'Bio-load' and bio-type profiles of Mycobacterium avium subspecies paratuberculosis infection in the domestic livestock population endemic for Johne's disease: a survey of 28 years (1985-2013) in India

Comparative evaluation of various in-house protocols on diagnostic performance for paratuberculosis IS900 PCR

BACKGROUND

Paratuberculosis is a worldwide endemic infectious disease of ruminants that results in high economic losses. Public health concerns are also being raised with human Crohn's disease. Therefore, control is becoming priority for governments. Control is largely dependent on "Test and Cull" or "Test and Segregate" policy. Hence, it is critical to assure the infection before making the decision. Commercial kits are costly especially in view of resource limited areas. Present study analyzed the performance various in house DNA isolation methods and PCR master mix combinations to optimize a protocol for confirmation of paratuberculosis bacilli shedding in feces.

METHODS AND RESULTS

Present study included five protocols of fecal DNA isolation (chemical, bio-chemical, physio-chemical and physical) and three reaction mixes (based on Qiagen, Genei and Thermo 2X master mixes) in nine different combinations using additives and tested their performance for IS900 PCR. Spiked fecal samples were used to select the best combination of DNA isolation method and PCR master mix (PRM). Selected combination was used to test reference (positive and negative) fecal samples and field samples. Findings revealed that combination physical method of DNA isolation and Genei based PRM (with additives; betaine DMSO and BSA) had lowest limit of detection. Sensitivity was 83% and specificity was 100% in comparison to fecal culture. High prevalence (23%) was reported for paratuberculosis on field samples.

CONCLUSION

Optimized protocol has acceptable sensitivity and can easily be adopted in resource-limited laboratories. High prevalence of paratuberculosis needs immediate implementation of the control strategies.

Ursolic Acid and Solasodine as Potent Anti-Mycobacterial Agents for Combating Paratuberculosis: An Anti-Inflammatory and In Silico Analysis

Mycobacterium avium subspecies paratuberculosis (MAP) infection in domestic livestock causes persistent diarrhea, weight loss, and death and is also a potential cause of Crohn's disease (CD) in humans; notably, treatments against MAP are insufficient, costly, and can cause adverse reactions. Hence, plant-derived bioactive constituents have been taken into consideration in this regard. Herein, we present the results of two bioactive constituents (Solasodine and Ursolic acid) that were evaluated for their safety and efficacy against MAP protein (Dephospho-Coenzyme A kinase (DPCK) by utilizing in vitro assays and different tools of in silico biology. The ADME/t-test, the drug-likeness property test, pharmacophore modelling, and PASS prediction have proven that both the constituents have better binding capacities than the available antibiotic drugs used to target protein inhibition pathways. Through our observations, it can be inferred that these two phytochemicals can be adequately used to treat paratuberculosis, thereby combating inflammatory bowel disorders (IBD) of an autoimmune nature.

Bacterial Species Associated With Human Inflammatory Bowel Disease and Their Pathogenic Mechanisms

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract with unknown etiology. The pathogenesis of IBD results from immune responses to microbes in the gastrointestinal tract. Various bacterial species that are associated with human IBD have been identified. However, the microbes that trigger the development of human IBD are still not clear. Here we review bacterial species that are associated with human IBD and their pathogenic mechanisms to provide an updated broad understanding of this research field. IBD is an inflammatory syndrome rather than a single disease. We propose a three-stage pathogenesis model to illustrate the roles of different IBD-associated bacterial species and gut commensal bacteria in the development of human IBD. Finally, we recommend microbe-targeted therapeutic strategies based on the three-stage pathogenesis model.

In vivo kinetics of peripheral cellular immune responses in Mycobacterium avium subspecies paratuberculosis (MAP) infected and vaccinated goats

