Mutants of rabies viruses in skunks: immune response and pathogenicity.

In studies to develop an oral rabies vaccine for wildlife, the immune response to and pathogenicity of two types of mutants of rabies viruses were examined. Forty-five small plaque mutants were selected from cultures of ERA rabies virus treated with 8-azaguanine or 5-fluorouracil and tested for pathogenicity in mice. Two of these mutants AZA 1 and AZA 2 (low pathogenicity in mice) were given to skunks by oral (bait), intestinal (endoscope) and intramuscular routes. Additionally, challenge virus standard (CVS) rabies virus and mutants of this and ERA rabies virus (CVS 3766 and 3713, and ERA 3629) that were resistant to neutralization by specific antiglycoprotein monoclonal antibodies (and apathogenic in mice) were tested by various routes in skunks. Skunks given AZA 1 and AZA 2 were challenged at three months postinoculation with street rabies virus. After oral administration, there were very low rates of seroconversion with AZA 1 and AZA 2 and on challenge only 2/7 given AZA 1 and 1/8 given AZA 2 survived. None of the skunks given the other mutants orally seroconverted. AZA 2 produced a high rate of seroconversion (8/8) by the intestinal route and all challenged skunks in this group survived (7/7). All skunks vaccinated intramuscularly with AZA 1 (4/4) or AZA 2 (4/4) developed high levels of rabies neutralizing antibodies and survived challenge. The mutant CVS 3766, while apathogenic when given intracerebrally to adult mice, was consistently pathogenic by this route (and intranasally) in skunks. These results demonstrate that skunks are highly resistant to oral immunization by live rabies virus vaccines and that pathogenicity (by intracerebral route) of the mutant CVS 3766 is markedly different in mice and skunks.     

The survival in sheep and infectivity to dogs of Taenia hydatigena and T. ovis in sheep

Lambs were reared from birth to 3 months of age on pasture contaminated with the eggs of either Taenia hydatigena or Taenia ovis. They were necropsied at 3, 6, 9 or 12 months. Almost all larvae that were viable at 3 months continued to survive throughout the experiment. Larvae of T. hydatigena were infective to dogs at 3 months, whereas those of T. ovis required more than 3 months to reach the infective stage.     

Afforestation,restoration and regeneration——Not all trees are created equal

Undulations in weather patterns have caused climate shifts of increased frequency and duration around the world. The need for additional research and model data on this pressing problem has resulted in a plethora of research groups examining a particular tree species or biome for negative effects of climate change. This review aims to （1） collect and merge recent research data on regeneration within old- and new-growth forests, （2） highlight and expand upon selected topics for additional discussion, and （3） report how shade tolerance, drought toler- ance, and inherent plasticity affect tree growth and development. Al- though shade and drought tolerance have been well studied by a number of research groups, this review reveals that in-depth analysis of a single or a few species in a given area will not generate the data required to implement a successful regeneration plan. Studies using historical accounts of previous species composition, information regarding site sea- sonality, species competition, and individual responses to drought and shade are needed to （1） develop best management plans and （2） ensure future modeling experiments are focused on a greater variety of species using more innovative methods to evaluate climate change effects.     

The use of eutectic mixture of lidocaine and prilocaine in mice (Mus musculus) for tail vein injections

ObjectiveTo investigate a topical local anesthesia technique as a means to prevent and/or diminish pain in mice in a laboratory setting associated with tail vein injections performed by personnel in training.Study designProspective, randomized experimental trial.AnimalsThirty six adult female, 23–28 g CD-1 mice from an in-house training colony. They were acclimated to routine training and handling classes.MethodsEutectic mixture of local anesthetics (EMLA) cream (2.5% lidocaine/2.5% prilocaine) or a bland ointment control (n = 18) was applied on the tail prior to intravenous injection. The injections were performed by novices, who had never attempted the procedure, and experienced personnel. All participants were blinded to treatment groups. Three injection attempts were allowed per animal. The mice were observed and scored by blinded evaluators for behavioral and physiological changes, including respiratory rate, vocalization, tail flick, and escape behaviors, during and after the injection.ResultsThis study demonstrates that aversive behaviors induced by lateral tail vein injection were not changed by the preemptive application of EMLA cream. The aversive behaviors associated with lateral tail vein injection were significantly affected by the number of injection attempts and the individual's experience level.Conclusions and clinical relevanceTopical EMLA cream did not reduce signs of aversive reaction to tail vein injection and thus we did not find support for its use in mouse training programs for tail vein injections.     

Aquacultural ponds as energy storage and waste recycling systems

Considerable research has been done in an attempt to utilize solar energy to improve the productivity of aquatic culture systems. At the same time solar energy research has identified energy storage as a problem in commercializing the use of solar energy for heating and other purposes. Thus, a system is proposed to combine aquacultural production facilities and solar energy storage with the possibility of later combining recycling of agricultural wastes into the combined system. System feasibility is being explored by use of mathematical simulation models. Six model components on interacting models are briefly outlined and progress on detailed model development is described. A model capable of predicting the hourly solar energy available at any point on the earth's surface for which cloud cover, clearness number and latitude are known, is described. Example model output is presented and compared to measured data.     

Duration of immunity in foxes vaccinated orally with ERA vaccine in a bait.

