The Consensus from the Mycobacterium avium ssp. paratuberculosis (MAP) Conference 2017

Mycobacterium paratuberculosis: A HERV Turn-On for Autoimmunity, Neurodegeneration, and Cancer?

Human endogenous retroviruses (HERVs) are remnants of ancient retroviral infections that, over millions of years, became integrated into the human genome. While normally inactive, environmental stimuli such as infections have contributed to the transcriptional reactivation of HERV-promoting pathological conditions, including the development of autoimmunity, neurodegenerative disease and cancer. What infections trigger HERV activation? Mycobacterium avium subspecies paratuberculosis (MAP) is a pluripotent driver of human disease. Aside from granulomatous diseases, Crohn's disease, sarcoidosis and Blau syndrome, MAP is associated with autoimmune disease: type one diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis (RA) and autoimmune thyroiditis. MAP is also associated with Alzheimer's disease (AD) and Parkinson's disease (PD). Autoimmune diabetes, MS and RA are the diseases with the strongest MAP/HERV association. There are several other diseases associated with HERV activation, including diseases whose epidemiology and/or pathology would prompt speculation for a causal role of MAP. These include non-solar uveal melanoma, colon cancer, glioblastoma and amyotrophic lateral sclerosis (ALS). This article further points to MAP infection as a contributor to autoimmunity, neurodegenerative disease and cancer via the un-silencing of HERV. We examine the link between the ever-increasing number of MAP-associated diseases and the MAP/HERV intersection with these diverse medical conditions, and propose treatment opportunities based upon this association.

Systematic assessment of the reliability of quantitative PCR assays targeting IS900 for the detection of Mycobacterium avium ssp. paratuberculosis presence in animal and environmental samples

Mycobacterium avium ssp. paratuberculosis (MAP) is the bacterium responsible for causing Johne's disease (JD), which is endemic to dairy cattle and also implicated in the etiology of Crohn's disease. The difficulty in diagnosing asymptomatic cows for JD makes this disease hard to control. Johne's disease is considered a priority under the One Health approach to prevent the spread of the causative agent to humans. Environmental screening is a strategic approach aimed at identifying dairy herds with animals infected with MAP. It serves as the initial step toward implementing more intensive actions to control the disease. Quantitative PCR (qPCR) technology is widely used for diagnosis. Given that genome sequencing is now much more accessible than ever before, it is possible to target regions of the MAP genome that allow for the greatest diagnostic sensitivity and specificity. The aim of this study was to identify among the published qPCR assays targeting IS900 the more cost-effective options to detect MAP and to validate them in the diagnostic context of JD. Mycobacterium avium ssp. paratuberculosis IS900 is a prime target because it is a multicopy genetic element. A total of 136 publications have reported on the use of IS900 qPCR assays over the past 3 decades. Among these records, 29 used the SYBR Green chemistry, and 107 used TaqMan technology. Aside from the 9 reports using commercial assays, 72 TaqMan reports cited previously published work, leaving us with 27 TaqMan qPCR designs. Upon closer examination, 5 TaqMan designs contained mismatches in primer or probe sequences. Additionally, others exhibited high similarity to environmental microorganisms or non-MAP mycobacteria. We assessed the performance of 6 IS900 qPCR designs and their sensitivity when applied to clinical or environmental samples, which varied from 4 to 56 fold overall. Additionally, we provide recommendations for testing clinical and environmental samples, as certain strategies used previously should be avoided due to poor qPCR design (e.g., the presence of mismatches) or a lack of specificity.

Proteomic Serum Profiling of Holstein Friesian Cows with Different Pathological Forms of Bovine Paratuberculosis Reveals Changes in the Acute-Phase Response and Lipid Metabolism

The lack of sensitive diagnostic methods to detect Mycobacterium avium subsp. paratuberculosis (Map) subclinical infections has hindered the control of paratuberculosis (PTB). The serum proteomic profiles of naturally infected cows presenting focal and diffuse pathological forms of PTB and negative controls (n = 4 per group) were analyzed using TMT-6plex quantitative proteomics. Focal and diffuse are the most frequent pathological forms in subclinical and clinical stages of PTB, respectively. One (focal versus (vs.) control), eight (diffuse vs. control), and four (focal vs. diffuse) differentially abundant (DA) proteins (q-value < 0.05) were identified. Ingenuity pathway analysis of the DA proteins revealed changes in the acute-phase response and lipid metabolism. Six candidate biomarkers were selected for further validation by specific ELISA using serum from animals with focal, multifocal, and diffuse PTB-associated lesions (n = 108) and controls (n = 56). Overall, the trends of the serum expression levels of the selected proteins were consistent with the proteomic results. Alpha-1-acid glycoprotein (ORM1)-based ELISA, insulin-like growth factor-binding protein 2 (IGFBP2)-based ELISA, and the anti-Map ELISA had the best diagnostic performance for detection of animals with focal, multifocal, and diffuse lesions, respectively. Our findings identify potential biomarkers that improve diagnostic sensitivity of PTB and help to elucidate the mechanisms involved in PTB pathogenesis.

Mycobacterium avium subsp. paratuberculosis in Wild Boar (Sus scrofa) in Portugal

Paratuberculosis, or Johne's disease, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic granulomatous enteritis affecting both domestic and wild ruminants. The agent was also found in wild mammals such as wild boar (Sus scrofa); however, the role of wild mammals in the epidemiology of MAP is unclear. During the research period, 941 free-ranging wild boar (S. scrofa) legally hunted in two locations in the central-eastern region of Portugal were examined. Ninety-seven wild boars exhibited one or more gross lesions and were tested for the presence of Mycobacterium avium subsp. paratuberculosis using acid-fast staining, mycobacterial culture, polymerase chain reaction (PCR), and histopathological examination. Forty-five animals (46.4%, 95% CI: 36.5-56.3%) were identified as infected, as indicated by positive results in culture and/or PCR. The findings revealed that the most significant risk factor was being a juvenile compared to yearlings and adults (OR = 10.2, 95% CI: 2.2-48.0). Based on our results, 37.9% (n = 11) of the infected animals were considered suitable for human consumption. Our findings offer novel insights into mycobacterial infections in wild boar populations in Portugal and suggest that wild boar could be a source of human infection if zoonotic potential is considered.

Fatty acids and lipid mediators in inflammatory bowel disease: from mechanism to treatment

Inflammatory Bowel Disease (IBD) is a chronic, relapsing inflammatory disorder of the gastrointestinal tract. Though the pathogenesis of IBD remains unclear, diet is increasingly recognized as a pivotal factor influencing its onset and progression. Fatty acids, essential components of dietary lipids, play diverse roles in IBD, ranging from anti-inflammatory and immune-regulatory functions to gut-microbiota modulation and barrier maintenance. Short-chain fatty acids (SCFAs), products of indigestible dietary fiber fermentation by gut microbiota, have strong anti-inflammatory properties and are seen as key protective factors against IBD. Among long-chain fatty acids, saturated fatty acids, trans fatty acids, and ω-6 polyunsaturated fatty acids exhibit pro-inflammatory effects, while oleic acid and ω-3 polyunsaturated fatty acids display anti-inflammatory actions. Lipid mediators derived from polyunsaturated fatty acids serve as bioactive molecules, influencing immune cell functions and offering both pro-inflammatory and anti-inflammatory benefits. Recent research has also highlighted the potential of medium- and very long-chain fatty acids in modulating inflammation, mucosal barriers, and gut microbiota in IBD. Given these insights, dietary intervention and supplementation with short-chain fatty acids are emerging as potential therapeutic strategies for IBD. This review elucidates the impact of various fatty acids and lipid mediators on IBD and delves into potential therapeutic avenues stemming from these compounds.

Immuno-reactivity evaluation of Mce-truncated subunit candidate vaccine against Mycobacterium avium subspecies paratuberculosis challenge in the goat models

BACKGROUND

Detection of an appropriate antigen with high immunogenicity can be a big step in the production of an effective vaccine for control of Johne's disease (JD). The aim of this study was to evaluate the efficacy of Mce-truncated protein as a subunit vaccine candidate for the control of JD in experimentally challenged goats.

MATERIALS AND METHODS

Six healthy goat kids were immunized with Mce-truncated protein, and two goats were kept as controls. All kids were twice challenged orally with live Mycobacterium avium subspecies paratuberculosis(MAP) strain and half the goats from both the categories were sacrificed at 7 and 10 months after start of challenge study. Culture of MAP was performed from all the necropsied tissues to determine the true JD infection status.

RESULTS

Mce-truncated protein only reacted with pooled vaccinated goat sera in western-blot. A significant increase in humoral immune response against Mce protein was also observed in vaccinated goats. Compared to the control group, vaccinated goats gained higher body weights and none of them shed MAP or showed histopatological lesions or colonization of MAP in their necropsy tissues.

CONCLUSIONS

The new Mce protein based vaccine provided significant immunity in goats as they could meet the challenge with live MAP bacilli. Although the vaccine used in this study showed the high potential as a new effective vaccine for the control of JD, further validation study is still required to successfully implement the vaccine for JD control program.

