Death of a neonatal lamb due to Clostridium perfringens type B in New Zealand     

JS Munday  H Bentall  D Aberdein  M Navarro  FA Uzal  S Brown 《New Zealand veterinary journal》2020,68(4):242-246

ABSTRACT

Case history and clinical findings: A flock of 20 sheep was kept within three paddocks on a single property. None of the animals in the flock had been vaccinated against any disease for at least three years. Abdominal bloating and haemorrhagic diarrhoea were observed in Lamb 1 at 24 hours-of-age. The lamb subsequently died within an hour of the onset of clinical signs. Lamb 2 was 3-days-old when observed to be recumbent with opisthotonus. The lamb was treated with dextrose, vitamins B1 and B12, and penicillin G, but died 4 hours later.

Pathological findings: Examination of Lamb 1 revealed markedly increased gas within the peritoneum and within dilated loops of intestine. The intestines were dark red and contained large quantities of haemorrhagic fluid. Histology of the intestines revealed peracute mucosal necrosis with minimal accompanying inflammation. The intestinal lumen contained cell debris, haemorrhage, and myriad large Gram-positive bacilli. The intestines of Lamb 2 did not appear bloated or reddened. However, multiple fibrin clots were visible within the pericardial sac. Histopathological examination revealed small foci of necrosis within the mucosa of the distal intestine. The necrotic foci were often associated with large numbers of large Gram-positive bacilli.

Immunohistochemsitry and molecular biology: Intestinal samples from Lamb 1 were processed for Clostridium perfringens immunohistochemistry, which revealed large numbers of intralesional, positively immunostained rods. Fragments corresponding to the expected sizes for genes encoding alpha, beta, and epsilon C. perfringens typing toxins were amplified by PCR from DNA extracted from formalin-fixed sections of intestine.

Diagnosis: Lamb dysentery due to C. perfringens type B.

Clinical relevance: C. perfringens bacteria have a worldwide distribution, but disease due to C. perfringens type B has only been diagnosed in a small number of countries and has never been reported in New Zealand or Australia. C. perfringens type B produce both beta toxin and epsilon toxins, therefore both haemorrhagic enteritis and systemic vascular damage can develop. As many animals are exposed to C. perfringens without developing disease, there must be additional unknown factors that resulted in disease in these particular sheep. Vaccines that specifically protect against C. perfringens type B are available and may be recommended for use in smaller non-commercial flocks, as in the present case.  相似文献   

种间关系对中条山油松人工林天然更新及群落稳定性的影响          下载免费PDF全文

裴顺祥  法蕾  杜满义  郭嘉  辛学兵 《林业科学研究》2022,35(1):150-157

[目的]为了揭示种间关系对中条山油松人工林天然更新及群落稳定性的影响,为油松人工林经营管理提供理论依据.[方法]基于中条山油松人工林群落样地调查数据,分析油松人工林下主要植物的种间关联性、生态位重叠及群落稳定性,并在此基础上探讨种间关联和生态位理论在油松人工林天然更新障碍及群落稳定性形成机制中的作用.[结果]中条山油松...  相似文献   

Value of existing serological tests for identifying badgers that shed Mycobacterium bovis     

Chambers MA  Pressling WA  Cheeseman CL  Clifton-Hadley RS  Hewinson RG 《Veterinary microbiology》2002,86(3):183-189

In the UK there has been a sharp rise in the incidence of bovine tuberculosis since the early 1990s and the badger has been identified as an important wildlife reservoir for this infection. Infected badgers can excrete Mycobacterium bovis, putting other badgers and cattle at risk of becoming infected. Vaccination has been proposed as an approach to reducing the excretion of M. bovis by tuberculous badgers. In order to evaluate the efficacy of a badger vaccine it will be necessary to accurately determine the number of badgers excreting M. bovis without removing them for post-mortem evaluation. The existing live tests for tuberculosis in the badger (culture, indirect ELISA, Western blot) have not been assessed for their ability to detect badgers excreting M. bovis. Over the past 18 years, badgers from 31 social groups have been trapped and sampled in a study area of the Cotswold escarpment. We have examined the serological responses of 128 badgers trapped between 1985 and 1998 from social groups where M. bovis infection was endemic. These responses were compared with culture from faeces, urine, tracheal aspirates and bite wound swabs taken from these animals while alive. ELISA was found to be more sensitive than Western blot in detecting badgers excreting M. bovis. The majority of culture-positive badgers excreted M. bovis intermittently over the period of study. As a result, there was only a 27.5% chance of sampling a badger for culture when it was excreting M. bovis. In contrast, a positive ELISA result correctly predicted 68.2% of badgers with a history of excreting M. bovis. In the absence of alternative live tests for the badger, the Brock Test indirect ELISA appears to be more valuable than culture for measuring the effect of vaccination on reducing the number of badgers at risk of transmitting tuberculosis.  相似文献   

国有苗圃所有制结构调整之我见     

周国平  李发凯 《江西林业科技》2001,(Z1)

