PLACE INVADERS
Invasive Diseases
Infectious Disease Also known as
Contagious DiseaseCommunicable DiseaseTransmissible Disease
Caused by a pathogen that causes disease
Not all infections cause disease that can be transmitted
Infectious Diseases Pathogens can be:
VirusesBacteriaParasitesFungiProtozoaPrions
Viruses Can Infect Plants People Animals Bacteria Other Single Celled-organisms
Viruses in Plants Transmitted by
-Chewing Animals such as Insects -Sucking Insects such as Aphids
-Fungi-Single-celled Organisms-People Through Tools or Hands-Generation to Generation Through Seeds and Pollen
-Nematodes
Viruses in Plants Don’t infect humans or animals
Reduce Yield Deform fruits and vegetables
Plum Pox Virus in peaches
Tomato Mosaic Virus in cucumbers
Examples of Plant Viruses
Pepper mild mottled virus
Tobacco Mosaic virus
Tobacco Mosaic Virus in Orchids
Examples of Plant Viruses
Potatoes infected with Y virus
Tobacco Mosaic virus in tomatoes
Healthy Eggplant (left) compared to damaged eggplant infected with Tomato Bushy Stunt virus
Would you eat these?
Virus Control In Plants Once plants are infected with viruses little can be done.
There is not effective treatment.
The best control is prevention.
Scientists are working on creating vaccines but they are in the early stages of research.
Virus Prevention Includes
insect control removing weeds that may harbor viruses or their insect vectors
grow from seeds for plants that transmit viruses through seed, use indexed seed
discard all virus infected plants disinfect tools used for vegetative propagation
Viruses In Animals Transmitted
Biting and/or Blood-sucking Insects
CoughingSneezingFecal-oral RouteDirect Blood to Blood Direct Body FluidsSexual transmission
Viruses In Animals Some Viruses can infect a number of species
Other Viruses are Species Specific
Viruses can mutate new “strain” of a virusexpand host populationsalter transmission method
Viruses need live tissue
Viruses In Animals Vaccines are used to create immunity to viruses
Antivirals can now be used to treat some virusesTamifluRelenza
Antibiotics DO NOT work on viruses!
Examples of Animal Viruses
Foot and Mouth Disease Hemorrhagic Fever Influenza (flu) Avian Influenza Herpes Viruses West Nile Virus Encephalitis Yellow Fever
Influenza Virus
Examples of Animal Viruses
Distemper Rabies Measles Polio Chickenpox Smallpox
Girl with Smallpox in Bangladesh in 1973
Bacteria Single-celled microorganisms Rods, spheres, spirals Reproduce by Binary fission
http://en.wikipedia.org/wiki/File:Binary_fission_anim.gif
Bacteria Live in every environment on earthSoilFresh water Salt waterAcidic hot springsOn all surfacesIn very inhospitable places
Live in and on the human body
Live in and on plants and animals
Bacteria Very important in nutrient cyclesNitrogen fixationDecomposition
Some bacteria beneficialProbioticsFermented foods
CheeseYogurtPicklesSourdough bread
Bacteria Some bacteria live symbiotically
Some bacteria harmfulpathogens
Most bacteria do not affect humans, plants or other animals
Most bacteria have not been classified or studied
Bacterial Diseases Cholera Tuberculosis Anthrax Leprosy Syphilis Bubonic plague Bacterial pneumonia Tetanus
Bacillus anthracis (Anthrax)
Eschericia Coli (E. Coli)http://en.wikipedia.org/wiki/File:E.-coli-growth.gif
Bacteria Exist virtually everywhere including in the air
So transmission is possible by every means
Bacterial can live for years in very inhospitable environmentsSpores in soil
Post-harvest Bacteria Bacteria do not only cause disease in plants and animals
Bacteria cause food spoilage
Bacteria cause food-borne illnesses
Food preservation and pasteurization techniques are used to prevent both
Parasites Live in or on a host and cause harmNourishmentProtection
May be as small as a single cell Protozoa1 to 2 micometers
May be a large wormHelminthsJust visible to naked eye to 2 meters long
Parasites May have a single permanent host
Or many intermediary hosts In animals, often excreted in feces
Infest animals and plantsHumansMammalsBirdsInsects
Parasites May Be Transmitted from human to human
Transmitted from animal to animal
Transmitted from human to animal
Transmitted from animal to human
Transmitted from human to bird to mammal and back to human
May be transmitted by insect vectors
Parasites Transmitted from fecal contamination
Transmitted from direct blood contamination
Transmitted by vectors
Diseases Caused by Parasites
Found in food or water Cause foodborne illness Cause waterborne illness Can range from mild discomfort to debilitating illness or even death
Transmitted primarily through fecal contamination
Diseases Caused by Parasites
Trichomoniasis Malaria Giardia Cryptosporidium Cyclospora Toxoplasmosis Trichinosis Tapeworms
Prevention of Parasitic Diseases
Proper hand washing with soap Drink either municipal treated water or boil water
Cook foods thoroughly Do not swallow or breath in water when swimming
Consume only pasteurized beverages
Use gloves when handling uncooked meat, cat litter, gardening.
Human Fungal Diseases Athlete’s Foot/Jock Itch Yeast Infections (Candida)
Thrush Ringworm Diaper Rash Fungal Sinusitis Nail Fungus Histoplasmosis
Plant Fungal Diseases
Powdery Mildew Fusarium Wilt Root rots Phytopthora infestans –
late blightCause of the Irish Potato Famine
Still the most pathogen of potato crops
Powdery Mildew
Diseases Caused by Fungi
Transmitted by contact with fungal spores
Transmitted by air Treated with antifungal agents in humans and animals
Treated with fungicides in plants
Protozoan Diseases Malaria, Giardia, Cryptosporidium, and Toxoplasmosis
African Sleeping Sickness Amebic Dysentery
Protozoan Diseases Transmitted by insect vectors
Tse Tse FlyMalarial mosquito
Transmitted in contaminated water
Transmitted in contaminated food
Contamination with cysts from infested fecal material
Prevention of Protozoan Diseases
Proper hand washing with soap
Boil water before drinking Cook foods thoroughly Prevent fly contamination of food
Drink only pasteurized beverages
Strict sanitation when working with lab animals
Treatment of Protozoan Diseases Drug treatments are available
Depending upon infestation, a sequential use of several drugs may be used.
Chlorine does not kill protozoans so heating water to 122°F is necessary
Diseases Caused by Prions Prions are a caused by a yet to be determined transmission agent
cause abnormal folding of proteins in the brain which leads to brain damage
Diseases Caused by Prions Mad Cow Disease – BSE Scrapie Chronic Wasting Disease Creutzfeld-Jakob Disease Kuru
Treatment of Prion Diseases
The disease is always fatal. No known treatment is available.
Brain and spinal tissue is removed from slaughtered animals prior to butchering to prevent any possible contamination by prions.
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