1. Infectious Diseases

2. Pathogens
Disease causing agents that have the ability to make you sick or even cause death
They are found in the air and food and on nearly every object or person who you come in contact with

3. Uncontrollable Risk Factors
Heredity
Chromosomal traits and family history
Aging
Vulnerability increases with age
Environmental Conditions
Unsanitary conditions, drugs, chemicals, and pollutants
Organism Resistance
Some pathogens are resistant to our body’s defenses and/or medical treatments

4. Controllable Risk Factors
Stress
Nutrition
Physical fitness level
Sleep
Drug use
Hygiene
High-risk behaviors

5. Routes of Pathogen Transmission
Direct Contact
Touching, kissing, sexual relations
Indirect Contact
Touching an object that an infected person has had contact with
Airborne Contact
Breathing in air that carries a pathogen
Food-borne infection
Eating something that is contaminated by microorganisms

6. Routes of Pathogen Transmission
Animal-borne pathogens
Animals can spread diseases through bites, feces, or by carrying infected insects into living areas
Water-borne diseases
Transmitted from drinking water, from foods washed or sprayed with contaminated water, or from wading or swimming in contaminated streams, lakes or reservoirs
Perinatally
Mothers can transmit diseases to an infant in the womb or as the baby passes through the vagina during birth

8. Bacteria Single-celled organisms
There are several thousands of species, but only about 100 cause diseases in humans
Most of the time it is not the bacteria that is causing the diseases, but it is the toxins that are produced by the bacteria
They can be seen under a standard microscope

9. Bacterial Diseases Staphylococcal Infections
These bacteria are normally on our skin at all times and usually do not cause problems
When a cut or break in the skin occurs, the bacteria may enter and cause an infection
Acne, boils, styes (eyelid infections), wounds are common staph infections

10. Bacterial Diseases Streptococcal Infections Pneumonia
Causes strep throat and scarlet fever
Pneumonia
One form is caused by a bacterial infection with the following symptoms chronic cough, chest pain, chills, high fever, fluid accumulation and eventual respiratory failure

11. Bacterial Diseases Legionnaire’s Disease Tuberculosis (TB)
A water-borne disease with symptoms similar to those of pneumonia
Tuberculosis (TB)
An airborne disease where bacteria infiltrate the lungs and cause a chronic inflammatory reaction
Symptoms include coughing, weight loss, fever and spitting up blood

12. Viruses Minute parasitic microbes that live inside another cell
Over 150 viruses are known to cause diseases in humans
Viral diseases are hard to treat because many can withstand heat, chemicals and large doses of radiation with little effect on their structure

13. Viral Diseases The Common Cold
There may be over 200 different viruses responsible
Carried into the nose and throat most of the time
Stress, allergies, and menstrual cycles appear to increase susceptibility

14. Viral Diseases Influenza (flu)
Symptoms include aches and pains, nausea, diarrhea, fever, and cold like ailments
In healthy people, it is usually not serious
However, when combined with other disorders, among the elderly, those with respiratory or heart disease, children under 5 the flu can be very serious

15. Viral Diseases Mononucleosis (mono or the kissing disease)
Symptoms include sore throat, fever, headache, nausea, chills, weakness or tiredness, lymph nodes may swell, jaundice, spleen enlargement, aching joints, and body rashes may occur
May be transmitted through body fluids but does not appear to be easily contracted through normal, everyday contact

16. Viral Diseases Hepatitis Causes inflammation of the liver
Symptoms include fever, headache, nausea, loss of appetite, skin rashes, pain in the upper right abdomen, dark yellow urine, and jaundice

17. Viral Diseases Hepatitis A (HAV) Hepatitis B (HBV) Hepatitis C (HBC)
Contracted from eating food or drinking water contaminated with human feces
Hepatitis B (HBV)
Spread through body fluids, usually during unprotected sex
Can lead to liver disease or liver cancer
Hepatitis C (HBC)
Some cases can be traced from people who share needles, blood transfusions or organ transplants
Usually causes chronic infections and if not treated may cause cirrhosis of the liver, liver cancer, or liver failure

18. Viral Diseases Measles
Symptoms appear about 10 days after exposure and include an itchy rash and a high fever and may lead to other problems such as rheumatic heart disease, kidney damage and neurological disorders

19. Other Pathogens
Fungi
Multicellular or unicellular primitive plants that inhabit our environment
Many are useful providing food such as mushrooms and cheeses
Some produce infections
Candidiasis (vaginal)
Athlete’s foot
Ringworm
Jock itch

20. Other Pathogens Protozoa
Microscopic, single-celled organisms that can cause disease
Trichomoniasis
transmitted sexually
Giardiasis
found in water
Malaria
Via mosquitoes

21. Other Pathogens Parasitic Worms
Usually associated with eating raw fish
Cooking fish and other foods to high temperatures will kill the worms and their eggs to prevent infestation
Pinworms
Tapeworms

22. The Immune System
Protects the body from potentially harmful substances
Any substance that is capable of triggering an immune response is an antigen
When invaded by an antigen, the body forms antibodies to destroy or weaken the antigen

23. Vaccines
A vaccination consists of an injection of a dead or weakened form of a disease-causing microorganism.
This organism can no longer cause the disease, but can still stimulate antibody production by white blood cells.
This type of immunity lasts a long time.