Infectious DiseasesInfectious Diseases

Infectious DiseaseInfectious Disease

• Aka Communicable Diseases

• Caused by micro-organisms

• Parasite – lives in/on and feeds on host

PathogensPathogens

• Pathogens– Micro-organisms– Enter the body– Multiply– Cause disease

• Bacteria

• Virus

• Fungi

BacteriaBacteria

• Single-cell micro-organisms

• Release toxins

• Examples– Food poisoning –bacteria in

food– Tetanus – bacteria on

objects/soilStaph

VirusVirus• Smallest parasite

• Enter cells and take over

• Multiply

• Cause colds/ flu

HIV

FungiFungi

• Not all are harmful– Mushroom/ yeast/ mold/ fungi

• Some cause rashes– Ringworm & athlete’s foot

Spreading Infectious DiseaseSpreading Infectious Disease

• Physical contact w/ infected person

• Contact w/ contaminated object

• Environmental sources

• Contact w/ contaminated animals

Contaminated AnimalsContaminated Animals

• Animal bites

• *Eating bad food*

• Rabies/ Malaria/ Bird flu

• HIV/ AIDS

Contaminated Object Contaminated Object

• Most infections die quickly when exposed to air

• Some can live on objects

• Lice

Contact w/ Contaminated Person Contact w/ Contaminated Person

• Skin to skin contact

• Sneeze/ cough

• Cold/ STI/ flu/ chicken pox

Environmental Sources Environmental Sources

• Food/ water/ soil

• Lead poisoning/ food poisoning

• Fungi/ mold/ pathogens in water

• Old food left out

• Contaminated animals

Stages of DiseaseStages of Disease

1. Exposure

2. Incubation Period

3. Prodromal Period

4. Acute Stage

5. Recovery Stage

6. Convalescence

7. Immunity

Exposure & IncubationExposure & Incubation

• Exposure = contact

•Incubation = growth/ maturation•No signs/ symptoms•Pathogen/ parasite grows and multiplies

Prodromal StageProdromal Stage

• Slight signs & symptoms

• Ex: achy/ sore/ tired

• Contagious!

Acute StageAcute Stage

• Severe symptoms

• Most contagious

• Most affected

Recovery StageRecovery Stage

• Signs/ symptoms begin to decrease

• Temperature is reduced

• Feeling better

CovalescenceCovalescence

• Infection is gone

• Still not quite 100%

• Can relapse

• Need rest, sleep, healthy diet, antibiotics

ImmunityImmunity• Feel 100%

• Body has antibodies

• Cannot catch same infection

Questions?Questions?