Ovine Johne's disease in Australia ‐ the first 20 years

Sergeant, E.

doi:10.1111/j.1751-0813.2001.tb13021.x

Cited by 40 publications

(32 citation statements)

References 20 publications

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“…Apart from these isolates, there are no known S strains from Australia with the capacity to grow on HEYϩMJ; in fact, until the development of media suitable for the cultivation of S strains in 1998 (48), a presumptive diagnosis of paratuberculosis due to the S strain was made when cultures on HEYϩMJ from animals that had typical histopathological lesions of paratuberculosis were negative. It is unknown why these isolates from the very early stages of the paratuberculosis epizootic in sheep in Australia (37) and not isolates obtained later in the epizootic can grow on HEYϩMJ. It is possible that there was no selective advantage in the biochemistry underlying this growth capacity, and it was lost during microbial evolution in the sheep population.…”

Section: Discussionmentioning

confidence: 99%

Culture Phenotypes of Genomically and Geographically Diverse Mycobacterium avium subsp. paratuberculosis Isolates from Different Hosts

et al. 2011

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Mycobacterium avium subsp. paratuberculosis causes paratuberculosis (Johne's disease) in ruminants in most countries. Historical data suggest substantial differences in culturability of M. avium subsp. paratuberculosis isolates from small ruminants and cattle; however, a systematic comparison of culture media and isolates from different countries and hosts has not been undertaken. Here, 35 field isolates from the United States, Spain, Northern Ireland, and Australia were propagated in Bactec 12B medium and Middlebrook 7H10 agar, genomically characterized, and subcultured to Lowenstein-Jensen (LJ), Herrold's egg yolk (HEY), modified Middlebrook 7H10, Middlebrook 7H11, and Watson-Reid (WR) agars, all with and without mycobactin J and some with sodium pyruvate. Fourteen genotypes of M. avium subsp. paratuberculosis were represented as determined by BstEII IS900 and IS1311 restriction fragment length polymorphism analysis. There was no correlation between genotype and overall culturability, although most S strains tended to grow poorly on HEY agar. Pyruvate was inhibitory to some isolates. All strains grew on modified Middlebrook 7H10 agar but more slowly and less prolifically on LJ agar. Mycobactin J was required for growth on all media except 7H11 agar, but growth was improved by the addition of mycobactin J to 7H11 agar. WR agar supported the growth of few isolates. The differences in growth of M. avium subsp. paratuberculosis that have historically been reported in diverse settings have been strongly influenced by the type of culture medium used. When an optimal culture medium, such as modified Middlebrook 7H10 agar, is used, very little difference between the growth phenotypes of diverse strains of M. avium subsp. paratuberculosis was observed. This optimal medium is recommended to remove bias in the isolation and cultivation of M. avium subsp. paratuberculosis.Mycobacterium avium subsp. paratuberculosis is the causative agent of Johne's disease of ruminants, which occurs in most countries. Usually it is an enteric infection with a long incubation period and progressively worsening granulomatous infiltration of the small and large intestines leading to weight loss and death. It is economically significant in farmed cattle, goats, sheep, and deer and is known to be capable of infecting a wide range of domesticated and free-living herbivores and occasionally also the carnivores that prey upon them (2, 4, 6, 15). Like many pathogenic mycobacteria, M. avium subsp. paratuberculosis is not host specific, and cross-species transmission is common where there are high contact rates. Although tissue colonization and histological lesions may occur, clinical disease in response to infection is rarely reported for nonruminant species, except for rabbits (2, 4). There is a long-standing debate about the role of M. avium subsp. paratuberculosis in chronic inflammatory bowel disease of humans, specifically Crohn's disease. Consequently, the isolation and cultivation of M. avium subsp. paratuberculosis are attempted in both vet...

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Section: Discussionmentioning

confidence: 99%

Culture Phenotypes of Genomically and Geographically Diverse Mycobacterium avium subsp. paratuberculosis Isolates from Different Hosts

et al. 2011

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“…Mortalities due to Johne's disease of only 1% of adult ewes in many cases would not have been suffi cient for farmers to seek help from a veterinarian. At no time was there any concerted effort to carry out an active surveillance programme for Johne's disease in sheep similar to that currently being pursued in Australia (Sergeant 2001). Given these factors, together with the practice of buying cull ewes for breeding purposes, it is highly likely that the reported cases of Johne's disease in sheep in New Zealand are a poor refl ection of the true prevalence.…”