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of paratuberculosis (ParaTB) also known as Johne's disease (JD) in ruminants, which is characterized by chronic intestinal inflammation. A similar counterpart has been observed in the form of Crohn's disease in humans. The present study is the first trail in goats to understand the peripheral cellular immune responses following experimental MAP infection and vaccination. Fifteen apparently healthy male kids (3-6 months old) of Barbari breed were included in this study. In the experimental study, 5 kids were infected with 'S 5' strain of MAP ("Indian Bison Type"), 5 were vaccinated (Indigenous Vaccine) against MAP infection (Singh et al., 2007) and the remaining 5 kids were uninfected and non-vaccinated controls. Kids were observed for a period of 180 days post exposure (infection and vaccination) and were tested for development of infection. Cellular immune responses (in blood) were recorded post-exposure by three assays. We measured the frequencies of CD4 and CD8T cells, estimated plasma IFNγ and TNα and in the third assay, in vitro cytokine production by peripheral blood mononuclear cells (PBMCs) from vaccinated, infected and controls were examined in response to polyclonal stimulation. The frequencies of peripheral CD4 and CD8T cells were comparable in control, infected and vaccinated animals except around day 49 post-infection where MAP infected animals showed a trend towards significantly reduced frequencies of CD4 T cells compared to apparently healthy controls. Significantly reduced plasma TNFα levels were also observed in infected animals compared to vaccinated animals,during the course of infection. Diminished levels (although non significant) of TNFα were observed in the supernatants from polyclonally stimulated PBMCs at around day 49 post infection. It is conceivable that the diminished cellular immune responses may coincide with an impairment (immune exhaustion) of perhaps antigen-specific CD4T cells that might, in the course of infection, contribute to the progressive nature of caprine paratuberculosis.

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.

Draft Genome Sequences of Two Bison-Type and Two Sheep-Type Strains of Mycobacterium avium subsp. paratuberculosis

Genome sequences of two type B and two type S strains of Mycobacterium avium subsp. paratuberculosis are presented. These strains were isolated in the United States from sheep, bison, and cattle suffering from Johne’s disease. These genomes will increase our understanding of the minor differences that exist among strains of this genetically stable subspecies.

Comparison of Mycobacterium avium subsp. paratuberculosis infection in cattle, sheep and goats in the Khuzestan Province of Iran: Results of a preliminary survey

Background

Paratuberculosis or Johne's disease, the chronic infectious granulomatous enteritis of ruminants, is a worldwide infection, which is caused by Mycobacterium avium subsp. paratuberculosis (MAP). The most common symptoms of this disease in cattle are loss of milk production, weight loss and diarrhoea, whereas in sheep and goats, the symptoms are emaciation, anorexia and severe disability.

Objectives

The aim of this study was to compare the seroprevalence of MAP in cattle, sheep and goats in the southwest of Iran.

Methods

Blood samples were randomly collected from 530 cattle, 568 sheep and 368 goats in southwest of Iran. Sera were tested by a commercial ELISA kit (ID vet; ID Screen® Paratuberculosis Indirect) for detection of antibodies of MAP.

Results

Overall apparent and true seroprevalence rate of MAP was 6.00% (95% CI: 4.90%–7.30%) and 13.25% (95% CI: 11.55%– 14.95%). Apparent and true seroprevalence of MAP, respectively, was 4.34% (95% CI: 3.88%–6.46%) and 9.19% (95% CI: 6.98%–11.98%) in cattle, 6.87% (95% CI: 5.05%–9.27%) and 15.37% (95% CI: 12.60%–16.60%) in sheep and 7.07% (95% CI: 4.82%–10.18%) and 15.86% (95% CI: 12.41%–20.01%) in goats, respectively. As a result, there was no significant relationship between animal species and MAP infection. Moreover, multivariate logistic regression showed that the infection rate is not associated with age, gender and geographical location in cattle, sheep and goats (P > 0.05).

Conclusion

This study confirms that the seroprevalence of MAP is relatively considerable in the cattle, sheep and goats in the southwest of Iran, although in cattle, it is less than goats and sheep. Therefore, preventive and control measures should be considered by animal health authorities and meat and dairy processing units.

