preventing spread of pathogens

• Pathogens are harmful microorganisms that cause disease
• Bacteria:

  • Examples: salmonella, TB
  • Produce toxins that damage cells and tissues
  • Reproduce by binary fission
  • Prokaryotes without a nucleus
  • Have circular strands of DNA
  • Flagellum for movement
  • Lack mitochondria
  • Largest are 10µm long
  • Living cells
• Virus:

  • Examples: measles, mumps, colds, chicken pox
  • Not cells, much smaller than bacteria
  • Have a protein coat with DNA located within nucleic acid
  • Infect and duplicate until the cell bursts
  • Can't be treated with antibiotics
• Fungi:

  • Examples: yeast, mushrooms, moulds, athlete's foot
  • Have thread-like structures called hyphae
  • Produce spores for easy spread
  • Use saprotrophic nutrition, secrete enzymes to digest food
  • Cell wall made of chitin, like an animal cell with a cell wall
• Protist:

  • Example: malaria (transmitted by mosquitoes)
  • Parasitic eukaryotes, unicellular, can be animal-like, plant-like, or fungi-like
  • Live on or inside another organism causing harm
• Vector:

  • Doesn't cause disease itself but spreads pathogens from one host to another
• Transmission methods:

  • *Airborne droplet*: through sneezing or coughing, entry point is the breathing system, defense includes mucus and cilia, prevention through tissues, isolation, and disinfection
  • *Contaminated food & drink*: through uncooked food or poor hygiene, entry point is the digestive system, defense by hydrochloric acid in the stomach, prevention by disinfecting surfaces and maintaining hygiene
  • *Direct contact*: includes STIs through skin contact, HIV through body fluids, and vectors, entry point is the skin or blood, defense by white blood cells, prevention through condom use, avoiding needle sharing, and using insecticides