Experimental infection of normal and immunosuppressed pigs with Pseudomonas pseudomallei

A single dose of 5 x 10(8) bacilli of Pseudomonas pseudomallei by intratracheal injection resulted in acute (21 cases) or chronic (19 cases) melioidosis in 40 of 48 pigs. Fifteen (10 acute and 5 chronic) had been immunosuppressed by cyclophosphamide before inoculation. The major clinical signs were initial fever, marked neutrophilia and, in the acute cases, respiratory distress. There were no signs of the nasal and ocular discharge, paresis or diarrhoea seen in acute cases in south-east Asia. The cyclophosphamide treatment caused a significant decrease in the neutrophil count by 7 d after inoculation in all 15 immunosuppressed pigs, and all were culture positive at necropsy. Eight of the 33 non-treated pigs were culture negative at necropsy. Pigs overcoming the initial phase of infection had more abscess-like nodules that were bacteriologically sterile at necropsy than the pigs with acute cases of melioidosis. P. pseudomallei was isolated predominantly from the spleen, lungs and the injection site. Although only one strain was used in this study, it is likely that Australian strains of P. pseudomallei are not as virulent as the south-east Asian isolates.     

Impacts of intensification of pastoral agriculture on soils: Current and emerging challenges and implications for future land uses

Abstract

AIM: To find evidence for localisation in the uterus, and fetal infection, of Leptospira spp. in farmed deer in the lower North Island of New Zealand during and shortly after the breeding season.

METHODS: Between February and July 2008, 116 blood samples, 120 kidneys, 120 uteri and 27 fetuses were collected from 120 mixed-age hinds from lines from nine farms, at a deer slaughter premises. Serum samples were tested for antibodies against Leptospira borgpetersenii serovar Hardjo-bovis and Leptospira interrogans serovar Pomona, using the microscopic agglutination test (MAT). For both serovars, a titre of >1:48 was considered positive. Samples from kidneys, uteri and fetal tissue were subjected to bacterial culture, using Ellinghausen-McCullough-Johnson-Harris (EMJH) medium, and real-time PCR, using DNA gyrase subunit B gene primers.

RESULTS: Thirty-four of 116 (29.3%) serum samples were positive for serovar Hardjo-bovis, and 13 (11.2%) for serovar Pomona. Seven of 120 kidneys were positive for serovar Hardjo-bovis by culture, and five of these, but no others, were positive by real-time PCR. Of 120 uteri, none was culture- or PCR-positive. None of 27 fetal samples was culture-positive but one was positive by real-time PCR. The dam of the PCR-positive fetus was culture-negative from the kidney, but had an MAT titre of 1:192 for Hardjo-bovis.

CONCLUSIONS: Attempts to isolate Leptospira spp. from the genital tracts and early fetuses of farmed deer were unsuccessful. However, molecular evidence suggested fetal infection in one case. This finding justifies further study of the role of leptospires in the genital tract and fetus and its association with reproductive loss in farmed deer.     

Effects of a topical anaesthetic formulation and systemic carprofen, given singly or in combination, on the cortisol and behavioural responses of Merino lambs to castration

Objective   To determine the effectiveness of a topical anaesthetic formulation (Tri-Solfen) with or without the administration of a non-steroidal anti-inflammatory drug (carprofen) on the pain and distress response associated with ring or surgical castration of ram lambs.
Procedures   Merino ram lambs (n = 78) were allocated to 10 treatment groups: 4 groups of knife-castrated lambs and 4 groups of ring-castrated lambs received carprofen (4 mg/kg SC) and Tri-Solfen; 2 control groups (sham) received carprofen at 0 or 4 mg/kg SC. Measurements included plasma cortisol and haptoglobin concentrations, haematology, and behaviour, including posture.
Results   Knife-castrated lambs had higher peak cortisol and integrated cortisol responses for the first 6 h after treatment and greater concentration s of circulating acute phase proteins than ring-castrated lambs, both of which were significantly different from the sham controls. Tri-Solfen applied to the knife castration wound significantly reduced both the peak plasma cortisol concentration and the integrated cortisol response for the first 6 h and improved lying behaviour in the first 12 h. Carprofen reduced the cortisol response to knife castration at 30 min, but elevated the cortisol responses at 24 and 48 h. Carprofen nearly halved the number of acute pain behaviours associated with ring castration. There were no significant additive or synergistic effects from combining the analgesic treatments. Tri-Solfen applied to the tail wound provided no detectible benefits during ring castration + tail docking.
Conclusions   The physiological and behavioural responses suggest that ring castration has less impact on the lamb than knife castration. The specific analgesic treatments can provide modest amelioration of the pain and discomfort associated with castration. Alternative doses or application methods may enhance their efficacy.     

Effect of ovine granulocyte-macrophage colony-stimulating factor on bovine in vitro embryo development and blastocyst interferon-τ secretion

This experiment examined the effects of including recombinant ovine granulocyte-macrophage colony-stimulating factor (GMCSF) in in vitro culture on secretion of interferon-τ (IFNT) by bovine blastocysts. At 32 h post-insemination (p.i.), cleaved bovine zygotes were selected and incubated with or without GMCSF for either 48 h only (between 32 and 80 h p.i., Early) or until day 9 p.i. (Throughout). Concentrations of GMCSF (ng/ml) examined were as follows: Experiment 1: 2, 5, 10 and 50 (Early only); Experiment 2: 50 (Early and Throughout); Experiment 3: 2 and 10 (Early and Throughout). In none of the experiments did GMCSF have an effect (p > 0.05) on the numbers of blastocysts formed or blastocyst characteristics as assessed by cell number, proportion of apoptotic cells or oxidation of pyruvate. When GMCSF was included in culture medium between 32 and 80 h p.i. (Early), IFNT concentrations were lower (in media drops recovered after culture of groups of embryos for 48 h between days 7 and 9 p.i. and normalized by the numbers of blastocysts developing within each drop) compared to no inclusion of GMCSF or GMCSF present Throughout culture (Experiment 2, p > 0.05; Experiment 3, p = 0.038). IFNT was present in media drops in which groups of embryos had been incubated between days 7 and 9 p.i. but in which no blastocysts had developed. Experimental treatment did not influence (p > 0.05) IFNT secretion by blastocysts incubated individually for 24 h. However, during the 24-h individual culture, blastocysts recovered on day 7 secreted less IFNT than blastocysts recovered on day 8 (mean ± SE; 15 ± 1.3 v 30 ± 3.6 pg/ml; p < 0.001). In conclusion, in contrast to previous studies in the ovine, GMCSF did not increase IFNT secretion but in agreement with the ovine did not affect bovine blastocyst development.     

南疆巴旦杏园朝鲜球坚蚧不同发育期的防治措施研究

为了探寻不同发育期朝鲜球坚蚧的有效防治新措施,根据朝鲜球坚蚧不同发育阶段的形态特征和生物学习性,对不同龄期的若虫采取刮皮涂干、树干注射和常规喷雾等措施进行防治.试验结果表明;在施药方法上,刮皮涂干和常规喷雾是最为适用的;在药效方面,在1龄若虫期喷雾施用的几种药剂中醋盐合剂对1龄若虫的喷洒防效达到了90%以上.通过施用脱叶剂处理叶片的方法来防治2龄若虫,试验所设3种浓度的脱叶剂均能间接起到防治作用,其效果均达到了95%以上.在3龄若虫期喷雾施用的几种药剂中95%酒精合剂的喷洒防效达到了90%以上.涂干防治3龄若虫期供试的几种药剂中,20%吡虫啉可溶性液剂1∶10的稀释液防效达到了90%以上.