Bio-typing of Mycobacterium avium subspecies paratuberculosis isolates recovered from the Himalayan sheep and goats

Information on bio-type profile of Mycobacterium avium subspecies paratubeculosis (MAP) in sheep flocks and goat herds of Himalayan region is not reported earlier. The aim of our study was to determine the bio-type of MAP infecting livestock of this region. A total of 71 faecal samples (sheep-57, goats-14) were screened by Ziehl-Neelsen (ZN) staining and IS900 PCR, and then processed for culture on Herrold's egg yolk medium (HEYM) having mycobactin J (MJ). Out of 71 faecal samples, MAP colonies were seen only in four samples (sheep-3 and goat-1). Isolates were confirmed as MAP on the basis of slow growth, acid fastness, MJ dependency, IS900 and IS1311 PCR. All the IS900 and IS1311 PCR positive samples were bio-typed by IS1311 PCR-REA (restriction endonuclease analysis), which confirmed all four isolates as 'bison type.' In IS1311 based phylogeny of MAP isolates by ClustalW method of the MegAlign program of DNASTAR Lasergene software, the four sequences of MAP isolates (NCBI sequence nos. MH988763, MH988765, MH988766 and MH988764) did not show any distinct clustering/grouping pattern. However, these four isolates showed a bit of closeness to the MAP sequences (KC990353.1 and KC990352.1) of 'bison type' isolated from wood bison in Canada. In conclusion, this is the first report on isolation and bio-type profile of MAP infecting sheep and goats of Himalayan region. Study will help in devising prevention and control strategies against spread of MAP infection in livestock population of Himalayan region.

Association of genetic variability in CD209 gene with bovine paratuberculosis disease: a case-control study in the Indian cattle population

This study aimed to explore the association of single nucleotide polymorphisms (SNPs) in CD209 gene with the occurrence of bovine paratuberculosis (PTB) disease caused by Mycobacterium avium subspecies paratuberculosis (MAP) in Indian cattle. A total of 213 animals were preliminarily selected on the basis of physical body condition score, which was then screened by a panel of diagnostic tests viz. Johnin, ELISA, fecal microscopy, and fecal culture, for the establishment of a case-control resource population. A total of four SNPs viz. rs208222804, rs211654540, rs208814257, and rs210748127 in CD209 gene were genotyped by PCR-RFLP. All SNPs, except rs210748127, were polymorphic in our population. Genotypic-phenotypic associations were assessed by the PROCLOGISTIC procedure of SAS 9.3. The SNP rs208814257 yielded three genotypes viz. CC, CG, and GG, which were significantly (p < 0.05) different in case as compared to the control population. The odds of CC and CG in comparison to GG genotype were 1.21 and 0.40, respectively. The CG genotype was significantly higher in control population, indicating that this genotype may provide resistance against PTB in our resource population. Upon validation in an independent, larger test population and following biological characterization, SNP rs208814257 can be incorporated in marker panel for selection of animals with greater resistance to MAP infection.

Prevalence of Mycobacterium avium subspecies paratuberculosis (MAP) infection in suspected diarrhoeic buffaloes and cattle reporting at Veterinary University in India

Murrah buffaloes, best breed for milk production are native of Haryana state. They contributes significantly to the farmer's income, livelihood and food (milk and meat) security, in the semi-tropical regions of North India. Johne's disease though endemic in the domestic livestock of the country, but reports are not available in the buffaloes suffering from morbidity due to progressive weakness and diarrhoea. We estimated the status of JD in diarrhoeic buffaloes and cattle reporting at Veterinary Clinical Complex of Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India, using conventional, serological and PCR assays.141 buffaloes suffering from chronic diarrhoea were screened to estimate sero-prevalence of MAP and 50.0 % young and 53.52 % adult animals were positive. Of 14 cattle screened, none of the young and 66.6 % adult cows were positive. In buffaloes, 66.1 and 6.77 %, fecal samples were positive in microscopy and IS900 PCR, respectively. Sero-prevalence of JD was very high in diarrhoeic buffaloes and cattle from Haryana state of India.Buffaloes positive for Mycobacterium avium subspecies paratuberculosis (MAP) infection had reduced total leukocyte count and lymphocytes.

