Genotype diversity in Indian isolates of Mycobacterium avium subspecies paratuberculosis recovered from domestic and wild ruminants from different agro-climatic regions

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.

Genetic diversity of bovine Mycobacterium avium subsp. paratuberculosis discriminated by IS1311 PCR-REA, MIRU-VNTR, and MLSSR genotyping

The aim of this study was to describe the genetic diversity of Mycobacterium avium subsp. paratuberculosis (MAP) obtained from individual cows in Korea. Twelve MAP-positive fecal DNA samples and 19 MAP isolates were obtained from 10 cattle herds located in 5 provinces in Korea. In addition, 5 MAP isolates obtained from the Czech Republic and Slovakia and 3 isolates from Australia were genotyped for comparison with the domestic isolates. The most prevalent strains in Korea were of the “bison-type” genotype (23 of 31 fecal DNA/isolates) and were distributed nationwide. The remaining MAP isolates (8) and all of the foreign isolates were identified as “cattle-type”. The bison-type strains which were discriminated only as INMV 68 in variable-number tandem repeats of mycobacterial interspersed repetitive units (MIRU-VNTR) typing. Multilocus short sequence repeat (MLSSR) typing differentiated the bison-type strains into 3 different subtypes. The cattle-type strains were divided into 3 subtypes by MIRU-VNTR and 8 subtypes by MLSSR. The allelic diversities in the MIRU-VNTR and MLSSR results were calculated as 0.567 and 0.866, respectively. These results suggest that MIRU-VNTR typing cannot provide a sufficient description of the epidemiological situation of MAP. Therefore, an alternative method, such as MLSSR, is needed for typing of MAP strains to elucidate the molecular epidemiology of MAP infections. Overall, this study is the first epidemiological survey report in Korea using both MIRU-VNTR and MLSSR typing methods, and it has provided basic data necessary to elucidate the characteristics of MAP infections in Korea.

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.

'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

Bio-load and bio-profile of Mycobacterium avium subspecies paratuberculosis was studied in the domestic livestock population of the country. Of the 23,429 farm and farmer's animals screened, average bio-load was 23.3% (Period of study; 28 years for goats; 13 years for sheep, cattle and buffaloes). Species-wise, bio-load was 20.1, 32.7, 39.3 and 28.3% in goats, sheep, cattle and buffaloes, respectively. Bio-load was significantly lower in time period A (P < 0.001) and B (P < 0.03), compared with period C. Geographical zone-wise, bio-load of MAP was significantly higher (P < 0.05) in Central zone compared with South, West, East and North zones. Bio-load in 11 states ranged from 16.2 to 87.8%. Of 8450, 5643, 8185 and 1151 samples screened by microscopy, culture, indigenous ELISA and IS900 blood PCR, 20.0, 10.6, 35.1 and 26.6% samples were positive, respectively. Bio-load was 32.8 and 31.6% in farm and farmer's goats and sheep, respectively, and 62.1% in farmer's cattle. MAP bio-load was also monitored in four farm units (three goats and one sheep) for breed improvement and three farm goats units for experimental purposes at Central Institute for Research on Goats in Mathura district. Of the 8025 goats and 1525 sheep that died from 1988 to 2013, 10.9 and 3.0% deaths were due to JD, respectively. On the basis of JD and suspected JD, 10.0 and 28.4% goats and 2.2 and 40.9% sheep, respectively were culled from the farm units in 25 years. Microscopic examination of 214 tissues (mesenteric lymph nodes and intestines) of 107 animals, it was observed that bio-load of MAP was high (25.0-60.0%) in farm animals. 'Indian Bison Type' was the dominant biotype, irrespective of domestic livestock species and the geographical zone.

International efforts at paratuberculosis control

Johne’s disease has spread with livestock movements across the globe during the past century. International interest and collaboration in research and disease control have increased in the past 20 years. Control within infected herds and flocks has traditionally focused on reducing the impacts on animal welfare and productivity. Endemically infected regions are also moving to reduce contamination of the farm environment and of farm products. Several countries have been working to safeguard apparently free livestock populations and regions.