This allows us to use the monitoring data with the tree vitality indicator crown condition/needle loss as a tool for forest health management, which may involve decisions about concrete counter measures like e.g. forest liming.     

TaqMan real-time PCR method for detection of <Emphasis Type="Italic">Discula destructiva</Emphasis> that causes dogwood anthracnose in Europe and North America

Dogwood anthracnose, caused by the asexual filamentous fungus Discula destructiva Redlin, is a disease of several Cornus L. species. First reported in the 1970s in the United States, the pathogen has devastated North American dogwood populations causing widespread loss that has greatly impacted forest ecosystems. In the early 2000s, the disease was discovered in Italy and Germany, spread probably through the ornamental nursery trade. The origin of D. destructiva in North America remains a mystery. To facilitate studies on its origin and dispersal, a fast and accurate method using real-time PCR was developed in this study to detect and quantify D. destructiva. The assay was validated with samples from the U.S., Italy, and Switzerland as well as phylogenetically closely related fungal species, and other fungi and oomycetes commonly found on Cornus. This method allows for fast and sensitive detection of D. destructiva in host tissue and should be useful in disease management and pest interception to prevent further spread of the pathogen.     

Adverse events in 50 cats with allergic dermatitis receiving ciclosporin

Ciclosporin is an immunosuppressive drug that has been used to treat allergies and other immune-mediated diseases in cats, dogs and humans. Information about the adverse effects of ciclosporin in cats has been limited to smaller studies and case reports. Adverse effects in dogs are mainly gastrointestinal in nature, but humans can also experience hypertension and altered renal function. The aim of this retrospective case series study was to document the occurrence and clinical appearance of adverse events in cats receiving ciclosporin to treat allergic skin disease. The medical records of 50 cats with allergic dermatitis treated with oral ciclosporin (1.9-7.3 mg/kg/day) were reviewed. Adverse events occurred in 66% (33 cats). Adverse events likely to be associated with ciclosporin included the following: vomiting or diarrhoea within 1-8 weeks of receiving ciclosporin (24%), weight loss (16%), anorexia and subsequent hepatic lipidosis (2%) and gingival hyperplasia (2%). Other adverse events less likely to be associated with ciclosporin therapy included the following: weight gain (14%), dental tartar and gingivitis (10%), otitis (4%), chronic diarrhoea (4%), inflammatory bowel disease with indolent gastrointestinal lymphoma (2%), urinary tract infection (2%), cataract (2%), elevated liver enzymes (2%), hyperthyroidism and renal failure (2%) and transient inappropriate urination (2%). Some cats experienced multiple adverse events. Case-control studies are needed to prove cause and effect of ciclosporin with regard to these adverse events.     

Anthocyanin-rich blackberry extract suppresses the DNA-damaging properties of topoisomerase I and II poisons in colon carcinoma cells

In the present study, we addressed the question whether cyanidin-3-glucoside (C3G) or complex C3G-rich blackberry extracts affect human topoisomerases with special emphasis on the contribution of the potential degradation products phloroglucinol aldehyde (PGA) and protocatechuic acid (PCA). In HT29 colon carcinoma cells a C3G-rich blackberry extract suppressed camptothecin- (CPT-) or doxorubicin- (DOX-) induced stabilization of the covalent DNA-topoisomerase intermediate, thus antagonizing the effects of these classical topoisomerase poisons on DNA integrity. As a single compound, C3G (100 μM) decreased the DNA-damaging effects of CPT as well, but did not significantly affect those induced by DOX. At the highest applied concentration (100 μM), cyanidin protected DNA from CPT- and DOX-induced damage. Earlier reports on DNA-damaging properties of cyanidin were found to result most likely from the formation of hydrogen peroxide as an artifact in the cell culture medium when the incubation was performed in the absence of catalase. The suppression of hydrogen peroxide accumulation, achieved by the addition of catalase, demonstrated that cyanidin does not exhibit DNA-damaging properties in HT29 cells (up to 100 μM). The observed effects on topoisomerase interference and DNA protection against CPT or DOX were clearly limited to the parent compound and were not observed for the potential cyanidin degradation products PGA and PCA.     

Blood gas analysis and cooximetry in retired racing Greyhounds

Objective – The purposes of this study were to evaluate the oxygen affinity of hemoglobin (Hb) in healthy retired racing Greyhounds via cooximetry, and to establish reference intervals for blood gases and cooximetry in this breed. Design – Prospective clinical study. Setting – University Teaching Hospital. Animals – Fifty‐seven Greyhounds and 30 non‐Greyhound dogs. Interventions – Venous blood samples were collected from the jugular vein and placed into heparinized tubes. The samples were analyzed within 30 minutes of collection using a blood gas analyzer equipped with a cooximeter. Measurements and Main Results – Greyhounds had significantly higher pH, PO₂, oxygen saturation, oxyhemoglobin, total Hb, oxygen content, and oxygen capacity and significantly lower deoxyhemoglobin and P₅₀ when compared with non‐Greyhound dogs. Conclusion – These findings support the fact that this breed is able to carry a higher concentration of total oxygen in the blood. As reported previously, this breed also has lower P₅₀ and, therefore, high oxygen affinity. In light of recent findings suggesting that in certain tissues a high affinity for oxygen is beneficial, this adaptation may be of benefit during strenuous exercise.     

Septic lens implantation syndrome in a cat

A 13-year-old female spayed domestic shorthair cat was presented initially for a change in the appearance of the left eye. On initial examination, a small penetrating wound was suspected as the cause for a corneal scar, an anterior cortical incipient cataract and mild iritis. The cat was not re-presented until 1 year later at which time ocular pain was marked. Severe anterior uveitis and glaucoma were diagnosed and the eye enucleated. Histopathology documented intralenticular coccoid bacteria and septic lens implantation syndrome.