B5 Communicable Diseases

• Define health


  A state of physical and mental well-being

  
• What is a communicable disease? Give 3 examples

  Communicable diseases are caused by pathogens like bacteria and viruses and can be passed from one person to another. Examples are Measles, Smallpox and Athletes foot.
• What is a non-communicable disease? Give 3 examples

  A noncommunicable disease is a non-infectious health condition that cannot be spread from person to person. Examples are depression, cancer and arthritis.
• Explain how other factors can affect health. Give specific examples?

  A: -Diet- if you do not get the right nutrients you can suffer from a range of diseases.

  
  

  -Stress- too much stress is linked to heart disease, certain cancers and mental health problems.

  
  

  -Life situation- where in the world you live, level of free health care, your gender and financial status can be linked with different diseases.
• Explain how health problems can interact. Give some examples

  A person can have different types of disease and health conditions at the same time, and these often interact:

  -Viruses living in cells, such as the human papilloma virus, can trigger changes that lead to cancers.

  -Defects in the immune system can make someone more likely to have a communicable disease.

  -Immune reactions can trigger allergies.

  -Severe physical health issues can lead to mental health problems, such as depression.

  -Malnutrition can lead to deficiency diseases, a weakened immune system, obesity, cardiovascular disease, type 2 diabetes, or cancer.
• What is a pathogen? Name the 3 examples

  Pathogens are microorganisms that cause infectious disease. Pathogens may be viruses, bacteria, protists or fungi.
• How do bacteria make you fell ill?

  They produce toxins that damage your cells and tissues
• How do viruses make you feel ill?

  They live inside your cells and replicate themselves using the cells' machinery to produce many copies of themselves. The cell will usually then burst., releasing all the new viruses. This cell damage is what makes you feel ill.
• Describe the 3 methods that pathogens can be spread. Give an example of each.

  Air - Droplet infection

  Direct contact - Sexual contact

  Water - Contamination
• Describe how to produce an uncontaminated culture of a microorganism

  To culture microorganisms you must provide them with everything they need. This means giving them a gel containing nutrients. They also need warmth and oxygen to grow.
• Why are uncontaminated cultures useful?

  They can be used to test how effective disinfectants or antibiotics are (so we can use the best one).
• Why don't you seal the lid onto the dish with Sellotape?

  Sellotape can become contaminated and bacteria could start to grow and mutate.
• Why are the petri dishes stored upside down?

  To stop condensation dripping on the agar
• Why do we only incubate the cultures at 25°C in school?

  Because anything above 25 degrees could highly increase the risk of growing a dangerous pathogens.
• How do bacteria reproduce?

  asexually through binary fission
• What are the optimum conditions for bacterial growth?

  Warm, moist, enough nutrients and oxygen.
• In optimal conditions how quickly can bacteria reproduce?

  every 20 minutes
• How can you investigate the antimicrobial properties of different antibiotics or disinfectants?

  You can investigate the effects of disinfectants and antibiotics on bacterial growth using agar plates and calculating the cross-sectional area of colonies grown, or of clear areas of agar.
• What was Semmelweis's observations that led to his theory about the spread of infection in his hospital?

  He noticed women in the labour ward much more likely to die of "child bed fever" if staffed by medical students instead of student midwives. This was because the medical students were dissecting dead bodies on the same day they were working in the labour ward, however the student midwives didn't.
• Why were other doctors so resistant to Semmelweis's ideas?

  - His ideas went against the then scientific opinion

  - The doctors didn't want to be to blame for many deaths.
• Describe 3 simple hygiene measures that can prevent the spread of pathogens

  -Hand washing

  -Vaccination

  -Isolating infected individuals
• How else can we prevent the spread of pathogens?

  Destroying or controlling vectors by using insecticides or destroying their habitat.
• What are the main symptoms of measles?

  Fever and a red skin rash
• How is the measles virus spread?

  The inhalation of droplets from sneezes and coughs
• Why is measles rare in the UK?

  Improved living conditions and a vaccination programme for young children
• What are the symptoms of HIV?

  Fever, weight loss, night sweats, diarrhea, fatigue
• When does HIV become AIDS?

  when t cell count drops below 200
• How is HIV spread?

  Sexual contact, or exchange of body fluids such as blood when drug users share needles.
• How can you prevent the spread of HIV?

  Using condoms, sterilisation of needles
• How can you prevent the development of AIDS?

  Regular use of antiretroviral drugs
• What are symptoms of Tobacco mosaic virus (plants)?

  -Distinctive mosaic pattern of discolouration on leaves

  -Reduced ability to photosynthesise

  -Seriously reduce yield of crop
• How is TMV spread?

  Direct contact between plants
• How can farmers reduce the spread of TMV?

  No treatment, however farmers can grow TMV-resistant strains of crops. Minimising human handling, good field hygiene, isolation and pest control can help prevent spread of TMV.
• Where can salmonella bacteria be found?


  Raw meat, chicken, eggs
• What are the symptoms of salmonella poisoning?

  Fever, stomach cramps, vomiting and diarrhoea
• How can we reduce the cases of food poisoning?

  In the UK, poultry are vaccinated against salmonella.
• What are the symptoms of gonorrhoea?

  -Thick yellow or green discharge

  -Pain when urinating
• What problems can untreated gonorrhoea causes?

  Can cause long-term pelvic pain, infertility and ectopic pregnancies. Babies born from infected mothers may have severe eye infections and may even become blind.
• Gonorrhoea used to be easily cured using antibiotics, why has this changed?


  There are now many antibiotic-resistant strains of gonorrhoea that have evolved so it is increasingly difficult to treat.
• What are crown galls? (plants)

  Masses of unspecialised cells that often grow at the join between the root and the shoot in infected plants