1. UNIT 2
HEALTH AND DISEASE

2. TOPICS: (WHAT TO LEARN )
 1. THE WHO DEFINITION OF HEALTH
 2. THE DETERMINANTS OF HEALTH
 3. TYPES OF DISEASES
 4. DEFINITION OF INFECTIOUS DISEASE
 5. WAYS OF TRANSMISSION OF INFECTIOUS
DISEASES
 6. EXTERNAL DEFENCES
 7. INTERNAL DEFENCES
 8. PERIOD OF INFECTIOUS DISEASE
 9. DEFINITION OF INFECTION
 10. THE TREATMENT AND PREVENTION OF
ILLNESS

3. 1. THE WHO DEFINITION OF HEALTH
According to the World Health
Organization (WHO), health is a
state of complete physical, mental
and social well-being and not only the
absence of disease.

4. When a person gets ill, we can
observe several symptoms such as
pain, tiredness, fever, vomiting,…

5. When we find alterations such as
inflammation, variation of blood
pressure, presence of particular
substances,… doctors can diagnose
an illness and those alterations are
called sign.

6. 2.
 Whether people are healthy or not, is determined
by their circumstances such as:
- The environment: far away from biologic
elements(microorganism), physic elements
(radiation and noise) and chemical elements
(pollutans).
- Acquisition of healthy habits and ways of living,
such as doing sports, no smoking, no drinking
alcoholic drinks, balanced eating,…
- Genetics factors that include inheritance of
characteristics and age.
- Health services, access and use of services that
prevent and treat diseases.

7. https://www.youtube.com/watch?v=zXjANz9r5F0
https://www.youtube.com/watch?v=efkGu24OxgQ

8. 3. TYPES OF DISEASE (ESQUEMA)
 Depending on:
Its origin: INFECTIOUS caused by pathogens: bacteria, virus,fungi,
protozoa.
NON INFECTIOUS: CANCER
Its frequency: SPORADIC (non common) .STROKE
ENDEMIC: they are exclusive of a region. MALARIA
The number of people affected:
EPIDEMIC: in one place. FLU (affects a lot of people in a short period of
time)
PANDEMIC: the whole world. AIDS (epidemics that spread to a lot of
countries)
Its developing speed: CHRONIC. DIABETES
ACUTE . FLU

9. 4. DEFINITION OF INFECTIOUS DISEASE
 It is a kind of illness caused by pathogenic
microorganisms( pathogens). It is also called
transmissible disease due to its potential of
transmission from a body to another.

10. Pathogens and disease
Today you will be learning about what pathogens are
and how they can spread

11. PATHOGENS
Think:
Are all bacteria bad?

12. 4. DEFINITION OF INFECTIOUS DISEASE
 It is a kind of illness caused by pathogenic
microorganisms( pathogens). It is also called
transmissible disease due to its potential of
transmission from a body to another.
 Types of pathogens:
BACTERIA: cause disease through their own or production of toxins.
Examples: TUBERCULOSIS, SALMONELLA, TETANUS
PROTOZOA: cause MALARIA, DYSENTERY
VIRUS: They aren´t living things. Examples: HIV, FLU; VARICELLA
FUNGI: cause mycosis. ATHLETE´S FOOT

13. Diseases caused by pathogens
Type of microbe: Bacteria
Name of disease: Cholera
Symptoms
The main symptoms are watery diarrhoea and vomiting. The severity of the diarrhoea
and vomiting can lead to rapid dehydration, and in some cases death.
How is the disease spread?
Transmission occurs primarily by drinking water or eating food that has been
contaminated by the faeces (waste product) of an infected person.
Prevention
Treating water before drinking it and properly disposing of sewage can prevent
outbreaks of the disease.
Treatment
The primary treatment is with lots of water and salts the body needs. This replaces what
was lost through vomiting and diarrhoea.

14. Diseases caused by pathogens
Type of microbe: Bacteria
Name of disease: Food poisoning
Symptoms
Food poisoning usually leads to diarrhoea and vomiting. It can be fatal by causing kidney
failure, especially in young children or elderly people.
How is the disease spread?
The disease is spread by eating contaminated food. It can also be spread by food that is
undercooked or by swimming or drinking in contaminated water.
Prevention
It can be prevented by ensuring all meat is thoroughly cooked and all vegetables are
washed in clean water. Cooking meat at a high temperature kills the bacteria. It is also
important to keep uncooked meat separate from other food items and surfaces.
Treatment
Most victims recover without treatment within 5 to 10 days. Antibiotics may be used to
prevent kidney complications.

15. Diseases caused by pathogens
Name of microbe: Varicella
Type of microbe: Virus
Name of disease: Chicken Pox
Symptoms
Chicken pox starts with an itchy rash on the head and neck. Other symptoms may
include fever, headache and a sore throat.
How is the disease spread?
The virus is spread through the air by coughs and sneezes. A person can be infectious
one to two days before the rash appears.
Prevention
A vaccine is available which protects against infection but it is not routinely offered in the
United Kingdom.
Treatment
There is no cure but the symptoms can be eased until the body clears the infection.