Investigating in vivo Mycobacterium avium subsp. paratuberculosis microevolution and mixed strain infections

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's Disease (JD) in ruminants, which is responsible for significant economic loss to the global dairy industry. Mixed strain infection (MSI) refers to the concurrent infection of a susceptible host with genetically distinct strains of a pathogen, whereas within-host changes in an infecting strain leading to genetically distinguishable progeny is called microevolution. The two processes can influence host-pathogen dynamics, disease progression and outcomes, but not much is known about their prevalence and impact on JD. Therefore, we obtained up to 10 MAP isolates each from 14 high-shedding animals and subjected them to whole-genome sequencing. Twelve of the 14 animals examined showed evidence for the presence of MSIs and microevolution, while the genotypes of MAP isolates from the remaining two animals could be attributed solely to microevolution. All MAP isolates that were otherwise isogenic had differences in short sequence repeats (SSRs), of which SSR1 and SSR2 were the most diverse and homoplastic. Variations in SSR1 and SSR2, which are located in ORF1 and ORF2, respectively, affect the genetic reading frame, leading to protein products with altered sequences and computed structures. The ORF1 gene product is predicted to be a MAP surface protein with possible roles in host immune modulation, but nothing could be inferred regarding the function of ORF2. Both genes are conserved in Mycobacterium avium complex members, but SSR1-based modulation of ORF1 reading frames seems to only occur in MAP, which could have potential implications on the infectivity of this pathogen. IMPORTANCE Johne's disease (JD) is a major problem in dairy animals, and concerns have been raised regarding the association of Mycobacterium avium subsp. paratuberculosis (MAP) with Crohn's disease in humans. MAP is an extremely slow-growing bacterium with low genome evolutionary rates. Certain short sequence repeats (SSR1 and SSR2) in the MAP chromosome are highly variable and evolve at a faster rate than the rest of the chromosome. In the current study, multiple MAP isolates with genetic variations such as single-nucleotide polymorphisms, and more noticeably, diverse SSRs, could simultaneously infect animals. Variations in SSR1 and SSR2 affect the products of the respective genes containing them. Since multiple MAP isolates can infect the same animal and the possibility that the pathogen undergoes further changes within the host due to unstable SSRs, this could provide a compensative mechanism for an otherwise slow-evolving pathogen to increase phenotypic diversity for overcoming host responses.

Sarcoidosis, Mycobacterium paratuberculosis and Noncaseating Granulomas: Who Moved My Cheese

Clinical and histological similarities between sarcoidosis and tuberculosis have driven repeated investigations looking for a mycobacterial cause of sarcoidosis. Over 50 years ago, "anonymous mycobacteria" were suggested to have a role in the etiology of sarcoidosis. Both tuberculosis and sarcoidosis have a predilection for lung involvement, though each can be found in any area of the body. A key histopathologic feature of both sarcoidosis and tuberculosis is the granuloma-while the tuberculous caseating granuloma has an area of caseous necrosis with a cheesy consistency; the non-caseating granuloma of sarcoidosis does not have this feature. This article reviews and reiterates the complicity of the infectious agent, Mycobacterium avium subsp. paratuberculosis (MAP) as a cause of sarcoidosis. MAP is involved in a parallel story as the putative cause of Crohn's disease, another disease featuring noncaseating granulomas. MAP is a zoonotic agent infecting ruminant animals and is found in dairy products and in environmental contamination of water and air. Despite increasing evidence tying MAP to several human diseases, there is a continued resistance to embracing its pleiotropic roles. "Who Moved My Cheese" is a simple yet powerful book that explores the ways in which individuals react to change. Extending the metaphor, the "non-cheesy" granuloma of sarcoidosis actually contains the difficult-to-detect "cheese", MAP; MAP did not move, it was there all along.

The evidence for Mycobacterium avium subspecies paratuberculosis (MAP) as a cause of nonsolar uveal melanoma: a narrative review

Background and Objective

Animal microorganisms have been proposed as a cause of human cancers associated with farming, agricultural occupation or residence, and related downstream exposures. Several studies have described uveal melanoma (UvM) as a farming-associated cancer. A possible suspect is the animal microorganism Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of paratuberculosis in dairy cows. This microbe is transmitted to humans through various means, including contact with animal faeces, contaminated dust and soil, organic fertilizers, and as workers in slaughterhouses/animal processing facilities. The objective of the current manuscript was to examine the putative association between Mycobacterium avium sub-species paratuberculosis and non-solar UvM.

Methods

Online data sources (PubMed, Scopus, Cochrane Library, and Google) published in English between 1980 to present were searched for key words pertaining to MAP exposure, farming-related occupations and activities, and locations with or in the vicinity of dairy cattle.

Key Content and Findings

While higher than expected rates of eye cancer have been suggested among dairy farmers, with MAP being ubiquitous in their environment, the involvement of MAP in the aetiology of non-solar UvMs (which account for ~97% of UvM cases) remains uncertain.

Conclusions

Alternative explanations exist and future cause-and-effect research is needed to answer this hypothesis. A precautionary approach to exposure continues to be a prudent strategy.

Genomic epidemiology of Mycobacterium avium subsp. paratuberculosis isolates from Canadian dairy herds provides evidence for multiple infection events

Mycobacterium avium subsp. paratuberculosis (MAP) is the pathogen responsible for paratuberculosis or Johne's Disease (JD) in ruminants, which is responsible for substantial economic losses worldwide. MAP transmission primarily occurs through the fecal-oral route, and the introduction of an MAP infected animal into a herd is an important transmission route. In the current study, we characterized MAP isolates from 67 cows identified in 20 herds from the provinces of Quebec and Ontario, Canada. Whole genome sequencing (WGS) was performed and an average genome coverage (relative to K-10) of ∼14.9 fold was achieved. The total number of SNPs present in each isolate varied from 51 to 132 and differed significantly between herds. Isolates with the highest genetic variability were generally present in herds from Quebec. The isolates were broadly separated into two main clades and this distinction was not influenced by the province from which they originated. Analysis of 8 MIRU-VNTR loci and 11 SSR loci was performed on the 67 isolates from the 20 dairy herds and publicly available references, notably major genetic lineages and six isolates from the province of Newfoundland and Labrador. All 67 field isolates were phylogenetically classified as Type II (C-type) and according to MIRU-VNTR, the predominant type was INMV 2 (76.1%) among four distinct patterns. Multilocus SSR typing identified 49 distinct INMV SSR patterns. The discriminatory index of the multilocus SSR typing was 0.9846, which was much higher than MIRU-VNTR typing (0.3740). Although multilocus SSR analysis provides good discriminatory power, the resolution was not informative enough to determine inter-herd transmission. In select cases, SNP-based analysis was the only approach able to document disease transmission between herds, further validated by animal movement data. The presence of SNPs in several virulence genes, notably for PE, PPE, mce and mmpL, is expected to explain differential antigenic or pathogenetic host responses. SNP-based studies will provide insight into how MAP genetic variation may impact host-pathogen interactions. Our study highlights the informative power of WGS which is now recommended for epidemiological studies and to document mixed genotypes infections.

Strain diversity in Mycobacterium avium subsp. paratuberculosis-positive bovine fecal samples collected in Switzerland

Paratuberculosis or Johne's disease is a chronic intestinal disease in domestic and wild ruminants. It affects global dairy economy and is caused by Mycobacterium avium subsp. paratuberculosis (MAP). The objective of this study was to analyze strain diversity in MAP-positive fecal samples by using a particular single nucleotide polymorphism (SNP) distinguishing between cattle (C-) and sheep (S-) type MAP and analysis of SNPs within gyrA and gyrB genes differentiating between Types I, II, and III. Moreover, mycobacterial interspersed repetitive unit and variable-number tandem repeat (MIRU-VNTR) analysis using eight established loci was performed. A total of 90 fecal samples from diseased animals presenting diarrhea and/or weight loss, originating from 59 bovine herds across 16 cantons of Switzerland were screened by PCR for the MAP-specific F57 and IS900 genes and were further subtyped. 96.7% and 3.3% of the samples contained C- and S-type MAP, respectively. Ten INRA Nouzilly MIRU-VNTR (INMV) profiles, with a discriminatory index of 0.802, calculated based on 65 epidemiological independent genotypes, were detected: INMV 1 (33.8%), INMV 2 (23.1%), INMV 6 (16.9%), INMV 9 (9.2%), INMV 116 (4.6%), INMV 3 (3.1%), INMV 5 (3.1%) and INMV 72 (1.5%), including two novel INMV profiles, namely INMV 253 (3.1%; S-type III) and INMV 252 (1.5%; C-type). INMV 1, INMV 2, and INMV 6 comprised almost 75% of the F57- and IS900-positive samples. Typing data from 11 herds suggest that there are some herds with intra-herd diversity of genotypes. The results of this study indicate a heterogeneity of MAP in Switzerland.

Mycobacterium avium subsp. paratuberculosis and Hashimoto’s thyroiditis: Is MAP the trigger?

