Taenia saginata cysticercosis in an Ohio cattle feeding operation

In January to March 1981, 37 slaughter cattle from a single Ohio feeding operation were determined, at postmortem inspection, to be infected with Taenia saginata cysticerci. A subsequent outbreak on this same farm in March 1983 involved 7 slaughter cattle. An epidemiologic investigation was conducted of possible sources of the T saginata ova; these included leakage of raw sewage onto the pasture after a flood in 1980, municipal sewage sludge application on the farm, defecation in feed or water by farm workers, and other off-farm sources. Temporal and spatial observations implicated raw sewage contamination of pastures as the most likely source of infection in the 1981 outbreak. The outbreak in 1983 was more likely associated with sludge application. The possibility of an infected worker exposing the cattle to infected feces was not excluded definitely as a possible source.     

Systemic and mucosal immune responses of pigs to parenteral immunization with a pepsin-digested Serpulina hyodysenteriae bacterin.

Serpulina hyodysenteriae infection of pigs, swine dysentery, causes a mucohemorrhagic diarrhoea resulting in significant economic losses to swine producers. The pathogenesis of this disease is poorly understood. Regardless, commercial vaccines have been developed and are in use. Thus, the present study was designed to examine cellular immune responses induced by parenteral S. hyodysenteriae vaccination. Significant antigen-specific interferon-gamma (IFN-gamma) and blastogenic responses were detected from peripheral blood lymphocytes isolated from vaccinated pigs. However, poor IFN-gamma responses were detected from colonic lymph node lymphocytes from these same pigs despite significant antigen-specific blastogenic responses. In addition, peripheral blood IFN-gamma responses were diminished by either in vitro depletion of CD4 expressing cells or by in vitro treatment with porcine IL-10. Colonic lymph node IFN-gamma responses were not inhibited by treatment with porcine IL-10. Vaccination also resulted in increased percentages of both mucosal and peripheral blood CD8 single positive cells with concurrent decreases in percentages of CD4 single positive cells as compared to percentages of these same populations from non-vaccinated pigs. In conclusion, these studies show that parenteral S. hyodysenteriae vaccination results in cellular immune responses detectable both peripherally (systemic immunity) as well as at the site of infection (mucosal immunity). However, it appears that regulatory mechanisms affecting IFN-gamma production in response to S. hyodysenteriae antigen differ between peripheral and colonic compartments.     

Cross-taxon congruence of species diversity and community similarity among three insect taxa in a mosaic landscape

Surrogate taxa as indicators for biodiversity are widely used in conservation biology and ecology. However, available studies on the congruence of species diversity patterns in different taxa yielded inconsistent results, and correlations between taxa were few. To conserve or restore biodiversity in agricultural landscapes, knowledge on the response of different taxa to management regimes is crucial. In the present study we evaluated the congruence of diversity and similarity patterns among three insect taxa, i.e., bees, grasshoppers, and aculeate wasps, in a mosaic landscape in the Swiss Alps comprising extensively used grassland under different management regimes. In addition, we studied the influence of land use on the diversity and species composition of the three taxa. While species numbers were not significantly correlated between any pair of taxa, community similarities were positively correlated between bees and grasshoppers. The number of red-listed species was not correlated with the total number of species in bees and in grasshoppers. None of the investigated taxa reflected the species numbers or community similarities of the other taxa well enough to qualify as a general indicator for biodiversity. Remarkably, land use clearly influenced species composition, while its effect on species numbers was not significant. All management regimes of the grassland in the study area contribute substantially to the overall diversity of the three insect taxa. Conserving the variety of agricultural land uses will be the most promising step towards the conservation of biodiversity in the study area.     

