Pathogens and Infectious Diseases

Section 1: Understanding Pathogens

Pathogens are microscopic organisms that cause infectious diseases.
There are four main types of pathogens: viruses, bacteria, fungi and protozoa.
Pathogens can be transmitted through various methods including, air, food, water and direct contact.
Each type of pathogen has specific methods of infection and unique impacts on the human body.

Section 2: Features of Different Pathogens

Viruses are the smallest type of pathogen, which invade host cells and reproduce inside them, ultimately destroying or damaging them.
Bacteria are single-celled organisms, some of which are harmful and can produce toxins that damage tissues and cells.
Fungi include moulds and yeasts. They are usually harmless but can cause infections on the skin, in the lungs and other parts of the body.
Protozoa are single-celled organisms that can cause diseases such as malaria and dysentery.

Section 3: Infectious Diseases

Infectious diseases are disorders caused by organisms such as bacteria, viruses, fungi or protozoa.
An individual can become infected through direct or indirect contact with an infected person or their secretions.
There are three types of infectious diseases based on their spread:
- Non-communicable diseases: cannot be transmitted from person to person.
- Communicable diseases: can spread from person to person.
- Vector-borne diseases: spread by vectors like mosquitoes.
Examples of infectious diseases include influenza, HIV/AIDS, tuberculosis and malaria.

Section 4: Protection Against Infections

The immune system is the body’s primary defense mechanism against pathogens and infections.
It has two major components: the innate immune system and the adaptive immune system.
Regular vaccinations and maintaining good hygiene are effective ways of preventing infections.
Use of antibiotics can help to treat bacterial infections, but they are not effective against viral infections.

Remember, understanding these concepts is the key to mastery in tackling questions related to pathogens and infectious diseases.