Hashimoto’s thyroiditis (HT) is an autoimmune disorder of the thyroid gland that can cause hypothyroidism. As HT is a multifactorial disorder, activation of immune responses in genetically predisposed individuals exposed to some environmental factors can contribute to it. Microorganisms, as environmental factors, including Mycobacterium avium ssp. paratuberculosis (MAP) by molecular mimicry, can be important in this autoimmune disorder. This study aimed to investigate the association between MAP and HT. This case–control study included 110 participants consisting of 60 HT patients and 50 healthy controls (HCs). Blood samples were collected. Nested PCR of the IS900 gene determined the presence of MAP DNA. The enzyme-linked immunosorbent assay (ELISA) was designed to identify antibodies (Abs) against the MAP3865c epitope, which has a homologous sequence with ZnT8 in the sera. The demographic information of all participants was recorded. Anti-TG, anti-TPO, TSH, anemia, and ruminant exposure were higer in HT patients than in the HCs (p < 0.05). MAP IS900 was detected significantly more in the patients (46.6% consisting of 30, 8.3, and 8.3% in clinical, subclinical, and unknown) than in the HCs (14%). The sera showed a remarkable frequency of reactivity against MAP3865c in the patients (38.3%) in comparison to the HCs (10%) (p = 0.0001). Furthermore, a significantly higher rate of livestock contact and traditional dairy consumption was found in individuals with MAP or anti-MAP3865c Abs positive result (p < 0.05). This study suggests a possible link between MAP and HT. These findings indicated that MAP frequency was not statistically different in the severity of HT and its shift into the clinical and subclinical forms; therefore, it could be assumed that MAPs are the initiators of the process. The results imply on a possible zoonosis transmission route of MAP from livestock products to humans. Further research is needed to confirm these results in larger groups of HT patients.

ALSUntangled #66: antimycobacterial antibiotics

Several infections have been associated with motor neuron diseases resembling ALS, including species of viruses, bacteria, and parasites. Mycobacterium avium subspecies paratuberculosis (MAP), most known for its probable etiologic association with Crohn's disease, has been suggested as another possible infectious cause of motor neuron disease. Two published case reports describe the successful treatment of ALS-like symptoms with antimycobacterial antibiotics. Both cases had atypical features. Based on these, we believe it would be reasonable to begin performing chest imaging in PALS who have features of their history or exam that are atypical for ALS such as pain, fevers, or eye movement abnormalities. If the chest imaging is abnormal, more specific testing for mycobacteria may be indicated. Until there is more clear evidence of an association between mycobacteria and ALS, we cannot endorse the widespread use of potentially toxic antimycobacterial antibiotics for PALS.

Interaction between microbiota and immunity and its implication in colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in the world. Besides genetic causes, colonic inflammation is one of the major risk factors for CRC development, which is synergistically regulated by multiple components, including innate and adaptive immune cells, cytokine signaling, and microbiota. The complex interaction between CRC and the gut microbiome has emerged as an important area of current CRC research. Metagenomic profiling has identified a number of prominent CRC-associated bacteria that are enriched in CRC patients, linking the microbiota composition to colitis and cancer development. Some microbiota species have been reported to promote colitis and CRC development in preclinical models, while a few others are identified as immune modulators to induce potent protective immunity against colitis and CRC. Mechanistically, microbiota regulates the activation of different immune cell populations, inflammation, and CRC via crosstalk between innate and adaptive immune signaling pathways, including nuclear factor kappa B (NF-κB), type I interferon, and inflammasome. In this review, we provide an overview of the potential interactions between gut microbiota and host immunity and how their crosstalk could synergistically regulate inflammation and CRC, thus highlighting the potential roles and mechanisms of gut microbiota in the development of microbiota-based therapies to prevent or alleviate colitis and CRC.

Mycobacterium paratuberculosis zoonosis is a One Health emergency

A singular pathogen has been killing animals, contaminating food and causing an array of human diseases. Mycobacterium avium subspecies paratuberculosis (MAP) is the cause of a fatal enteric infectious disease called Johne's (Yo'-nees), a disorder mostly studied in ruminant animals. MAP is globally impacting animal health and imparting significant economic burden to animal agriculture. Confounding the management of Johne's disease is that animals are typically infected as calves and while commonly not manifesting clinical disease for years, they shed MAP in their milk and feces in the interval. This has resulted in a "don't test, don't tell" scenario for the industry resulting in greater prevalence of Johne's disease; furthermore, because MAP survives pasteurization, the contaminated food supply provides a source of exposure to humans. Indeed, greater than 90% of dairy herds in the US have MAP-infected animals within the herd. The same bacterium, MAP, is the putative cause of Crohn's disease in humans. Countries historically isolated from importing/exporting ruminant animals and free of Johne's disease subsequently acquired the disease as a consequence of opening trade with what proved to be infected animals. Crohn's disease in those populations became a lagging indicator of MAP infection. Moreover, MAP is associated with an increasingly long list of human diseases. Despite MAP scientists entreating regulatory agencies to designate MAP a "zoonotic agent," it has not been forthcoming. One Health is a global endeavor applying an integrative health initiative that includes the environment, animals and humans; One Health asserts that stressors affecting one affects all three. Recognizing the impact MAP has on animal and human health as well as on the environment, it is time for One Health, as well as other global regulatory agencies, to recognize that MAP is causing an insidious slow-motion tsunami of zoonosis and implement public health mitigation.

Quantitative Risk Assessment of Exposure to Mycobacterium avium subsp. paratuberculosis (MAP) via Different Types of Milk for the Slovenian Consumer

This study aimed to assess the risk of exposure to Mycobacterium avium subsp. paratuberculosis (MAP) via milk for the Slovenian consumer. MAP is suspected to be associated with several diseases in humans, therefore the risk of exposure should be better understood. The primary source of MAP for humans is thought to be cattle, in which MAP causes paratuberculosis or Johne’s disease. We developed a stochastic quantitative risk assessment model using Monte Carlo simulations. Considering the assumptions and uncertainties, we estimated the overall risk of exposure to MAP via milk to be low. For people consuming raw milk from MAP positive farms, the risk was high. On-farm pasteurisation reduced the risk considerably, but not completely. The risk of exposure via pasteurised retail milk was most likely insignificant. However, with a higher paratuberculosis prevalence the risk would also increase. Given the popularity of raw milk vending machines and homemade dairy products, this risk should not be ignored. To reduce the risk, consumers should heat raw milk before consumption. To prevent a potential public health scare and safeguard farmers’ livelihoods, a reduction in paratuberculosis prevalence should be sought. Our results show that culling clinically infected cows was insufficient to reduce milk contamination with MAP.

Neglected Facts on Mycobacterium Avium Subspecies Paratuberculosis and Type 1 Diabetes

Civilization factors are responsible for the increasing of human exposure to mycobacteria from environment, water, and food during the last few decades. Urbanization, lifestyle changes and new technologies in the animal and plant industry are involved in frequent contact of people with mycobacteria. Type 1 diabetes is a multifactorial polygenic disease; its origin is conditioned by the mutual interaction of genetic and other factors. The environmental factors and certain pathogenetic pathways are shared by some immune mediated chronic inflammatory and autoimmune diseases, which are associated with triggers originating mainly from Mycobacterium avium subspecies paratuberculosis, an intestinal pathogen which persists in the environment. Type 1 diabetes and some other chronic inflammatory diseases thus pose the global health problem which could be mitigated by measures aimed to decrease the human exposure to this neglected zoonotic mycobacterium.

Genome-wide association analysis for susceptibility to infection by Mycobacterium avium ssp. paratuberculosis in US Holsteins

Paratuberculosis, or Johne's disease, is a chronic, granulomatous, gastrointestinal tract disease of cattle and other ruminants caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP). Control of Johne's disease is based on programs of testing and culling animals positive for infection with MAP and concurrently modifying management to reduce the likelihood of infection. The current study was motivated by the hypothesis that genetic variation in host susceptibility to MAP infection can be dissected and quantifiable associations with genetic markers identified. Two separate GWAS analyses were conducted, the first using 897 genotyped Holstein artificial insemination sires with phenotypes derived from incidence of MAP infection among daughters based on milk ELISA testing records. The second GWAS analysis was a case-control design using US Holstein cows phenotyped for MAP infection by serum ELISA or fecal culture tests. Cases included cows positive for either serum ELISA, fecal culture, or both. Controls consisted of animals negative for all tests conducted. A total of 376 samples (70 cases and 306 controls) from a University of Minnesota Johne's management demonstration project and 184 samples (76 cases and 108 controls) from a Michigan State University study were used. Medium-density (sires) and high-density (cows) genotype data were imputed to full genome sequence for the analyses. Marker-trait associations were analyzed using the single-step (ss)GWAS procedure implemented in the BLUPF90 suite of programs. Evidence of significant genomic contributions for susceptibility to MAP infection were observed on multiple chromosomes. Results were combined across studies in a meta-analysis, and increased support for genomic regions on BTA7 and BTA21 were observed. Gene set enrichment analysis suggested pathways for antigen processing and presentation, antimicrobial peptides and natural killer cell-mediated cytotoxicity are relevant to variation in host susceptibility to MAP infection, among others. Genomic prediction was evaluated using a 5-fold cross-validation, and moderate correlations were observed between genomic breeding value predictions and daughter averages (∼0.43 to 0.53) for MAP infection in testing data sets. These results suggest that genomic selection against susceptibility to MAP infection is feasible in Holstein cattle.

