Download History of Virology

LECTURE 2:
History of Virology
Professor Johnston often said that if you didn't know history, you didn't know
anything. You were a leaf that didn't know it was part of a tree. ~Michael
Crichton, Timeline
Viro100:
Virology
3 Credit hours
NUST Centre of Virology & Immunology
• On the primeval Earth, the surface of the
planet is just cooling and beginning to harden
into a crust
• Rain forms pools containing many organic
molecules and the first simple life forms
appear.
• The first viruses also appear. It is not clear
where they have come from:
» Independent entities
» Cellular origins
» Regressive evolution
1. Independent entities maybe these early viruses
evolved from the self replicating molecules,
believed to have existed in the primitive prebiotic
'RNA world' along a parallel course to cellular
organisms.
2. Cellular origins perhaps they are sub-cellular,
functional assemblies of macromolecules which
have escaped their origins inside primitive cells.
3. Regressive evolution maybe these early viruses are
degenerate life forms which have lost many
functions that other organisms possess and have
only retained the genetic information essential to
their parasitic way of life.
The Year 3700 BC
• The first written record of a
virus infection consists of a
heiroglyph from ancient
Egypt, drawn in
approximately 3700 BC,
• Which depicts a temple
priest called Ruma showing
typical clinical signs of
paralytic poliomyelitis
The Year 1193 BC
• The Pharaoh Siptah rules Egypt from 12001193 BC when he dies suddenly at the age of
about 20.
• His mummified body lays undisturbed in his
tomb in the Valley of the Kings until 1905
when the tomb was excavated.
• The mummy shows that his left leg was
withered and his foot was rigidly extended
like a horse's hoof - classic paralytic
poliomyelitis.
The Year 1143 BC
• Ramesses V's preserved mummy shows
that he died of smallpox at about the age
of 35 in 1143 BC.
• The pustular lesions on the face of the
mummy are very similar to those of more
recent patients .
• However, his head also displays a major
wound inflicted either before or shortly
after death.
The Year 1000 BC
• Smallpox was endemic in China by 1000BC. In
response, the practice of variolation is
developed.
• Recognizing that survivors of smallpox
outbreaks are protected from subsequent
infection,
The Year 1796
• In 1796, Edward Jenner vaccinated an 8 year old
boy, James Phipps, with material from a cowpox
lesion on the hand of a milkmaid, Sarah Nelmes.
James, who had never had smallpox , developed
a small lesion at the site of vaccination which
healed in 2 weeks.
• On 1st July 1796, Jenner challenged the boy by
deliberately inoculating him with material from a
real case of smallpox
The Year 1892
• On 12th February, Dmitri Iwanowski, a Russian
botanist, presents a paper to the St. Petersburg
Academy of Science which shows that extracts from
diseased tobacco plants can transmit disease to other
plants after passage through ceramic filters fine
enough to retain the smallest known bacteria.
• This is generally recognized as the beginning of
Virology.
• Unfortunately, neither Iwanowski nor the scientific
community fully realize the significance of these
results.
Notable Persons and their
Contribution to the Science of
Virology
Walter Reed (1851-1902)
• During the Spanish-American War & subsequent
building of the Panama Canal, American deaths
due to yellow fever were very high.
• The disease also appeared to be spreading slowly
northward into the continental United States.
• Through experimental transmission to mice, in
1900 Walter Reed demonstrated that yellow
fever was caused by a virus, spread by
mosquitoes.
Karl Landsteiner (1868-1943)
• Karl Landsteiner (1868-1943) and
Erwin Popper proved that
poliomyelitis was caused by a
virus.
• Landsteiner and Popper were the
first to prove that viruses could
infect humans as well as animals.
Francis Peyton Rous (1879-1970)
• Francis
Peyton
Rous
(1879-1970)
demonstrated that a virus (Rous sarcoma
virus) can cause cancer in chickens. (For
this work, he was eventually awarded the
Nobel Prize, in 1966)
• Rous is the first person to show that a virus
could
cause
cancer
in
animals.
Felix d'Herelle (1873-1949)
• Following Frederick Twort's work, Felix
d'Herelle independently recognizes viruses
which infect bacteria, which he calls
bacteriophages (eaters of bacteria).
• The discovery of bacteriophages provided
an invaluable opportunity to study virus
replication.
