Experimental enteric infection of gnotobiotic piglets with Chlamydia suis strain S45

Enteric chlamydial infections of pigs with Chlamydia (C.) suis are frequent and often subclinical. The enteric pathogenicity of C. suis strain S45 was investigated in gnotobiotic piglets. Piglets from three litters (n=31) were inoculated with egg-grown chlamydiae at 2-3 days of age (n=17) or used as controls (n=14). They were observed for clinical signs, killed and necropsied sequentially at 2-13 days postinoculation (DPI). Feces were collected daily and investigated with an ELISA for chlamydial antigen. At necropsy, specimens were collected for histopathology and for immunohistochemical, PCR-based, and serological (complement fixation test, ELISA) detection of chlamydiae. Chlamydial replication and associated symptoms and lesions were observed from 2 to 13 DPI and were particularly pronounced within the first week PI. Clinical symptoms consisted of moderate-to-severe diarrhea, slight and transient anorexia, weakness and body weight loss. Immunohistochemistry and ELISA revealed that chlamydial replication was particularly marked at 2-4 DPI and primarily located in the small intestinal villus enterocytes. Further sites of replication included large intestinal enterocytes, the lamina propria and Tunica submucosa, and the mesenteric lymphnodes. Histopathological changes included moderate-to-severe villus atrophy with flattened enterocytes and focal villus tip erosions, and moderate mucosal inflammatory cell infiltrates and lymphangitis in the small intestine. PCR of spleen tissue and blood was mostly negative for chlamydiae, indicating that they did not substantially disseminate into the host up to 13 DPI. All sera were negative for anti-chlamydial antibodies. In conclusion, C. suis strain S45 elicited significant enteric disease and lesions in gnotobiotic piglets indicating its pathogenic potential for swine.     

Reduced growth of Lucilia cuprina larvae fed serum from sheep treated with anthelmintics

The effect of three commonly used anthelmintics, levamisole hydrochloride, ivermectin and closantel, on the development of the sheep blowfly, Lucilia cuprina, was determined. Sheep were treated with each anthelmintic using the manufacturers' recommended dose for helminth control. Both ivermectin and closantel significantly (p < 0.05) reduced the growth rate of larvae of L cuprina cultured in vitro on serum from these sheep. Levamisole hydrochloride had no effect. Ivermectin was effective for less than 6 days after treatment, whereas closantel significantly reduced larval growth 21 days after treatment. Dose-response experiments showed that lower concentrations of both ivermectin and closantel were not as effective in reducing larval growth.     

农业用地供给侧改革的可行举措探讨

通过梳理我国农业用地在利用中所存在的制度层面、利用层面、管理层面和其他层面的问题,结合我国推进农业用地实行供给侧改革的目的,从4个方面制度供给、利用供给、管理供给和其他供给提出我国在实行农业用地供给侧改革的可行举措,为我国推进农业用地的供给侧改革提供理论依据。     

Evaluation of a Burdizzo Castrator for Neutering of Dogs

A Burdizzo castrator was evaluated for the neutering of dogs. Histological and morphological changes of spermatic cells and peripheral serum testosterone after challenge with a GnRH-analogue (gonadorelin) were assessed. There was a control group (G1), a surgically castrated group (G2) and a Burdizzo group (G3) divided in two, G3a receiving two crunches in each spermatic cord and G3b receiving one crunch in each spermatic cord. Sixteen days after application of the Burdizzo blood samples were taken from the dogs at 30 min interval during 2 h; after the second sample the dogs were treated with 1 mug/kg body weight of gonadorelin i.v. The same protocol of gonadorelin challenge was performed in G1 and G2 dogs. The G2 dogs were surgically castrated after the second blood sample, before the gonadorelin treatment, and the G1 dogs after the last blood sample. The excised gonads were examined histologically, and sperm smears were prepared from the caudae epididymidis. The testes and plexus pampiniformis of the G1 and G2 dogs had a normal histological appearance, and they had morphologically normal epididymal sperm cells. In all G3 dogs, there was an acute fibrosis with an inflammatory reaction in the plexus pampiniformis. The testes from the G3a dogs showed diffuse areas of infarction and degeneration of the parenchyma. Similar but less diffuse lesions were seen in group 3b dogs. The deferent ducts from all G3 dogs showed vasitis and/or sperm granulomas. Azoospermia or sperm malformations were observed in the epididymal smears from the G3 dogs. Testosterone concentration in the G1 dogs increased after gonadorelin application (p < 0.0001). The G2 dogs had basal testosterone levels after castration (p < 0.001) and did not respond to gonadorelin. Groups 3a and b showed a slight but non-significant increase in testosterone concentration after gonadorelin challenge, supposedly due to the reduction of testicular blood flow and loss of testicular interstitial tissue.     

