Brief introduction of concepts in Medical microbiology and parasitology.

1. MICROBIOLOGY &
PARASITOLOGY
By Mr. Vincent Ejakait

2. CONTENT
 Definition of terms
 Historical development of microbiology
 Ecological relationship
 Factors promoting growth & development of microorganisms
 Importance of microorganisms
 Classification of microorganisms
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3. Definitions
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4. DEFINITIONS
MICROBIOLOGY:
 Is the study of microscopic organisms, such as bacteria, viruses,
fungi and protozoa.
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5. PARASITOLOGY:
 Is the study of parasites, their hosts, and the relationship between
them.
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6. IMMUNOLOGY:
 Is the study of the immune system, which protects us from
infection
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7. History
 People attributed diseases to witchcraft and the devil.
 Later they believed disease was caused by miasma (an unpleasant
or unhealthy smell)
 1632-1723 Antoni van Leeuwenhoek: was the first to demonstrate
the presence of micro-organisms via a microscope
 Louis Pasteur: showed that there were germs present in the
environment
 Louis Pasteur: opened the field of sterilization
 He also developed vaccines (anthrax vaccine)
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8. History cont..
Robert Koch’s contribution:
 Described methods of preparing cultures
 Discovered the causative agents of:
 Tuberculosis
 Cholera
 Fleming and Chain developed penicillin in 1929 from a fungus
called PenicilliumMr. Vincent Ejakait
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9. History cont..
 For more of the history, check the class email for the handout on
History of microbiology and immunology
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10. Ecological Characteristics
 Host: Is an organism that harbors a guest organism
 Parasites: Is an organism that lives within or on a host
 Pathogens: Is a biological agent that causes disease or illness to its
host.
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11. Ecological relationships
The interaction among organisms within or between overlapping
niches can be characterized into 5 types of relationships:
1. Competition
2. Predation
3. Commensalism
4. Mutualism
5. Parasitism
Symbiosis
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12. 1. Competition
 Competition is when
individuals or populations
compete for the same resource
 An example is lions and hyenas
that compete for prey.
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13. 2. Predation
 Predation is when one organism
eats another organism to obtain
nutrients.
 The organism that is eaten is
called the prey.
 Examples are owls that eat mice,
and lions that eat gazelles.
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14. 3. Commensalism
 Commensalism is a relationship
in which one organism benefits
while the other is neither
helped nor harmed.
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15. 4. Parasitism
 Parasitism is a relationship in which
one organism benefits and the other
organism is harmed, but not always
killed.
 The organism that benefits is called
the parasite,
 The one that is harmed is the host.
 Example such as intestinal worms
that live inside the host
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16. 5. Mutualism
 Mutualism is a
relationship in which
both species benefit.
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17. Summary of symbiosis
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18. Factors promoting growth and development
of micro-organisms
 Nutrients: All microorganisms need food
 Temperature: Very high and very low temperatures discourage
growth
 pH Levels: most organisms prefer neutral pH
 Moisture: All microorganisms require some level of water
 Oxygen requirement: Some organisms are anaerobes and aerobes
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19. Importance of Micro-organisms
 For vaccine production e.g polio vaccine from the virus
 For production of food: yeast used to make bread, bacteria
important for making yoghurt.
 Soil microbes help to recycle nutrients:
 Used in the brewing of alcohol
 Fungi help in the degradation of living things that have died
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20. Classification of micro-organisms
 Bacteria
 Fungi
 Virus
 Protozoa
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