Red foxes (Vulpes vulpes) vaccinated orally with the ERA strain of rabies vaccine in a bait were challenged after 83 mo. Ten of 11 foxes that had seroconverted following vaccination resisted challenge with a virulent rabies virus which produced clinical signs of rabies in 6 of 6 unvaccinated foxes. Five of 11 vaccinated animals retained titers of rabies virus neutralizing antibody throughout the period. Although 6 of 11 had no detectable antibody at the time of challenge, 5 of these 6 resisted challenge and had an anamnestic response, as indicated by elevated titers of antibody when measured at day 77 postchallenge. These results show that foxes can be immunized successfully with a single oral dose of ERA vaccine, probably with protection against a lethal rabies challenge, for at least 7 y.     

Naphthalophos combinations with benzimidazoles or levamisole as effective anthelmintics for sheep

Objective: To investigate the relative efficacy and safety of the anthelmintic naphthalophos in sheep, either given alone or in combination with benzimidazole (fenbendazole and albendazole) or levamisole anthelmintics.
Design: A parasitological study using faecal egg count reduction tests, a validating slaughter trial and field safety trials.
Procedure: Faecal egg count reduction tests were carried out on 13 farms. Naphthalophos and combinations of naphthalophos with levamisole and fenbendazole were included in the drench tests. On one property a controlled efficacy study was carried out to validate faecal egg count reduction test findings. In this trial, sheep were slaughtered 10 days after treatment and the remaining parasites recovered from the gastro-intestinal tract. Safety trials were carried out on eight farms where approximately 50 000 sheep were treated with naphthalophos and albendazole that were tank mixed in the backpack.
Results: The efficacy of naphthalophos alone in faecal egg count reduction tests ranged from 59 to 98% with one test showing 95% reduction. The efficacy of naphthalophos and levamisole ranged from 74 to 100%, with 5 farms showing 95% reduction. The efficacy of naphthalophos and fenbendazole ranged between 88 and 100% with 95% reduction achieved on 10 farms. The controlled efficacy study showed a good correlation between the faecal egg count reduction tests and numbers of parasites recovered, except for Nematodirus where the faecal egg count reduction tests overestimated efficacy. The mortality rate in the safety trials was 0.05%, with most fatalities occurring on one farm.
Conclusion: The combination of naphthalophos and fenbendazole was more effective than a combination of naphthalophos and levamisole, and will provide a sufficiently safe drench rotation option.     

Effects of elevated carbon dioxide and ozone on potato tuber quality in the European multiple-site experiment ‘CHIP-project’

Potato (Solanum tuberosum L cv. Bintje) was exposed to ambient and elevated carbon dioxide (CO₂), to ambient and elevated ozone (O₃) and to elevated levels of both gases during two growing seasons, 1998 and 1999. Experiments in open-top chambers (OTC) were carried out in Finland, Sweden, Ireland, United Kingdom, Germany and Belgium and a FACE (Free Air Carbon dioxide Enrichment) experiment was carried out in Italy. In OTCs the plants were grown under ambient CO₂ concentrations or with 550 and 680 μl l⁻¹ CO₂ alone or in combination with ambient or elevated O₃ concentrations (target seasonal mean of 60 nl l⁻¹ 8 h per day). In the FACE systems the plants were exposed to ambient or 550 μl l⁻¹ CO₂. In the OTC experiments the reducing sugar content of potato tubers decreased significantly with increased concentration of O₃. The starch content of potato tubers decreased, with negative impact on tuber quality, but the ascorbic acid concentration increased as a function of the AOT40 (The sum of the differences between hourly ozone concentration and 40 nl l⁻¹ for each hour when the concentration exceeds 40 nl l⁻¹ during a relevant growing season). However, simultaneous exposure to elevated CO₂ counteracted the ozone effect. With increase in the CO₂ exposure, glycoalkaloid and nitrate concentrations decreased yielding improved quality, while the citric acid concentration decreased causing a higher risk for discoloration after cooking. The amount of dry matter and starch increased significantly in the FACE experiment.     

Demographic, familial and trait predictors of fruit and vegetable consumption by pre-school children

OBJECTIVE: To examine the contribution to fruit and vegetable eating in children of potential predictive variables within the domains of demographics, parental feeding practices and personality traits. DESIGN: Cross-sectional survey. SETTING: Questionnaires were distributed to parents through 22 London nursery schools. SUBJECTS: Questionnaires were completed and returned by 564 parents or principal caregivers of 2-6-year-old children. RESULTS: Significant predictors of children's fruit and vegetable intake emerged from all three domains examined. Demographic variables associated with child's vegetable consumption were mother's education and child's age and gender. Only ethnicity was significantly associated with fruit consumption. Parental consumption, breast-feeding and early introduction to fruit and vegetables were related to intake of both. Family meal times were associated with higher intake of vegetables, but not of fruit. Two characteristics of children themselves (food neophobia and enjoyment of food) were strongly related to the consumption of fruit and vegetables. Subsequent multivariate analyses revealed that parental intake and child food neophobia independently predicted intake of both foods. In the presence of these, fruit consumption was affected by breast-feeding and early introduction to fruit, whereas vegetable consumption was related only to child's gender and enjoyment of food. CONCLUSIONS: These findings may be used to inform future interventions aimed at increasing children's consumption of fruit and vegetables. Parents should be made aware of the possible impact of their own behaviour on the eating habits of their children.