Comparative evaluation of Mycobacterium avium subspecies paratuberculosis (MAP) recombinant secretory proteins as DTH marker for paratuberculosis

Delayed type hypersensitivity (DTH) based skin test is an important onsite animal herd screening procedure for detecting the early stages of the chronic mycobacterial infections. DTH testing plays a vital role in the diagnosis of paratuberculosis infection. However, there are questions over the specificity of this test due to cross-reactive epitopes present on the purified protein derivative (PPD) prepared from the whole cell secretory proteins. PPD may contain proteins shared with other mycobacteria especially environmental species. Therefore, it is needed to test alternate paratuberculosis specific secretory antigens. Present study explored the potential of recombinant secretory proteins (MAP2168c, MAP1693c, MAP3547c, MAP4308c and MAP2677c) as DTH markers. The published literature shows that these proteins as strong cell mediated markers with specificity to paratuberculosis bacilli. To determine the positive skin thickness cutoff, herds of farm animals with history of endemic paratuberculosis were selected and thickness of >2.0 mm was reported as the positive cutoff. Preliminary findings on pilot scale animals report the usefulness of recombinant secretory proteins as DTH markers over traditional Johnin assay. Traditional Johnin reported more false positives and negatives compared to gold standard fecal PCR and field reference plate ELISA test. Present findings encourage and demand further research.

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.

Vaccine approaches for the 'therapeutic management' of Mycobacterium avium subspecies paratuberculosis infection in domestic livestock

High endemicity of Johne’s disease (JD) in herds adversely affects heavy milk yielding breeds by reducing the per animal productivity and ‘productive life-span’. This review evaluates different vaccines used for its control and summarizes the benefits of ‘global vaccine’ in the four major domestic livestock species, namely goat, sheep, buffalo and cattle. Vaccines developed by using ‘native strains’ revealed both 'therapeutic' and preventive effects in domestic livestock. The 'therapeutic' role of vaccine in animals suffering from clinical JD turned out to be valuable in some cases by reversing the disease process and animals returning back to health and production. Good herd management, improved hygiene, ‘test and cull’ methodology, proper disposal of animal excreta and monitoring of MAP bio-load were also regarded as crucial in the 'therapeutic' management of JD. Vaccine approaches have been widely adopted in JD control programs and may be considered as a valuable adjunct in order to utilize huge populations of otherwise un-productive livestock. It has been shown that vaccination was the preeminent strategy to control JD, because it yielded approximately 3–4 times better benefit-to-cost ratios than other strategies. Internationally, 146 vaccine trials/studies have been conducted in different countries for the control of JD and have shown remarkable reduction in its national prevalence. It is concluded that for JD, there cannot be global vaccines or diagnostic kits as solutions have to come from locally prevalent strains of MAP. Despite some limitations, vaccines might still be an effective strategy to reduce or eradicate JD.

Assessment of lipid profile and acute phase protein in Mycobacterium avium subspecies paratuberculosis infected and healthy goats

Present study is based on 24 goats that were located in goat herds endemically infected with Mycobacterium avium subspecies paratuberculosis (MAP) infection. Objective of the study was to access the variations in the lipid profile and acute phase proteins in the serum samples driven from non-infected (negative and physically healthy) and infected (positive and physically weak) goats with MAP infection, cause of incurable Johne’s disease (JD) in domestic livestock. Infected goats had significantly higher cholesterol and albumin levels and significantly ‘reduced level’ of high density lipoprotein (HDL) and ‘reduced level’ of the density of lipoproteins (LDL) in comparison to non-infected goats. Lipid profile and acute phase proteins could be further explored for their significance in pathogenesis and diagnosis of JD in domestic livestock including goats.

Development and evaluation of LAMP-coupled lateral flow device for the detection of MAP in livestock at point of care resource-limited areas

The Mycobacterium avium subspecies paratuberculosis (MAP) causes paratuberculosis (Johne's disease), a systemic and chronic inflammation of intestine that affects bovine, small ruminants like goat and sheep. The disease has a greater economic importance in cattle and in small ruminants. But its effective control is impeded due to lack of rapid and accurate diagnostics. The present study is aimed at developing a LAMP-coupled lateral flow device (LFD) for rapid detection of paratuberculosis in livestock animal species such as cattle and in small ruminants at resource-limited areas. LAMP primers with biotin and FITC end tags were designed for IS900 gene specific for MAP. To determine sensitivity of LAMP assay, 10-fold serial dilutions were made from 10 ng/μl MAP stock DNA and were compared with PCR. The detection limits of LAMP-coupled LFD were defined and reactions were repeated for reproducibility. The specificity was evaluated using other infectious bacteria such as M. bovis, M. tuberculosis, Brucella abortus, Leptospira interrogan, Yersinia enterocolitica, Salmonella typhimurium, Listeria monocytogens, and Staphylococcus aureus. A total of 95 samples turned positive for LAMP-coupled LFD out of 389 fecal samples. All the cultural-positive and PCR-positive samples showed positive in LAMP-coupled LFD. Nine samples with negative cultures turned positive in LAMP assay. The overall sensitivity and specificity of the LAMP-coupled LFD assays were 100% and 97.02% respectively in comparison with the culture as the gold standard method. The sensitivity detection limit of developed assay was 10 fg/μl and specificity was 100%. This assay successfully detected MAP not only by using bacterial DNA but also in clinical fecal samples. The clear band formation at control and test positions was observed on LAMP-coupled LFD. The developed assay is a simple, rapid, easy to perform, and is very useful in early diagnosis of Mycobacterium avium subsp. paratuberculosis at point of care resource-limited areas.

