2.2.2 (Chapter 11) – Health and Disease Lesson Objectives: To define the terms ‘health’ and ‘disease’ To discuss different categories of disease
So what is ‘health’? What do we mean by ‘health’? What are the characteristics of health? Healtha person’s physical, mental and social condition World Health Organisation (WHO): ‘a state of complete physical, mental and social well-being and not merely the absence of disease and infirmity’
Fulfilling life Good Poor Happiness Healtha person’s physical, mental and social condition Positive outlook More than just the absence of disease! Well adjusted to society Can undertake physical and mental tasks without difficulty
EVERYONE is born with the genetic potential for growth and development … they need good health to grow and realise their potential both as humans and within society. World Health Organisation (WHO; an agency of the UN): “Good health is a fundamental human right” • Shelter • Nutrition • Exercise • Sleep and rest • Good hygiene • Access to medical and social care What do we NEED for good health?
So what is ‘disease’? What do we mean by ‘disease’? Diseasea disorder or malfunction of the mind or body which leads to a departure from good health
Diseasea disorder or malfunction of the mind or body which leads to a departure from good health What are the causes of disease? How do you know if you have a disease? (what are the characteristics?) Single cause eg: malaria Multifactorial eg: heart disease Signs (symptoms) – physical and/or mental ACUTE eg: influenza CHRONIC eg: TB
The 9 categories (types) of disease ‘Miss D. Pind’ M ental P I hysical nfectious S I ocial nherited S N elf-inflicted on-infectious D egenerative D eficiency
Name this infection. The infection is…. ….. a cold or flu This infection is caused by…. …..a virus
Name this infection. The infection is…. …..athletes foot This infection is caused by…. …..a fungus
Name this infection. The infection is…. …..warts This infection is caused by…. …..a virus
Name this infection. The infection is…. …..chicken pox This infection is caused by…. …..a virus
Name this infection. The infection is…. …..food poisoning This infection is caused by…. …..bacteria
Name this infection. The infection is…. …..measles This infection is caused by…. …..a virus
Name this infection. The infection is…. …..fungal nail infection This infection is caused by…. …..obviously a fungus
Name this infection. The infection is…. …..impetigo This infection is caused by…. …..bacteria
Name this infection. The infection is…. …..oral thrush This infection is caused by…. …..a fungus
Types of pathogenic organisms … Virus Bacteria Fungi Single celled organisms Protozoa
They can be breathed in through the mouth or nose They can enter through cuts or bites in the skin Pathogen = An organism that causes a disease = a kind of parasite (an organism that lives in a very close relationship with another organism, the host, and does it harm … a well adapted pathogen will not kill its host) Pathogens can enter the body in a number of ways ... HOST …or other natural openings…
Contaminated food/water Air Vectors (eg: insects) So how are diseases spread? Direct contact Contaminated needles Indirect contact
Contaminated food/water Air Vectors (eg: insects) So how are diseases spread? Micropredator that actively delivers the parasite to the next host Direct contact Contaminated needles Indirect contact
Define ‘health’ Define ‘disease’ a person’s physical, mental and social condition a disorder or malfunction of the mind or body which leads to a departure from good health What have you learnt today? What do we need for good health? What is the WHO? World Health Organisation Shelter, nutrition, exercise, sleep and rest, health and social care, good hygiene What are the 9 categories of disease? MISS D PIND
Homework Go to WHO website: • Write a brief description of what the WHO is and it’s remit. • Then choose one disease of your choice to research, write a 200 word review of the information on that website on your chosen disease.
Tuberculosis Lesson Objectives: To describe the causes & means of transmission of TB To assess the worldwide importance of this disease To describe the roles of different factors in the prevention and control of TB
KEY WORDS Incidence Prevalence Mortality Endemic Epidemic Pandemic The number of NEWcases in a population occurring in a given time period The number of people in a population with a disease within a given time period The number of people who have died of a certain disease in a given time period An infectious disease that is always present in a population When a disease suddenly spreads rapidly to affect many people (eg: influenza) When a disease spreads over a very large area (eg: a continent or the whole world; we are having pandemics of AIDS and TB at present)
TB Impact? Symptoms? Prevalence? What do you already know? Cause? Prevention? Treatment? http://www.youtube.com/watch?v=JtyX694ubio Basic Summary http://www.nhs.uk/conditions/Tuberculosis/Pages/Introduction.aspx Better!!
