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Mycobacterial Diseases in Animals

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A special issue of Veterinary Sciences (ISSN 2306-7381).

Deadline for manuscript submissions: closed (30 September 2019) | Viewed by 61505

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Special Issue Editors

Prof. Dr. Shigetoshi Eda

E-Mail Website
Guest Editor

Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996, USA
Interests: infectious diseases; immunology; epidemiology; mathematical modeling; diagnosis; biosensor
Special Issues, Collections and Topics in MDPI journals

Prof. Dr. Graham J. Hickling

E-Mail Website
Guest Editor

Institute of Agriculture, The University of Tennessee, Knoxville, TN 37996, USA
Interests: wildlife disease ecology; zoonotic disease

Special Issue Information

Dear Colleagues,

Mycobacterial diseases are a significant threat to humans and other animals. According to WHO statistics, tuberculosis (TB) is one of the top 10 causes of human deaths worldwide, with 10 million people falling ill with TB in 2017, and 1.6 million dying from the disease. Bovine tuberculosis, mainly caused by Mycobacterium bovis, is a zoonotic risk and a significant economic threat to agricultural industries. Johne’s disease, a mycobacterial disease that mainly affects ruminants, is another economic threat to agriculture. Mycobacteria in wild species as diverse as seals and armadillos are of potential zoonotic concern.

Mycobacteria are sturdy organisms that can persist in the environment. Therefore, system-oriented solutions and One Health approaches are critically important for control and eventual eradication of mycobacterial diseases. In this Special Issue, we will collect scientific works from a broad range of research fields to better understand current challenges, opportunities and successes in the research field of “Mycobacterial Diseases in Animals”.

Suitable topics for contributions to the Special Issue include:

Microbiology and genetics of mycobacteria
Host immunity against mycobacterial infection
Host–pathogen interactions
Host susceptibility
Experimental methods
Epidemiology and mathematical modeling of mycobacterial disease
Zoonotic risk
Diagnosis, treatment and vaccination
Opportunities and alternatives for mycobacterial disease management and control

Contributions are not limited to the above list; we particularly encourage submissions with a focus on systems and/or One Health approaches in this field of study.

Prof. Dr. Shigetoshi Eda
Prof. Dr. Graham J. Hickling
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Veterinary Sciences is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Mycobacterium bovis
Mycobacterium avium subsp. paratuberculosis
microbiology
immunology
susceptibility
epidemiology
diagnosis
control and management
Johne's disease
bovine tuberculosis

Published Papers (14 papers)

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18 pages, 282 KiB

Open AccessArticle

Australian Veterinarians’ Perceptions Regarding the Zoonotic Potential of Mycobacterium avium Subspecies Paratuberculosis

by Kamal R. Acharya, Karren M. Plain, Richard J. Whittington and Navneet K. Dhand

Vet. Sci. 2020, 7(1), 33; https://doi.org/10.3390/vetsci7010033 - 19 Mar 2020

Cited by 5 | Viewed by 3882

Abstract

Public concerns over exposure to Mycobacterium avium subspecies paratuberculosis (MAP) or MAP components via foods of animal origin could have negative trade consequences, despite the absence of conclusive scientific evidence of a causal association between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn’s disease (CD). This study was conducted among Australian veterinarians to understand (a) their perceptions regarding the role of MAP in the causation of CD (an ordinal outcome), and (b) their consideration of the adoption of the precautionary principle against Johne’s disease (JD; a binary outcome). Ordinal and binary logistic regression analyses were performed to evaluate the association of explanatory variables with the above outcomes, respectively. Almost one-third of the respondents (32.2%) considered that MAP was likely to be involved in the causation of CD whereas more than two-thirds (69.8%) agreed with the adoption of the precautionary principle against JD. Veterinarians who were concerned about exposure to and/or getting infected with MAP were more likely to consider MAP as a causative agent of CD (odds ratio: 7.63; 95% CI: 1.55, 37.63) and favor the adoption of the precautionary principle against JD (odds ratio: 6.20; 95% CI: 1.90, 20.25). Those perceiving MAP as a causative agent of CD were also more likely to favor the adoption of the precautionary principle against JD (odds ratio: 13.2; 95% CI: 1.26, 138.90). The results suggest that Australian veterinarians, particularly those who consider MAP as a causative agent of CD are concerned about exposure to MAP and favor the adoption of the precautionary principle against JD. These findings can be useful for animal health authorities for designing JD control programs and policies. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

