Chemical restraint of peccaries with tiletamine/zolazepam and xylazine or tiletamine/zolazepam and butorphanol

Objective To evaluate the use of a combination of tiletamine/zolazepam and xylazine (TZX) in collared and white‐lipped peccaries and to compare its efficacy as an anesthetic technique with that of tiletamine/zolazepam and butorphanol (TZB). Study design Prospective experimental trial. Animals Seven white‐lipped peccaries (Tayassu pecari) (four females and three males) and four collared peccaries (Tayasu tajacu) (two males and two females). Methods Animal immobilization was attempted with TZX and TZB (IM) on two different occasions. Heart and respiratory rates (HR, RR), rectal temperature (RT), sedation, muscle relaxation, posture, auditory response and analgesia were evaluated every 15 minutes during immobilization. Induction, anesthesia, standing and walking time were determined after drug administration. Results Doses for white‐lipped peccaries were 1.23 ± 0.26 mg kg^?1 (mean ± SD) of TZ and 1.23 ± 0.26 mg kg^?1 of X, and 1.46 ± 0.09 mg kg^?1 of TZ and 0.14 ± 0.008 mg kg^?1 of B; doses for collared peccaries were 1.51 ± 0.29 mg kg^?1 of TZ and 1.51 ± 0.29 mg kg^?1 of X and 1.68 ± 0.02 mg kg^?1 of TZ and 0.17 ± 0.002 mg kg^?1 of B. In white‐lipped peccaries, both drug combinations provided a smooth induction and good immobilization for more than an hour. Anesthesia and standing times were significantly longer in animals given TZB, whereas walking time was significantly longer in animals given TZX. A significant decrease in HR was observed with both treatments. Respiratory rate decreased significantly with TZX, but the rate remained higher than with TZB. Induction and recovery quality in white‐lipped peccaries was better with TZB than with TZX. Neither protocol provided adequate immobilization in collared peccaries. Conclusion and clinical relevance At the doses described, TZB is effective in providing a long period of immobilization, whereas TZX is adequate for short to medium immobilization in white‐lipped peccaries. Neither drug combination was effective in collared peccaries at the doses given.     

Effect of rice growth stages and silicon on sheath blight development

ABSTRACT The objective of this study was to determine the effect of silicon (Si) and rice growth stages on tissue susceptibility to sheath blight (Rhizoctonia solani Kühn) under controlled conditions. Rice plants (cv. Rio Formoso) were grown in pots containing low-Si soil amended with Si at 0, 0.48, 0.96, 1.44, and 1.92 g pot(-1) and inoculated with R. solani at the following days after emergence: 45 (four-leaf stage), 65 (eight-leaf stage), 85 (tillering), 117 (booting), and 130 (panicle exsertion). For plants inoculated with R. solani at all growth stages, Si concentration in straw increased as rate of Si increased from 0 to 1.92 g pot(-1). Concentration of calcium in the straw did not differ among plant growth stages. Although incubation period was not affected by the amount of Si added to the soil, this variable was shorter at booting and panicle exsertion stages. As the rates of Si increased in the soil, the total number of sheath blight lesions on sheaths and total area under the relative lesion extension curve decreased at all plant growth stages. The severity of sheath blight was lower at booting and panicle exsertion stages as the rates of Si increased in the soil. In general, plants grown in Si-nonamended pots and inoculated with R. solani were more vulnerable to infection at all growth stages, but especially at 45 days after emergence. Plant dry weights for inoculated plants increased as the Si rates increased from 0 to 1.92 g pot(-1). The greatest dry weight increases occurred for plants inoculated at booting and panicle exsertion stages. Si fertilization is a promising method for controlling sheath blight in areas where soil is Si deficient and when cultivars that exhibit an acceptable level of resistance to sheath blight are not available for commercial use.     

Evaluation of the local analgesic effect of ketamine in the palmar digital nerve block at the base of the proximal sesamoid (abaxial sesamoid block) in horses