Demodex spp. infestation and suspected demodicosis of alpacas (Vicugna pacos) in New Zealand

Extract

Ectoparasites known to cause skin lesions in alpacas (Vicugna pacos) include the mites Sarcoptes scabiei, Chorioptes bovis and Psoroptes spp., and the lice Microthoracius mazzai and Bovicola breviceps (Cicchino et al. 1998 Cicchino, AC, Munoz, Cobenas ME, Bulman, GM, Diaz, JC and Laos, A. 1998. Identification of Microthoracius mazzai (Phthiraptera: Anoplura) as an economically important parasite of alpacas. Journal of Medical Entomology, 35: 922–930.  [Google Scholar]; Foster et al. 2007 Foster, A, Jackson, A and D'alterio, GL. 2007. Skin diseases of South American camelids. In Practice, 29: 216–223. [Crossref], [Web of Science ®] , [Google Scholar]). Occasionally, Demodex spp. infestations have been reported or mentioned as incidental fi ndings in llamas (Lama glama) (Atlee et al. 1997 Atlee, BA, Stannard, AA, Fowler, ME, Willemse, T, Ihrke, PJ and Olivry, T. 1997. The histology of the normal llama skin. Veterinary Dermatology, 8: 165–176. [Crossref], [Web of Science ®] , [Google Scholar]) and alpacas (Foster et al. 2007 Foster, A, Jackson, A and D'alterio, GL. 2007. Skin diseases of South American camelids. In Practice, 29: 216–223. [Crossref], [Web of Science ®] , [Google Scholar]). So far, only Sarcoptes scabiei (McKenna et al. 2005 McKenna, PB, Hill, FI and Gillett, R. 2005. Sarcoptes scabiei infection on an alpaca (Lama pacos. New Zealand Veterinary Journal, 53: 213–213. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]), Chorioptes bovis (Arthur 1997 Arthur, DG. 1997. Diseases of lamoids in New Zealand. Surveillance, 24(1): 29–30.  [Google Scholar], non-peer reviewed) and Bovicola breviceps (Palma et al. 2006 Palma, RL, McKenna, PB and Aitken, P. 2006. Confirmation of the occurrence of the chewing louse Bovicola (Lepikentron) breviceps (Insecta: Phthiraptera: Trichodectidae) on alpacas (Lamas pacos) in New Zealand. New Zealand Veterinary Journal, 54: 253–254. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) have been recorded on lamoids in New Zealand. Here, we report the first record of Demodex spp. infestation of an alpaca in New Zealand.     

Introduction to the Swiss way of teaching veterinary pathology in the twenty-first century: application of e-learning modules

The teaching of pathology within the veterinary medical curriculum extends through the entire training period and has a dual role. General pathology deals with principles of disease processes as a basis for understanding the reactions of a multi-cellular organism to adverse effects; organ pathology builds on the principles of general pathology and explains the malfunctions of individual organs. Pathology is heavily image dependent and best taught in a highly interactive manner. The Institute of Veterinary Pathology, University of Zurich (IVPZ), has been actively developing concepts for teaching pathology in the new veterinary curriculum, which demands more active participation from students, with 20% of their study time devoted to individual study using traditional materials (books, articles, etc.) and e-learning modules. The Swiss Virtual Animal Pathologist is designed to cover and support the central elements of the Veterinary Pathology curriculum of the Vetsuisse Faculty. The needs of students and staff of the participating institutions for an interactive learning platform to supplement the existing face-to-face lectures and tutorials are the highest priority of this initiative.     

Biodiversity assessment and conservation strategies

The efficient representation of all species in conservation planning is problematic. Often, species distribution is assessed by dividing the land into a grid; complementary sets of grids, in which each taxon is represented at least once, are then sought. To determine if this approach provides useful surrogate information, species and higher taxon data for South African plants and animals were analyzed. Complementary species sets did not coincide and overlapped little with higher taxon sets. Survey extent and taxonomic knowledge did not affect this overlap. Thus, the assumptions of surrogacy, on which so much conservation planning is based, are not supported.     

Exposed water ice discovered near the south pole of Mars

The Mars Odyssey Thermal Emission Imaging System (THEMIS) has discovered water ice exposed near the edge of Mars' southern perennial polar cap. The surface H2O ice was first observed by THEMIS as a region that was cooler than expected for dry soil at that latitude during the summer season. Diurnal and seasonal temperature trends derived from Mars Global Surveyor Thermal Emission Spectrometer observations indicate that there is H2O ice at the surface. Viking observations, and the few other relevant THEMIS observations, indicate that surface H2O ice may be widespread around and under the perennial CO2 cap.