Evaluation of newly developed 'six recombinant secretary proteins based 'cocktail ELISA' and 'whole cell lysate' based 'indigenous ELISA' and tissue microscopy' with 'Gold standard' histo-pathology for the diagnosis of Johne's disease in slaughtered goats and buffaloes

Three screening tests {(newly developed, six recombinant secretory proteins based 'cocktail ELISA', in-house robust 'indigenous ELISA' based on semi-purified protoplasmic antigens and tissue microscopy were evaluated with 'Gold standard', histo-pathology for the diagnosis of Johne's disease in goats and buffaloes. Serum and tissues {mesenteric lymph nodes and intestines) were driven from farmer's goats (n = 77) and buffaloes (n = 40) slaughtered for harvesting meat and farm goats (n = 77), died and necropsied. Twenty seven (35%) goats and 23 (57.5%) buffaloes were positive in all the four tests. Of 134 tissues screened by histo-pathology, 79.8% MLN and 76.8%, intestines, were positive for MAP infection. In tissue microscopy, 55.2 and 52.3%, goats and buffaloes were positive, respectively. Of 117 sera screened by i_ELISA, 58.4 and 70.0%, goats and buffaloes were positive, respectively. Whereas, c_ELISA detected 55.8 and 62.5%, goats and buffaloes, positives, respectively. Twelve tissues (70.5%) of goats necropsied were positive, both in tissue microscopy and histo-pathology. Most significant gross findings were serous atrophy of the fat and mild to moderate, diffuse thickening of terminal ileum, especially at ileo-caecal junction with or without transverse / longitudinal corrugations. In histo-pathology grade III and IV lesions were significantly low as compared to grade I and II. Of the four tests used for screening 268 samples, histo-pathology was most sensitive (78.3%), followed by i_ELISA (62.3%), c_ELISA (58.9%) and tissue microscopy (58.9%). Between two ELISA tests, c_ELISA using six recombinants secretory proteins, had higher specificity as compared to i_ELISA.

Genetic association of polymorphisms in bovine TLR2 and TLR4 genes with Mycobacterium avium subspecies paratuberculosis infection in Indian cattle population

Toll like receptors (TLRs) are pattern recognition molecules involved in cellular recognition of Mycobacterium avium subspecies paratuberculosis (MAP), the infectious agent causing Paratuberculosis (PTB), a notified disease of domestic and wild ruminants. The present study was undertaken to investigate the presence of single nucleotide polymorphisms (SNPs) in TLR2 and TLR4 gene and to evaluate association of these SNPs with occurrence of PTB in Indian cattle. A total of 213 cattle, were subjected to multiple diagnostic tests viz. Johnin PPD, ELISA test (Indigenous and Parachek kit method), fecal microscopy and fecal culture for detection of MAP infection. Based on screening results 51 animals each were assigned to case and control population. Two SNPs viz. rs55617172, rs41830058 in TLR2 gene and two SNPs viz. rs8193046, rs8193060 in TLR4 gene and were genotyped by PCR-RFLP method. All SNPs were found to be polymorphic except rs41830058 in the case-control population. Both SNPs in TLR4 gene but none in TLR2 genes were significantly associated with the occurrence of PTB in our population. The genotypes in SNP rs8193046 and SNP rs8193060 were significantly (P < 0.01) different in case-control population. These findings suggest that SNPs rs8193046 and rs8193060 are likely a potential marker against MAP infection and a selection programme eliminating AG genotype for rs8193046 and CT genotype for rs8193060 might be beneficial in conferring resistance to MAP infection in Indian cattle population.