OBJECTIVE: To evaluate the local analgesic effect of ketamine in a palmar digital nerve block at the base of the proximal sesamoid (abaxial sesamoid block) in horses. ANIMALS: 36 mature healthy Andalusian horses. PROCEDURE: Horses were randomly assigned to 4 groups of 9 horses each and received an abaxial sesamoid block in a randomly chosen forelimb with 1 of the following: saline (0.9% NaCl) solution, 1% ketamine solution, 2% ketamine solution, or 3% ketamine solution. To determine analgesia, the radiant heat lamp-hoof withdrawal model was used as a noxious thermal stimulus. Before each nerve block, baseline hoof withdrawal reflex latency (HWRL, time between lamp illumination and withdrawal of the hoof) was determined; after the nerve block, local analgesic effects were determined by measuring HWRL at 2 and 5 minutes after injection and then every 5 minutes for a total period of 1 hour. RESULTS: Significant differences in HWRL were found between baseline values and values at 2 to 15 minutes following a nerve block with ketamine. Significant differences were found between HWRL values at every time point from 2 to 10 minutes following a nerve block with saline solution, compared with 1 or 2% ketamine solution. Similarly, significant differences were found between HWRL values at every time point from 2 to 15 minutes following a nerve block with saline solution, compared with 3% ketamine solution. CONCLUSIONS AND CLINICAL RELEVANCE: Abaxial sesamoid block with ketamine ensures adequate analgesia in horses with an onset of action of 2 minutes and a maximal duration of action of 15 minutes.     

Evaluation of survival of Actinobacillus pleuropneumoniae and Haemophilus parasuis in four liquid media and two swab specimen transport systems

OBJECTIVE: To determine duration and rates of recovery of Actinobacillus pleuropneumoniae and Haemophilus parasuis from 4 liquid media and 2 swab specimen transport systems and compare findings with those of Escherichia coli. SAMPLE POPULATION: One strain each of A pleuropneumoniae (biovar 1, serotype 1), H parasuis (serovar 5), and E coli (serotype O149:K91:H19). PROCEDURE: Strains were incubated in brain heart infusion broth supplemented with horse serum and other nutrients or in horse serum alone, with and without nicotinamide-adenine dinucleotide in both instances, for 150 days at 4 degrees C or room temperature (21 degrees C). Similarly, strains were tested in Stuart and Amies transport systems after storage at room temperature for 8 days. RESULTS: Colony counts greater than those of the initial inoculum were observed after incubation in horse serum for A pleuropneumoniae but not for H parasuis. Overall, incubation at 4 degrees C in the 4 liquid media resulted in longer recovery duration and higher rates than at room temperature. Culture of H parasuis resulted in lower recovery rates and shorter durations of recovery than culture of A pleuropneumoniae, except for culture in horse serum. Haemophilus parasuis survived longer than A pleuropneumoniae in the transport systems, and all organisms survived longer in the Amies system. CONCLUSIONS AND CLINICAL RELEVANCE: Survival of A pleuropneumoniae and H parasuis indicated that horse serum prolongs survivability, which may result in exposure of more animals during a prolonged period. The Amies system might be a good choice for collection of clinical samples from animals, especially for recovery of H parasuis.     

Evaluation of the safety of ivermectin-praziquantel administered orally to pregnant mares

OBJECTIVE: To evaluate the safety of an orally administered ivermectin and praziquantel paste with regard to variables associated with clinical findings, parturition, lactation, maternal care, and neonate viability in pregnant mares. ANIMALS: 40 pregnant mares. PROCEDURE: Mares were randomly allocated into treatment (n = 20) and control (20) groups and administered a placebo or 3 times the therapeutic dosage of ivermectin (0.6 mg/kg) and praziquantel (4.5 mg/kg) at 14-day intervals until parturition. Physical examinations were performed on mares and their foals after parturition (on postpartum days 30, 60, and 90) to identify any drug-related effects. As an aid in assessing general health, hematologic and serum biochemical analyses were performed monthly on the mares. RESULTS: In blood constituents, minor alterations that were not biologically important were observed. Reproductive performance was not affected by the unusual treatment duration or high dosage, although the drugs were administered during a crucial period of equine embryonic development (30 to 60 days). Neither adverse effects on mares nor abortions occurred. Follow-up evaluations of the foals for a 3-month period did not detect any abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of the ivermectin-praziquantel paste appears to be safe in pregnant mares and their foals.     

In vitro and in vivo efficacy of alpha-cyclodextrin for treatment of experimental cryptosporidiosis

The efficacy of alpha-cyclodextrin against infection by Cryptosporidium parvum was evaluated using in vitro and in vivo models. Cyclodextrins are water-soluble cyclic hexamers of glucose units with hydrophobic cavities capable of solubilizing lipophiles and are widely used as drug excipients in the pharmaceutical industry. The viability of purified C. parvum oocysts, exposed for 30, 60, 90, 120 min and 24h to different concentrations of alpha-cyclodextrin (2.5, 5, 7.5, 10, 12.5 and 15%), was evaluated by inclusion or exclusion of two fluorogenic vital dyes and by an excystation technique. Preventive and curative efficacies against cryptosporidial infections, at different doses (2.5 and 5%) and regimes of administration of alpha-cyclodextrin, were determined in an experimental neonatal mice model. Results of the viability assay showed a decrease in oocyst viability that was associated with an increase in exposure time, for each of the concentrations used. Moreover, a high proportion of nonviable oocysts (81%) was observed when C. parvum oocysts were exposed to alpha-cyclodextrin (2.5%) for 24h. The intensity of infection, determined 7 days post-inoculation by examination of intestinal homogenates, was significantly lower (P<0.05) than in the control litters, for all the assays carried out with alpha-cyclodextrin. Only 38.8% of the animals became infected when the alpha-cyclodextrin solution (5%) was administered 2h before inoculated oocysts, and every 24h at 1 and 2 days post-inoculation.     