13 pages, 405 KiB

Open AccessArticle

Exploring the Risk Posed by Animals with an Inconclusive Reaction to the Bovine Tuberculosis Skin Test in England and Wales

by Elizabeth May, Alison Prosser, Sara H. Downs and Lucy A. Brunton

Vet. Sci. 2019, 6(4), 97; https://doi.org/10.3390/vetsci6040097 - 30 Nov 2019

Cited by 4 | Viewed by 4241

Abstract

The single intradermal comparative cervical tuberculin (SICCT) test is the primary test for ante-mortem diagnosis of bovine tuberculosis (TB) in England and Wales. When an animal is first classified as an inconclusive reactor (IR) using this test, it is not subject to compulsory slaughter, but it must be isolated from the rest of the herd. To understand the risk posed by these animals, a case-control study was conducted to measure the association between IR status of animals and the odds of them becoming a reactor to the SICCT at a subsequent test. The study included all animals from herds in which only IR animals were found at the first whole herd test in 2012 and used data from subsequent tests up until the end of 2016. Separate mixed-effects logistic regression models were developed to examine the relationship between IR status and subsequent reactor status for each risk area of England and for Wales, adjusting for other explanatory variables. The odds of an animal becoming a subsequent reactor during the study period were greater for IR animals than for negative animals in the high-risk area (odds ratio (OR): 6.85 (5.98–7.86)) and edge area (OR: 8.79 (5.92–13.04)) of England and in Wales (OR: 6.87 (5.75–8.22)). In the low-risk area of England, the odds were 23 times greater, although the confidence interval around this estimate was larger due to the smaller sample size (11–48, p < 0.001). These findings support the need to explore differential controls for IR animals to reduce the spread of TB, and they highlight the importance of area-specific policies. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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18 pages, 13617 KiB

Open AccessArticle

Influence of Colostrum and Vitamins A, D₃, and E on Early Intestinal Colonization of Neonatal Holstein Calves Infected with Mycobacterium avium subsp. paratuberculosis

by Judith Stabel, Lucas Krueger, Caitlin Jenvey, Taylor Wherry, Jesse Hostetter and Donald Beitz

Vet. Sci. 2019, 6(4), 93; https://doi.org/10.3390/vetsci6040093 - 20 Nov 2019

Cited by 4 | Viewed by 4086

Abstract

Exposure of neonates to Mycobacterium avium subsp. paratuberculosis (MAP) via infected dams is the primary mode of transmission of Johne’s disease. Little is known about the impacts of feeding colostrum and supplemental vitamins on the gut microbiome in calves exposed to MAP. In the present study, calves were assigned at birth to one of six treatment groups: (1) Colostrum deprived (CD), no vitamins; (2) colostrum replacer (CR), no vitamins; (3) CR, vitamin A; (4) CR, vitamin D₃; (5) CR, vitamin E; (6) CR, vitamins A, D₃, E, with five calves per treatment in a 14-day study. All calves were orally inoculated with MAP on days 1 and 3 of the study. Differences due to vitamin supplementation were not significant but treatment groups CR-A, CR-E, and CR-ADE had higher numbers of MAP-positive tissues overall. Shannon diversity indices demonstrated regional differences in microbial communities, primarily Proteobacteria, Bacteroidetes, and Firmicutes, between the ileum, cecum, and spiral colon of all calves. CD calves exhibited increased richness compared with CR calves in the cecum and spiral colon and harbored increased Proteobacteria and decreased Bacteroidetes in the mucosa compared with the lumen for all three tissues. Overall, supplementation with vitamins did not appear to influence gut microbiome or impact MAP infection. Feeding of colostrum influenced gut microbiome and resulted in fewer incidences of dysbiosis. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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18 pages, 2148 KiB

