Mycobacterial infection in goats: Diagnosis and pathogenicity of the organism

Counterimmunoelectrophoresis of serum samples and intradermal tuberculin testing were compared with cultural results for the diagnosis of mycobacterial infection in a goat herd. Only eight of 47 culture-positive animals were not identified by a combination of the other two methods.Typical isolates resembled Mycobacterium paratuberculosis in cultural characteristics and mycobactin dependence but serologically resembled Mycobacterium avium. One isolate was inoculated into guinea-pigs, mice, chickens and calves and, although the infection in guinea-pigs, mice and chickens resembled that of M. paratuberculosis, it did not cause Johne's-like disease in calves.     

Studies on the efficiency of absorbed bovine PPD in tuberculin and serological tests

The passive haemagglutination, enzyme-linked immunosorbent assay and indirect fluorescent antibody tests were applied to study the non-specific reactions in experimentally infected guinea pigs and tuberculin positive bovines. These cross-reactions were greatly decreased after absorption of either sera with avian PPD or bovine PPD antigen with anti-avian PPD serum. The use of both absorbed sera and antigen raised the specificity of PHA and ELISA to 100%. The use of absorbed sera rendered the IFA specific in 95%. The absorption has reduced the sensitivity of ELISA, IFA and PHA by 14, 27 and 29%, respectively.     

不同接种方法对奶牛PPD变态反应结果的影响

通过对奶牛PPD点眼、皮内注射、浅层肌肉注射、多次进针接种等不同方法的变态反应，对比观察其反应结果，得出了一次性成功的皮内注射是PPD接种的最佳方式，而点眼法和浅层肌肉注射、多次进针接种，可使变态反应呈现出假阴性和假阳性事件，提出掌握娴熟的皮内注射方法和技能是提高PPD变态反应结果准确性的关键。     

新疆部分地区牛结核病PPD监测与分析

2001年-2003年对新疆部分地区（巴州、阿克苏、博州、伊犁、昌吉、塔城和石河子）牛结核病用“提纯结核茵素皮内变态反应”进行调查,调查数据用SPSS软件统计建立模型,显示2001年-2003年七地州检测牛只分别为16793,21153头和43951头,阳性率分别为0．46％,0．33％和0．57％。其中,巴州地区阳性率明显偏高。昌吉和石河子地区2001年-2002年保持一个较低的水平,2003年牛结核病的阳性率较前两年升高了1％。     

Use of the johnin PPD interferon-gamma assay in control of bovine paratuberculosis

Although the interferon-gamma (IFN-γ) assay for measurements of cell-mediated immune (CMI) responses to paratuberculosis PPD (johnin) has been available for close to 20 years, the assay has not yet emerged as the long desired test to identify infected animals at an early time point. Among other issues, this relates to problematic interpretation of the test results and maybe an over-expectation of what can be deducted from this kind of test given the chronic nature and slow development of infection of paratuberculosis. Over a number of years a modified IFN-γ assay with addition of recombinant bovine IL-12 to the PPDj stimulation of blood samples from the heifer group in more than 20 Danish dairy herds which also perform surveillance of MAP antibodies in milk have been performed. The results indicate that IFN-γ assay results are specific for paratuberculosis, but the IFN-γ assay result of an individual animal cannot establish whether the animal is infected or predict the future progression of disease in this animal. The IFN-γ assay should thus be used on a group of animals to test the level of exposure to paratuberculosis bacteria the animals have experienced, and thereby assist in maintaining rational in-herd management procedures and in the establishment of paratuberculosis status of a given herd. Indeed, for any diagnostic test applied in paratuberculosis, both the diagnostic target condition and the purpose of the diagnostic testing must be considered before any meaningful estimates of sensitivity or specificity can be given.     

Mycobacterial infections in equids: Clinical characteristics and diagnostic techniques

Mycobacterial infections in equids are relatively rare but the case report (Charlesworth 2017) detailed in this issue highlights that Mycobacterium bovis infections may still result in clinical signs in this incidental host and have zoonotic potential. Most reported cases of M. bovis in horses have a protracted disease course, with features including pyrexia, weight loss and oedema with a nonspecific inflammatory profile. As such, the clinical features of disease overlap with conditions such as neoplasia, peritonitis, protein‐losing enteropathies and bacterial infections including Rhodococcus equi and Lawsonia intracellularis. In this clinical satellite article, mycobacterial infections in equids are considered in terms of incidence and mode of transmission, key clinical features and perhaps most importantly, in terms of the diagnostic techniques that can be used in order to reach a definitive (ante mortem) diagnosis. The major zoonotic risk to veterinary personnel is likely to occur at the time of post‐mortem examination of infected horses, and awareness of these potential risks remains of the utmost importance.     

两种奶牛结核病检测方法与PPD检测符合率比较

对新疆某规模化奶牛场的2 106头奶牛用PPD进行普检,共检出结核病阳性牛26头;随机采集20头阴性牛和26头阳性牛抗凝血和全血,进行牛结核γ-干扰素ELISA试验和胶体金检测,然后将检测结果与PPD检测结果进行比对。结果显示:3种方法检测均为阳性的16份,均为阴性的10份,总符合率为57%。PPD和γ-干扰素ELISA相比,均为阳性的23份,阳性符合率为88%(23/26),均为阴性的11份,阴性符合率为55%(11/20);PPD和胶体金检测相比,均为阳性的19份,阳性符合率为73%(19/26),均为阴性的19份,阴性符合率为95%(19/20)。结果表明:3种检测方法的符合率较低;每种检测方法各有优缺点,γ-干扰素ELISA敏感性较高,而胶体金特异性较高。因此,在实际操作中应根据需要,合理选择相应检测方法。     

PPD的批次与注射方式对PPD皮内变态反应检疫的影响

为了探究在牛结核病检疫中出现的使用不同批次的PPD和皮下注射PPD等情况是否会对检疫结果的判定造成干扰。本试验首次通过在豚鼠背部采用皮下注射法和皮内交替注射同一厂家不同批次的结核菌素提纯蛋白衍化物(Purified protein derivative of tuberculin,PPD)的方法,参照《结核菌素提纯蛋白衍化物(PPD)制造及检定规程》于每次注射后24h、48h和72h观察皮试处是否产生迟发型变态反应。试验结果为皮内组(不同批次PPD皮内注射)和皮下组(同一批次PPD皮下注射)经3次注射后的皮试结果与标准参照组的皮试结果无差异,且在每次皮试后的24h、48h和72h皮试处均未出现局部红斑硬结。本试验证明了PPD皮内变态反应检疫结果判定不受PPD皮下接种及PPD的不同批次的干扰。     

Applying the One Health Concept to Mycobacterial Research – Overcoming Parochialism

Mycobacterial infections remain a public health problem. Historically important, globally ubiquitous and with a wide host range, we are still struggling to control mycobacterial infections in humans and animals. While previous reviews have focused on individual mycobacterial infections in either humans or animals, a comprehensive review of the zoonotic aspect of mycobacteria in the context of the One Health initiative is lacking. With the purpose of providing a concise and comprehensive resource, we have collated literature to address the zoonotic potential of different mycobacterial species and elaborate on the necessity for an inter‐sectorial approach to attain a new vision to combat mycobacterial infections.