35.1: Infectious Disease

Immunology: Chapter 35 p. 1010

Infectious disease

When microorganisms cause physiological changes that disrupt normal body functions

Causes?

Virus Bacteria Fungi Protists Parasites *remember…a pathogen is a disease

causing microorganism* Look at p. 1010-1011 and read

characteristics of each

Koch’s postulates

1. Pathogen must always be found in the body of a SICK organism and should not be found in a healthy one

2. The pathogen must be isolated and grown in the laboratory in pure culture

3. When the cultured pathogens are introduced into a healthy host, they should cause the same disease that infected the original host.

4. The injected pathogen must be isolated from the second host…it should be identical to the original pathogen

Won the Nobel Prize in 1905! Postulates are guidelines that help

identify causes of new and emerging disease

Write…

What is a symbiont? How is a different from a pathogen?

How diseases spread

Coughing Sneezing Physical contact Exchange of body fluids Contaminated water or food To humans from infected animals

Cool fact!

“Pathogens are often spread by symptoms of disease, such as sneezing, coughing or diarrhea In many cases, these symptoms are changes in host behavior that help pathogens spread and infect new hosts.” p. 1012

Zoonoses: The Animal Connection

Any disease that can be transmitted from animals to humans is called a ZOONOSIS

i.e. mad cow disease, west nile, lyme disease

Vectors

Carriers that transport the pathogen but usually do not get sick themselves

This includes: 1. bitten by an infected animal 2. consumes the met of an infected

animal 3. comes in close contact with an

infected animal’s wastes or secretions