Pathogens Bacteria and Viruses

Pathogens Organism that causes disease Types: Examples? Bacteria, viruses, fungi, protists Examples? Plasmodium  malaria HIV  AIDS HPV  genital warts, cervical cancer Dermatophytes  athlete’s foot Salmonella  food poisoning

How do they spread? Coughing, sneezing, and physical contact Exchange of body fluids Contaminated water or food Animal vectors

Emerging Diseases Formerly unknown or newly evolved diseases Ex. AIDS in the 1980’s West Nile Virus H1N1 Drug-resistant TB Ebola We often do not have a way to control them Our bodies have little resistance to them

Emerging Diseases

Bacterial Diseases How do they cause disease? Other examples: Destroy living cells Directly infect cells Indirectly – may trigger an immune response that damages cells Releasing toxins Poisons interfere with our cells’ activities E.g. Botulism paralyzes muscles Other examples: TB, Tetanus, Lyme disease, Strep throat

Controlling bacterial infections Wash surfaces/hands  washes away bacteria Use chemicals  disinfectants Properly store our food  refrigeration Cook food fully  kills bacteria Heat sterilization  e.g. surgical tools Antibiotics  treat bacterial infections Vaccines – prepare immune system

Viral Diseases How do they cause disease? Examples: Attack and destroy specific types of cells Can change patterns of growth and development of cells  leads to cancer Examples: Common cold, influenza (flu), HIV/AIDS, chicken pox, Hepatitis B, HPV

Controlling viral diseases Vaccines Good hygiene – wash hands, use Kleenex! Avoid contact with sick individuals Antibiotics DO NOT work against viruses Few antiviral drugs