The document discusses infection, including its definition, types, causes, sources, and modes of transmission. It defines infection as the invasion and multiplication of microorganisms such as bacteria, viruses, and parasites within the body. There are several types of infections including primary, secondary, hospital-acquired, and latent infections. Infections can be caused by a variety of microbes including viruses, bacteria, fungi and parasites. Sources of infection are either endogenous from inside the body or exogenous from outside sources. Modes of transmission include direct or indirect contact, inhalation, ingestion, insects, congenitally from mother to fetus, and iatrogenically during medical procedures.

1. Topic- Infection
Source & Spread
Presented by – CHHAVI SAINI

2. Introduction-
• Definition - The invasion and multiplication of microorganism
such as bacteria, viruses, and parasites that are not normally
present within the body.
OR
• The multiplication of microorganisms (parasite) in the body or
tissue of host is known as infection.
• Infectivity – The ability of infection agent to enter, survive &
multiply in the host.

3. Types of Infection-
• 1- Primary infection
• 2-Re-infection
• 3-Secondary infection
• 4-Hospital Acquired infection OR Nosocomial infection
• 5-Cross infection
• 6-Sub-clinical OR In-apparent infection
• 7-Latent infection
• 8- Focal infection
• 9- Iatrogenic infection

4. • Primary infection- Initial infection of a microorganism in
host.
• Re-infection- Subsequent infection after primary infection
from the same microorganism.
• Secondary infection-New microorganism sets up an infection
in a pre-existing infectious disease.
• Hospital Acquired Infection- Infection developed in
hospitalized patient, not present at the time of their
admission.
[Also known as “Nosocomial Infection”]
TYPES-

5. TYPES-
• Cross infection- Infection transferred from one patient to
another.
• Sub- clinical OR In-apparent infection- When clinical
symptoms are not visible.
• Latent infection- The microorganism may remain in the tissue
in a ‘latent or hidden form’.
• Focal infection- Infection occurs in a localized region in the
body such as a particular organ or part of a body.
• Iatrogenic infection- Cause of an infection by any medical
activity, including investigation, therapy or other conditions.

6. Causes of Infection
• The organisms that cause infections are very diverse like…
Viruses
Bacteria
Fungi
Parasites
• You can acquire an infection in many different ways, such as
Direct- from a person with an infection.
Indirect-from contaminated food or water, and even through
the bite of an insect.

7. Source of Infection
• Depending upon source , infection is divided into ---
1-Endogenous infection
2-Exogenous infection
Endogenous infection- When infection acquired from “Inside”
the body.
Exogenous infection- When infection acquired from “Outside”
the body.

8. Mode of Transmission
• 1- Contact- Direct or indirect contact.
• 2-Inhalation- Inhalation of contaminated items.
• 3-Ingestion- Ingestion of contaminated items.
• 4-Insect- Transmission through insect.
• 5-Congenital – From mother to her fetus.
• 6-Iatrogenic OR Lab infection-During diagnosis or lab work.