Contact Transmission Zoonotic Disease Disease spread from animals from infected tissues or fluids and feces EX Rabies Caused by a virus in skunks raccoons etc From animal saliva Leptospirosis Small rodents spread from bacteria in urine Tularemia Rabbits or rodents rabbit fever Non Communicable Disease where microbe from environments contaminate the fomite Vehicle Transmission 1 Air 2 Water 3 Food Microbe is most commonly shed into vehicle from either human or animal Inanimate objects also spread pathogen EX Stachybotrys A fungi that grows on damp walls that can eventually lead to death of infant or child when infection gets to lungs Airborne Transmission Spread during respiratory infections coughing sneezing droplets Microscopic particles Aerosols travel farther than a meter Droplets Larger particles Waterborne Transmission Ex Water contaminated with fecal material is used or ingested by humans indirect fecal oral Causes gastrointestinal disease o Giardia infections Protozoa drinks water that looks clean from ponds but is infected from animal feces o Vibrio Cholerae Mixes drinking water with sewage water tends to happen after natural disasters Foodborne Transmission Usually causes gastrointestinal diseases Ex Food poisoning Salmonella Staphylococcus microbes get into food then produce toxins Norovirus Food contaminated from ill person common on cruise ships Vector Transmission Vectors feed on humans blood skin tissues mosquitos lice etc 1 Mechanical Vectors Physically transports pathogen to new host 2 Biological Vectors Most common pathogen must replicate or undergo some type of developmental change microbes replicate in vector Malaria Caused by protozoa vector is mosquito The sick person has protozoa in red blood cells The healthy mosquito picks up microbe and develops in the intestinal tract and ends up in mosquitos salivary glands Then mosquito injects healthy person with parasite Density of Host is more common in winter because more people are confined indoors in smaller spaces ID50 Infectious Dose how many cells of a microbe it takes to cause a disease in typical person EX Salmonella 10 000 20 000 cells Shigella 200 cells
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