Wendell Stanley (1887-1955)
• Wendell Stanley (1887-1955) crystallizes
tobacco mosaic virus (TMV) and shows that
it remains infectious (Nobel Prize, 1946).
• Stanley successfully isolated TMV in pure
crystalline state, he concluded that it must
be protein or special class of enzyme.
• Stanley's work is the first step towards
describing the molecular structure of any
virus and helps to further illuminate the
nature of viruses.
Max Theiler (1899-1972)
• Max Theiler was the first to propagate
yellow fever virus in chick embryos and
successfully produced an attenuated
vaccine. Theiler's vaccine was so safe and
effective that it is still in use today!
• This work saved millions of lives and set the
model for the production of many
subsequent vaccines. For this work, Theiler
was awarded the Nobel Prize in 1951.
The Year 1939
Emory Ellis (1906-) and Max Delbrück (1906-1981)
• Established the concept of the "one step virus
growth cycle" essential to the understanding of
virus replication.
• This work laid the basis for the understanding of
virus replication and life cycle
• They demonstrated virus particles do not
"grow" but are instead assembled from
preformed components.
The Year 1941
• George Hirst demonstrated that influenza virus
agglutinates red blood cells.
• This was the first rapid, quantitative method of measuring
eukaryotic viruses.
The Year 1945
• Salvador Luria (1912-1991)
and Alfred Hershey (19081997) demonstrated that
bacteriophages mutate.
(Nobel Prize, 1969)
Salvador Luria
(1912-1991)
• This work proves that similar
genetic mechanisms operate
in viruses as in cellular
organisms and lays the basis
for the understanding of
antigenic variation in viruses.
Alfred Hershey
(1908-1997)
The Year 1949
John Enders (18971985)
Thomas Weller (1915–)
Frederick Robbins
(1916–)
John Enders, Thomas Weller (1915–) and Frederick Robbins
(1916–) were able to grow poliovirus in vitro using human
tissue culture. (Nobel Prize, 1954) This development led to the
isolation of many new viruses in tissue culture.
The Year 1950
• André Lwoff (1902-1994) Louis Siminovitch and Niels Kjeldgaard
discovered lysogenic bacteriophages in Bacillus megaterium
irradiated with ultra-violet light and coined the term prophage.
(Nobel Prize, 1965).
• Also in 1950, the World Health Organization proposed a
programme to eradicate smallpox from the Americas. This was
acheived in 8 years.
The Year 1952
Renato Dulbecco showed that animal viruses can
form plaques in a similar way to bacteriophages.
(Nobel Prize, 1975)
Alfred Hershey (1908-1997) and Martha
Chase demonstrated that DNA was the
genetic material of a bacteriophage.
The Year 1957
Alick Isaacs and Jean Lindemann discovered
interferon.
Although the initial hopes for interferons as
broad spectrum antiviral agents equivalent to
antibiotics have faded, interferons were the
first cytokines to be studied in detail.
The Year 1963
Baruch Blumberg discovers hepatitis B virus (HBV). (Nobel
Prize, 1976)
Blumberg went on to develop the first vaccine against the
HBV, considered by some to be the first vaccine against
cancer because of the strong association of hepatitis B with
liver cancer.
The Year 1970
Howard Temin (1934-1994) and David Baltimore independently
discovered reverse transcriptase in retroviruses. (Nobel Prize,
1975).
The discovery of reverse transcription established a pathway
for genetic information flow from RNA to DNA, refuting the socall "central dogma" of molecular biology.
Year 1973
Peter Doherty and Rolf Zinkernagl demonstrate the basis of
antigenic recognition by the cellular immune system. (Nobel
Prize, 1996)
The demonstration that lymphocytes recognize both virus
antigens and major histocompatibility antigens in order to kill
virus-infected cells established the specificity of the cellular
immune system.
Year 1983
Luc Montaigner and Robert Gallo announced the discovery of
human immunodeficiency virus (HIV), the causative agent of
AIDS.
In only two years since the start of the AIDS epidemic the
agent responsible has been identified.
Year 2001
The complete nucleotide sequence of the human genome is
published.
About 11% of the human genome is composed of retroviruslike retrotransposons: "transposable elements in which
transposition involves a process of reverse transcription with
an RNA intermediate similar to that of a retrovirus".
History is a kind of introduction to more
interesting people than we can possibly meet in
our restricted lives; let us not neglect the
opportunity. ~Dexter Perkins
Thank You!