Open AccessArticle

The Role of Phosphatidylinositol Mannosides in the Serological Diagnosis of Mycobacterial Infections

by Ad P. Koets, Marielle H. van den Esker, Karel Riepema and Douwe Bakker

Vet. Sci. 2019, 6(4), 91; https://doi.org/10.3390/vetsci6040091 - 13 Nov 2019

Cited by 1 | Viewed by 3918

Abstract

Accurate diagnosis of mycobacterial infections, such as bovine tuberculosis and paratuberculosis, remains challenging. Available direct diagnostic tests aimed at detecting the pathogen are highly specific but lack sensitivity, depending on the stage of infection and the prevalence of infection in a population. The sensitivity of indirect diagnostic assays that measure the host immune response to infection is similarly affected by disease characteristics. The choice of antigen used to detect a host response to infection has a critical impact on test sensitivity and specificity. Many indirect tests rely on crude antigen preparations and cell-free extracts, of which the production is poorly standardized. Moreover, these preparations contain ample uncharacterized cross-reactive compounds. To enhance serological test specificity, existing assays depend on the pre-treatment of samples and a relatively high cut-off value, that in turn influences test sensitivity. Research therefore focuses on the identification of more specific, defined antigens to improve diagnostics. In the current study, we extracted phosphatidylinositol mannosides (PIMs) and investigated their potential use in antibody-based tests. Our results demonstrate that specific IgG class antibodies are generated against PIMs in cows, but this is unrelated to tuberculosis or paratuberculosis infection status, making these antigens unsuitable for diagnostic applications. In addition, we demonstrate that PIMs are widely present in crude antigen preparations and in serum pre-absorption buffer. Our results indicate that PIMs are cross-reactive compounds with immunodominant B cell epitopes that could impair serological test specificity. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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10 pages, 1526 KiB

Open AccessArticle

Purification and Characterisation of Badger IgA and Its Detection in the Context of Tuberculosis

by Deanna Dalley, Sandrine Lesellier, Francisco J. Salguero and Mark A. Chambers

Vet. Sci. 2019, 6(4), 89; https://doi.org/10.3390/vetsci6040089 - 02 Nov 2019

Cited by 3 | Viewed by 3776

Abstract

European badgers are a wildlife reservoir of bovine tuberculosis in parts of Great Britain. Accurate diagnosis of tuberculosis in badgers is important for the development of strategies for the control of the disease. Sensitive serological tests for badger TB are needed for reasons such as cost and simplicity. Assay of mucosal IgA could be useful for diagnosing respiratory pathogens such as Mycobacterium bovis and for monitoring the response to mucosal vaccination. To develop an IgA assay, we purified secretory IgA from badger bile, identifying secretory component (SC), heavy chain (HC) and light chain (LC), at 66, 46 and 27 Kda, respectively, on the basis of size comparison with other species. Monoclonal antibodies (mAbs) were generated to purified IgA. We selected two for ELISA development. The detection limit of the IgA-specific mAbs was found to be approximately 20 ng/mL when titrated against purified badger bile. One monoclonal antibody specific for badger IgA was used to detect IgA in serum and tracheal aspirate with specificity to an immunodominant antigen of M. bovis. An M. bovis infection dose-dependent IgA response was observed in experimentally infected badgers. IgA was also detected by immunohistochemistry in the lungs of bTB-infected badgers. With further characterisation, these represent new reagents for the study of the IgA response in badgers. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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18 pages, 3594 KiB

