|
| Ignore the
contribution of host, vector, and environment to disease susceptibility/response |
| Colonization
state (e.g., +PPD skin test for tuberculosis in the absence of disease)
violates Koch’s second postulate |
| Many pathogens cannot be
propagated on lifeless (cell-free) medium in the lab; these pathogens cannot
fulfill Koch’s third postulate |
| Viruses, parasites, uncultivated
bacteria may not grow in pure culture |
| Host range restriction of
pathogens |
| Do not consider the possibility
of disease produced by a microbial community rather than a single pathogen |
| Not completely specific |
|