Microbes are everywhere, including in us and on us - numerically, we are half bacteria, and this normal flora keeps us healthy.

However, dangerous pathogens are one of the biggest threats to human health around the world. Infections of most body sites are very common and can be extremely serious.


It could be very helpful to have epidemiology of certain pathogens around the world...


In order to show that a pathogen is the cause of a disease, Koch's postulates must be met:

  1. the same organism must be found in all cases of a given disease
  2. the organism must be isolated and grown in a pure culture
  3. ogranisms from this culture must reproduce the disease in a healthy susceptible animal
  4. the organism must again be isolated and then used to reinfect another animal