Quantitative pollen requirements of solitary bees: Implications for bee conservation and the evolution of bee–flower relationships

Knowledge about the quantitative pollen requirements of solitary bees is crucial for the preservation of endangered bee species and the understanding of the evolution of bee–flower relationships. We estimate the number of flowers required to rear a single larva for 41 European bee species (i) by comparing the pollen content of brood cells with the pollen quantity contained in the flowers of the bees’ host plants and (ii) by deducing the pollen requirements from a regression model describing the relationship between the average bee dry body mass and the average brood cell pollen content. The flower requirements of the bee species examined vary by three orders of magnitude. Depending on both bee species and host plant, from seven to 1100 flowers or from 0.9 to 4.5 flower heads are needed to rear a single larva. As only about 40% of the pollen contained in a flower was found to be available to a single female bee, these minimal figures have to be multiplied by a factor of approximately 2.5 to obtain a realistic estimate of bee flower requirements. The amount of pollen lost from flowers for bee nutrition is surprisingly high. We hypothesize that the recent decline of many bee species may have its main cause in a food shortage provoked by a decrease in flower diversity and quantity following habitat destruction and modern agricultural practices. The substantial pollen losses to bees as documented in this study support earlier findings on floral adaptations against excessive pollen harvesting by bees.     

Effects of azadirachtin on the regulation of midgut peristalsis by the stomatogastric nervous system inLocusta migratoria

A single injection of azadirachtin into nymphal and adult locusts results in a decrease of food intake but not in reduced food utilization. Feeding deterrency is correlated with a gradual inhibition of midgut peristalsis. Gut movement is under the control of the stomatogastric nervous system, especially the ingluvial ganglion, as demonstrated in anin vitro system. Serotonin is the most potent peristalsis-stimulating drugin vitro. Concurrent with the cessation of midgut peristalsis after azadirachtin injection, a depletion of the serotoninergic cell bodies in the frontal ganglion can be observed. Midgut preparations which show strongly inhibited contractions due to previous azadirachtin treatmentin vivo are minimally, or not at all, stimulatedin vitro by serotonin, depending on the amount of time that has elapsed since treatment. When midgut preparations of untreated locusts are challenged with azadirachtinin vitro, peristalsis is suppressed in a dose-dependent manner. Simultaneous application of azadirachtin and serotonin results in a slight stimulation of midgut peristalsis. We propose the hypothesis that azadirachtin interferes with the serotoninergic system of the stomatogastric ganglia and thus inhibits midgut peristalsis. The molecular mechanism of the action of azadirachtin remains to be determined.     

Lesions in chickens with spontaneous or experimental infectious hepato-myelopoietic disease (inclusion body hepatitis) in Germany.

A group of 83 two-to-eighteen-week-old chickens with acute infectious hepato-myelopoietic disease (a German form of inclusion-body-hepatitis) were observed to have the following histologic lesions: panmyelophthisis, small foci of liver necrosis, often with intranuclear inclusion bodies in hepatocytes (15 to 20% of chickens), involution-like atrophy of the bursa of Fabricius and thymus, loss of lymphatic tissue in spleen and cecal tonsils, and nonpurulent myocarditis. In 18 survivors 6 to 8 weeks after clinical signs of disease, nonpurulent myocarditis but normal lymphatic organs and bone marrow were present. A group of 75 chickens were infected after hatching with the field isolant "1942." Between the 3rd and 9th weeks postinoculation the same histologic changes-though mostly milder-were demonstrated. This syndrome differs somewhat from the syndrome described as inclusion body hepatitis in America and Europe.     

Screening of medicinal and ornamental plants for insecticidal and growth regulating activity

Extracts of 121 medicinal and ornamental plants were screened for insecticidal and growth regulating activity to milkweed bug, Oncopeltus fasciatus Dallas. The most effective extracts stemmed from Inula helenium L., Rumex crispus L., R. acetosa L., Asarum europaeum L., and Calendula officinalis L. All these extracts exerted growth inhibiting activities and moderate or low acute toxicity. Most promising were extracts of dried roots of I. helenium. Besides a moderate chronic toxicity which reduced the fitness of the milkweed bug, the treatment produced overaged nymphs, supernumerary nymphs, disturbances of the moulting process, morphological defects, delay of adult maturation and reduction of fecundity. In addition, I. helenium extracts had a strong antifeedant effect when topically applied and very strong repellent effect when applied to the food (peeled sunflower kernels). It is obvious that the extract contains several active constituents. Such a cocktail may reduce the threat of rapid resistance development.