infectious disease 40-1. what is disease? disease –any change in the body, other than injury, that...
TRANSCRIPT
Infectious Disease
40-1
What is Disease?
• Disease– Any change in the body, other than injury, that
disrupts the normal functions of the body– Disease has many causes
• Bacteria• Viruses• Environmental Factors (cigarette smoke, pollution)• Genetics
Koch’s Postulate
• Koch said:– Disease is caused by
microorganisms and NOT by curses, evil spirits or night vapors
– Yes, for thousands of years, people believed that diseases were caused by those things.
Infectious Disease
• Infectious = can be passed from person to person
• Pathogens – Cause disease– EX:
• Bacteria• Viruses• Protists• Worms
Bacteria
• Single Celled living organisms– Asexual reproduction– Multiply by themselves
• Can easily be seen with a microscope!!
• Live & breed in warm, moist environments
• Prokaryotes: no nucleus
Bacteria and Humans
• Most bacteria = harmless
• Good for humans!– many places on our bodies – Intestines…digestion
Bacteria as Pathogens
• Bacteria as Pathogens– Break down tissues– Release toxins– EX:
• Streptococcus (Strep Throat)• Diptheria• Botulism• Anthrax• E. coli (found in food)
Bacteria
Treatments for Bacterial Infection
• Antibiotics– Kill bacteria, but not body
cells– Interfere with the cellular
processes of the bacteria– One antibiotic will kill
many different kinds of bacteria
– Examples: Penicillin, Amoxicillin
Virus• 1000 times smaller than
bacteria!!– Cannot be seen with a
microscope
• Cannot live or reproduce on their own– Must invade a host cell– Contain RNA or DNA but
none of the equipment to reproduce
Virus• Pathogenic
• Mutate often
• Examples:– Common cold– Influenza– Smallpox– Warts– HIV
Virus
Treatments for Viral Infection
• Best treatment:– Rest– Water– No help from Doc!
• Antibiotics are NOT effective against viruses because the virus live within your own body’s cells.
Why you feel sick when you have an infection
• Symptoms caused by your body’s response to the infection– Fever
• kill the pathogen
– Vomiting, Runny nose, coughing • physically remove the pathogen
– You feel tired because your body is working overtime fighting the infection
In Review• An Infectious Disease is
– Disease that can be passed from person to person
• A Pathogen is– A disease causing agent
• Bacteria– Single-celled living organisms– Killed by Antibiotics
• Virus– Tiny particles, need host cell in order to
replicate– Antibiotics are INEFFECTIVE