Association of Bovine CLEC7A gene polymorphism with host susceptibility to paratuberculosis disease in Indian cattle

Bovine CLEC7A gene, encodes Dectin-1, an important pattern recognition molecule that generates proinflammatory response against mycobacterium. The aim of the present study was to identify single nuceotide polymorphisms (SNPs) in the gene CLEC7A and to evaluate association of these SNPs with occurrence of paratuberculosis (PTB) in cattle. A total of 213 cattle from three different farms were subjected to single intradermal Johnin test, ELISA test, faecal microscopy and faecal culture for establishment of case-control resource population. A total 6 SNPs viz. rs110353594, rs110671821, rs110343521, rs41654445, rs109429379 and rs109280145 in gene CLEC7A were investigated for association with susceptibility/resistance to PTB. All the six SNPs were found to be polymorphic in case-control population. SNP rs41654445 was significantly (P < .01) associated with PTB and odds ratio (OR) indicated that TT genotype had more prevalence than CC and CT genotype in case population and probability for getting PTB infection in animals with T allele was 12 times more as compared to C allele. For SNP rs110353594, T allele was significantly (P < .01) higher in case population as compared to control population and the probability for getting infection in animals with C allele was one third as compared to T allele. SNP rs41654445 was non-synonymous, while SNP rs110353594 was located in promoter region suggesting their functional role in the immune response against bovine PTB. SNP s41654445 and rs110353594 can be incorporated in marker panel for selection of animals with greater resistance to MAP after validation in independent, larger resource population and following biological characterization.

A national serosurvey to determine the prevalence of paratuberculosis in cattle in Bhutan following detection of clinical cases

Johne's disease is an economically important ruminant disease predominantly affecting cattle, sheep and goats. The economic losses are due to early culling, reduced growth rate, progressive weight loss and reduced production. It is caused by Mycobacterium avium subspecies paratuberculosis (MAP). Johne's disease was reported in cattle in Bhutan, based on clinical signs and histopathology; in the late 1990s samples from one mithun that was suspected to have died due to this disease was confirmed by molecular testing at the Faculty of Veterinary Science, University of Sydney, Australia. However, no detailed study on prevalence of JD has been attempted in Bhutan. Objective of this study was to conduct serosurveillance to determine the national prevalence of Johne's disease in cattle for the period 2013–2014 to provide the basis for planning a future control strategy. A national serosurvey was conducted wherein a two‐stage sampling procedure was used with 95% confidence and an error level of ±0.05. The sample size required for the survey was calculated using the software‐Survey Toolbox for Livestock Diseases, available as Epitools at http://www.ausvet.com.au. A total of 1123 serum samples were collected from an administrative structure of 52 villages, 40 sub‐districts and 15 districts. Serum samples were tested using commercially available antibody enzyme linked immunosorbent assay. Statistical analysis was performed using GraphPad Prism 5.0. Illustration such as maps was produced using QGIS version 2.18 ‘Las Palmas. The mean national apparent prevalence of Johne's disease was found to be 2.31 (26/1123) (95% CI: 0.80–4.50) with an estimated true prevalence was found to be 8.00 (95% CI: 2.00–17.00). Trongsa district had the highest prevalence (12.96) followed by Zhemgang (4.34), Lhuntse (4.25), Sarpang (3.89), Bumthang (3.60), Trashigang (2.67) and Haa (2.63). Prevalence for all other districts was 2.00 or below. Seropositive samples were reported from all over the country with varying levels of sero‐positivity. In the recent past many more cattle were imported from India to boost dairy production. Nevertheless, the wide distribution of seroreactive JD cattle all over the country is a concern for future control. Therefore, in future, a detailed study on the impact of cattle import with regard to disease incursion such as Johne's disease and other diseases should be undertaken.

