Pathogens Flashcards
What are the five major classes of pathogens?
- Bacteria
- Viruses
- Fungi
- Protozoa
- Multi-cellular Parasites
Define Endotoxins
Structural component of bacteria released when bacteria are lysed.
Define Exotoxins
Toxin excreted by a microorganism.
List 5 examples of Protozoa.
Coccidiosis, Cryptosporidium, Toxoplasmosis, Trichomoniasis, Neospora
List 6 examples of Multi-Cellular Parasites.
Large Roundworms, Trichinosis, Tapeworm, Lice, Ticks, Mange
How to Fungi reproduce?
Asexually- spores or mycelia fragmentation
Sexually- meiosis
List all 4 of Koch’s Postulates.
- The microorganism must be found in all organisms suffering from the disease, but should not be found in healthy animals.
- The microorganism must be isolated from a diseased organism and grown in pure culture.
- The cultured microorganism should cause disease when introduced into a healthy organism.
- The microorganism must be re-isolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
Describe the germ theory of Edward Jenner.
Took cowpox blister, scratched it into the skin of a young boy, then inoculated him with smallpox. No disease.
Described the germ theory of Delafond.
Blood from dead sheep contained anthrax microorganisms that would reproduce.
Describe the germ theory of Koch.
Animals injected with anthrax germs became ill, discovered bacteria that caused TB, cholera, anthrax.
Describe the germ theory of Pasteur.
Developed first effective vaccine (to anthrax). Took the invention of the microscope.
Describe the 3 shapes of bacteria.
Cocci- circular
Bacillus- rod
Spirillum- spiral
List the 6 arrangements of cocci.
Coccus, diplococci, staphylococci, streptococci, sarcina, tetrad.
Describe Bacteria.
Unicellular organisms which have cell walls but lack organelles and an organized nucleus, including some that can cause disease.
Describe Viruses.
Viruses contain a protein coat surrounding an RNA or DNA core of genetic material. They are capable of growth and multiplication ONLY in living cells. They are easily transmitted due to size and often very contagious. Viruses also cannot live or reproduce independently.
Describe Fungi.
Fungi includes yeast, molds, and mushrooms. The reproduce both asexually and sexually. The cell walls contain chitin (long hard polymer that makes up the exoskeletons of crustaceans). Fungi are often difficult to eliminate due to sores and fragmentation. Some produce a poisonous substance called mycotoxin.
List one example of Fungi.
Ringworm
List 4 toxins of Fungi.
Aflatoxins, Vomitoxine, Ergot alkaloids, fusarium-zearalenone
Describe Protozoa.
Unicellular eukaryotes either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris. They produce oocysts (protozoan spore), a highly resistant stage which may survive for a long time in the fecal material if the host or in the soil.
Describe Multi-Cellular Parasites.
Any of the large multicellular parasites. They typically have a complicated lifecycle with multiple phases and can be difficult to control due to life stages and drug resistance.
