Chain of Infection

Area where the causative agent can live 

• mode of transmission
• portal of exit
• reservoir
• portal of entry

Way that causative agent transmits to another host

• portal of entry
• portal of exit
• reservoir
• mode of transmission

Pathogen that causes disease

• portal of exit
• susceptible host
• causative agent
• portal of entry

infection acquired while in a hospital setting

• direct contact
• opportunistic infection
• indirect contact
• nosocomial infection

pathogen transmitted through air, soil, food or feces

• direct contact
• indirect contact
• opportunistic infection
• nosocomial infection

way for causative agent to escape the reservoir

• portal of entry
• portal of exit
• reservoir
• causative agent

person who gets a disease because of weak defenses

• causative agent
• susceptible host
• reservoir
• portal of entry

infection acquired while body defenses are weak

• nosocomial
• opportunistic 
• direct
• indirect

way for the causative agent to enter a new reservoir

• portal of entry
• portal of exit
• direct
• indirect

person to person contact

• direct
• indirect
• mode of transmission
• reservoir