Mycobacterium avium subspecies paratuberculosis - an important food borne pathogen of high public health significance with special reference to India: an update

This review underlines the public health significance of 'Indian Bison Type' of Mycobacterium avium subspecies paratuberculosis (MAP) and also its potential as 'zoonotic infection'. In the absence of control programs, bio-load of MAP is increasing and if we take total population of animals (500 million plus) and human beings (1.23 billion plus) into account, the number of infected animals and human beings will run into millions in India. Our research on screening of over 26,000 domestic livestock for MAP infection using 4 different diagnostic tests (microscopy, culture, ELISA and PCR), during last 31 years has shown that the average bio-load of MAP in the livestock population of India is very high (cattle 43%, buffaloes 36%, goats 23% and sheep 41%). 'Mass screening' of 28,291 human samples between 2008-2016 revealed also high bio-load of MAP. It has been proved that MAP is not in-activated during pasteurization and therefore live bacilli are continuously reaching human population by consumption of even pasteurized milk and other milk products. Live bacilli have also been recovered from meat products and the environment thus illustrating the potential of MAP as pathogen of public health concern. However, at present, there is inadequate scientific evidence to confirm a conclusive link between MAP infection and Johne's disease in ruminants and some cases of Crohn's disease in human beings.

Molecular markers for resistance against infectious diseases of economic importance

Huge livestock population of India is under threat by a large number of endemic infectious (bacterial, viral, and parasitic) diseases. These diseases are associated with high rates of morbidity and mortality, particularly in exotic and crossbred cattle. Beside morbidity and mortality, economic losses by these diseases occur through reduced fertility, production losses, etc. Some of the major infectious diseases which have great economic impact on Indian dairy industries are tuberculosis (TB), Johne's disease (JD), mastitis, tick and tick-borne diseases (TTBDs), foot and mouth disease, etc. The development of effective strategies for the assessment and control of infectious diseases requires a better understanding of pathogen biology, host immune response, and diseases pathogenesis as well as the identification of the associated biomarkers. Indigenous cattle (Bos indicus) are reported to be comparatively less affected than exotic and crossbred cattle. However, genetic basis of resistance in indigenous cattle is not well documented. The association studies of few of the genes associated with various diseases, namely, solute carrier family 11 member 1, Toll-like receptors 1, with TB; Caspase associated recruitment domain 15, SP110 with JD; CACNA2D1, CD14 with mastitis and interferon gamma, BoLA--DRB3.2 alleles with TTBDs, etc., are presented. Breeding for genetic resistance is one of the promising ways to control the infectious diseases. High host resistance is the most important method for controlling such diseases, but till today no breed is total immune. Therefore, work may be undertaken under the hypothesis that the different susceptibility to these diseases are exhibited by indigenous and crossbred cattle is due to breed-specific differences in the dealing of infected cells with other immune cells, which ultimately influence the immune response responded against infections. Achieving maximum resistance to these diseases is the ultimate goal, is technically possible to achieve, and is permanent. Progress could be enhanced through introgression of resistance genes to breeds with low resistance. The quest for knowledge of the genetic basis for infectious diseases in indigenous livestock is strongly warranted.

Current status of Mycobacterium avium subspecies paratuberculosis infection in animals & humans in India: What needs to be done?

Mycobacterium avium subspecies paratuberculosis (MAP) has emerged as a major health problem for domestic livestock and human beings. Reduced per animal productivity of domestic livestock seriously impacts the economics of dairy farming globally. High to very high bioload of MAP in domestic livestock and also in the human population has been reported from north India. Presence of live MAP bacilli in commercial supplies of raw and pasteurized milk and milk products indicates its public health significance. MAP is not inactivated during pasteurization, therefore, entering into human food chain daily. Recovery of MAP from patients with inflammatory bowel disease or Crohn's disease and animal healthcare workers suffering with chronic gastrointestinal problems indicate a close association of MAP with a number of chronic and other diseases affecting human health. Higher bioload of MAP in the animals increases the risk of exposure to the human population with MAP. This review summarizes the current status of MAP infection in animals as well as in human beings and also highlights the prospects of effective management and control of disease in animals to reduce the risk of exposure to human population.