Use of ATP-Binding Cassette Subfamily A Member 13 (ABCA13) for Sensitive Detection of Focal Pathological Forms of Subclinical Bovine Paratuberculosis

Bovine paratuberculosis (PTB) is a chronic enteritis caused by Mycobacterium avium subspecies paratuberculosis (Map) that causes a heavy economic impact worldwide. Map infected animals can remain asymptomatic for years while transmitting the mycobacteria to other members of the herd. Therefore, accurate detection of subclinically infected animals is crucial for disease control. In a previous RNA-Seq study, we identified several mRNAs that were overexpressed in whole blood of cows with different PTB-associated histological lesions compared with control animals without detected lesions. The proteins encoded by two of these mRNAs, ATP binding cassette subfamily A member 13 (ABCA13) and Matrix Metallopeptidase 8 (MMP8) were significantly overexpressed in whole blood of animals with focal histological lesions, the most frequent pathological form in the subclinical stages of the disease. In the current study, the potential of sensitive early diagnostic tools of commercial ELISAs, based on the detection of these two biomarkers, was evaluated in serum samples of 704 Holstein Friesian cows (566 infected animals and 138 control animals from PTB-free farms). For this evaluation, infected animals were classified into three groups, according to the type of histological lesions present in their gut tissues: focal (n = 447), multifocal (n = 59), and diffuse (n = 60). The ELISA based on the detection of ABCA13 was successfully validated showing good discriminatory power between animals with focal lesions and control animals (sensitivity 82.99% and specificity 80.43%). Conversely, the MMP8-based ELISA showed a poor discriminatory power between the different histological groups and non-infected controls. The ABCA13-based ELISA showed a higher diagnostic value (0.822) than the IDEXX ELISA (0.517), the fecal bacterial isolation (0.523) and the real-time PCR (0.531) for the detection of animals with focal lesions. Overall, our results indicate that this ABCA13 ELISA greatly improves the identification of subclinically infected animals with focal lesions that are undetectable using current diagnostic methods.

Long History of Queries about Bovine Paratuberculosis as a Risk Factor for Human Health

Motto: All truth passes through three stages [...].

Goat Paratuberculosis: Experimental Model for the Evaluation of Mycobacterium Persistence in Raw Milk Cheese

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of chronic proliferative enteritis found in ruminants, known as paratuberculosis (PTB). The spread of PTB is increasing in countries with advanced animal husbandry practices, leading to significant economic losses. Moreover, a supposed zoonotic role of MAP in Crohn's disease (CD) in humans has been discussed by the scientific community; however, although the association between MAP and CD has generally been accepted, it is still up for debate if MAP is the main cause of CD, a contributing factor, or merely a commensal organism for the development of CD. The aim of this study was to assess the survival of MAP during the entire production process of a traditional Italian goat's raw milk fresh cheese, the "Robiola di Roccaverano", assessing the survival rate and persistence of MAP in the final product. A mix of MAP field isolates from goats of the Roccaverano area and a reference ATCC strain were used to carry out milk in experimental inoculation. Samples of milk, curd and cheese were taken in two consecutive batches of production. Microbiological challenge tests, evaluated by f57-qPCR, showed a significant decrease in MAP charge during the cheesemaking process for both batches, suggesting the productive process has an impact on MAP survival.

Mycobacterium avium subsp. paratuberculosis (MAP) molecular diversity in cattle, sheep, and goats from Latin America and the Caribbean: a systematic review

This study aimed to systematically collect and appraise the scientific evidence to answer the research question: What MAP genotypes have been isolated from cattle, sheep, and goats in Latin America and the Caribbean? An electronic search was conducted on three platforms (i.e., OVID®, Web of Science®, SciELO) as well as on the proceedings of the International Colloquium on Paratuberculosis. Inclusion and exclusion criteria were defined a priori and conserved through the systematic process and only articles published in peer-reviewed journals were considered. A total of 26 articles met the definitive inclusion criteria. All were published in English, in 15 different journals, and between 1989 and 2020. The relevant articles reported the use of six different genotyping techniques (i.e., polymerase chain reaction-restriction endonuclease analysis, restriction fragment length polymorphism, type-specific-PCR, mycobacterial interspersed repetitive units-variable number of tandem repeats, multi-locus short sequence repeat, single nucleotide polymorphism) in isolates from seven countries. Genotypes found so far in the region using typing techniques were mainly C type. MIRU-VNTR mostly reported INMV 1, INMV 2, and INMV 11 subtypes, among others. MLSSR reported genotypes from four different countries, reporting nine different subtypes of which 7g–10g–4ggt was the most common for loci 1, 2, and 8, respectively. Regardless the high diversity of techniques used so far to genotype Latin American and Caribbean MAP isolates, the original question of this systematic review has been answered. In addition, a relative genetic similarity between MAP strains recovered from cattle, goats, and sheep unrelatedly of the matrix and geographic origin was identified.

Warm, Sweetened Milk at the Twilight of Immunity - Alzheimer's Disease - Inflammaging, Insulin Resistance, M. paratuberculosis and Immunosenescence

This article prosecutes a case against the zoonotic pathogen Mycobacterium avium ss. paratuberculosis (MAP) as a precipitant of Alzheimer’s disease (AD). Like the other major neurodegenerative diseases AD is, at its core, a proteinopathy. Aggregated extracellular amyloid protein plaques and intracellular tau protein tangles are the recognized protein pathologies of AD. Autophagy is the cellular housekeeping process that manages protein quality control and recycling, cellular metabolism, and pathogen elimination. Impaired autophagy and cerebral insulin resistance are invariant features of AD. With a backdrop of age-related low-grade inflammation (inflammaging) and heightened immune risk (immunosenescence), infection with MAP subverts glucose metabolism and further exhausts an already exhausted autophagic capacity. Increasingly, a variety of agents have been found to favorably impact AD; they are agents that promote autophagy and reduce insulin resistance. The potpourri of these therapeutic agents: mTOR inhibitors, SIRT1 activators and vaccines are seemingly random until one recognizes that all these agents also suppress intracellular mycobacterial infection. The zoonotic mycobacterial MAP causes a common fatal enteritis in ruminant animals. Humans are exposed to MAP from contaminated food products and from the environment. The enteritis in animals is called paratuberculosis or Johne’s disease; in humans, it is the putative cause of Crohn’s disease. Beyond Crohn’s, MAP is associated with an increasing number of inflammatory and autoimmune diseases: sarcoidosis, Blau syndrome, autoimmune diabetes, autoimmune thyroiditis, multiple sclerosis, and rheumatoid arthritis. Moreover, MAP has been associated with Parkinson’s disease. India is one county that has extensively studied the human bio-load of MAP; 30% of more than 28,000 tested individuals were found to harbor, or to have harbored, MAP. This article asserts an unfolding realization that MAP infection of humans 1) is widespread in its presence, 2) is wide-ranging in its zoonosis and 3) provides a plausible link connecting MAP to AD.

Mycobacterium avium subsp. paratuberculosis Proteome Changes Profoundly in Milk

Mycobacterium avium subspecies paratuberculosis (MAP) are detectable viable in milk and other dairy products. The molecular mechanisms allowing the adaptation of MAP in these products are still poorly understood. To obtain information about respective adaptation of MAP in milk, we differentially analyzed the proteomes of MAP cultivated for 48 h in either milk at 37 °C or 4 °C or Middlebrook 7H9 broth as a control. From a total of 2197 MAP proteins identified, 242 proteins were at least fivefold higher in abundance in milk. MAP responded to the nutritional shortage in milk with upregulation of 32% of proteins with function in metabolism and 17% in fatty acid metabolism/synthesis. Additionally, MAP upregulated clusters of 19% proteins with roles in stress responses and immune evasion, 19% in transcription/translation, and 13% in bacterial cell wall synthesis. Dut, MmpL4_1, and RecA were only detected in MAP incubated in milk, pointing to very important roles of these proteins for MAP coping with a stressful environment. Dut is essential and plays an exclusive role for growth, MmpL4_1 for virulence through secretion of specific lipids, and RecA for SOS response of mycobacteria. Further, 35 candidates with stable expression in all conditions were detected, which could serve as targets for detection. Data are available via ProteomeXchange with identifier PXD027444.

The Paratuberculosis Paradigm Examined: A Review of Host Genetic Resistance and Innate Immune Fitness in Mycobacterium avium subsp. Paratuberculosis Infection

Paratuberculosis, or Johne's Disease (JD) is a debilitating chronic enteritis mainly affecting ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP). This organism causes worldwide economic losses to the livestock industry, and is of public health importance due to the potential zoonotic risk between MAP and Crohn's disease (CD) in humans. Without economical treatments, or a vaccine capable of preventing infection without causing cross-reactions with bovine tuberculosis, test-and-cull methods for disease control are imperative. Unfortunately, difficulties in diagnostics and long subclinical stage hinder adequate control and is further complicated by variation in MAP exposure outcome. Interestingly, the majority of infections result in asymptomatic presentation and never progress to clinical disease. One contributing factor is host genetics, where polymorphisms in innate immune genes have been found to influence resistance and susceptibility to disease. Candidate genes identified across studies overlap with those found in CD and tuberculosis including; Solute carrier family 11 member 1 gene (SLC11A1), Nucleotide-binding-oligomerization domain containing gene 2 (NOD2), Major histocompatibility complex type II (MHC-II), and Toll-like receptor (TLR) genes. This review will highlight evidence supporting the vital role of these genes in MAP infection outcome, associated challenges, and implications for the future of JD research.