Open AccessArticle

Characterization of Ethanol Extracted Cell Wall Components of Mycobacterium avium Subsp. paratuberculosis

by John P. Bannantine, Ashutosh Wadhwa, Judith R. Stabel and Shigetoshi Eda

Vet. Sci. 2019, 6(4), 88; https://doi.org/10.3390/vetsci6040088 - 31 Oct 2019

Cited by 4 | Viewed by 4501

Abstract

Antigens extracted using ethanol (EtOH) and incorporated in the EtOH vortex ELISA (EVELISA) test have previously shown high specificity and sensitivity for detecting Mycobacterium avium subspecies paratuberculosis (Map) and M. bovis infections in cattle. The objective of this study is to define the components present in the EtOH extract. We show that this extract is composed of lipid, carbohydrate, and proteins on the surface of the bacilli, and that EtOH removes the outer layer structure of Map which comprise these elements. To identify proteins, polyclonal antibodies to the EtOH prep were produced and used to screen a Map genomic expression library. Seven overlapping clones were identified with a single open reading frame, MAP_0585, common to all. MAP_0585, which encodes a hypothetical protein, was recombinantly produced and used to demonstrate strong reactivity in sera from hyperimmunized rabbits, but this protein is not strongly immunogenic in cattle with Johne’s disease. A panel of monoclonal antibodies was used to determine the presence of additional proteins in the EtOH extract. These antibodies demonstrated that a well-known antigen, termed MPB83, is present in M. bovis EtOH extracts and a fatty acid desaturase (MAP_2698c) is present in Map EtOH extracts, while lipoarabinomannan was common to both. The lipid and carbohydrate components of the extract were analyzed using thin layer chromatography and lectin binding, respectively. Lectin biding and protease treatment of the EtOH extract suggest the antigenic component is carbohydrate and not protein. These results give further insight into this important antigen prep for detecting mycobacterial diseases of cattle. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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10 pages, 13715 KiB

Open AccessArticle

Mongoose (Herpestes auropunctatus) May Not Be Reservoir Hosts for Mycobacterium bovis in Fiji Despite High Population Density and Direct Contact with Cattle

by Philip J. Hayton, Richard J. Whittington, Colin Wakelin, Paul Colville, Aoife Reid, Leo Borja and Jenny-Ann Toribio

Vet. Sci. 2019, 6(4), 85; https://doi.org/10.3390/vetsci6040085 - 24 Oct 2019

Cited by 3 | Viewed by 4567

Abstract

The presence of a wildlife reservoir for Mycobacterium bovis complicates the eradication of bovine tuberculosis (BTB) from domestic cattle populations. For the BTB eradication program in Fiji, there is concern about the small Indian mongoose (Herpestes auropunctatus), which is overabundant and in direct contact with cattle. Consequently, a survey of mongooses trapped on three BTB affected dairy farms led to necropsy of 85 mongooses during January–February 2017. Thirty (35%) mongooses had gross pathological changes including possible granulomas detected at necropsy, and tissues from these animals were taken for histopathological examination. Granulomatous lesions were present in 53% of animals examined histopathologically but acid-fast bacilli were not observed and the majority of lesions in lung and kidney were associated with the nematodes Pulmostrongylus herpestis and Capillaria sp., respectively. Nevertheless, assuming test sensitivity of 35% for the current study, from this sample of 85 mongooses it can be concluded with 95% confidence that if present in the mongoose population susceptible to trapping, M. bovis prevalence was ≤10%. The prevalence of intercurrent lesions raised concerns about gross pathology as a screening test for M. bovis infection in mongooses in Fiji, and therefore pathogen detection methods such as bacterial culture and direct tissue PCR are recommended for future surveys. These are needed to completely rule out the mongoose as a reservoir host for M. bovis in Fiji. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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10 pages, 730 KiB

Open AccessArticle

by Alejandro Benítez-Guzmán, Hugo Esquivel-Solís, Cecilia Romero-Torres, Camila Arriaga-Díaz and José A. Gutiérrez-Pabello

