Bacteria, why do they make me sick?/Bacteria make me sick

CHAPTER 2



BACTERIA
MAKE ME SICK

Bacteria and Diseases

A disease is the presence of infection and its symptoms.

The infectious disease, or infective process caused by the virulent bacteria, starts with the colonization, which is the presence of the bacteria in the body. Then, the infection occurs, which is when bacteria attack the cells or tissues using their mechanisms or virulence factors.

Now… could you define the following concepts in your own words? Disease Invasion Adhesion

Other Pathogenic Microorganisms

The virus

Viruses are organisms that have genetic material protected by a protein structure.

This microscopic organism can cause different diseases when it goes inside a cell and reproduces himself in it.

How does my body react?

However, Infection does not necessarily lead to disease. If the host’s immune system acts appropriately, the person can be infected not having the symptoms. Additionally, bacteria are not the only microorganisms able to make human beings sick. There are also different pathogen viruses, such as flu viruses.

Bacteria and body’s defenses

As mentioned, a bacterial infection doesn’t always lead to disease and this is thanks to our immune system, which, roughly, is able to distinguish self from nonself.

There are two types of immunity: innate or natural immunity (IIS) and the acquired immunity (AIS).

Innate or natural immunity (IIS)

• It’s the first line of defense against invasive microorganisms (bacteria, viruses, and fungi).

• It is present since birth; it is nonspecific and lacks memory.

The IIS has three components:

• Physical and chemical barriers; such as skin, cilia, mucosae and secretions. By continuous cleaning, they protect us and prevent the foreign particles entering the body.

• The humoral component is composed of antibodies and the complement system.

• The cellular component, which is the cells that are part of the Innate Immune System: neutrophils, eosinophils, basophils, mast cells, and Natural Killers lymphocytes (NK lymphocytes).

Acquired Immunity (AIS)

• Acquired immunity is not present at birth, it increases with age and it is specific, and it has a memory. This is why it is also called adaptative.

• It is composed of antibodies, T lymphocyte receptors and the molecules of the major histocompatibility complex.

In general, the innate and acquired immune responses are not activated independently. Their optimal performance is when they complement each other.

In particular, the AIS’ antibodies are able to direct the IIS’ components toward the relevant objects.