Foot-and-mouth disease virus

Foot-and-mouth disease virus (FMDV) is an aphthovirus of the family Picornaviridae and the etiological agent of the economically most important animal disease. As a typical picornavirus, FMD virions are nonenveloped particles of icosahedral symmetry and its genome is a single stranded RNA of about 8500 nucleotides and of positive polarity. FMDV RNA is infectious and it replicates via a complementary, minus strand RNA. FMDV RNA replication is error-prone so that viral populations consist of mutant spectra (quasispecies) rather than a defined genomic sequence. Therefore FMDV in nature is genetically and antigenically diverse. This poses important challenges for the diagnosis, prevention and control of FMD. A deeper understanding of FMDV population complexity and evolution has suggested requirements for a new generation of anti-FMD vaccines. This is relevant to the current debate on the adequacy of non-vaccination versus vaccination policies for the control of FMD.

Résumé

Le virus de la fièvre aphteuse est un aphtovirus de la famille des Picornaviridae et l'agent de la maladie animale la plus importante sur le plan économique. En tant que picornavirus typique, le virus de la fièvre aphteuse est nu, sous forme d'icosaèdre et son génome comprend un acide ribonucléique monobrin avec environ 8500 nucléotides et une polarité positive. L'acide ribonucléique de ce virus est infectieux et il se réplique par l'intermédiaire d'un brin d'ARN moins, complémentaire. La réplication de l'acide nucléique de ce virus conduit à des erreurs, de telle sorte que les populations virales comprennent un ensemble de mutants (quasi espèce) plutôt qu'une séquence génomique bien définie. Par suite, le virus de la fièvre aphteuse est génétiquement et antigéniquement varié. Ceci entraîne des difficultés importantes pour le diagnostic, la prévention et la maîtrise de la fièvre aphteuse. Une connaissance plus approfondie de la complexité et de l'évolution de la population de ce virus a conduit à des besoins pour une nouvelle génération de vaccines aphteux. Ceci est lié au débat actuel sur le choix d'une politique de vaccination ou de non-vaccination dans la lutte contre la fièvre aphteuse.     

Evaluation of a specific immunochemotherapy for the treatment of canine visceral leishmaniasis

The efficacy of specific immunochemotherapy against Leishmania infantum infection in dog was studied. The effects on transmission of the disease, as well as the cellular and humoral immune response were examined. The treated animals showed a significant reduction in the infection rates that were detected in Phlebotomus perniciosus females fed on the dog. The humoral immune response, assayed with an indirect immunofluorescence antibody test (IFAT), did not show significant variations under the influence of the therapy. The characterisation of the peripheral blood mononuclear cells (PBMC) using flow cytometry indicated a significant increase in the proportion of T lymphocytes, especially of CD4/TcR(alpha)(beta)(+) and CD4/CD45RA(+) cells, without showing evidence for modifications in the other leukocyte subsets. Cellular lymphoproliferation studies indicated a lack of a specific response to soluble leishmanial antigen (SLA), but the non-specific lymphoproliferative capacity assayed with phytohemagglutinin (PHA) was maintained.     

Assessment of relevant factors and relationships concerning human dermal exposure to pesticides in greenhouse applications

Principal component analysis (PCA) was applied to the gas chromatographic data obtained from 23 different greenhouse trials. This was used to establish which factors, including application technique (very small, small, medium and large drop-size), crop characteristics (short/tall, thin/dense) and pattern application of the operator (walking towards or away from the treated area) are relevant to the dermal exposure levels of greenhouse applicators. The results showed that the highest exposure by pesticides during field applications in greenhouses, in the climatic conditions and in the crop conditions typical of a southern European country, occurs on the lower legs and front thighs of the applicators. Similar results were obtained by hierarchical cluster analysis (HCA). Drop-size seems to be very important in determining total exposure, while height and density of crops have little influence on total exposure under the conditions of the present study. No pesticide type is a major factor in total exposure. The application of multiple regression analysis (MRA) allowed assessment of the relationships between the pesticide exposure of the less affected parts of the body with the most affected parts.