Vet. Sci. 2019, 6(4), 81; https://doi.org/10.3390/vetsci6040081 - 18 Oct 2019

Cited by 3 | Viewed by 3725

Abstract

Molecular typing of bacterial isolates provides a powerful approach for distinguishing Mycobacterium bovis (M. bovis) genotypes. It is known that M. bovis strain virulence plays a role in prevalence and spread of the disease, suggesting that strain virulence and prevailing genotypes are associated. However, it is not well understood whether strain virulence correlates with particular genotypes. In this study, we assessed the in vitro intracellular growth of 18 M. bovis isolates in bovine macrophages as an indicator of bacterial virulence and sought a relationship with the genotype identified by spoligotyping. We found 14 different spoligotypes—11 were already known and three spoligotypes had never been reported before. We identified 2 clusters that were phylogenetically related, containing 10 and 6 strains, respectively, and 2 orphan strains. Intracellular growth and phagocytic rates of 18 M. bovis strains were heterogeneous. Our results suggest that M. bovis intracellular growth and phagocytosis are independent of the bacterial lineage identified by spoligotyping. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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18 pages, 4224 KiB

Open AccessArticle

Modelling Bovine Granuloma Formation In Vitro upon Infection with Mycobacterium Avium Subspecies Paratuberculosis

by J. Hunter Rice, Margaret M. McDaniel, Alyson Holland and Shigetoshi Eda

Vet. Sci. 2019, 6(4), 80; https://doi.org/10.3390/vetsci6040080 - 12 Oct 2019

Cited by 6 | Viewed by 4764

Abstract

Mycobacterium avium subspecies paratuberculosis (Map) causes chronic granulomatous disease in cattle and ruminant livestock, causing substantial economic losses. Current vaccines delay clinical signs but cannot train the immune system to fully eradicate latent Map. During latency, Map uses host defenses, cage-like macrophage clusters called granuloma, as incubators for months or years. We used an in vitro model to investigate the early coordination of macrophages into granuloma upon Map infection over ten days. We found that at multiplicities of infection (MOI; Map:macrophages) of 1:2 and below, the macrophages readily form clusters and evolve pro-inflammatory cytokines in keeping with a cell-mediated immune response. At higher MOIs, viability of host macrophages is negatively impacted. At 1:4 MOI, we quantified viable Map in our model and confirmed that intracellular Map reproduced over the first five days of infection. Host cells expressed Type 1-specific cytokines, and Map-infected macrophages displayed reduced motility compared to Map-exposed, uninfected macrophages, suggesting an important role for uninfected macrophages in the early aggregative response. Reported is the first in vitro JD granuloma model capturing Map and macrophage viability, size distribution of resulting clusters, motility of monocyte-derived macrophages, and cytokine response during clustering, allowing quantitative analysis of multiple parameters of the Map-specific granulomatous response. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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18 pages, 961 KiB

Open AccessArticle

Effects of Age and Environment on Adaptive Immune Responses to Mycobacterium avium subsp. paratuberculosis (MAP) Vaccination in Dairy Goats in Relation to Paratuberculosis Control Strategies

by Ad Koets, Lars Ravesloot, Robin Ruuls, Annemieke Dinkla, Susanne Eisenberg and Karianne Lievaart-Peterson

