What is a pathogen?
Any microbe that causes a disease.
What are the 4 types of pathogen?
Bacteria, Viruses, Fungi, and Parasites.
What are the defining features of bacteria?
-Single celled micro-organism.
-Replicate rapidly by binary fission.
-Can divide to create two identical daughter cells.
-And conjugation (transfer genetic material to another bacteria through direct contact).
-Transfer of DNA from one cell to another.
What are the types of bacteria? What are their shapes?
-Cocci (spherical)
-Bacilli (rods)
-Spirilla (spirals)
-Vibrios (“commas”)
-Spirochaetes (corkscrews)
What are the defining features of viruses?
-Made up of DNA or RNA surrounded by a protein coat.
-Replicate by attaching to a host cell and imparting genetic material into it.
-Some can survive for a long time in the environment, others only for a few hours.
Each virus is a nucleic acid (DNA/RNA) surrounded by a coating. This is called the envelope or capsid. The shape of the coating affects how the virus infects a host.
What are the defining features of fungi?
-Present in soil, air, and water.
-Range from microscopic moulds to large mushrooms.
-Dermatophytes: Replicate by spores.
-Yeasts: Replicate by binary fission and spread by direct contact. -Yeasts: Fixed shape and complex structure.
What are Protozoa, Helminths, and Ectoparasites.
Protozoa are single-celled endoparasites.
Helminths are large, macroparasite, worms which live inside of their host.
Ectoparasites are parasitic arthropods which live on the outside of their host.
What are the defining features of protozoa?
-Single celled organisms.
-Replicate by multiple fission.
-Amoeba: Can change shape.
What are the methods of disease transmission?
Direct or indirect transmission.
What are direct disease transmission methods?
-Person to person/Animal to animal contact.
-Person to animal/Animal to person (zoonotic/zoonosis).
-Droplet spread.
What are indirect disease transmission methods?
-Airborne transmission.
-Food and drinking water.
-Animal to person contact.
-Environmental reservoirs.
What are vectors and fomites?
-Vectors: An organism that can spread disease.
-Fomites: An inanimate object that can spread disease.
What are the types of immunity?
Passive and Active immunity.
What is passive immunity?
-When ready-made antibodies from another source are introduced to the body.
-Fast acting.
-Only lasts a short period of time.
-Breastfeeding provides a baby with natural passive immunity.
What is active immunity?
-When the body is activated and produces the antibodies needed to fight infection.
-Slow acting.
-Provides long-lasting protection.
-Primary response when a microorganism enters the body is described as natural active immunity.
-Vaccines provide artificial active immunity.