Communicable diseases

• What is a disease?

  a disease is an illness or disorder of the body or mind that leads to poor health
• What is a communicable disease?

  communicable/infectious diseases are caused by pathogens and are transmissible, both plants and animals can be affected by pathogens
• What's an infectious disease?

  Disease caused by a pathogen that passes from infected individuals to uninfected individuals
• What are some examples of communicable diseases?

  cholera, HIV/AIDS, malaria, tuberculosis
• what's a non-communicable disease?

  long-term diseases that are not caused by pathogens
• what are some examples of non-communicable diseases?

  lung cancer, cardiovascular disease, depression, cystic fibrosis, vitamin deficiencies
• What microorganisms are pathogens?

  • bacteria - reproduce rapidly and can produce toxins which damage tissues of the body
  • viruses - reproduce rapidly within host cells causing cell damage
  • fungi
  • protoctists
• What are pathogens?

  microorganisms that cause disease
• How does transmission occur?

  transmission either occurs through direct contact, contaminated water or in droplets carried in the air
• What is the simplest way to prevent disease?

  stop pathogens from spreading
• How can we stop the spread of disease?

  • good hygiene
  • effective sanitation
  • waste disposal
• What's the process of hygienic food prep?

  • keep food cold to slow down bacteria and fungi reproduction
  • wash hands and clean surfaces to avoid contamination
  • cook food thoroughly to kill pathogens
  • use separate utensils for uncooked meat and cover food to prevent contamination
  • this prevents direct contact transmission
• What's the process of personal hygiene?

  • washing with soap, especially after using the bathroom, to remove pathogens to prevent direct contact transmission
  • use tissues to catch sneezes and coughs and dispose of used tissues to prevent airborne transmission
• what's the process of waste disposal?

  • dispose of waste food to prevent prevalence of flies which act as a vector
  • cover rubbish bins and remove to the landfill for disposal or burning regularly to prevent direct transmission
• What's the process of sanitation?

  • homes and public places should have plumbing and drains to remove faeces and waste safely; these drains can carry pathogens
  • raw sewage should be treated to remove solid waste and kill pathogens before being released into the environment to prevent waterborne transmission
• What are 2 other methods of reducing transmission in the population?

  • vaccinations
  • destroying vectors that carry the disease
• What are two common diseases caused by viruses?

  The common cold and the flu
• Why are viruses not classified as living organisms?

  They do not fulfil the 7 life processes
• What do viruses lack that cells have?

  Nuclei, organelles, and cytoplasm
• How do viruses monitor or create change in their internal environment?

  They cannot monitor or create change
• How do viruses reproduce?

  By inserting genetic material into host cells
• What happens to the host cell after many viral copies are made?

  The host cell may burst open
• What do viral particles do after the host cell bursts?

  They can infect other cells
• How do viruses reproduce rapidly?

  by inserting their genetic material into host cells and creating new protein capsules to build new viral particles
• What are measles?

  • a highly contagious and a potentially serious viral infectious disease that can be fatal if complications arise
  • measles is most often seen in children - most young children are vaccinated against it
• What are the main symptoms of measles?

  • fever
  • red skin rash
  • most people recover well however it can cause blindness and brain damage
• How is measles spread?

  • the virus is spread by the inhalation of droplets from coughs and sneezes which makes it very infectious
• What's the treatment and prevention for measles?

  • there is no treatment for measles, so if someone becomes infected they need to be isolated to stop the spread of the virus
  • measles is now greatly reduced in the UK as a result of improved living conditions and a vaccination programme for young children
• What is HIV?

  Human immunodeficiency virus(HIV) is a virus that can eventually lead to acquired immunodeficiency syndrome (AIDS)
• what are the symptoms of HIV?

  • HIV starts with a flu-like illness
  • if untreated it can travel to the lymph nodes and attack cells of the immune system
  • it can stay hidden in the immune system for many years until the immune system is so badly damaged it can no longer deal with other infections or cancer(this is late-stage HIV infection, known as AIDS)
• How is HIV spread?

  • direct sexual contact
  • the exchange of bodily fluids such as blood, for example, can be transmitted when drug users share needles
  • from mother to child during birth or in breast milk
• what's the treatment and prevention for HIV?

  • there is no cure for HIV, although the use of antiretroviral drugs sued early in the infection can now effectively control the disease to slow or halt the progress to AIDS
• What is tobacco mosaic virus?

  • a widespread plant pathogen that infects about 150 species of plants including tomato plants and cucumbers
• What are the symptoms of tobacco mosaic virus?

  • distinctive mosaic pattern of discolouration of the leaves as the virus infects the chloroplasts
  • the plant will not grow as much due to the lack of photosynthesis - this reduces the yield of crops
• how is tobacco mosaic virus spread?

  • plants in direct contact with an infected plant
  • virus can stay in the soil for about 50 years
• what's the treatment and prevention for tobacco mosaic virus?

  • there is no treatment for tobacco mosaic virus and the best method of control is good field hygiene to prevent the spread of the virus, farmers are also using tobacco mosaic virus - resistant strains of crop plants
• What are bacterial pathogens?

  Cells that can infect plants and animals
• Are all bacteria harmful?

  No, not all bacteria are pathogens
• Where are hundreds of different bacterial species found?

  Skin and large intestine
• What role do bacteria on the skin play?

  They act as competitors to harmful pathogens