Infection
in·fec·tion
•Invasion and multiplication of
pathogenic microorganisms in a bodily part or tissue, which may produce
subsequent tissue injury and progress to overt disease through a variety of cellular or toxic mechanisms.
•The pathological
state resulting
from having been infected.
What is an Infection?
A
harmful invasion and spread of foreign species, or pathogen, in a host. Such as
–VIRUS
• Small
pox, measles, influenza, Ebola
–PRIONS
•Cow’s
disease
–BACTERIA
•Tuberculosis,
pneumonia, salmonella, anthrax
–FUNGUS
•Athlete’s foot, ring worm
–PROTISTS
•Malaria, toxoplasmosis, Algae
•
Disease
and Infectious Disease
–Disease
•Any
deviation from a condition of good health and
well-being
–Infectious Disease
A
disease condition caused by the presence or growth
of infectious microorganisms
or parasites
•Pathogenicity and Virulence
–Pathogenicity
•The
ability of a microbe to cause disease
•This
term is often used to describe or compare
species
–Virulence
•The
degree of pathogenicity in a microorganism
•This
term is often used to describe or compare strains
within a species
Principles of Infection
•Understanding the basic principles of
infection is
essential for any health care worker in any field of
health care.
Disease transmission
Prevention of disease transmission
Nature of Microorganisms
•Microorganisms (microbes) are small,
living
organisms that are not visible to the naked eye.
•Pathogens (germs) are microorganisms
that cause
disease.
Non-pathogens
are microorganisms that do not
cause disease; can be beneficial
Nature of Microorganisms
•Saprophytes
•Parasites
•Pathogens
Signs & Symptoms of Infection
Redness
Swelling
• Tenderness
• Warmth
• Drainage
• Red streaks leading away from the wound
Development of Infection: Clinical Signs and Symptoms
Local signs
Inflammation
Purulent exudate if bacterial infection; serous exudate if viral
Tissue necrosis
Lymphadenopathy
Respiratory effects
Systemic signs
Fever, fatigue, headache, nausea