Vet. Sci. 2019, 6(3), 62; https://doi.org/10.3390/vetsci6030062 - 01 Jul 2019

Cited by 11 | Viewed by 4501

Abstract

Paratuberculosis infection is caused by Mycobacterium avium subsp. paratuberculosis (MAP). In the Netherlands, 75% herd level prevalence of caprine paratuberculosis has been estimated, and vaccination is the principal control strategy applied. Most goat dairy farms with endemic paratuberculosis systematically vaccinate goat kids in the first months of life with a commercially available whole cell MAP vaccine. We hypothesized that the development of adaptive immune responses in goats vaccinated at young age depends on the environment they are raised in, and this has implications for the application of immune diagnostic tests in vaccinated dairy goats. We evaluated the early immune response to vaccination in young goat kids sourced from a MAP unsuspected non-vaccinated herd and raised in a MAP-free environment. Subsequently we compared these with responses observed in birth year and vaccination matched adult goats raised on farms with endemic paratuberculosis. Results indicated that initial adaptive immune responses to vaccination are limited in a MAP-free environment. In addition, adult antibody positive vaccinated goats raised in a MAP endemic environment are less likely to be IS900 PCR-positive as compared to antibody negative herd mates. We conclude that test-and-cull strategies in a vaccinated herd are currently not feasible using available immune diagnostic tests. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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9 pages, 728 KiB

Open AccessArticle

Mycobacterium avium subsp. paratuberculosis ELISA Responses in Milk Samples from Vaccinated and Nonvaccinated Dairy Goat Herds in The Netherlands

by Saskia Luttikholt, Karianne Lievaart-Peterson, Maaike Gonggrijp, Marian Aalberts, Gerdien van Schaik and Piet Vellema

Vet. Sci. 2019, 6(2), 58; https://doi.org/10.3390/vetsci6020058 - 22 Jun 2019

Cited by 4 | Viewed by 4121

Abstract

The aims of our study were to calculate the most appropriate cut-off value for milk samples in a serum-validated Mycobacterium avium subsp. paratuberculosis (MAP) ELISA and to analyze MAP ELISA responses in milk samples from vaccinated and nonvaccinated dairy goats in the Netherlands. Analyzed herds were representative for location and herd size of dairy goat herds in the Netherlands. A significantly higher proportion of the analyzed 49 herds were organic as compared with the total Dutch dairy goat population. First, the MAP ELISA was optimized using 992 paired serum and milk samples. At a cut-off of 25 S/P%, the relative sensitivity (Se) was 58.4% (n = 992, 95% CI: 48.8%−67.6%) and relative specificity (Sp) was 98.5% (n = 992, 95% CI: 97.5%−99.2%), as compared to serum ELISA results. The percentage of positively tested herds was 78.2% (n = 49, 95% CI: 63.4%−88.1%). The percentage of positive milk samples per herd (n = 22) was on average 4.6% (median, min, and max of 4.7%, 0.0%, and 10.7%, respectively). Average age of ELISA-positive (3.2 years) and -negative goats (3.2 years) was not different. Significantly more vaccinated goats tested positive (6.7%) as compared with nonvaccinated goats (1.1%). This study shows that a high number of vaccinated and nonvaccinated commercial dairy goat herds in the Netherlands have MAP-ELISA-positive goats. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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10 pages, 498 KiB

Open AccessFeature PaperArticle

Novel Amphiphilic Cyclobutene and Cyclobutane cis-C₁₈ Fatty Acid Derivatives Inhibit Mycobacterium avium subsp. paratuberculosis Growth

by Denise K. Zinniel, Wantanee Sittiwong, Darrell D. Marshall, Govardhan Rathnaiah, Isin T. Sakallioglu, Robert Powers, Patrick H. Dussault and Raúl G. Barletta

