养殖大菱鲆肠炎病的流行病学和病原学研究

[目的]肠炎病是目前大菱鲆养殖行业中比较常见的疾病之一,该病感染率高,传播迅速。[方法]从山东半岛3个不同的养殖厂肠炎病发病大菱鲆体内分离致病菌,对其进行了常规生理生化特征测试和16S rRNA基因序列对比研究。[结果]从发病大麦鲆体内共分离到了株优势细菌。理化特征分析结果显示这3株菌中有2株分别与溶藻弧菌(Vibrio alginolyticus)和大菱鲆弧菌(Vibrio scophthalmi)表型特征非常相似,另1株细菌被证实为非弧菌属的细菌,具体定种尚需进一步研究。分析这2株弧菌属细菌的16S rRNA基因序列并构建了系统发育树,结果表明这些菌株与溶藻弧菌(Vibrio alginolyticus)和大菱鲆弧菌(Vibrio scophthalmi)的亲缘关系最近。[结论]从发病大菱鲆体内分离菌株的2株细菌被鉴定为溶藻弧菌(Vibrio alginolyticus)和大菱鲆弧菌(Vibrio scophthalmi)。     

Molecular characterization of canine coronavirus strains circulating in Brazil

To characterize canine coronavirus (CCoV) circulating in diarrheic puppies in Brazil, 250 fecal samples collected between 2006 and 2012 were tested. By using RT-PCR to partially amplify the M gene, CCoV RNA was detected in 30 samples. Sequence analysis of the M protein grouped eight strains with CCoV-I and another 19 with CCoV-II prototypes. To genotype/subtype the CCoV strains and assess the occurrence of single or multiple CCoV infections, RT-PCR of the S gene was performed, and 25/30 CCoV-positive strains amplified with one or two primer pairs. For 17/25 samples, single infections were detected as follows: six CCoV-I, nine CCoV-IIa and two CCoV-IIb. Eight samples were positive for more than one genotype/subtype as follows: seven CCoV-I/IIa and one CCoV-I/IIb. Sequence analysis revealed that the CCoV-I and IIa strains shared high genetic similarity to each other and to the prototypes. The Brazilian strains of CCoV-IIb displayed an aminoacid insertion that was also described in CCoV-IIb-UCD-1 and TGEV strains. Among the 25 CCoV-positive puppies, five had a fatal outcome, all but one of which were cases of mixed infection. The current study is the first reported molecular characterization of CCoV-I, IIa and IIb strains in Brazil.     

Clostridium perfringens toxin-types in lambs and kids affected with gastroenteric pathologies in Italy

A study was carried out in the South of Italy to assess the role of clostridia in neonatal diseases of lambs and kids. Eighty-seven lambs and 15 kids belonging to 25 flocks were examined and Clostridium perfringens was the microorganism most commonly identified. C. perfringens isolates were analysed by polymerase chain reaction (PCR), in order to determine the prevalence of the genes cpa, cpb, cpb2, etx, iap and cpe. The most prevalent toxin-type of C. perfringens was found to be type A found in 84% of the cases with clostridial enterotoxaemia. No C. perfringens type B, C or E were found. C. perfringens type D was isolated in 16% of the cases. About 24% of the isolates were cpb2 positive. The prevalence of cpb2 across the different C. perfringens types varied. The beta(2)-toxin gene cpb2 was detected in 4/21 (19%) type A isolates, in 1/2 type D isolates, and in 1/2 type DE (cpe-carrying type D) isolates. The high rate of positivity to cpb2 among the isolates suggests that a vaccine based on the beta(2)-toxin, should be included in the vaccination schedule of the animals to confer adequate protection and to prevent the disease.     

Oxidants and antioxidants in disease: oxidative stress in farm animals

Important infectious diseases in farm animals, such as pneumonia and enteritis, are thought to be associated with the so-called oxidative stress, i.e. a chemical phenomenon involving an imbalance in the redox status of the individual animal. The specifics of oxidative stress and how it may result in disease or be prevented are complex questions with no simple answers. However, the considerable literature on the subject suggests that many researchers consider oxidative stress-related mechanisms to be important early events in disease development. A particularly intriguing aspect is that, at least theoretically, oxidative stress should be easily prevented with antioxidants yet the use of antioxidants as therapy remains controversial. The present knowledge on oxidative stress in farm animals is the topic of this review.     

水貂病毒性肠炎诊断方法研究进展

水貂肠炎病毒（MEV）是一种自主复制性的最小的动物DNA病毒。研究表明,MEV是引起水貂病毒性肠炎的病原体,能够引起水貂剧烈腹泻,具有较高的发病率和死亡率。本文对水貂病毒性肠炎诊断方法进行了阐述。     

TYK2基因与家兔肠炎的易感性研究

[目的]研究TYK2基因在家兔肠炎发生中的遗传效应,探讨其是否可以作为家兔抗病育种的辅助选择标记。[方法]通过构建病例组-对照组肠炎兔群和低纤维诱导的肠炎兔群,PCR产物纯化后直接测序,以及qRT-PCR法检测TYK2基因在回肠和结肠组织中的mRNA表达水平。[结果]发现TYK2基因外显子区域有5个c SNP,只有c.1477(c.1477,CT)位点发生非同义突变,导致氨基酸p.Leu 404 Phe(LF)的改变,C等位基因增加了肠炎的易感性(OR:1.36;95%CI 1.269~2.151;P=0.019),而等位基因T对肠炎的发生起到了一定的保护作用(OR:0.81,95%CI 0.352~0.960;P=0.018)。TYK2基因不同基因型和不同肠炎程度的mRNA水平均呈现差异表达(P0.05)。[结论]TYK2(c.1477,CT)是家兔肠炎易感风险基因,为家兔的抗病育种提供了一个可靠的辅助选择标记。