Infection Prevention and Control
Scientific Knowledge Base
● Nature of infection
○ Infection
■ The invasion of a susceptible host by pathogens, or microorganism which
results in disease
○ Colonization
■ Presence and growth of microorganisms without a host without tissue
invasion or damage
■ Higher in “risk groups” where people live or work in a tight space with
people
○ Communicable disease
■ The infectious process transmitted from one person to another
○ Symptomatic
■ Clinical signs and symptoms are present
○ Asymptomatic
■ Clinical signs and symptoms are not present
6 Links in the Chain of Infection
● Infectious agent or pathogen
● Reservoir or source for pathogen growth
● Portal of exit
● Mode of transmission
● Portal of entry
○ Could be the same as portal of exit
● susceptible host
● Question
○ Which chain in the link of infection will this represent?
Types of Pathogens and Infectious Agents
● Pathogens are disease producing microorganism
● Virulence is the ability of the pathogen to invade and cause the disease in a host
● Groups of Pathogens
○ Bacteria
■ Aerobic > anaerobic
○ Viruses
■ Smallest of microbes
○ Fungi
■ Molds and yeast
○ Prions
■ Rare
○ Parasites
■ Protozoa and worms
Herpes Zoster Shingles
● Viral Infection
● Initially produces chickenpox then lies dormant in the nervous system
Scientific Knowledge Base
● Nature of infection
○ Infection
■ The invasion of a susceptible host by pathogens, or microorganism which
results in disease
○ Colonization
■ Presence and growth of microorganisms without a host without tissue
invasion or damage
■ Higher in “risk groups” where people live or work in a tight space with
people
○ Communicable disease
■ The infectious process transmitted from one person to another
○ Symptomatic
■ Clinical signs and symptoms are present
○ Asymptomatic
■ Clinical signs and symptoms are not present
6 Links in the Chain of Infection
● Infectious agent or pathogen
● Reservoir or source for pathogen growth
● Portal of exit
● Mode of transmission
● Portal of entry
○ Could be the same as portal of exit
● susceptible host
● Question
○ Which chain in the link of infection will this represent?
Types of Pathogens and Infectious Agents
● Pathogens are disease producing microorganism
● Virulence is the ability of the pathogen to invade and cause the disease in a host
● Groups of Pathogens
○ Bacteria
■ Aerobic > anaerobic
○ Viruses
■ Smallest of microbes
○ Fungi
■ Molds and yeast
○ Prions
■ Rare
○ Parasites
■ Protozoa and worms
Herpes Zoster Shingles
● Viral Infection
● Initially produces chickenpox then lies dormant in the nervous system