Therapeutic management of Mycobacterium avium subspecies paratuberculosis infection with complete resolution of symptoms and disease in a patient with advanced inflammatory bowel syndrome

BACKGROUND

A 26-year-old male had a history of frequent bowel movements, mushy stool with mucus and loss of 25 kg body weight in 6 months was diagnosed as a case of inflammatory bowel disease (IBD). The patient did not respond to routine and standard treatment for IBD. His condition was steadily deteriorating, and he was in a very precarious state when he reported to us.

METHODS

Upon laboratory investigation by using IS900 specific PCR [which is specific for Mycobacterium avium subspecies paratuberculosis (MAP)], the blood and stool samples were found negative. However, the presence of low titer MAP-antibodies by indigenous ELISA were found followed by detection of the typical acid-fast MAP bacilli (with 3 + or 4 + grade) microscopically. The MAP stool culture was positive after 6 months incubation. The biotyping by IS1311 specific polymerase chain reaction restriction enzyme (PCR-RE) confirmed infection with 'Indian Bison Type Genotype', a dominant biotype infecting the domestic livestock population of India. Standard anti-MAP therapy was initiated under supervision of the treating physician. The drug of choice in prescribed treatment regimen included Isoniazid (5 mg/kg), Rifampicin (10 mg/kg), Ethambutol (15-25 mg/kg) once a day for 24 weeks and Clarithromycin (250 mg)/Levofloxacin (250 mg) twice a day for 6 weeks.

RESULTS

Following treatment, the patient started improving progressively with reduction in bowel movement frequency and gained body weight with an enhanced appetite propensity. Upon follow-up of the patient after 1 year of treatment, stool-microscopy and stool-culture were found negative for MAP. Till the recent past, the patient was further monitored for disease relapse, if any.

CONCLUSIONS

This patient has experienced a complete resolution of IBD using a combination of anti-MAP antibiotics. The initial detection of heavy shedding of acid-fast MAP bacilli and typical colony morphology with its characterization obtained from culturing of stool sample indicated the infection of MAP. Interestingly, the present case is one more example of the linkage of demonstrable MAP infection treated with anti-MAP therapy in the presence and then absence of disease in the human host.

Mycobacterium avium ssp. paratuberculosis in the Food Supply: A Public Health Issue

This article examines the policy implications of Mycobacterium avium subspecies paratuberculosis (MAP) as a zoonotic pathogen and the public health risks posed by the presence of MAP in food, particularly milk products. Viable MAP has been cultured from commercially pasteurized milk in the US. Dairy pasteurization standards and regulations are examined in light of this finding. On the basis of the precautionary principle, the authors suggest options to reduce exposure to MAP, including (1) increased federal authority to regulate pasteurization of all dairy products, (2) modification of pasteurization standards in order to more effectively kill MAP, (3) removal of the Pasteurized Milk Ordinance (PMO) provision that allows states to override federal policy in intrastate dairy sales, and (4) creation of a mandatory Johne's Disease Control Program. These measures would reduce human exposure to MAP and may reduce the risk of diseases associated with MAP.

A Mycobacterium species for Crohn's disease?

In ruminants Mycobacterium avium subspecies paratuberculosis (MAP) is the causative organism of a chronic granulomatous inflammatory bowel disease called Johne's disease (JD). Some researchers have hypothesised that MAP is also associated with Crohn's disease (CD), an inflammatory bowel disease in humans that shares some histological features of JD. Despite numerous attempts to demonstrate causality by researchers, direct microbiological evidence of MAP involvement in CD remains elusive. Importantly, it has not been possible to reliably and reproducibly demonstrate mycobacteria in the tissue of CD patients. Past attempts to visualise mycobacteria in tissue may have been hampered by the use of stains optimised for Mycobacterium tuberculosis complex (MTB) and the lack of reliable bacteriological culture media for both non-tuberculous mycobacteria (NTM) and cell-wall-deficient mycobacteria (CWDM). Here we describe a Ziehl-Neelsen (ZN) staining method for the demonstration of CWDM in resected tissue from patients with Crohn's disease, revealing the association of CWDM in situ with host tissue reactions, and posit this as a cause of the tissue inflammation. Using the ZN stain described we demonstrated the presence of CWDM in 18 out of 18 excised tissue samples from patients diagnosed as having Crohn's disease, and in zero samples out of 15 non-inflammatory bowel disease controls.

Is vaccination a viable method to control Johne's disease caused by Mycobacterium avium subsp. paratuberculosis? Data from 12 million ovine vaccinations and 7.6 million carcass examinations in New South Wales, Australia from 1999-2009

BACKGROUND

Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne's disease (or paratuberculosis), a chronic wasting disease of ruminants and other animals resulting from granulomatous enteritis. There are increasing concerns that MAP is zoonotic. The prevalence of Johne's disease is increasing worldwide. In an attempt to control an epidemic of ovine Johne's disease (OJD) in New South Wales (NSW), a government/industry sponsored voluntary vaccination/on-farm management program commenced in 2000. We report herein an observational study of changes in disease prevalence as vaccination progressed, based on abattoir surveillance data for OJD from 1999 to 2009. We also discuss the epidemiological, policy, regulatory, research, economic and sociological elements that contributed to the development of a mature control program, whose aim was to halt the epidemic spread of OJD in a naïve sheep population.

METHODS

NSW was divided into areas of "High" (HPA), "Medium" (MPA) and "Low" (LPA) OJD prevalence. A killed whole cell vaccine (Gudair®) was administered to sheep from 2000 to 2009. Trained examiners evaluated the viscera of adult sheep carcasses at slaughter for gross evidence of OJD. MAP infection was confirmed by histopathology.

PRINCIPAL FINDINGS

From 2000-2009, 12 million vaccine doses were administered in NSW (91%; 10.9 million in the HPA). Many of the vaccinated flocks were suffering > 5% annual mortality in adult sheep, with some individual flocks with 10-15% losses attributable to OJD. A total of 7.6 million carcasses were examined (38%; 2.9 million from the HPA). Overall, 16% of slaughter consignments (sheep consigned to the abattoir from a single vendor) were positive for OJD, of which 94% were from the HPA. In the HPA, the percentage of animals with lesions attributable to OJD at slaughter fell progressively from 2.4% (10,406/432,860) at commencement of vaccination in 2000 to 0.8% (1,573/189,564) by 2009. Herd immunity from vaccination in the HPA was estimated at 70% by 2009, the target commonly espoused for an effective control program based on vaccination. This coincided with a progressive decrease in reports of clinical disease and mortalities in vaccinated flocks.

SIGNIFICANCE

We show a decrease in the prevalence of lesions attributable to OJD in NSW concomitant with initiation of voluntary vaccination, on-farm management plans, abattoir monitoring and feedback of animal prevalence data to sheep producers. We conclude that a target of ≤ 1% regional prevalence of OJD affected sheep at slaughter is achievable using these interventions.

Bovine Intelectin 2 Expression as a Biomarker of Paratuberculosis Disease Progression

Simple Summary

The potential of the bovine intelectin 2 as a biomarker of Mycobacterium avium subsp. paratuberculosis infection was investigated using quantitative immunohistochemical analysis of ileocecal valve samples of animals with increasing degrees of lesion severity (focal, multifocal and diffuse histological lesions) and control animals without detected lesions. Significant differences were observed in the mean number of intelectin 2 immunolabelled cells between the three histopathological types and the control. Specifically, the mean number of intelectin 2 labelled cells was indicative of disease progression as the focal group had the highest number of intelectin 2 secreting cells followed by the multifocal, diffuse and control groups indicating that intelectin 2 is a good biomarker for the different stages of Mycobacterium avium subsp. paratuberculosis infection. Quantification of bovine intelectin 2 secreting cells could constitute a good post-mortem tool, complementary to histopathology, to improve detection of Mycobacterium avium subsp. Paratuberculosis infections, especially latent forms of infection.

Abstract

Paratuberculosis (PTB), a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP), is responsible for important economic losses in the dairy industry. Our previous RNA-sequencing (RNA-Seq) analysis showed that bovine intelectin 2 (ITLN2) precursor gene was overexpressed in ileocecal valve (ICV) samples of animals with focal (log2 fold-change = 10.6) and diffuse (log2 fold-change = 6.8) PTB-associated lesions compared to animals without lesions. This study analyzes the potential use of ITLN2, a protein that has been described as fundamental in the innate immune response to infections, as a biomarker of MAP infection. The presence of ITLN2 was investigated by quantitative immunohistochemical analysis of ICV samples of 20 Holstein Friesian cows showing focal (n = 5), multifocal (n = 5), diffuse (n = 5) and no histological lesions (n = 5). Significant differences were observed in the mean number of ITLN2 immunostained goblet and Paneth cells between the three histopathological types and the control. The number of immunolabelled cells was higher in the focal histopathological type (116.9 ± 113.9) followed by the multifocal (108.7 ± 140.5), diffuse (76.5 ± 97.8) and control types (41.0 ± 81.3). These results validate ITLN2 as a post-mortem biomarker of disease progression.

Developing smarter vaccines for paratuberculosis: From early biomarkers to vaccine design

Vaccines for paratuberculosis have been used for over a hundred years but the disease continues to affect ruminant health and livestock industries globally. Mycobacterium avium subspecies paratuberculosis which causes the disease also known as Johne's disease is a subversive pathogen able to undermine both innate and adaptive host defense mechanisms. This review focuses on early protective immune pathways that lead to some animals becoming resilient to infection to provide a road map for designing better vaccines and emphasizes the need for harnessing the potential of mucosal immunity.

