This document discusses types of infections caused by microbes and immunity. There are two main types of infections - viral infections caused by viruses, and bacterial infections caused by bacteria. Bacteria can infect any part of the body and cause illnesses like pneumonia and meningitis. Viruses are smaller than bacteria and cannot reproduce on their own. There are four types of immunity - innate immunity present at birth, adaptive immunity developed after exposure, active immunity from exposure or vaccination, and passive immunity from maternal antibodies that provide short term protection for newborns.

1. Prepared By:
Ayesha Rubab
Tashfeen Gulfaraz
Iqra Noor

2. Infection is the invasion of an organism’s
body tissues by disease-cause agents, there
multiplication and reaction of host tissues to
these organisms and toxin the produce.

3. Types of Infection
There are two types of infections:
Viral Infection
Bacterial Infection

4. Viral Infection
It is caused by a virus. An individual may become
infected by :
 Inhaling the virus;
 Being bitten by infected insects or parasites;
 Through sexual contact.

5. Bacterial Infection
It is a proliferation of harmful strains of bacteria on or
inside the body. Bacteria can infect any part of a body.
Pneumonia, Meningitis and Food poison are just a few
illnesses that may be caused by harmful bacteria,
Shapes of Bacteria:
 Rod Shape(bacilli);
 Spherical Shape(Cocci);
 Helical Shape(Spirilla).

6. Bacteria vs Virus
Bacteria Infection Viral Infection
 Bacteria’s are larger than
viruses
 Bacteria’s are capable of
reproducing on their own;
 Virus are much smaller than
Bacteria;
 Viruses are not capable of
reproducing on their own;

7. Similarities Between
Bacterial & Viral Infection
There are many things in common both types of
infection caused by microbes, bacteria and viruses
respectively and spread by things such as:
 Coughing and Sneezing;
 Contact with infected people, especially through
kissing and sex;
 Contact with creatures, including pets, livestock and
insects such as fleas and ticks.

8. IMMUNITY
Immunity is a balanced state of multicellular and
organisms having adequate biological defenses to fight
infection, diseases, or other unwanted biological
invasion, while having adequate tolerance to avoid
allergy, autoimmune diseases.

9. Types of Immunity
There are four types of immunity:
 Innate (natural) Immunity;
 Adaptive(Acquired) Immune System;
 Active Immunity;
 Passive Immunity.

10. Innate(Natural) Immunity
It is a natural resistant component such as intact skin,
salivary enzymes and neutrophils, natural killer cells,
which provide initial response against infection that is
present in an individual at birth prior to exposure to a
pathogen or antigen.

11. Adaptive (Acquired) Immune
System
It is that which develops antibodies after an attack of
disease or by a pregnant mother passing through the
placenta to a fetus or by vaccination

12. Active Immunity
It refer to the method of exposing the body to an antigen
for generating an adaptive immune response. The
response takes days/weeks to develop but may be long
lasting.
For example, recovery from Hepatitis-A virus gives a
natural active immune response that usually leading life
long protection.

13. Passive Immunity
It refer to the method of imparting IgG antibodies to
keep safe against infections. Its gives immediate but
short lived protection such as several weeks to 3 or 4
months at most. It occurs during pregnancy.
The transfer of maternal tetanus antibodies across the
placenta provides passive immune to newborn baby for
several weeks/months until such antibody is degraded
and lost.

14. Thank You