ABR Vol 4 [4] December 2013 1 | P age ©2013 Society of Education, India
Advances in Bioresearch
Adv. Biores., Vol4 (4) December 2013: 01-08
©2013 Society of Education, India
Print ISSN 0976- 4585; Online ISSN 2277-1573
Journal’s URL:http://www.soeagra.com/abr/abr.htm
CODEN: ABRDC3
REVIEW ARTICLE
Mycobacterium avium subspecies paratuberculosis: an Emerging
Animal Pathogen of Global Concern
Deepak Kumar Verma*
Department of Biotechnology, Faculty of Natural and Computational Sciences
University of Gondar, P.O. Box. 196, Gondar, Ethiopia
ABSTRACT
Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of Johne’s disease (JD), which has some
pathological similarities with Crohn’s Disease in human beings. The role of MAP in the causation of CD is under
investigation since last 100 years. Both the disease (JD and CD) have been primarily and thoroughly investigated by
western countries, where high prevalence was reported and has been rising since both are incurable. In India, limited
information is available on the status on the presence of MAP infection in animal and humans. The live MAP bacilli have
been recovered from raw and pasteurized milk and from human population in the country. These reports indicated that
MAP infection has been established in animals in India and humans may get the MAP exposure through food chain or
contaminated environment. Present review summarized the information on the status of MAP in animal and humans,
economic losses and morbidity and mortality due to JD and CD at national and international level.
Keywords: Mycobacterium avium subspecies paratuberculosis, Johne’s disease, Paratuberculosis, Crohn’s disease,
Zoonosis.
Received 09/08/2013 Accepted 28/10/2013 ©2013 Society of Education, India
INTRODUCTION
Pathogens that are transmitted between environment, animals (domestic or wild) and humans present
major challenges for the animal and human health. Among such pathogens, genus Mycobacterium is well
represented by M. bovis, M. tuberculosis, M. avium ssp. avium, M. avium subsp .
paratuberculosis etc that are shared by different species of animal and primates. These pathogens
resist adverse environmental conditions and degradation [36]. Mycobacterium tuberculosis is the
most successful human pathogen, infecting nearly one third of human population and currently number
one cause of deaths due to single infectious agent in the world [87]. Recently, Mycobacterium avium
subsp. paratuberculosis (MAP) has emerged as major and successful animal pathogen with significant
zoonotic and public health concerns [23]. MAP is an established cause of Johne’s disease (JD) in domestic
and wild animals and has also been associated with the Crohn’s disease in humans. The role of MAP in the
etiology of Crohn’s disease (CD) has been debated for last nine decades. However, evidences suggesting
association of MAP with human CD have provided time to time [29, 52, 71, 79]. While this debate on
etiology of CD is going on, MAP is insidiously entering in the human food chain and has been isolated from
retailed pasteurized milk supplies, milk and milk products and water [74, 99]. Association of MAP with
CD, presence in immuno-compromised patients [63] posses serious threat to human health globally. This
review summarized the prevalence of MAP in animals and its association with cases of CD in human
beings at national and international levels with special reference to Indian sub-continent and its potential
classification as zoonotic disease.
THE ORGANISM (Mycobactrium avium subspecies paratuberculosis)
MAP is a member of Mycobacterium avium complex of Mycobacteriaceae family. It is aerobic, short slender
rod of 1-2 mm long and 0.5 mm wide, non-motile gram positive acid fast bacteria [18]. MAP is extremely
fastidious and primary culture requires more than 8 weeks of incubation. Since MAP fail to synthesize
soluble iron chelating compound (mycobactin), cultivation media must be supplemented with mycobactin
[93]. MAP like other mycobacteria have thick waxy cell wall containing 60% lipid layer, which confers it
properties of acid fastness, hydrophobicity [60], resistance to chemicals e.g. chlorine [99] and physical
processes e.g. pasteurization [25]. MAP share some antigenic determinant and has similar characteristic
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