Relevance of inducible nitric oxide synthase for immune control of Mycobacterium avium subspecies paratuberculosis infection in mice

Mycobacterium avium

subspecies paratuberculosis (MAP) causes Johne’s disease (JD), an incurable chronic intestinal bowel disease in ruminants. JD occurs worldwide and causes enormous economic burden in dairy industry. Research on JD pathobiology is hampered by its complexity which cannot completely be mimicked by small animal models. As a model the mouse allows dissecting some pathogenicity features of MAP. However, for unknown reasons MAP exhibits reduced growth in granulomas of infected mice compared to other Mycobacterium avium subspecies. Here, we characterized immune reactions of MAP-infected C57BL/6 mice. After infection, mice appeared fully immunocompetent. A strong antigen-specific T cell response was elicited indicated by IFNγ production of splenic T cells re-stimulated with MAP antigens. Function of splenic dendritic cells and proliferation of adoptively transferred antigen-specific CD4⁺ T cells was unaltered. Isolated splenic myeloid cells from infected mice revealed that MAP resides in CD11b⁺ macrophages. Importantly, sorted CD11b⁺CD11c⁻ cells expressed high level of type 2 nitric oxide synthase (NOS2) but only low levels of pro- and anti-inflammatory cytokines. Correspondingly, MAP-infected MAC2 expressing myeloid cells in spleen and liver granuloma displayed strong expression of NOS2. In livers of infected Nos2^−/−mice higher bacterial loads, more granuloma and larger areas of tissue damage were observed 5 weeks post infection compared to wild type mice. In vitro, MAP was sensitive to NO released by a NO-donor. Thus, a strong T cell response and concomitant NOS2/NO activity appears to control MAP infection, but allows development of chronicity and pathogen persistence. A similar mechanism might explain persistence of MAP in ruminants.

Presence of Infection by Mycobacterium avium subsp. paratuberculosis in the Blood of Patients with Crohn's Disease and Control Subjects Shown by Multiple Laboratory Culture and Antibody Methods

Mycobacterium avium subspecies paratuberculosis (MAP) has long been suspected to be involved in the etiology of Crohn's disease (CD). An obligate intracellular pathogen, MAP persists and influences host macrophages. The primary goals of this study were to test new rapid culture methods for MAP in human subjects and to assess the degree of viable culturable MAP bacteremia in CD patients compared to controls. A secondary goal was to compare the efficacy of three culture methods plus a phage assay and four antibody assays performed in separate laboratories, to detect MAP from the parallel samples. Culture and serological MAP testing was performed blind on whole blood samples obtained from 201 subjects including 61 CD patients (two of the patients with CD had concurrent ulcerative colitis (UC)) and 140 non-CD controls (14 patients in this group had UC only). Viable MAP bacteremia was detected in a significant number of study subjects across all groups. This included Pozzato culture (124/201 or 62% of all subjects, 35/61 or 57% of CD patients), Phage assay (113/201 or 56% of all subjects, 28/61 or 46% of CD patients), TiKa culture (64/201 or 32% of all subjects, 22/61 or 36% of CD patients) and MGIT culture (36/201 or 18% of all subjects, 15/61 or 25% of CD patients). A link between MAP detection and CD was observed with MGIT culture and one of the antibody methods (Hsp65) confirming previous studies. Other detection methods showed no association between any of the groups tested. Nine subjects with a positive Phage assay (4/9) or MAP culture (5/9) were again positive with the Phage assay one year later. This study highlights viable MAP bacteremia is widespread in the study population including CD patients, those with other autoimmune conditions and asymptomatic healthy subjects.

Efficiency of DNA Isolation Methods Based on Silica Columns and Magnetic Separation Tested for the Detection of Mycobacterium avium Subsp. Paratuberculosis in Milk and Faeces

Timely and reliable detection of animals shedding Mycobacterium avium subsp. paratuberculosis (MAP) should help to effectively identify infected animals and limit infection transmission at early stages to ensure effective control of paratuberculosis. The aim of the study was to compare DNA extraction methods and evaluate isolation efficiency using milk and faecal samples artificially contaminated by MAP with a focus on modern instrumental automatic DNA isolation procedures based on magnetic separation. In parallel, an automatic and manual version of magnetic separation and two methods of faecal samples preparation were compared. Commercially available DNA isolation kits were evaluated, and the selected kits were used in a trial of automatic magnetic beads-based isolation and compared with the manual version of each kit. Detection of the single copy element F57 was performed by qPCR to quantify MAP and determine the isolation efficiency. The evaluated kits showed significant differences in DNA isolation efficiencies. The best results were observed with the silica column Blood and Tissue kit for milk and Zymo Research for faeces. The highest isolation efficiency for magnetic separation was achieved with MagMAX for both matrices. The magnetic separation and silica column isolation methods used in this study represent frequently used methods in mycobacterial diagnostics.

Rifabutin-Loaded Nanostructured Lipid Carriers as a Tool in Oral Anti-Mycobacterial Treatment of Crohn's Disease

Oral anti-mycobacterial treatment of Crohn's disease (CD) is limited by the low aqueous solubility of drugs, along with the altered gut conditions of patients, making uncommon their clinical use. Hence, the aim of the present work is focused on the in vitro evaluation of rifabutin (RFB)-loaded Nanostructured lipid carriers (NLC), in order to solve limitations associated to this therapeutic approach. RFB-loaded NLC were prepared by hot homogenization and characterized in terms of size, polydispersity, surface charge, morphology, thermal stability, and drug payload and release. Permeability across Caco-2 cell monolayers and cytotoxicity and uptake in human macrophages was also determined. NLC obtained were nano-sized, monodisperse, negatively charged, and spheroidal-shaped, showing a suitable drug payload and thermal stability. Furthermore, the permeability profile, macrophage uptake and selective intracellular release of RFB-loaded NLC, guarantee an effective drug dose administration to cells. Outcomes suggest that rifabutin-loaded NLC constitute a promising strategy to improve oral anti-mycobacterial therapy in Crohn's disease.

A Protective Vaccine against Johne's Disease in Cattle

Johne’s disease (JD) caused by Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) is a chronic infection characterized by the development of granulomatous enteritis in wild and domesticated ruminants. It is one of the most significant livestock diseases not only in the USA but also globally, accounting for USD 200–500 million losses annually for the USA alone with potential link to cases of Crohn’s disease in humans. Developing safe and protective vaccines is of a paramount importance for JD control in dairy cows. The current study evaluated the safety, immunity and protective efficacy of a novel live attenuated vaccine (LAV) candidate with and without an adjuvant in comparison to an inactivated vaccine. Results indicated that the LAV, irrespective of the adjuvant presence, induced robust T cell immune responses indicated by proinflammatory cytokine production such as IFN-γ, IFN-α, TNF-α and IL-17 as well as strong response to intradermal skin test against M. paratuberculosis antigens. Furthermore, the LAV was safe with minimal tissue pathology. Finally, calves vaccinated with adjuvanted LAV did not shed M. paratuberculosis post-challenge, a much-desired characteristic of an effective vaccine against JD. Together, this data suggests a strong potential of testing LAV in field trials to curb JD in dairy herds.

Detection of latent forms of Mycobacterium avium subsp. paratuberculosis infection using host biomarker-based ELISAs greatly improves paratuberculosis diagnostic sensitivity

Bovine paratuberculosis (PTB) is a chronic granulomatous enteritis, caused by Mycobacterium avium subsp. paratuberculosis (MAP), responsible for important economic losses in the dairy industry. Current diagnostic methods have low sensitivities for detection of latent forms of MAP infection, defined by focal granulomatous lesions and scarce humoral response or MAP presence. In contrast, patent infections correspond to multifocal and diffuse types of enteritis where there is increased antibody production, and substantial mycobacterial load. Our previous RNA-Seq analysis allowed the selection of five candidate biomarkers overexpressed in peripheral blood of MAP infected Holstein cows with focal (ABCA13 and MMP8) and diffuse (FAM84A, SPARC and DES) lesions vs. control animals with no detectable PTB-associated lesions in intestine and regional lymph nodes. The aim of the current study was to assess the PTB diagnostic potential of commercial ELISAs designed for the specific detection of these biomarkers. The ability of these ELISAs to identify animals with latent and/or patent forms of MAP infection was investigated using serum from naturally infected cattle (n = 88) and non-infected control animals (n = 67). ROC analysis revealed that the ABCA13-based ELISA showed the highest diagnostic accuracy for the detection of infected animals with focal lesions (AUC 0.837, sensitivity 79.25% and specificity 88.06%) and with any type of histological lesion (AUC 0.793, sensitivity 69.41% and specificity 86.57%) improving on the diagnostic performance of the popular IDEXX ELISA and other conventional diagnostic methods. SPARC and MMP8 showed the highest diagnostic accuracy for the detection of animals with multifocal (AUC 0.852) and diffuse lesions (AUC 0.831), respectively. In conclusion, our results suggest that quantification of ABCA13, SPARC and MMP8 by ELISA has the potential for implementation as a diagnostic tool to reliably identify MAP infection, greatly improving early detection of MAP latent infections when antibody responses and fecal shedding are undetectable using conventional diagnostic methods.

