Communicable diseases

• What are communicable diseases caused by?


  Infective organisms known as pathogens
• How can bacteria be classified?


  By their basic shapes and cell walls
• What is the shape of bacilli bacteria?


  Rod-shaped
• What is the term for a chain of bacilli?

  Streptobacilli
• What shape are cocci bacteria?


  Spherical
• What is a pair of cocci called?

  Diplococci
• What is the term for a chain of cocci?

  Streptococci
• What is a cluster of cocci called?


  Staphylococci
• What shape is vibrio bacteria?


  Comma-shaped
• What shape is spirillum bacteria?


  Spiral
• What shape is spirochaete bacteria?


  Cork-screw
• What are viruses classified as?


  Non-living infectious agents
• What is the size range of viruses?


  0.02-0.3 µm in diameter
• What are bacteriophages?


  Viruses that infect bacteria
• What are protoctista?


  A group of eukaryotic organisms with various feeding methods
• How do viruses replicate inside host cells?


  They insert their genetic material into the host DNA and use the host's machinery
• How do some protozoa cause disease?


  By taking over the genetic material of the host cell
• How do fungi cause disease?


  By digesting and destroying host cells
• How do most bacteria cause disease?


  By producing toxins that damage host cells
• What is the process of viral infection?


  Attachment, insertion of nucleic acid, replication, synthesis, assembly, and lysis
• What are the two main types of pathogen transmission?


  Direct and indirect transmission
• What is direct transmission?


  Transmission through direct contact or ingestion
• What are fomites?


  Inanimate objects that can transfer pathogens
• How can droplet inhalation lead to infection?


  By inhaling droplets containing pathogens expelled from an infected person
• What is a vector in the context of disease transmission?


  An organism that transmits pathogens from one host to another
• How can humans act as vectors for animal diseases?


  By minimizing close contact with animals and washing hands
• What factors affect the transmission of communicable diseases in animals?


  Overcrowding, poor nutrition, and compromised immune systems
• How does climate change affect disease transmission?


  It can introduce new vectors and diseases
• What is direct transmission in plants?


  Contact between a healthy plant and any part of a diseased plant
• What is indirect transmission in plants?


  Soil contamination by pathogens or spores
• What factors affect the transmission of communicable diseases in plants?


  Susceptible crop varieties, overcrowding, and poor nutrition
• How do plants recognize pathogen attacks?


  Through receptors that respond to pathogen molecules
• What is callose and its role in plant defense?


  A polysaccharide that acts as a barrier against pathogens
• How does callose help prevent pathogen spread?


  By sealing off infected cells and blocking sieve plates
• What are examples of plant defensive chemicals?


  Insect repellents, insecticides, and antibacterial compounds
• What is the role of the skin in preventing pathogen entry?


  It covers the body and forms a barrier against pathogens
• How do phagocytes contribute to pathogen defense?


  By engulfing and digesting invading pathogens
• What initiates blood clotting?

  Contact of platelets with collagen in damaged tissues
• What is the role of histamines in the inflammatory response?


  They dilate blood vessels and increase permeability
• What is the function of cytokines in the immune response?


  They attract phagocytes to the site of infection