Module 4

• Communicable disease


  A disease that can be passed between animals and plants
• Pathogens


  Harmful microorganisms that cause communicable diseases
• Types of pathogens


  • Bacteria
  • Fungi
  • Virus
  • Protoctista
• Direct transmission


  Physical contact made between an infected animal or plant, spreading the pathogen
• Indirect transmission


  Pathogens are not spread through physical contact
• Examples of indirect transmission

  • Animal vectors
  • Airborne transmission
  • Fomites
  • Human movement
• A weak immune system makes it much harder to fight off disease
• Weak immune systems include

  • HIV infection sufferers
  • Elderly people
  • Babies and young children
  • Chronic underlying conditions
• Crowded spaces


  • Nursing homes
  • Prisons
  • Hospitals
  • Homeless shelters
• Poor access to healthcare can mean diseases are not treated early enough
• Poor healthcare is a key issue in many developing countries
• TB (Tuberculosis)


  An infectious disease of the lungs caused by bacteria
• Pathogen for TB


  Mycobacterium tuberculosis
• Pathogen in cattle for TB

  Mycobacterium bovis
• Treatment for TB


  Use of antibiotics and vaccinations
• TB is spread


  Via infected droplets from the lungs
• Bacterial meningitis


  Results in inflammation of the membranes surrounding the brain and spinal cord
• Pathogens for bacterial meningitis


  Streptococcus pneumoniae<|>Haemophilus influenza type B
• Transmission of bacterial meningitis

  Via direct contact
• Ring rot


  A bacterial disease affecting potatoes and tomatoes
• Pathogen for ring rot

  Clavibacter michiganensis
• Transmission of ring rot

  Planting infected material and indirect contact with contaminated equipment
• HIV/AIDS


  A viral disease that cannot be treated with antibiotics
• Pathogen for HIV


  Human Immunodeficiency Virus (HIV)
• Transmission of HIV


  Via direct contact with infected bodily fluids
• Influenza


  A viral disease caused by different strains of virus
• Pathogens for influenza


  Influenza virus A, B, and C
• Transmission of influenza


  Through both direct and indirect contact
• Tobacco mosaic disease


  A viral disease affecting tobacco plants and tomatoes
• Pathogen for tobacco mosaic disease

  Tobacco mosaic virus
• Black sigatoka


  A disease affecting the leaves of banana plants
• Pathogen for black sigatoka

  Black sigatoka fungus
• Ringworm


  A fungal infection that is most common in cattle
• Pathogen for ringworm


  Trichophyton verrucosum
• Athlete's foot


  A fungal infection affecting the feet
• Pathogen for athlete's foot

  Fungi species within the genus Trichophyton
• Malaria


  A disease caused by protists resulting in cyclical symptoms of fever and chills
• Pathogen for malaria


  Several species of Plasmodium
• Transmission of malaria


  Insect vectors, especially the female Anopheles mosquito
• Late blight


  A disease caused by protist that affects potatoes and tomatoes