Anti-Mycobacterium paratuberculosis (MAP) therapy for Crohn's disease: an overview and update

The role of Mycobacterium avium subspecies paratuberculosis (MAP) in the pathogenesis of Crohn's disease (CD) has been strongly debated for many years. MAP is the known aetiological agent of Johne's disease, a chronic enteritis affecting livestock. At present, due to the paucity of high-quality data, anti-MAP therapy (AMT) is not featured in international guidelines as a treatment for CD. Although the much-quoted randomised trial of AMT did not show sustained benefits over placebo, questions have been raised regarding trial design, antibiotic dosing and the formulation used. There are several lines of evidence supporting the CD and MAP association with uncontrolled and controlled trials demonstrating effectiveness, including a retrospective review of cases treated at our own institution. Here, we provide an overview of the evidence supporting and refuting AMT in CD before focussing on updates of the current research in the field, including the ongoing trials with the novel RHB-104 formulation and the MAP vaccine trial. While controversial, gastroenterologists are often asked about long-term combination antibiotic therapy for CD. There has been broadcast and social media coverage surrounding this, particularly with regard to current trials. Although patients should not be deterred from treatments of proven effectiveness, this review aims to help with commonly asked questions and highlights our own approach for the use of anti-MAP in specific circumstances.

"They've got to be testing and doing something about it": Farmer and veterinarian views on drivers for Johne's disease control in dairy herds in England

There needs to be an understanding of the reasons why key stakeholders engage in disease control efforts if disease is to be successfully and sustainably controlled. It is increasingly recognised within veterinary epidemiology and policy making in animal health that these 'people factors' are important influences on the success or otherwise of animal disease control programmes. Research methodologies adopted from the social sciences offer ways to understand this important dimension through investigating the attitudes and opinions of the key actors involved. The study reported in this paper, based on qualitative interview research, investigates the views of dairy farmers and cattle veterinarians on the drivers and incentives for controlling Johne's disease in English dairy herds. Twenty semi-structured interviews involving 17 dairy farmers and seven veterinarians were conducted in two dairy-intensive regions of England. The findings demonstrate the varied influences of veterinary advice and encouragement; appreciation of the economic cost of the disease at herd level; a voluntary national control plan; and fear of a future consumer food scare as the main reasons to engage in Johne's disease control on dairy farms. The study demonstrates how a combination of a voluntary industry-led control scheme, compulsory participation through retailer and processor contractual requirements, and threats of reputational harm and market loss have strongly influenced farmer and veterinary behaviour in relation to Johne's control without statutory involvement. The findings illustrate the importance of considering the political economy and societal impact of animal disease.

Novel recombinant Mce-truncated protein based ELISA for the diagnosis of Mycobacterium avium subsp. paratuberculosis infection in domestic livestock

Johne’s disease (JD) is an infectious wasting condition of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP) in domestic livestock of every country that has been investigated. Controlling JD is problematic due to the lack of sensitive, specific, efficient, and cost-effective diagnostic tests. A major challenge in the development of diagnostics like ELISA is the selection of an ideal antigen/(s) that is pathogen-specific and allows sensitive recognition. Therefore, the purpose of this study was to identify and use Mce-truncated protein-based ELISA assay for the diagnosis of MAP infection with high sensitivity and specificity. In silico epitope prediction by epitope mapping throughout the whole length of MAP2191 protein revealed that C-terminal portion of this protein presented potential T- and B-cell epitopes. Therefore, a novel Mce-truncated protein encoded by the selected region of MAP2191 gene was expressed, purified with Ni-NTA gel matrix and confirmed by SDS PAGE and western blot. A profiling ELISA assay was developed to evaluate sera from MAP infected and non-infected ruminant species for antibodies against Mce-truncated protein to infer the immunogenicity of this protein in the host. Using this Mce protein-based ELISA, 251 goats, 53 sheep, 117 buffaloes, and 33 cattle serum samples were screened and 49.4, 51.0, 69.2, and 54.6% animals, respectively, were found positive. Comparing with i-ELISA, the new Mce-based ELISA kit showed a relatively higher specificity but suffered from slightly reduced sensitivity. Mce-based ELISA excluded apparently false positive results of i-ELISA. Mce protein was found to be antigenic and Mce-ELISA test could be employed as a diagnostic test for JD in domestic livestock in view of the a relatively higher specificity and accuracy. The antigenic potential of Mce antigen can also be exploited for the development of a new vaccine for the control of MAP infection.

Regional Dichotomy in Enteric Mucosal Immune Responses to a Persistent Mycobacterium avium ssp. paratuberculosis Infection

Chronic enteric Mycobacterium avium ssp. paratuberculosis (MAP) infections are endemic in ruminants globally resulting in significant production losses. The mucosal immune responses occurring at the site of infection, specifically in Peyer's patches (PP), are not well-understood. The ruminant small intestine possesses two functionally distinct PPs. Discrete PPs function as mucosal immune induction sites and a single continuous PP, in the terminal small intestine, functions as a primary lymphoid tissue for B cell repertoire diversification. We investigated whether MAP infection of discrete vs. continuous PPs resulted in the induction of significantly different pathogen-specific immune responses and persistence of MAP infection. Surgically isolated intestinal segments in neonatal calves were used to target MAP infection to individual PPs. At 12 months post-infection, MAP persisted in continuous PP (n = 4), but was significantly reduced (p = 0.046) in discrete PP (n = 5). RNA-seq analysis revealed control of MAP infection in discrete PP was associated with extensive transcriptomic changes (1,707 differentially expressed genes) but MAP persistent in continuous PP elicited few host responses (4 differentially expressed genes). Cytokine gene expression in tissue and MAP-specific recall responses by mucosal immune cells isolated from PP, lamina propria and mesenteric lymph node revealed interleukin (IL)22 and IL27 as unique correlates of protection associated with decreased MAP infection in discrete PP. This study provides the first description of mucosal immune responses occurring in bovine discrete jejunal PPs and reveals that a significant reduction in MAP infection is associated with specific cytokine responses. Conversely, MAP infection persists in the continuous ileal PP with minimal perturbation of host immune responses. These data reveal a marked dichotomy in host-MAP interactions within the two functionally distinct PPs of the small intestine and identifies mucosal immune responses associated with the control of a mycobacterial infection in the natural host.

Proposing BCG Vaccination for Mycobacterium avium ss. paratuberculosis (MAP) Associated Autoimmune Diseases

Bacille Calmette-Guerin (BCG) vaccination is widely practiced around the world to protect against the mycobacterial infection tuberculosis. BCG is also effective against the pathogenic mycobacteria that cause leprosy and Buruli's ulcer. BCG is part of the standard of care for bladder cancer where, when given as an intravesicular irrigant, BCG acts as an immunomodulating agent and lessens the risk of recurrence. Mycobacterium avium ss. paratuberculosis (MAP) causes a fatal enteritis of ruminant animals and is the putative cause of Crohn's disease of humans. MAP has been associated with an increasingly long list of inflammatory/autoimmune diseases: Crohn's, sarcoidosis, Blau syndrome, Hashimoto's thyroiditis, autoimmune diabetes (T1D), multiple sclerosis (MS), rheumatoid arthritis, lupus and Parkinson's disease. Epidemiologic evidence points to BCG providing a "heterologous" protective effect on assorted autoimmune diseases; studies using BCG vaccination for T1D and MS have shown benefit in these diseases. This article proposes that the positive response to BCG in T1D and MS is due to a mitigating action of BCG upon MAP. Other autoimmune diseases, having a concomitant genetic risk for mycobacterial infection as well as cross-reacting antibodies against mycobacterial heat shock protein 65 (HSP65), could reasonably be considered to respond to BCG vaccination. The rare autoimmune disease, relapsing polychondritis, is one such disease and is offered as an example. Recent studies suggesting a protective role for BCG in Alzheimer's disease are also explored. BCG-induced energy shift from oxidative phosphorylation to aerobic glycolysis provides the immunomodulating boost to the immune response and also mitigates mycobacterial infection-this cellular mechanism unifies the impact of BCG on the disparate diseases of this article.

relA is Achilles' heel for mycobacterial pathogens as demonstrated with deletion mutants in Mycobacterium avium subsp. paratuberculosis and mycobacterium bovis bacillus Calmette-Guérin (BCG)

Studies with Mycobacterium avium subsp. paratuberculosis (Map) in cattle revealed deletion of relA, a global regulator gene, abrogated ability of the mutant to establish a persistent infection, attributed to development of an immune response that cleared infection. Analysis of the recall response demonstrated presence of CD8 cytotoxic T cells that kill intracellular bacteria. Replication of the primary response demonstrated the CTL response could be elicited with the ΔMap/relA mutant or the target of the immune response, a 35 kD membrane protein. Follow up comparative studies with Mycobacterium bovis bacillus Calmette-Guérin (BCG) and a BCG relA (ΔBCG/relA) deletion mutant revealed deletion of relA enhanced the CTL response compared to BCG. Analysis of the cytokine profile of cells proliferating in response to stimulation with BCG or BCG/relA showed increased expression of IFN-γ, TNF-α, and IL-17 by cells stimulated with ΔBCG/relA in comparison with BCG. The proliferative and CTL responses were markedly reduced in response to stimulation with heat killed BCG or ΔBCG/relA. Intracellular bacterial killing was mediated through the perforin, granzyme B (GnzB), and the granulysin pathway. The data indicate relA is the Achilles' heel for pathogenic mycobacteria and deletion may be key to improving efficacy of attenuated vaccines for mycobacterial pathogens.

