Environmental factors
The primary method of MAP transmission is believed to be a
direct fecal-oral cycle. The process is quite similar to the transmission
of other enteric infections, whereby any exposure to
manure from shedders can potentially lead to new infections.
However, there is still a possibility of indirect transmission, such
as through manure contamination of water bowls and machinery
used for feed delivery. Therefore, any management activities that
directly or indirectly lead to exposure of susceptible animals to
manure from shedding animals could be considered risk factors
of infection; these will be reviewed in detail in the section on
disease control strategies. The efficiency of transmission by these
pathways depends upon factors such as number of organisms
shed in the feces and the organism’s survival characteristics in
the environment (41).