********** STEPS IN THE INFECTIOUS PROCESS **********
| PATHOGEN | HOST |
| Transmission of the pathogen to the host | The host encounters sufficient numbers of the pathogen via vertical or horizontal routes |
| Entry of the pathogen into the body with or without (+/-) attachment to the skin or mucous membranes | The host's nonspecific defenses of skin and mucous membranes are evaded or overcome |
| Local multiplication and spread of the pathogen on the surface of the skin or mucous membranes with or without (+/-) local invasion of tissues | Additional nonspecific defenses of body surfaces and local tissues (e.g. interferon, phagocytosis, complement and inflammation) and specific immune defenses (e.g. secretory IgA) are evaded or overcome |
| Systemic spread and multiplication of the pathogen into deeper body tissues and blood. | The host's nonspecific defenses of deeper body tissues and blood (e.g. the RES system, complement, inflammation, and iron limitation) and specific immune defenses (humoral and/or cellular) are evaded or overcome. |
| Exit of the pathogen from the host | The pathogen is shed from the body at a site and in sufficient numbers to insure spread to a fresh host |
| Pathology/ Disease The pathogen damages the host because of: (1) invasion and multiplication in tissues (locally or systemically) (2) toxin production, (3) immunopathology, or (4) a combination of the above |
The Host: (1) Clears the pathogen and recovers (2) Cannot clear the pathogen (asymptomatic carriage, persistent, slow, or latent infections are established) (3) Succumbs to the infection |
Modified from: Mims, C.A., N.J. Dimmock, A. Nash, and J. Stephen. 1995. Mims' Pathogenesis of Infectious Disease (4th ed.) Academic Press, London.
********** STEPS IN THE INFECTIOUS PROCESS **********
| PATHOGEN | HOST |
| Transmission of the pathogen to the host | Host encounters the pathogen via vertical or horizontal routes |
| Entry of the pathogen into the body (+/-) attachment | Host nonspecific defenses are evaded or overcome |
| Local multiplication and spread of the pathogen (+/-) local invasion | Host nonspecific and specific defenses are evaded or overcome |
| Systemic spread and multiplication of the pathogen | Host nonspecific and specific defenses are evaded or overcome |
| Exit of the pathogen from the host | Pathogen is shed from the body and is transmitted to a new host |
| Pathology/ Disease The pathogen damages the host |
The host recovers, remains infected, or succumbs to infection |
Modified from: Mims, C.A., N.J. Dimmock, A. Nash, and J. Stephen. 1995.
Mims' Pathogenesis of Infectious Disease (4th ed.) Academic Press, London.