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Biology and Geology · Biology and Geology ESO 3 YEAR 2015 -16. Unit 2 DISEASES:CAUSES,...
Transcript of Biology and Geology · Biology and Geology ESO 3 YEAR 2015 -16. Unit 2 DISEASES:CAUSES,...
Biology and Geology
ESO 3
YEAR 2015 -16
Unit 2
DISEASES:CAUSES, TRANSMISSION AND CONTROL
ILLNESSES
An illness is any physical or mental alteration
that causes an organism to malfunction.
Types of Diseases
NON TRANSMISSIBLES DISEASES
They may be genetic, nutritional, degenerative,
etc.. They aren´t produced by pathogenic
agents.
TRANSMISSIBLES DISEASES OR
INFECTIOUS DISEASES
It can be passed from one person to another.
They are caused by bacteria, viruses, fungi,
protozoa and metazoa.
Bacteria
Good bacteria or friendly bacteria are those
that are in the digestive system and help it to
work and inhibit the growth of bad bacteria.
BACTERIAL DISEASES
They are caused by different pathogenic
bacteria.
Salmonella Streptococcus
Bacterial Diseases
The ill-effects of a bacterial disease are
caused mainly by poisonous products
produced either by the bacteria or by the
cells which they invade.
Bacterial poisons are called toxins.
Symptons: raised temperature, headache,
tiredness and weakness and sometimes
diarrhoea and vomiting.
Examples of Bacterial Diseases
Scarlet fever
Tetanus, botulism
Tonsillitis, boils
Tuberculosis, cholera, whooping cough
Food poisoning, gonorrohea or syphilis
WE CAN USE DRUGS (ANTIBIOTICS) AGAINST BACTERIA
Viral Diseases
The common cold virus
The flu
AIDS
Bacterial Viruses
Virus Reproduction
Viruses
They can reproduce only inside other cells,
and so all viruses are parasitic. Viruses don´t
produce toxins.
The harm they cause is probably the result of
the destruction of the cells they invade.
We cannot use antibiotics or other drugs
against viruses.
You can get immunity but unfortunately many
viruses can change by mutation.
Examples of Virus Diseases
The common cold
Flu
AIDS
Herpes, mumps, measles, chickenpox,
rubella or hepatitis.
Fungal parasites
Athlete´s foot
Ringworm
Candida
Fungi deseases
Several species of fungus give rise to the
various forms of this disease. The fungus
attacks the epidermis and produces a patch
of inflammed tissue.
The region of the body affected will depend
on the species of fungus.
All forms of the disease are very contagious.
They are spread by contact with an infected
person or their personal property.
Examples of Fungal Diseases
Candida
Tinea
- Ringworm
- Tinea of the crutch
- Tinea of the scalp
- Athlete´s foot
Protozoan Parasites
There are relatively few protozoa which
parasitize humans, but those that do cause
serious diseases.
Two of these are malaria and amoebic
dysentery.
malaria
vector protozoo
Metazoan parasites
They can be worms or arthropodes. Lice (louse)
Diseases transmission mechanisms
A) Direct transmission
The pathogenic agent is transmitted from
infected people to healthy people.
Through saliva or mucus expelled when
coughing or sneezing.
Direct contact.
Diseases Transmission Mechanisms
B) Indirect transmission: They may also involve
a vector.
The main vector are: contaminated water,
contaminated food and through an
arthropod´s bite.
Airborne, droplet or aerosol infection
If the droplets contain viruses or bacteria,
they may cause disease when they are eaten
with food or inhaled.
When the droplets evaporates bacteria often
die but viruses remain infectious floating in
the air for a long time.
Virus: cold, flu, measles, chikenpot and some
bacterias as Streptococci (Sore throats)
Contamination of Water
If disease bacteria gets into water supplies
used for drinking, hundreds of people can
become infected. Example: cholera or
typhoid.
Some of these bacteria will pass out with
faeces. If the faeces get into streams or
rivers they be carried into reservoirs of water
used for drinking.
To prevent this from happening faeces must
be made harmless and drinking water
purified.