Implications of Cattle Trade for the Spread and Control of Infectious Diseases in Slovenia

The objectives of this study were to gain insight into the structure of the cattle trade network in Slovenia and to evaluate the potential for infectious disease spread through movements. The study considered cattle movements between different types of premises that occurred between August 1, 2011 and July 31, 2016 with the exclusion of the movements to the end nodes (e.g., slaughterhouses). In the first part, we performed a static network analysis on monthly and yearly snapshots of the network. These time scales reflect our interest in slowly spreading pathogens; namely Mycobacterium avium subsp. paratuberculosis (MAP), which causes paratuberculosis, a worldwide economically important disease. The results showed consistency in the network measures over time; nevertheless, it was evident that year to year contacts between premises were changing. The importance of individual premises for the network connectedness was highly heterogeneous and the most influential premises in the network were collection centers, mountain pastures, and pastures. Compared to random node removal, targeted removal informed by ranking based on local network measures from previous years was substantially more effective in network disassociation. Inclusion of the latest movement data improved the results. In the second part, we simulated disease spread using a Susceptible-Infectious (SI) model on the temporal network. The SI model was based on the empirically estimated true prevalence of paratuberculosis in Slovenia and four scenarios for probabilities of transmission. Different probabilities were realized by the generation of new networks with the corresponding proportion of contacts which were randomly selected from the original network. These diluted networks served as substrates for simulation of MAP spread. The probability of transmission had a significant influence on the velocity of disease spread through the network. The peaks in daily incidence rates of infected herds were observed at the end of the grazing period. Our results suggest that network analysis may provide support in the optimization of paratuberculosis surveillance and intervention in Slovenia. The approach of simulating disease spread on a diluted network may also be used to model other transmission pathways between herds.

Alternative Vaccination Routes against Paratuberculosis Modulate Local Immune Response and Interference with Tuberculosis Diagnosis in Laboratory Animal Models

Paratuberculosis (PTB) is an enteric granulomatous disease caused by Mycobacterium avium subsp. paratuberculosis (MAP) that mainly affects ruminants. Current vaccines have shown to be cost–effective control reagents, although they are restricted due to cross-interference with bovine tuberculosis (bTB). Therefore, novel vaccination strategies are needed and this study is focused on evaluating alternative vaccination routes and their effect on the local immune response. The MAP oral challenge rabbit model was used to evaluate and compare an experimental inactivated MAP vaccine through oral (VOR) and intradermal (VID) routes. The VID group presented the highest proportion of animals with no visible lesions and the lowest proportion of animals with MAP positive tissues. Immunohistochemistry analysis revealed that the VID group presented a dominantly M1 polarized response indicating an ability to control MAP infection. In general, all vaccinated groups showed lower calprotectin levels compared to the non-vaccinated challenged group suggesting less active granulomatous lesions. The VID group showed some degree of skin test reactivity, whereas the same vaccine through oral administration was completely negative. These data show that PTB vaccination has an effect on macrophage polarization and that the route influences infection outcome and can also have an impact on bTB diagnosis. Future evaluation of new immunological products against mycobacterial diseases should consider assaying different vaccination routes.

Biomarkers for Detecting Resilience against Mycobacterial Disease in Animals

Paratuberculosis and bovine tuberculosis are two mycobacterial diseases of ruminants which have a considerable impact on livestock health, welfare, and production. These are chronic "iceberg" diseases which take years to manifest and in which many subclinical cases remain undetected. Suggested biomarkers to detect infected or diseased animals are numerous and include cytokines, peptides, and expression of specific genes; however, these do not provide a strong correlation to disease. Despite these advances, disease detection still relies heavily on dated methods such as detection of pathogen shedding, skin tests, or serology. Here we review the evidence for suitable biomarkers and their mechanisms of action, with a focus on identifying animals that are resilient to disease. A better understanding of these factors will help establish new strategies to control the spread of these diseases.

Capacity to Elicit Cytotoxic CD8 T Cell Activity Against Mycobacterium avium subsp. paratuberculosis Is Retained in a Vaccine Candidate 35 kDa Peptide Modified for Expression in Mammalian Cells

Studies focused on development of an attenuated vaccine against Mycobacterium avium subsp. paratuberculosis (Map), the causative agent of paratuberculosis (Ptb) in cattle and other species, revealed that deletion of relA, a global gene regulator, abrogates the ability of Map to establish a persistent infection. In the absence of relA, cattle develop CD8 cytotoxic T cells (CTL) with the ability to kill intracellular bacteria. Analysis of the recall response to a relA mutant, Map/ΔrelA, with cells from a vaccinated steer demonstrated that a 35-kDa membrane peptide (MMP) is one of the targets of the response. This observation suggested that it might be possible to develop a peptide-based vaccine. As reported here, the gene encoding the hypothetical MMP ORF, MAP2121c, was modified for expression in mammalian cells as a first step in developing an expression cassette for incorporation into a mammalian expression vector. The modified sequence of MMP, tPA-MMP, was mutated to generate two additional sequences for the study, one with substitutions to replace five potential residues that could be glycosylated, tPA-MMP-5mut, and one with substitutions to replace the first two potential residues that could be glycosylated, tPA-MMP-2mut. The sequences were placed in an expression cassette to produce peptides for analysis. An ex vivo platform was used with flow cytometry and a bacterium viability assay to determine if modifications in the gene encoding MMP for expression in mammalian cells altered its capacity to elicit development of CD8 CTL, essential for its use in a peptide-based vaccine. Monocyte-depleted PBMC (mdPBMC) were stimulated with antigen-presenting cells (APC) pulsed with different MMP constructs. CD4 and CD8 T cells proliferated in response to stimulation with MMP (control) expressed in Escherichia coli (eMMP), tPA-MMP, and tPA-MMP-2mut. CD8 T cells retained the capacity to kill intracellular bacteria. The tPA-MMP-5mut failed to elicit a proliferative response and was not included in further studies. The data show that the expression cassettes containing MMP and MMP-2mut can be used to screen and select a mammalian expression vector for the development of an efficacious peptide-based vaccine against Ptb.

PtpA and PknG Proteins Secreted by Mycobacterium avium subsp. paratuberculosis are Recognized by Sera from Patients with Rheumatoid Arthritis: A Case-Control Study

Purpose

Rheumatoid arthritis (RA) can result from complex interactions between the affected person’s genetic background and environment. Viral and bacterial infections may play a pathogenetic role in RA through different mechanisms of action. We aimed to evaluate the presence of antibodies (Abs) directed against two proteins of Mycobacterium avium subsp. paratuberculosis (MAP) in sera of RA subjects, which are crucial for the survival of the pathogen within macrophages. Moreover, we analyzed the correlation of immune response to both proteins with the following homologous peptides: BOLF1_305–320, MAP_4027_18–32 and IRF5_424–434 to understand how the synergic role of Epstein–Barr virus (EBV) and MAP infection in genetically predisposed subjects may lead to a possible deregulation of interferon regulatory factor 5 (IRF5).

Materials and methods

The presence of Abs against protein tyrosine phosphatase A (PtpA) and protein kinase G (PknG) in sera from Sardinian RA patients (n=84) and healthy volunteers (HCs, n=79) was tested by indirect ELISA.

Results

RA sera showed a remarkably high frequency of reactivity against PtpA in comparison to HCs (48.8% vs 7.6%; p<0.001) and lower but statistically significant responses towards PknG (27.4% vs 10.1%; p=0.0054). We found a significant linear correlation between the number of swollen joints and the concentrations of antibodies against PtpA (p=0.018). Furthermore, a significant bivariate correlation between PtpA and MAP MAP_4027_18–32 peptide has been found, suggesting that MAP infection may induce a secondary immune response through cross-reaction with IRF5 (R²=0.5).

Conclusion

PtpA and PknG are strongly recognized in RA which supports the hypothesis that MAP infection may be involved in the pathogenesis of RA.

Peripheral blood bovine lymphocytes and MAP show distinctly different proteome changes and immune pathways in host-pathogen interaction

Mycobacterium avium subsp. paratuberculosis (MAP) is a pathogen causing paratuberculosis in cattle and small ruminants. During the long asymptomatic subclinical stage, high numbers of MAP are excreted and can be transmitted to food for human consumption, where they survive many of the standard techniques of food decontamination. Whether MAP is a human pathogen is currently under debate. The aim of this study was a better understanding of the host-pathogen response by analyzing the interaction of peripheral blood lymphocytes (PBL) from cattle with MAP in their exoproteomes/secretomes to gain more information about the pathogenic mechanisms of MAP. Because in other mycobacterial infections, the immune phenotype correlates with susceptibility, we additionally tested the interaction of MAP with recently detected cattle with a different immune capacity referred as immune deviant (ID) cows. In PBL, different biological pathways were enhanced in response to MAP dependent on the immune phenotype of the host. PBL of control cows activated members of cell activation and chemotaxis of leukocytes pathway as well as IL-12 mediated signaling. In contrast, in ID cows CNOT1 was detected as highly abundant protein, pointing to a different immune response, which could be favorable for MAP. Additionally, MAP exoproteomes differed in either GroEL1 or DnaK abundance, depending on the interacting host immune response. These finding point to an interdependent, tightly regulated response of the bovine immune system to MAP and vise versa.