INFECTIOUS DISEASE What is Infectious Disease A disease

INFECTIOUS DISEASE

What is Infectious Disease? • A disease caused by the presence of a living thing in the body.

What are Pathogens? • Organisms that cause disease.

Four Types of Pathogens… • • Viruses Bacteria Fungi Protists

VIRUSES • A tiny, nonliving particle that invades and then reproduces inside a living cell.

BACTERIA • Single-celled organisms that lack a nucleus (prokaryotes)

FUNGUS • A eukaryotic organism that has cell walls, uses spores to reproduce, and is a heterotroph that feeds by absorbing its food.

PROTISTS • A eukaryotic organisms that cannot be classified as an animal, plant, or fungus.

How Do Pathogens Spread? • Pathogens can spread through contact with either an infected person; soil, food, or water; a contaminated object; or an infected animal.

Infected People • Direct physical contact (kissing, shaking hands, etc) • Indirect contact (sneezing, coughing, etc)

Soil, Food, Water • Some pathogens occur naturally in the environment. • Some pathogens contaminate food and water, spreading disease when drinking and eating.

Contaminated Objects • Some pathogens can survive outside a person’s body. • Contact with contaminated objects can infect a person (towels, silverware, etc).

Infected Animals • If an animal is infected with a pathogen and bites a person, it can pass the pathogen to the person. • Example: Rabies, Lyme Disease, etc.