Vet. Sci. 2019, 6(2), 46; https://doi.org/10.3390/vetsci6020046 - 24 May 2019

Cited by 5 | Viewed by 4771

Abstract

Mycobacterium avium subspecies paratuberculosis (Map) is the etiologic agent of Johne’s disease in ruminants and has been associated with Crohn’s disease in humans. An effective control of Map by either vaccines or chemoprophylaxis is a paramount need for veterinary and possibly human medicine. Given the importance of fatty acids in the biosynthesis of mycolic acids and the mycobacterial cell wall, we tested novel amphiphilic C₁₀ and C₁₈ cyclobutene and cyclobutane fatty acid derivatives for Map inhibition. Microdilution minimal inhibitory concentrations (MIC) with 5 or 7 week endpoints were measured in Middlebrook 7H9 base broth media. We compared the Map MIC results with those obtained previously with Mycobacterium tuberculosis and Mycobacterium smegmatis. Several of the C₁₈ compounds showed moderate efficacy (MICs 392 to 824 µM) against Map, while a higher level of inhibition (MICs 6 to 82 µM) was observed for M. tuberculosis for select analogs from both the C₁₀ and C₁₈ groups. For most of these analogs tested in M. smegmatis, their efficacy decreased in the presence of bovine or human serum albumin. Compound 5 (OA-CB, 1-(octanoic acid-8-yl)-2-octylcyclobutene) was identified as the best chemical lead against Map, which suggests derivatives with better pharmacodynamics may be of interest for evaluation in animal models. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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17 pages, 906 KiB

Open AccessArticle

Elucidating Transmission Patterns of Endemic Mycobacterium avium subsp. paratuberculosis Using Molecular Epidemiology

by Rebecca M. Mitchell, Annabelle Beaver, Elena Knupfer, Abani K. Pradhan, Terry Fyock, Robert H. Whitlock and Ynte H. Schukken

Vet. Sci. 2019, 6(1), 32; https://doi.org/10.3390/vetsci6010032 - 20 Mar 2019

Cited by 7 | Viewed by 5030

Abstract

Mycobacterial diseases are persistent and characterized by lengthy latent periods. Thus, epidemiological models require careful delineation of transmission routes. Understanding transmission routes will improve the quality and success of control programs. We aimed to study the infection dynamics of Mycobacterium avium subsp. paratuberculosis (MAP), the causal agent of ruminant Johne’s disease, and to distinguish within-host mutation from individual transmission events in a longitudinally MAP-defined dairy herd in upstate New York. To this end, semi-annual fecal samples were obtained from a single dairy herd over the course of seven years, in addition to tissue samples from a selection of culled animals. All samples were cultured for MAP, and multi-locus short-sequence repeat (MLSSR) typing was used to determine MAP SSR types. We concluded from these precise MAP infection data that, when the tissue burden remains low, the majority of MAP infections are not detectable by routine fecal culture but will be identified when tissue culture is performed after slaughter. Additionally, we determined that in this herd vertical infection played only a minor role in MAP transmission. By means of extensive and precise longitudinal data from a single dairy herd, we have come to new insights regarding MAP co-infections and within-host evolution. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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Review

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22 pages, 298 KiB

Open AccessReview

Application of Transcriptomics to Enhance Early Diagnostics of Mycobacterial Infections, with an Emphasis on Mycobacterium avium ssp. paratuberculosis

by Marielle H. van den Esker and Ad P. Koets

Vet. Sci. 2019, 6(3), 59; https://doi.org/10.3390/vetsci6030059 - 26 Jun 2019

Cited by 18 | Viewed by 4726

Abstract

Mycobacteria cause a wide variety of disease in human and animals. Species that infect ruminants include M. bovis and M. avium ssp. paratuberculosis (MAP). MAP is the causative agent of Johne’s disease in ruminants, which is a chronic granulomatous enteric infection that leads to severe economic losses worldwide. Characteristic of MAP infection is the long, latent phase in which intermittent shedding can take place, while diagnostic tests are unable to reliably detect an infection in this stage. This leads to unnoticed dissemination within herds and the presence of many undetected, silent carriers, which makes the eradication of Johne’s disease difficult. To improve the control of MAP infection, research is aimed at improving early diagnosis. Transcriptomic approaches can be applied to characterize host-pathogen interactions during infection, and to develop novel biomarkers using transcriptional profiles. Studies have focused on the identification of specific RNAs that are expressed in different infection stages, which will assist in the development and clinical implementation of early diagnostic tests. Full article

(This article belongs to the Special Issue Mycobacterial Diseases in Animals)

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