Host invasion by microorganisms

()Map\Tab WIKIBLOOD (Map/Tab) IMMUNOLOGY

Introduction

One of the main causes of disease is infection by microorganisms, with four types so far identified:

• Viruses
• Bacteria
• Fungi
• Parasites- comprising protozoa and helminths

All exist as either:

• Primary pathogens (obligate): presence always corresponds with disease
• Secondary (opportunistic): prerequisites must be fulfilled before disease occurs

Microorganisms can enter the body by three routes:

• Contact: typically seen in dermatological infections
• Aerosol: typically respiratory infections
• Orofecal:typically enteric infections

References

• Murphy, K., Travers, P. and Walport, M. (2008) Janeway's Immunobiology. 7th ed. New York: Garland Science Publishing.