Section: Sheepmentioning

confidence: 97%

“…The substantial funding of Johne's control programmes by state and federal governments in Australia can be justifi ed on the basis of their low prevalence and the restricted distribution of Johne's disease in sheep (Sergeant 2001). The certifi cation of fl ocks as being at low risk of having Johne's disease has much to recommend it, but the potential Achille's heal of the Australian programme is the lack of cost-effective tools to eradicate M. paratuberculosis from infected fl ocks.…”

Section: Crohn's Diseasementioning

confidence: 99%

Johne's disease in New Zealand: the past, present and a glimpse into the future

Lisle

2002

New Zealand Veterinary Journal

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Extract • Johne's disease is endemic in cattle and sheep in New Zealand and is spreading in farmed deer. • Procedures for the control of Johne's disease in New Zealand have been sporadic and often ineffective. • Characterisation of strains of Mycobacterium paratuberculosis using molecular biological techniques have revealed two distinct strain types. One type has been found in cattle, goats and deer, and the other in sheep, goats and deer • Vaccination has been identified as an important method for the control of Johne's disease in New Zealand but the side effects of the current oil-based vaccines severely limit their use. • There is increasing international concern that M. paratuberculosis may cause Crohn's disease in humans • Demands for food free of M. paratuberculosis would have very serious consequences for the meat and dairy industries in New Zealand and overseas. • The cattle, sheep, goat and deer industries need to jointly develop a strategy for the control of Johne's disease in New Zealand.

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“…paratuberculosis ( Map ) is the causal agent of paratuberculosis or Johne's disease (JD), a chronic inflammatory bowel disease of domesticated ruminants including cattle, sheep, goats and farmed deer, and wildlife worldwide [1], [2], [3]. Paratuberculosis causes major economic losses to the global dairy industry due to lower milk production and reduced slaughter value [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Mycobacterium Avium subsp. Paratuberculosis Isolates Induce In Vitro Granuloma Formation and Show Successful Survival Phenotype, Common Anti-Inflammatory and Antiapoptotic Responses within Ovine Macrophages Regardless of Genotype or Host of Origin

et al. 2014

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The analysis of the early macrophage responses, including bacterial growth within macrophages, represents a powerful tool to characterize the virulence of clinical isolates of Mycobcaterium avium susbp. paratuberculosis (Map). The present study represents the first assessment of the intracellular behaviour in ovine monocyte-derived macrophages (MDMs) of Map isolates representing distinct genotypes (C, S and B), and isolated from cattle, sheep, goat, fallow deer, deer, and wild boar. Intracellular growth and survival of the selected isolates in ovine MDMs was assessed by quantification of CFUs inside of the host cells at 2 h p.i. (day 0) and 7 d p. i. using an automatic liquid culture system (Bactec MGIT 960). Variations in bacterial counts over 7 days from the baseline were small, in a range between 1.63 to 1.05-fold. After 7 d of infection, variations in the estimated log10 CFUs between all the tested isolates were not statistically significant. In addition, ovine MDMs exhibited enhanced anti-inflammatory, antiapoptotic and antidestructive responses when infected with two ovine isolates of distinct genotype (C and S) or with two C-type isolates from distinct hosts (cattle and sheep); which correlated with the successful survival of these isolates within ovine MDMs. A second objective was to study, based on an in vitro granuloma model, latter stages of the infection by investigating the capacity of two Map isolates from cattle and sheep to trigger formation of microgranulomas. Upon 10 d p.i., both Map isolates were able to induce the formation of granulomas comparable to the granulomas observed in clinical specimens with respect to the cellular components involved. In summary, our results demonstrated that Map isolates from cattle, sheep, goats, deer, fallow-deer and wild boar were able not only to initiate but also to establish a successful infection in ovine macrophages regardless of genotype.

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Ovine Johne's disease in Australia ‐ the first 20 years

Cited by 40 publications

References 20 publications

Culture Phenotypes of Genomically and Geographically Diverse Mycobacterium avium subsp. paratuberculosis Isolates from Different Hosts

Culture Phenotypes of Genomically and Geographically Diverse Mycobacterium avium subsp. paratuberculosis Isolates from Different Hosts

Johne's disease in New Zealand: the past, present and a glimpse into the future

Mycobacterium Avium subsp. Paratuberculosis Isolates Induce In Vitro Granuloma Formation and Show Successful Survival Phenotype, Common Anti-Inflammatory and Antiapoptotic Responses within Ovine Macrophages Regardless of Genotype or Host of Origin

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