Host-pathogen relationship

• neutrophil scavenges and phagocytoses a bacterium

• almost all pathogens have evolved some mechanism to evade innate immune defense

Microbes and the human host

• there are very few microbes that are always pathogenic, but they include anthrax, rabies

• many microbes are potentially pathogenic, and these are the microbes that we encounter in medicine day in, day out

• most microbes are never pathogenic

Iceberg model for human infectious disease

• poliomyelitis in a child is almost never symptomatic: 0.1 to 1% are clinically apparent

• Rubella, the cause of German measles: 50% of infections are clinically apparent

• rabies: 100% of infections are clinically apparent, and almost inevitably fatal

Category: Microbiology Notes