Microorganism (micro: small, Organism: A living system).
Two main forms:
- Unicellular: Bacteria, protozoans, some
Multicellular: Algae, Fungi etc
Unique Category: Viruses,
Department of Microbiology
National University of Singapore
GEK1534 Microbes which changed human history
Tutorial 1: A/Prof Lee Yuan Kun
Is it a good idea for a microbe to cause disease?
How do pathogens spread among humans? Transmission and opportunities for interrupting the spread.
Tutorial with Dr Barkham
GEK1534 NUS 2012
Epidemiology: the study of the distribution of diseases: transmission, control, who, where, when, how.
Gut Microbes: The Puppet Masters!
Anton van Leeuwenhoek
Build his own microscopes
Germ theory of disease
The doctrine that infectious diseases
are of microbic origin
Inverse relationship between infect
The Mad Cow Disease: A
disease that causes us to
Bovine Spongiform Encephalopathy (BSE)
Green Revolution: Between 1943 and the late 1970s,
research, development, and technology transfer initiatives
AIDS is going to kill
half of the US
population in 20
Discovery of a new disease
Major cities in US: LA, SF, NYC
Clusters of homosexual males
Rare infections previously limited to
Salmonella: The germ that
change the face of medical
Salmonella infection is a common bacterial disease that affects the
intestinal tract. Salmonella bacteria typically live in the intestines of
animals and humans and are shed through feces. Humans
Anthrax, from the hero of
Germ Theory of Disease to the
weapon of terrorist
The microorganism must be
observed in every case of
It must be isolated and
grown in pure culture
The pure culture must,
when inoculated into a
Age 25? You are too old!
Infectious diseases & antibiotics
The average live expectancy during the early
Roman Empire was 25.
There is an old Chinese saying, life beyond
70 is rare since antiquity.
More recent years.
Singapore 1957 life expectancy 61-year
Are we ready for a pandemic flu
1918 pandemic flu outbreak killed 40 millions!
Italians introduced this term: Disease attributed to
the influence of the stars
Also possible influenza di freddo or influence of a
Influenza vs Common
presaged the modern Europe
Plague first appeared during the reign of
Emperor Justinian in the 6th century AD.
Restricted outbreaks over the next 2
1347 beginning of the Great Pestilence
Buboes: enormous, painful swellings d
Imagine that Europeans dress as us and speak an Asian
Could this happen?
The answer: Yes, this almost happened.
Why didnt it happened?
The answer: The great Mongol Empire didnt occupied
Europe long enough.
The Mongol Empire almost did it, but wh
A brief history of microbiology
Microbiology is the
study of minute organisms
that are hardly visible by
Microbes look very different
Microbes are of different sizes
Anton van Leuwenhoek