Zusammenfassung der Ressource
Infectious Disease
- Causes of Disease
- Health = a state of physical,
mental and social well-being,
including the absence of
disease and infirmity.
- A pathogen = an organism
that can cause disease e.g.
bacteria, fungi and viruses.
- Parasite = an organism that lives in
or on another organism and causes
damage to the organism e.g.
tapeworms, roundworms and fleas.
- Diseases can also be caused by
genetic defects, nutritional deficiencies
and environmental factors e.g. toxicity.
- Infectious disease = diseases that
are passed between individuals
e.g. malaria, HIV and TB.
- Malaria
- Caused by the
parasite Plasmodium
- Plasmodium is a eukaryotic,
single-celled parasite.
- It is transported by mosquitoes, which
are vectors (they don't cause the
disease but spread the infection by
transferring it from one host to another.
- Mosquitoes transfer the
Plasmodium parasite into an
animal's blood when they feed
on them.
- Plasmodium infects the
liver and RBCs and
disrupts the blood supply
to the vital organs.
- AIDS
- Caused by HIV
- HIV infects human white blood cells as it can
only reproduce inside the cells of the organism
it has infected because it cannot reproduce on
its own.
- After the virus has reproduced, it kills
the WBC at it leaves.
- HIV is spread by unprotected sex,
infected bodily fluids e.g. blood by
sharing needles, and from mother
to foetus (through placenta/breast
milk/during childbirth)
- AIDS is a condition where
the immune system
deteriorates and
eventually fails due to the
loss of WBCs. The
sufferer is more
vulnerable to other
infections e.g. pneumonia.
- TB
- Tuberculosis is a
lung disease
caused by the
bacterium
Mycobacterium
tuberculosis.
- It is spread through droplets
in the air e.g. when a person
sneezes and someone else
breathes it in.
- Many people with TB don't show symptoms but
if they become weakened e.g. by malnutrition,
then the infection can become active. Then they
will show symptoms and pass it on.
- Global Impact
- Developing Countries
- Limited access to good
healthcare so people are less
likely to be diagnosed and treated.
- Limited health education so
people do not learn about
the transmission of diseases.
- Limited equipment to
reduce spread of
infections.
- Overcrowded
conditions
increases risk of
droplet
transmission.