Marty Misener from Southwest Ontario Veterinary Services, Mycobacterium Avium: “Turning The Ship”


Mycobacteria  as  a  group  are  known  for causing diseases such as tuberculosis. The various   species   of   Mycobacteria   are relatively  comfortable  in  hopping  across host species lines and this includes humans. For that

reason  the  presence  of  Mycobacterial  infection  in pigs  and  other  food  animals  is  treated  as  a  food

safety    issue    which    can    lead    to    carcass condemnations.


Mycobacterial  infections  in  pigs  are  commonly caused by the Mycobacterium avium (bird) complex

(MAC).  Globally,  the  importance  of  the  MAC infections  in  humans  is  rising  because  of  its  higher

prevalence    and    also    higher    mortality    rates particularly  in  advanced  countries.   In  addition,

treatment of the MAC infections in humans tends to be  complicated  because  of  its  increasing  resistance

to  antimicrobial  agents.  European  studies  have documented  the  MAC  occurrence  in  the  lymph

nodes,  tonsils,  diaphragm,  meat  and  other  organs. The  lesions  of  MAC  can  be  spotted  by  meat

inspectors   at   slaughter   and   a   granulomatous lymphadenitis is common.


In  a  recent  case  in  Ontario,  growing  pigs  were exposed   to   Mycobacterium   avium   when   they

consumed    a    peat    moss    product    that    was contaminated  with  the  Mycobacteria  avium.  The

peat  moss  had  been  top  dressed  on  to  their  feed. Having the carcass condemnations is tough enough.

Finding  out  that  condemnations  will  continue  until the  last  pigs  that  consumed  the  contaminated  peat

moss go to market is an even tougher pill to swallow as  you  wait  for  the  production  pipeline  to  clear.


Take Home Message

Sometimes it can take a long time to “turn the ship”.


Submitted by Marty Misener, DVM

Ref: Hulinova  Stromerova  N,  Faldyna  M.Mycobacterium  avium  complex infection  in  pigs:  A  review.  Comp  Immunol  Microbiol  Infect  Dis.  2018 Apr;57:62-68. doi: 10.1016/j.cimid.2018.06.005.


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