所有制结构的调整是国有苗圃发展壮大的出路所在.笔者从必要性,战略方向,基本途径等三个方面阐述了看法.  相似文献   

3种阔叶树育苗技术及苗木生长规律研究初探   总被引：2，自引：0，他引：2  

刘志强  肖水清  邹元熹  肖才发 《江西林业科技》2001,(3):14-15

通过对闽楠，蓝果树，东京野茉莉的育苗试验，研究苗木生长规律，掌握生理生物学特性。  相似文献   

Analysis of embedded gas detection system based on nano-porphyrin arrays     

LUO Xiao gang  BAI Xing hong  HOU Chang jun  HUO Dan qun  FA Huan bao  YANG Mei 《保鲜与加工》2011,(12):48-53

In view of the necessity of gas detection in environment, an embedded gas detection system is designed based on the basic principles of chromatography change of chemical reaction between nano-porphyrin arrays and micro-gas, which takes ARM9 S3C2440A as the core and nano-porphyrin array as the sensors. The overall program, the circuit organization and control software of the main function module such as spectrum signal acquisition, processing and monitoring are presented. With energy conservation differential equation, the control model of temperature and flow rate in the sample chamber is established, which can precisely control the detection conditions of chemical sensors. Some typical trace gases such as ammonia, enanthaldehyde, cyclohexane and hexanal are tested by the system, and the results show that the system can achieve rapid and accurate detection of trace volatile gas.  相似文献   

阔叶红松林山杨伐根分解过程中真菌动态研究     

法蕾  赵秀海 《北京林业大学学报》2006,(Z2)

山杨是长白山阔叶红松林中的常见阔叶树种,择伐后的伐根很多.山杨伐根在多种真菌的作用下逐渐分解,不断地向周围释放养分,构成保证森林生态系统稳定循环的一个重要环节.随分解的不断进行,山杨伐根上的真菌的种类和数量都呈现出一定的变化趋势.真菌数量高峰出现在伐后的第5年,而种类高峰则出现在伐后的第7年.这一时间上的交错现象是由真菌的不同分解能力引起的.分解能力强的主要分解菌将难于分解的木质素、纤维素等分解为易于利用的小分子物质,为其他真菌提供了营养来源,便于其他真菌的定殖.另外,伐根上的真菌数量还与伐根桩径呈正相关关系.  相似文献   

Mycobacterial disease in a population of 339 cats in Great Britain: II. Histopathology of 225 cases, and treatment and outcome of 184 cases     

Gunn-Moore DA  McFarland SE  Schock A  Brewer JI  Crawshaw TR  Clifton-Hadley RS  Shaw DJ 《Journal of Feline Medicine and Surgery》2011,13(12):945-952

This study investigated 339 cases of feline mycobacterial infection, with histopathology findings from 225 cases, and treatment and outcome information from 184 cases. Tissue samples from cats with cutaneous lesions or suspicious masses at exploratory laparotomy were submitted to the Veterinary Laboratories Agency for mycobacterial culture over a 4-year period to December 2008. The study reviewed the files for information about histopathology, treatment and outcome, and blindly reviewed histopathological changes (including staining for acid-fast bacteria [AFB]) in a sub-set of 45 cases. When a cat is suspected of having a mycobacterial infection, accurate identification of the species involved helps to determine possible treatment options and prognosis. The study confirmed that histopathology and the presence of AFB are useful tools in the recognition of mycobacterial infection. Unfortunately, they did little to help determine the species of mycobacteria involved. The study identified a group of cats that were negative for AFB at the primary laboratory, but from which mycobacteria could be cultured; commonly Mycobacterium bovis or Mycobacterium microti. The study also identified a group of cats which where culture negative, despite typical signs of mycobacterial infection and positive AFB staining. Many cases responded favourably to treatment (56% of the cases where information was available), and many cats gained complete remission (42%). However, relapses were common (64%) and often followed by pulmonary and/or systemic spread that may have resulted from treatment with short courses of single drugs. This study shows that the diagnosis and treatment of feline mycobacteriosis is complex and challenging.  相似文献   

Diagnostic kits for fish disease     

R S Clifton-Hadley 《The Veterinary record》1986,118(21):595-596

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Escherichia coli O115 forms fewer attaching and effacing lesions in the ovine colon in the presence of E. coli O157:H7     

La Ragione RM  Best A  Aktan I  Clifton-Hadley FA  Dugdale AH  Weyer U  Crawley T  Townsend P  Cooley WA  Johnson L  Wangoo A  Woodward MJ  Wales AD 《Research in veterinary science》2012,93(1):42-45

Escherichia coli O115 has been isolated from healthy sheep and was shown to be associated with attaching-effacing (AE) lesions in the large intestine. Following previous observations of interactions between E. coli O157 and O26, the aim of the present study was to assess what influence an O115 AE E. coli (AEEC) would have on E. coli O157 colonisation in vitro and in vivo. We report that E. coli O115- and O157-associated AE lesions were observed on HEp-2 cells and on the mucosa of ligated ovine spiral colon. In single strain inoculum, E. coli O115 associated intimately with HEp-2 cells and the spiral colon in greater numbers than E. coli O157:H7. However, in mixed inoculum studies, the number of E. coli O115 AE lesions was significantly reduced suggesting negative interference by E. coli O157. Use of the ligated colon model in the present work has allowed in vitro observations to be extended and confirmed whilst using a minimum of experimental animals. The findings support a hypothesis that some AEEC can inhibit adhesion of other AEEC in vivo. The mechanisms involved may prove to be of utility in the control of AE pathovars.  相似文献