pathogens and disease

• what is a pathogen?

  a microorganism that causes infectious diseases
• what are the 3 ways pathogens are spread?

  1. direct contact
  2. water/air
  3. vectors
• what is a vector?

  an organism that carries and passes on the pathogen
• what are the 4 types of disease?

  1. viruses
  2. protists
  3. bacterial
  4. fungal
• what are 4 ways to prevent infectious diseases?

  1. simple hygiene measures
  2. destroying vectors
  3. isolating infected individuals so they can't pass on the pathogen
  4. giving people at risk a vaccination
• name 2 examples of a viral disease?

  1. measles
  2. HIV
• viruses reproduce rapidly in body cells causing damage to them
• what are the symptoms of measles?

  fever and a red skin rash
• how is measles spread?

  by breathing in droplets from coughs and sneezes
• how is HIV spread?

  sexual contact or exchanging bodily fluids
• at first HIV causes a flu-like illness but if left untreated then the virus enters the lymph nodes and attacks the body immune cells
• late stage HIV (AIDS) is when a bodies immune system is damaged and can't fight off other infections or cancers
• bacteria may damage cells directly or produce toxins that damage tissues
• name 2 bacterial diseases?

  1. salmonella
  2. gonorrhoea
• salmonella is a type of food poisoning caused by bacteria
• what causes salmonella?

  the bacteria are ingested in food which wasn't cooked properly/ prepared in hygienic conditions
• what are the symptoms of salmonella?

  the bacteria secrete toxins which cause fever, abdominal cramps, vomiting and diarrhoea
• how is salmonella prevented?

  chickens in the UK are vaccinated against salmonella to control the spread
• Gonorrhoea is an STD caused by bacteria
• how is gonorrhoea spread?

  sexual contact
• what are the symptoms of gonorrhoea?

  a thick yellow or green discharge from the vagina or penis and pain when urinating
• how is gonorrhoea treated?

  penicillin
• how to prevent gonorrhoea?

  barrier methods of contraception eg condoms
• what is a protist?

  a single celled organism that are eukaryotic
• what is a disease spread by a protist?

  malaria
• the protist uses a particular type of mosquito as a vector; it is passed on person to person when they're bitten by the mosquito
• what does malaria cause?

  a servere fever which reoccurs and can be fatal
• how to prevent malaria?

  using mosquito nets, anti mosquito spray, removing stagnant waters so they can't breed
• what is an example of a fungal disease?

  rose black spot
• how is rose black spot spread?

  spores are carried from plant to plant by water/wind
• symptoms of rose black spot?

  purple or black spots develop on leaves causing them to turn yellow and drop early
• with rose black spot, the loss of leaves will stunt the growth of the plant because photosynthesis is reduced
• how is rose black spot treated?

  Fungicides and removing and destroying the affected leaves