Types of Pathogens

Pathogens

• A pathogen is a microorganism that causes a disease.
• There are four main types of pathogens: viruses, bacteria, fungi, and protists.

Types of Pathogens

• Viruses: cause diseases such as HIV (potentially leading to AIDS) in animals and tobacco mosaic virus in plants.
• Bacteria: cause diseases such as Salmonella in animals and Agrobacterium in plants.
• Fungi: cause diseases such as athlete's foot in animals and rose black spot in plants.
• Protists: cause diseases such as malaria in animals and downy mildew in plants.

Life Cycle of Pathogens

• All pathogens have a simple life cycle: infect a host, reproduce or replicate, spread from the host, and infect other organisms.
• Pathogens have structural adaptations that enable them to complete their life cycles and cause further disease.

Communicable Diseases

• Diseases caused by pathogens are called communicable diseases.
• Communicable diseases can be transferred from one person to another.

Non-Communicable Diseases

• Inherited genetic disorders, such as cystic fibrosis, are not caused by pathogens.
• Deficiency diseases, such as scurvy (caused by a lack of vitamin C), are not caused by pathogens.
• Diseases like cancer, which develop as a result of exposure to carcinogens or incorrect cell division, are not caused by pathogens.

Transmission of Pathogens

• Transmission can occur in various ways, including:
  • Direct contact
  • Indirect contact
  • Airborne transmission
  • Vector transmission (e.g., through insects)
  • Contaminated food and water
  • Infected bodily fluids