Health & Disease: Disease Types

• Communicable & Non-Communicable Disease:

  Defining health-

  • The World Health Organisation (WHO) defines health as 'a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity'
  • This means that health is not just dependent on whether an individual is physically sick or not.
  • There are lots of factors that should be considered when assessing the health of an individual which includes mental health as well as the level of social support in place
• Communicable diseases:

  • Communicable diseases are caused by microorganisms called pathogens which can spread between individuals
  • E.g. chickenpox, a common childhood disease, is caused by a viral pathogen called the varicella-zoster virus
• Communicable Diseases Table:

  
• Non-communicable diseases:

  • Non-communicable diseases are not caused by pathogens and cannot be passed on between individuals
  • Their effects on health tend to be longer-lasting
  • Examples include: asthma, CHD and most cancers
  • The risk of developing non-communicable diseases may be increased by certain factors (including diet, stress and life situations) as these factors may have a profound effect on both physical and mental health
• Non-communicable diseases:

  • Eating a balanced diet that provides the right amount of energy and nutrients helps maintain good health whereas a poor diet can lead to deficiencies, obesity, diabetes and poor mental health
  • Constantly being under stress can lead to cardiovascular issues (such as high blood pressure, increasing the risk of CHD) and poor mental health
  • Where a person lives and their income can have a profound impact on health - this affects the standard of healthcare that is accessible to them (and what they can afford), what food they buy etc.
• Risk Factors in Non-Communicable Diseases Table:

  
• Risk Factors in Non-Communicable Diseases Table:

  
• Interactions Between Diseases:

  Susceptibility

  • If an individual suffers from one disease, they are likely to be more susceptible to other diseases
  • This is because the immune system may be compromised in some way or the different types of disease may interact in ways that affect the health of the individual negatively 
  • Defects in the immune system mean that an individual is more likely to suffer from infectious diseases
  • Individuals infected with HIV eventually end up with reduced numbers of lymphocytes (a type of white blood cell) circulating around the blood
• Interactions Between Diseases:

  • This reduces the ability of the immune system to tackle opportunistic infections like pneumonia
  •  Viruses living in cells can be the trigger for cancers; the HPV virus can infect cells of the cervix in women resulting in cervical cancer developing in some cases, whereas some strains of the hepatitis virus can cause liver cancer
• Interactions Between Diseases:

  • Immune reactions initially caused by a pathogen can trigger allergies such as skin rashes and asthma - these often develop as a result of an overactive immune response
  • Severe physical ill health can lead to depression and other mental illness; both can impact the immune system negatively and affect lifestyle choices made by the individual, further compounding the effects of poor health
• The interaction of HIV and AIDS:

  • Human Immunodeficiency Virus (HIV) destroys white blood cells in the immune system
  • Initial symptoms are flu-like
  • This includes headaches, high temperature, joint and muscle pains
  • If untreated, the virus compromises the immune system leading to the onset of Acquired Immune Deficiency Syndrome (AIDS)
  • AIDS is used to refer to several life-threatening illnesses which may result from having a compromised immune system
  • The most common of these is pneumonia
• The interaction of HIV and AIDS:

  • The virus infects a certain type of lymphocyte of the immune system
  • Normally lymphocytes seek out and destroy pathogens that enter the body, producing antibodies that attach to pathogens, enhancing phagocytic activity
  • However, HIV avoids being recognised and destroyed by lymphocytes by repeatedly changing its protein coat
  • It then infects a certain type of lymphocyte and uses the cells’ machinery to multiply
  • This reduces the number of lymphocytes of the immune system
  • And therefore the number of antibodies that can be made
• The interaction of HIV and AIDS:

  • As a result, the body has a reduced ability to tackle infections, eventually leading to AIDS (Acquired immunodeficiency)
• How HIV affects lymphocytes:

  
• How HIV affects lymphocytes...

  
• The interaction of HPV and cervical cancer:

  • Human Papilloma Virus (HPV) can be associated with cervical cancer
  • HPV is sexually transmitted, though is not thought to affect men, who are carriers of the virus
  • HPV viruses living in cells can be the trigger for cervical cancer in women
  • Girls aged 12-13 are injected with a vaccine for HPV
  • Before they reach the age of sexual activity
  • Vaccination triggers an immune response
  • Which reduces the risk of viruses spreading in a subsequent infection
  • So in turn, the risk of cervical cancer in those girls/women is reduced