16. Diseases caused by pathogens
Type of microbe: Virus
Name of disease: Hepatitis B
Symptoms
The virus affects the liver. It causes, vomiting, jaundice (makes you look yellow) and
sometimes death.
How is the disease spread?
The virus spreads by transfer of bodily fluids. This can be during sex.
Prevention
Vaccines for the prevention of hepatitis B have been routinely used since the early 1980s.
Treatment
Most patients recover after a few months without treatment. But some patients have
lasting liver damage.

17. Diseases caused by pathogens
Type of microbe: Virus
Name of disease: Influenza (Flu)
Symptoms
Common symptoms of flu include chills, fever, sore throat, muscle pains, coughing and
severe headaches
How is the disease spread?
The virus is spread through the air by coughs and sneezes or by touching a
contaminated surface (e.g. if someone blows their nose and then touches a door
handle.) Flu can spread fast – causing an epidemic.
Prevention
A vaccine is available which protects against infection.
The vaccine is often recommended each winter for people that are ‘at risk’ such as the
elderly or people with damaged immune systems.
Treatment
Infected people are advised to get plenty of rest and drink lots of fluids.

18. Diseases caused by pathogens
Type of microbe: Bacteria
Name of disease: Tuberculosis (TB)
Symptoms
The bacteria infects the lungs. TB causes chest pain and a very bad cough. Occasionally,
people who are infected may cough up blood. Usually fatal if left untreated.
How is the disease spread?
TB is spread when people infected with the bacteria cough and sneeze.
Prevention
A vaccine is available which gives protection for around 10 years.
Treatment
Antibiotics can be used to kill the bacteria.
However, some strains of TB are becoming resistant to the antibiotics and are harder to
kill.

19. Type of pathogen: Bacteria or Virus Type of pathogen: Bacteria or Virus
Name of disease: Name of disease:
Symptoms Symptoms
How is the disease spread? How is the disease spread?
Prevention Prevention
Treatment Treatment

20. 5. WAYS OF TRANSMISSION OF INFECTIOSUS DISEASES
 Transmission is the passing of a disease from an infected
individual to an uninfected individual.
 Pathogens may be transmitted by several ways:
I. Direct physical contact. Touching an infected person,
including sexual contact such as MEASLES (sarampión) and
sexually transmitted diseases (STDs).
II. Indirect contact. Through objects or droplets released by
coughing or sneezing like flu (influenza).
III. Fecal- oral transmission. Usually from a contaminated food
or water, such as cholera or salmonella.
IV By air. Pathogen can be on dust particles or floating in the air,
such as tuberculosis.
V. Vector borne transmission. Carried by insects or other
animals, such as malaria or black death.

21. 6. EXTERNAL DEFENCES
Stop diseases getting into our bodies (and foreign
particles) :
 STRUCTURAL : skin and mucosa (internal and
external covering) : Digestive and respiratory
cavities.
 BIOCHEMICAL: saliva, tears, gastric acid.
 MECHANICAL: they drag pathogens. Cilia and
mucus.
 ECOLOGICAL: non pathogenic microorganisms
compete with pathogenic microorganisms.

22. 7. INTERNAL DEFENCES
 NON SPECIFIC: PHAGOCYTE
They are white blood cells. Carry out phagocytosis,
ingestion of harmful foreign particles.
 SPECIFIC: LYMPHOCYTE
They are white blood cells. There are two types:
B Cells: produce antibodies
T Cells: kill specific pathogens through lisis.

24. 8. PERIODS OF INFECTIOUS DISEASE
 Period of incubation :
- It´s the interval occurring between the start of the infection and the
appearance of symptoms.
- The patient does not know it yet.
- The length of this periods depends on the pathogen characteristics.
 Period of illness:
- It´s the beginning of appearance of symptoms.
- The patient is starting to get sick.
 Period of convalescence(recovery)
- The pathogens have been eliminated
- The body repairs the damage caused by the infection

25. 9. INFECTION
 It is the colonisation of the body by microorganisms which cause
a disease.
 There are a lot of different kinds of infections:
a. Opportunistic infection: when a pathogen which live in one
part of the body normally passes to a different part of the body
causing a disease.(example AIDS)
b. Local infection: it is limited to a small area of the body.
(example pharyngitis).
c. Systemic infection: it starts by a local infection then it
spreads for all over the body (example tetanus).
d. Latent infection. It´s inactive though continuing to infect
(Herpesvirus).
e. Chronic infection. It is an infection that develops slowly and
lasts a long time (example Hepatitis C).

26. 10. THE TREATMENT AND
PREVENTION OF ILLNESS
 It´s health care through three levels:
- Primary Health Care with PHC primary health
care physicians.
- Specialised doctors: they are specialists in organs
such as cardiologist, neurologist.
- Hospitalization: in Hospital where we carry out
medical test and operations.