INFECTION
Presented by : Nitiakaliyani a/p Balasubramaniam
LEARNING OUTCOMES:
By end of the session, the student will be able to:
1. Define infection.
2. State the classification of infection.
3. Explain pathogenicity, virulence, invasiveness
and colonization.
4. Discuss the stages of infectious process.
5. Identify the main sources of infection.
INFECTION
Definition:
Invasion and multiplication of microorganism into
the body, causing damage to tissues and diseases
to host.
INFECTION
Disease producing microorganisms are called
pathogens
 The ability of a microorganism to produce
disease is called pathogenicity.
The frequency with which a pathogens
causes disease is called virulence
INFECTION
The ability of a pathogen to invade tissues are
called invasiveness.
The presence of microorganisms on the body
surface (eg. skin, mouth, intestine) without
causing disease in the person is called
colonization.
RECAP
CLASSIFICATION OF INFECTIONS
1.
2.
3.
4.
5.
6.
7.
8.
9.
Local Infection
Systemic Infection
Bacteremia
Septicemia
Acute Infections
Chronic infections
Nosocomial infections
Cross- infections
Iatrogenic infections
CLASSIFICATION OF INFECTIONS
1. Local Infection
A local infection is limited to the specific part of the
body where the microorganisms remains. Exhibits
redness, swelling and pain. Eg. pimples.
CLASSIFICATION OF INFECTIONS
2. Systemic Infection
Systemic infection is when the microorganisms
spread and damage different parts of the body.
Symptoms include fever, fatigue and headache
CLASSIFICATION OF INFECTIONS
3. Bacteremia
Bacteri means “bacteria” + Haima means “blood”.
The presence of bacteria in the blood.
CLASSIFICATION OF INFECTIONS
4. Septicemia
Septi means “sepsis”.
Widespread destruction of tissues due to
absorption of disease causing bacteria or their
toxins from the bloodstream.
5. Acute Infections
Acute infections generally appear suddenly or last
a short time. Eg. Chicken pox, cough and cold
CLASSIFICATION OF INFECTIONS
6. Chronic infections
It may occur slowly over a very long period and
last months, years or lifetime. e.g. Cancer
7. Nosocomial (hospital-acquired) infections
Noso means “disease”.
Komeion means “take care of”.
Define as any infection acquired during
hospitalization.
Common infections sites are urinary tract,
respiratory tract, bloodstream and wounds
8. Cross- infections
The transfer of infection from one patient to another
in hospital.
Example: MRSA (Methicillin-resistant
Staphylococcus aurens) infections.
CLASSIFICATION OF INFECTIONS
9. Iatrogenic infections
Iatro means “the healer or doctor”.
gennan means “produced by”.
The direct result of diagnostic or therapeutic
procedures.
RECAP
1. What are the classification of infections ?
• Local Infection
• Systemic Infection
• Bacteremia
• Septicemia
• Acute Infections
• Chronic infections
• Nosocomial infections
• Cross- infections
• Iatrogenic infections
STAGES OF THE INFECTIOUS
PROCESS
Once a pathogen has gained entrance into
the body, the course of infection progress
through 4 stages:
1. Incubation period
2. Prodromal period
3. Period of illness
4. Convalescent period
STAGES OF THE INFECTIOUS
PROCESS
STAGES OF THE INFECTIOUS
PROCESS
1. Incubation period
Is the time interval between entry of an infectious
agent into the host and the onset of symptom.
The infectious agent invades the tissues and
begins to multiply to produce an infection.
STAGES OF THE INFECTIOUS
PROCESS
2. Prodromal period
An early stage of a developing disease.
During this period, the infectious agent continues
to invade and multiply in the host.
STAGES OF THE INFECTIOUS
PROCESS
3. Period of illness
The time during which the person experience
symptoms of the particular disease eg.
Headache, sore throat.
RECAP
What are the 4 stages of infectious process?
1. Incubation period
2. Prodromal period
3. Period of illness
4. Convalescent period
MAIN SOURCES OF INFECTION
Humans
Environment
Other animals and birds
SUMMARY
Infection is defined as the invasion of pathogenic
microorganisms and their multiplication causing
damage to tissues and diseases to the host.
There are nine classification of infection.
Infection process are consists of 4 stages.
THANK YOU