TB – symptoms Some people become infected and develop TB quite quickly whilst others harbour the bacteria for many years … … it may become active when the immune system is weakened eg: malnutrition, HIV/AIDS persistent cough coughing up blood fever loss of appetite emaciation tiredness night sweats (caused by release of hormone-like compounds)
TB – treatment • Samples of sputum (pus and mucus) taken from lungs for analysis – identified using a microscope • Chest x-rays (fibrosis, calcification, pneumonia) • Skin tests • Sufferers isolated for most infectious stage (2-4 weeks) • Treated for 9 months to a year with antibiotics – bacteria are slow growing and not sensitive to the drugs Antibiotic – Streptomycin (1940s) has been used to decrease incidence of TB Drug resistance – found after 1950s READ p167-168 on TB
TB – treatment http://www.youtube.com/watch?v=XvxCs8IlyQk
TB – the cause first isolated in 1882 by a German physician named Robert Koch who received the Nobel prize for this discovery Two bacteria: Mycobacterium tuberculosis Mycobacterium bovis Live inside human cells, particularly the lungs, though can spread through the entire body (even bone tissue) Also occurs in cattle – spreads to humans through meat and milk
TB – the cause Bacilli in air in tiny droplets of liquid Cough, sneeze, talk, spit Inhaled Kidneys Bone Lining of the brain Spinal cord Infectious stage: 2-4 weeks Taken into the lungs PRIMARY TB Local lung infection (pneumonia) Lymph nodes become enlarged SECONDARY TB Macrophages (phagocytic WBCs) coat the TB bacilli in thick waxy coat (‘walled off’) Leads to scar tissue forming (fibrosis)
TB – impact ‘The biggest killer of women in the world’ - WHO Deaths in women aged 15-44 years: 9% TB, 3% war, 3% HIV, 3% heart disease • Quite hard to catch - spreads most rapidly when there is overcrowding, especially if people are: • Homeless • Living in poor, substandard housing • Prisoners • Have low immunity eg: malnutrition, HIV positive • IV drug users, alcoholics or have diabetes
TB – prevalence M. bovis – spread from cattle to humans: 1850-1950 ~800,000 deaths in the UK Now very few in developed countries Estimated that 30% of the world’s population is infected with TB (~1.8 billion) 8-10 million people infected per year 2-3 million die per year (eg: in 2002 - 2 million deaths due to TB) ~1 person per second contracts TB By 2020 nearly 1 billion will be newly infected, of which 70 million will die (WHO)
TB – prevalence The leading cause of death of HIV positive people. Those with HIV are 100x more likely to develop TB than other members of the population Has been prevalent for thousands of years … evidence in 4000 year old Egyptian mummies Found primarily in: eastern Europe (250,000 cases/year) Asia (3 million cases/year) Africa (28% of all cases) A worldwide pandemic Bangladesh, China, India, Indonesia, Pakistan, Philippines
TB – prevalence Incidence in the UK decreased BEFORE introduction of the vaccine (1950s) due to improvement in housing and diet … showing a resurgence now • Resistant strains • HIV/AIDS pandemic • Poor housing in inner cities • Rising homelessness • Breakdown of TB control programmes (partial treatment) • Migration
TB – prevention Address social issues such as overcrowding Isolation of infected people Break the lifecycle! Prevention Vaccinations Better treatment (maybe not antibiotics?)
TB – prevention Vaccinations update: 2004 Contains 2 TB proteins that stimulate a strong immune response in humans (taken from naturally immune individuals) • Vaccinations – Injected: • BCG Bacille Calmette Guérin – some protection
TB Impact? Symptoms? Prevalence? So what do we know now? Cause? Prevention? Treatment?
Think, Pair, Share How can we prevent TB, now and in the future?
HIV/AIDS Lesson Objectives: To describe the causes & means of transmission of HIV/AIDS To assess the worldwide importance of this disease To describe the roles of different factors in the prevention and control of HIV/AIDS
What’s the difference? • HIV means human immunodeficiency virus – so it’s the name of the pathogen that causes the disease • AIDS means Acquired immune deficiency syndrome – so it’s the name of the disease • http://www.nhs.uk/conditions/HIV/Pages/Introduction.aspx Basic SUMMARY
The nature of HIV • Viruses are very small! • HIV is a ball of protein and lipid around RNA and reverse transcriptase (an enzyme). It’s a member of the group of viruses called retroviruses • Once inside a cell the enzyme makes a ‘DNA version’ of the virus’s RNA • The infected cell then follows the code on the ‘new’ DNA to make new viruses.
HIV – the cause HIV only reproduce when inside a host cell. HIV infects T lymphocytes. Dr Robert Gallow, National Cancer Institute, 1984 – isolated HTLVIII which causes AIDS AIDS is not a disease – it is a collection of opportunistic diseases associated with acquired immunodeficiency
HIV – symptoms Initial infection: Flu-like symptoms Fever Headache Tiredness Enlarged lymph nodes Later symptoms: Lack of energy Weight loss Frequent fevers and sweats Yeast infections (oral or vaginal) Skin rashes or flaky skin Pelvic inflammatory disease in women Short-term memory loss Shingles Children grow slowly or are sick frequently Months to years after infection
HIV – symptoms AIDS: Coughing and shortness of breath Seizures and lack of coordination Difficult/painful swallowing Forgetfulness Confusion Diarrhoea Fever Vision loss Nausea, abdominal cramps and vomiting Weight loss and extreme fatigue Severe headaches Coma
HIV – symptoms • HIV develops into AIDS due to opportunistic infections such as: • oral thrush (Candida albicans) • pneumonia (Pneumocystis carinii) – an unusual form of pneumonia • Leads to collapse of the immune system, meaning the body cannot detect and deal with: • cancer (eg: Kaposi’s sarcoma – a rare skin cancer caused by a herpes-like virus) • dementias • TB • malaria • malnutrition TB + HIV: A dual Epidemic http://www.youtube.com/watch?v=MnvdYfgb2DA
HIV – the cause • Spread by intimate human contact: • direct exchange of bodily fluids (eg: sexual intercourse, blood donation, sharing of needles, over the placenta) • may pass through breast milk – viral particles and infected lymphocytes are found in breast milk • high risk individuals – haemophiliacs treated with Factor VIII from many donors
HIV – impact Affects economic development of countries as it affects primarily 20-30 year olds (potentially the most economically productive) Drugs expensive eg: major impact on the growth of some African states HIV leaving a cell
HIV – prevalence Pandemic in early 1980s 47 million infected with HIV by 1998 of which 14 million had already died 980,000 cases reported in USA since 1981 1 million Americans may be infected, ¼ of whom don’t know Leading killer of 25-22 year old African-American males