Concurrent Resolution of Chronic Diarrhea Likely Due to Crohn's Disease and Infection with Mycobacterium avium paratuberculosis

Examination of samples of stool from a 61-year-old male patient, presenting with the clinical symptoms of Crohn's disease (CD), revealed massive shedding of acid fast bacilli with the morphology of Mycobacterium avium paratuberculosis (MAP), the causative agent of Johne's disease in cattle. MAP was cultured from the stool. Biotyping of the bacterium isolated from cultures of stool demonstrated, it was the Indian Bison biotype of MAP, the dominant biotype infecting livestock and humans in India. Based on this finding and because the patient was unresponsive to standard therapy used in India to treat patients with gastrointestinal inflammatory disorders, the patient was placed on a regimen of multi-antibiotic therapy, currently used to treat tuberculosis and CD. After 1 year of treatment, the patient's health was restored, concurrent with cessation of shedding of MAP in his stool. This patient is the first case shown to shed MAP from the stool who was cured of infection with antibiotics and who was concurrently cured of clinical signs of CD.

Trends and advances in the diagnosis and control of paratuberculosis in domestic livestock

Paratuberculosis (pTB) is a chronic granulomatous enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP) in a wide variety of domestic and wild animals. Control of pTB is difficult due to the lack of sensitive, efficacious and cost-effective diagnostics and marker vaccines. Microscopy, culture, and PCR have been used for the screening of MAP infection in animals for quite a long time. Besides, giving variable sensitivity and specificity, these tests have not been considered ideal for large-scale screening of domestic livestock. Serological tests like ELISA easily detects anti-MAP antibodies. However, it cannot differentiate between the vaccinated and infected animals. Nanotechnology-based diagnostic tests are underway to improve the sensitivity and specificity. Newer generation diagnostic tests based on recombinant MAP secretory proteins would open new paradigm for the differentiation between infected and vaccinated animals and for early detection of the infection. Due to higher seroreactivity of secretory proteins vis-à-vis cellular proteins, the secretory proteins may be used as marker vaccine, which may aid in the control of pTB infection in animals. Secretory proteins can be potentially used to develop future diagnostics, surveillance and monitoring of the disease progression in animals and the marker vaccine for the control and eradication of pTB.

On deaf ears, Mycobacterium avium paratuberculosis in pathogenesis Crohn’s and other diseases

The historic suggestion that Mycobacterium avium subsp. paratuberculosis (Map) might be a zoonotic pathogen was based on the apparent similarity of lesions in the intestine of patients with Crohn’s disease (CD) with those present in cattle infected with Map, the etiological agent of Johne’s disease. Reluctance to fully explore this possibility has been attributed to the difficulty in demonstrating the presence of Map in tissues from patients with CD. Advances in technology have resolved this problem and revealed the presence of Map in a significant proportion of patients with CD and other diseases. The seminal finding from recent investigations, however, is the detection of Map in healthy individuals with no clinical signs of disease. The latter observation indicates all humans are susceptible to infection with Map and lends support to the thesis that Map is zoonotic, with a latent stage of infection similar to tuberculosis, where infection leads to the development of an immune response that controls but does not eliminate the pathogen. This clarifies one of the reasons why it has been so difficult to document that Map is zoonotic and associated with the pathogenesis of CD and other diseases. As discussed in the present review, a better understanding of the immune response to Map is needed to determine how infection is usually kept under immune control during the latent stage of infection and elucidate the triggering events that lead to disease progression in the natural host and pathogenesis of CD and immune related diseases in humans.

Comparative Evaluation of Different Test Combinations for Diagnosis of Mycobacterium avium Subspecies paratuberculosis Infecting Dairy Herds in India

A total of 355 cows were sampled (serum, n = 315; faeces, n = 355; milk, n = 209) from dairy farms located in the Punjab state of India. Faeces and serum/milk samples were screened by acid fast staining and “indigenous ELISA,” respectively. IS900 PCR was used to screen faeces and milk samples. Bio-load of MAP in dairy cows was 36.9, 15.6, 16.3, and 14.4%, using microscopy, serum ELISA, milk ELISA and milk PCR, respectively. Estimated kappa values between different test combinations: serum and milk ELISA, faecal microscopy and faecal PCR, milk ELISA and milk PCR, faecal PCR and serum ELISA were 0.325, 0.241, 0.682, and 0.677, respectively. Estimation of the relative sensitivity and specificity of different tests in the present study indicated that “serum ELISA” and “milk ELISA” were good screening tests, add “milk PCR” was “confirmatory test” for MAP infection. Combination of milk ELISA with milk PCR may be adopted as a model strategy for screening and diagnosis of JD in lactating/dairy cattle herds in Indian conditions.