Recovery of Yersinia pseudotuberculosis from the faeces of healthy cattle

Attempts were made to recover and serologically identify Yersinia pseudotuberculosis from the faeces of groups of nine to twenty clinically healthy cattle eight to thirteen months old on each of 50 farms in the northern part of New Zealand. Yersinia pseudotuberculosis was recovered from 134 (26.3%) of 509 faeces samples from cattle on 42 (84%) farms and from nine of ten samples on two of these farms. Serotypes I, II, and III were identified, of which serotype III was by far the most common and accounted for 125 (93.2%) of the 134 isolates. Because of the common occurrence and widespread distribution of Y. pseudotuberculosis it is suggested that the clinical significance of isolation of this micro-organism from faeces samples or intestinal contents should be treated with caution.     

Prevalence and in-vitro antimicrobial sensitivity of Bordetella bronchiseptica in the nasal cavity of pigs

The prevalence of Bordetella bronchiseptica in the nasal cavity of pigs and the in-vitro sensitivity of isolates to a variety of antimicrobial agents was investigated. B.Bronchiseptica was recovered from 372 nasal swabs collected from 1000 (37.2%) pigs slaughtered at 20-30 weeks old at an abattoir. The swabs were collected from groups of 5-206 pigs derived from 25 herds. All isolates tested against bacitracin, clindamycin, furazolidone, penicillin, spectinomycin, streptomycin and tylosin were found to be resistant. Of the 372 isolates tested against ampicillin and erythromycin 22 (6%) were sensitive to the former and 365 (98%) were moderately sensitive to the latter, the remainder were resistant. All isolates tested against neomycin and tetracycline were sensitive and with few exceptions, (2%), they were also sensitive to chloramphenicol. Overall, 259 of the 372 (70%) isolates were sensitive to sulphonamides, identical results being obtained with sulphadiazine, sulphafurazole and a trimethoprim-sulphamethoxazole combination. An association between in-vitro resistance to sulphanomides and extensive use of this group of drugs was demonstrated on three of eight farms investigated.     

First record of the Q biotype of the sweetpotato whitefly, <Emphasis Type="Italic">Bemisia tabaci</Emphasis>, in Guatemala

Bemisia tabaci (Gennadius) adults and immatures were collected from poinsettia plants at two commercial production greenhouses in Guatemala during an invited tour to observe IPM practices within the facilities. Despite extensive scouting, only low numbers of insects were collected from vegetable, weed and wild ornamentals species located close to these facilities. Prior to molecular and biochemical analyses, whitefly immatures were initially identified as B. tabaci using morphological characters of the pupae to distinguish them from the greenhouse whitefly. The biotype status of adults and immatures was then established using esterase isozyme patterns and MTCO1 sequencing. The Q biotype was the only biotype found on commercially grown poinsettia plants. The previously recorded B biotype was observed outside the greenhouse facilities on Lactuca spp., Hibiscus spp. and Euphorbia spp. (wild poinsettia). The New World biotype was observed on wild poinsettia and field-grown beans (Phaseolus spp.). This is the first report of the Q biotype in Guatemala, and serves notice of the need for greater vigilance in the management of whiteflies on poinsettia mother stock used as a source of cuttings for export to the USA.     

Evaluating natural resource amenities in a human life expectancy production function

This study examined the effect of natural resource amenities on human life expectancy. Extending the existing model of the life expectancy production function, and correcting for spatial dependence, we evaluated the determinants of life expectancy using county level data. Results indicate that after controlling for socio-demographic and economic factors, medical facilities and risk factors, counties with natural amenities such as high proportion of land in forests, farmland, rangeland and water bodies, as well as mild climate such as longer sunlight hours during winter and cooler year around temperature exhibited longer life expectancies at birth. In addition, counties containing state parks and outdoor recreation facilities, and those located near federal wilderness parks were associated with the longer expectancies at birth. Findings from this study have several implications for natural resource economics and management, public health, and human development. An important message of our findings is that the traditional approach of public health should be extended beyond just controlling diseases or treating patients to a more comprehensive approach that also acknowledges the preservation and utilization of natural resources, environmental amenities, and outdoor recreation opportunities in maintaining public health, quality of life, and overall human development.     

Valuing diversity and spatial pattern of open space plots in urban neighborhoods

This study evaluates how urban residents value variety, spatial configuration, and patterns of open space in their neighborhoods. Quantitative matrices that were borrowed from landscape ecology were first used to measure the variety and spatial arrangement of open space plots and landuses around houses. Amenity values of those measures were then evaluated in a hedonic regression that was corrected for identification problem caused by the endogeneity of landuse variables. Empirical estimates from this research reveal that urban residents positively valued the varieties of open space but negatively valued the diversity within developed land uses in their neighborhoods. Similarly, open space plots with square shape and smooth, straight edges were preferred to those with more complex shapes and irregular edges. Further, residents preferred open spaces in few larger plots to many smaller pieces that are scattered throughout the neighborhood. Findings from this study will be useful in enhancing the quality and amenity value of open spaces and conceivably increase local property tax base.     

Ecological impacts of invasive carp in Australian dryland rivers

相似文献   

Bovine leptospirosis: The detection of haemolysin inhibitors in sera from experimentally and naturally infected cattle

For laboratory diagnosis of respiratory disease it is of overwhelming importance that the specimens taken are adequate, taken from the correct site and at the correct time. The lower regions of the respiratory tract are particularly difficult to sample but are more likely to yield the causative agent of a pneumonia. Infections involving the upper respiratory tract are much easier to sample and appropriate aspiration apparatus can be used. Consideration must be given to the timing of sample collection in relation to the life cycle of the causative micro-organism. Sampling of several animals is recommended.

Diagnosis may be achieved by isolation in culture of the causative agent or the demonstration of the agent by indirect methods such as electron microscopy and ELISA. Clinical biochemical tests may reflect systemic metabolic changes induced by microbial infections and give an indication of the severity of the disease and its prognosis.

Pulmonary function tests have limited application in animals and are only likely to be used under experimental conditions and in horses and small animals.     

Ten years after the arrival in Ghana of Larger Grain Borer: Farmers' responses and adoption of IPM strategies

Small-scale on-farm storage of maize in Africa is changing, in part due to shifts in the threat from insect pests. A questionnaire survey of 242 households in four closely situated districts in the Volta Region of Ghana, where Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) arrived ten years ago, was used to show how maize storage practices have changed over the last five years. The survey included asking farmers about changing use of contact insecticides in maize storage in order to guide research and future recommendations. We found high uptake of recommendations developed by a project for reducing Larger Grain Borer damage. Farmers are being pro-active in preventing extensive damage from this pest by replacing the wood of their storage structures, increasing inspection of maize in their stores, and increasing their use of grain protectants. There were differences in post-harvest practices according to district, ethnic group and gender. Grain protectants (traditional methods or commercially available products) were used by 45% of farmers. Cost was the most often cited constraint to the use of recommended commercial products. Farmers reported that their three most important sources of information on maize storage were the agricultural extension services, radio programmes and local networks of friends, family and fellow farmers.     

Adaptation of a complement fixation test for large scale serological diagnosis of bovine leptospirosis

Details are given of a method of performing a semi-automated complement fixation test for the diagnosis of bovine leptospirosis. A “Dynatiter” machine is used which enables 288 sera to be tested per hour. In a comparative study it was shown that using this semi-automated test fewer than 5% of antibody titres differed from those obtained using a manual test, either with single antigens or a polyvalent antigen.