Outcome of equids with clinical signs of West Nile virus infection and factors associated with death

OBJECTIVE: To determine outcome of equids in the western United States with clinical signs of West Nile virus (WNV) infection and identify factors associated with risk of death in infected equids. DESIGN: Cross-sectional study. ANIMALS: 484 equids in Nebraska and Colorado. PROCEDURE: Owners of 484 equids with laboratory-confirmed West Nile virus infection in Nebraska and Colorado were contacted by telephone, and a questionnaire was used to obtain information on signalment, management, clinical signs, date of disease onset, duration of disease, WNV vaccination status, and health status at the time of the interview. RESULTS: 137 of 482 (28.4%) animals died or were euthanatized. Ataxia, lethargy, muscle fasciculations, and weakness were the most common clinical signs of disease. Animals > or = 3 years old were more likely to die than were animals < or = 2 years old. Unvaccinated equids were twice as likely to die as were animals that had been vaccinated at least once prior to the onset of disease. Animals that were recumbent and unable to rise were 78 times as likely to die as were animals that never lost the ability to rise. Females were 2.9 times as likely to die as males. Two hundred seventy-one of 339 (79.9%) animals that survived recovered fully; mean duration of disease for these animals was 22.3 days. CONCLUSIONS AND CLINICAL RELEVANCE: Among equids with WNV infection, age, vaccination status, an inability to rise, and sex were associated with the risk of death.     

A simple random amplified polymorphic DNA genotyping method for field isolates of Dermatophilus congolensis

Dermatophilus congolensis is the pathogenic actinomycete that causes dermatophilosis in cattle, lumpy wool in sheep and rain scald in horses. Phenotypic variation between isolates has previously been described, but its genetic basis, extent and importance have not been investigated. Standard DNA extraction methods are not always successful for D. congolensis due to its complex life cycle, one stage of which is encapsulated. Here we describe the development of rapid and reliable DNA extraction and random amplified polymorphic DNA (RAPD) methods that can be used for genotyping D. congolensis field isolates. Our results suggest that genotypic variation between isolates correlates with host species. Several DNA extraction methods and RAPD protocols were compared. An extraction method based on incubation of the bacterium in lysozyme, sodium dodecyl sulphate (SDS) and proteinase K treatments and phenolic extraction yielded high-quality DNA, which was used to optimize RAPD-polymerase chain reaction (PCR) protocols for two random primers. An alternative rapid, non-phenolic extraction method based on proteinase K treatment and thermal shock was selected for routine RAPD typing of isolates. DNA extracted from reference strains from cattle, sheep and horse using either method gave reproducible banding patterns with different DNA batches and different thermal cyclers. The rapid DNA extraction method and RAPD-PCR were applied to 38 D. congolensis field isolates. The band patterns of the field and type isolates correlated with host species but not with geographical location.     

Supplementation with bypass fat in silvopastoral systems diminishes the ratio of milk saturated/unsaturated fatty acids

This study was conducted to evaluate if supplementing bypass fat to cows under silvopastoral systems, increases the concentration of unsaturated fatty acids in milk, thus improving the saturated/unsaturated ratio without a negative effect on total milk yield in fat or protein. Two concentrations of two different sources of bypass fat were evaluated for 40 days, each in a group of 24 multiparous Lucerna (Colombian breed) cows. A cross-over design of 8 Latin squares 3 × 3.was used The variables submitted to analysis were body condition, daily milk production and milk composition. Body condition, milk yield and milk quality were not different but there was a significant decrease in the amount of saturated fatty acid in both experiments while the unsaturated fat increased significantly in experiment 1 and remained stable in experiment 2. Results, such as these have as far as we know, not been reported previously and they provide an approach for the improvement of milk as a “functional food”.     

The effects of obesity and fatty acids on the feline immune system

Obesity is a rising problem in cats. It is a risk factor for several diseases and has been linked to impaired immunity. The goal of this study was to determine the effect of body composition and effects of diet on immune function in cats. Twenty-eight short-term obese and 12 lean cats with equal gender distribution were evenly and randomly divided into two groups which were either fed a diet containing saturated (SFA) or long-chain n-3 polyunsaturated fatty acids (3-PUFA) for a period of 6 months prior to testing. Blood was collected by venipuncture from the jugular vein. Blood samples were analyzed in a double blind fashion. A complete blood count was performed and lymphocyte distribution was examined by flow cytometric analysis with specific fluorescein-conjugated subset markers. Immune function was measured as follows: the proliferative activity of different cellular fractions was tested with polyclonal mitogens such as lipopolysaccharide (LPS), phytohaemagglutinin (PHA), phorbol 12-myristate 13-acetate (PMA), Ca ionophore, and concanavalin A. Innate immune functions assessed were phagocytosis and natural killer cell (NK) cytotoxicity. A similar immune innate and adaptive immune response was elicited regardless of diet or body condition. However, there was no correlation between body condition, diet, and any of the quantitative and qualitative functional responses of the immune system. We conclude that short-term obesity and the fatty acid composition of the diet do not alter immune responses in cats.     

Changes in Lipid Composition After In-Vitro Selection for Glyphosate Tolerance in Tobacco

After a one-step selection procedure with glyphosate added to the callus medium, tobacco regenerants were obtained from calluses surviving on field doses of the herbicide. The lipid and sterol compositions of potted plants from the two original cultivars which underwent the selection procedure but without glyphosate, and the selected regenerants were investigated. Controls were derived from micropropagation and not from seeds. They served as appropriate controls for comparison with glyphosate regenerants, i.e. they underwent exactly the same experimental conditions except for the glyphosate treatment. Plant regeneration was strongly (at one-step selection) or fully (at stepwise selection) inhibited. Only a few glyphosate-tolerant plants (seven of Nevrokop A₂₄ and five of Zlatna arda) were obtained which were cloned and potted. At least 10 plants of one clone per genotype were used for the further biochemical analyses. The spraying of the tobacco plants from the cultivars with glyphosate led to a decrease of monogalactosyl diacylglycerol content and increase of the saturated fatty acids in all glycolipid classes. The concentration of stigmasterol increased and that of sitosterol decreased only in Zl.arda variety. In the regenerants there were different changes in lipid composition, concerning mainly a decrease of monogalactosyl diacylglycerols (MGDG) and an increase of digalactosyl diacylglycerols (DGDG) in Zl.arda-derived regenerants and increase of the amounts of neutral lipids and decrease of phospholipids (PL) in the Nevrokop A₂₄-derived regenerants. Surprisingly, after treatment of the regenerants with glyphosate, the MGDG amounts in these regenerants were higher than in the controls, which could mean a lesser ability to control ion permeability.     

In vitro polyploidization of Mecardonia tenella, a native plant from South America

Mecardonia tenella is an herbaceous plant widely distributed in the temperate region of South America. Both plant architecture and flower size are characteristics that can be improved to become a viable new ornamental plant. Chromosome doubling by the use of agents such as colchicine is an available methodology to this end. Nodal segments from in vitro grown plants of M. tenella were submerged in the following doses of colchicine in 1% (v/v) dimethyl-sulfoxide (DMSO) solution (%, v/v): 0.0, 0.001 and 0.01 (24 and 48 h). The DNA content of the regenerated plants was measured by flow cytometer. A total of 68 tetraploid plants were detected out of 126 colchicine treated plants. The flowers and leaves of the tetraploid plants were bigger compared to those from the wild diploid type (control). Under field conditions, the selected tetraploid plants showed a more compact shape than the control plants.