Picornaviruses

1
Picornaviruses
Classification

• Aphthovirus 7 serotypes
• Cardiovirus 2 serotypes
• Enterovirus 111 serotypes
• Hepatovirus 2 serotypes
• Rhinovirus 105 serotypes
• Total 230 viruses

2
Rhinoviruses

• Cause of 'the common cold' (but not the only
  one!). 105 serotypes (hence repeated
  infections).
• Little consequence in itself, but predisposes to
  secondary bacterial infections - a major problem
  in infants and elderly.

3
Rhinoviruses

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  ?????.
• ??? ????? ???? ???? ?? ????? ????? ?????
  (Plinney of Rome) ????? "???? ??????? ????? ??
  ????".
• The polio vaccines are one of the triumphs of
  modern medicine, but many people would say that
  the lack of a cure for the common cold is one of
  the great failings.

4
Rhinoviruses

• The difficulty of creating a vaccine for the
  common cold lies in the diversity of rhinovirus.

5
Rhinoviruses

• Over one hundred types of rhinovirus have been
  discovered as they strike people around the
  world, and new strains appear continually.

6
Rhinoviruses

• Rhinovirus is a moving target that is not
  effectively combated with a single vaccine.
• Antiviral drugs, however, are a possible solution.

7
Picornaviruses
Classification

• Aphthovirus 7 serotypes
• Cardiovirus 2 serotypes
• Enterovirus 111 serotypes
• Hepatovirus 2 serotypes
• Rhinovirus 105 serotypes
• Total 230 viruses

8
Enteroviruses

• Enterovirus infections are common in humans
  seasonal peak in autumn frequently undiagnosed
• Polioviruses 3 serotypes
• Coxsackieviruses group A 23 serotypes
• Coxsackieviruses group B 6 serotypes
• Echoviruses 31 serotypes
• Enteroviruses 38 serotypes
• Total 111 serotypes

9
Polioviruses

• They cause poliomyelitis (flaccid muscular
  paralysis).
• As with all the Enteroviruses, they are
  transmitted by the faecal-oral route.
• These are the prototypic Picornaviruses there
  are 3 distinct serotypes.
• Next slide is a high resolution
  computer-generated image reconstruction of a
  poliovirus particle.

10
Poliovirus and Rhinovirus
11
??????? ??? ??????????????

• Antibodies bind to the surface of picornaviruses
  and stop them from attacking cells.
• In the previous slide, rhinovirus is bound to a
  receptor protein on the cell surface, shown in
  blue.

12
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• Antibodies bind to the surface of rhinovirus and
  poliovirus in this same position and block their
  attachment to the surfaces of cells.
• The right picture shows fragments of antibodies
  (in light blue) bound to rhinovirus.

13
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• The intact antibodies are much larger than the
  small fragments seen here, so seven to ten
  antibodies are enough to form a bulky barrier on
  each virus to block attachment and infection.

14
Note the icosahedral symmetry which is clearly
visible in this image.
15
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• Poliomyelitis

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28
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29
Weller, Enders Robbins

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30
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31
Weller, Enders Robbins

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  ?????? ??????? ???? ??? ???, ?????? ???? 1949,
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  ?????.

32
The Nobel Prize in Physiology or Medicine 1954
"for their discovery of the ability of
poliomyelitis viruses to grow in cultures of
various types of tissue"
John Franklin Thomas Huckle Frederick
Chapman Enders Weller
Robbins
33
Jonas Salk

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  ???? ???????.
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  ?, ??? ?.

34
Jonas Salk

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  ???? ??? ?????? ??????.
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  ????????? ?????.

35
Jonas Salk

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  ?????.
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  ????? ?? ?????? ?????? ?? ????.
• ????? ????? ?????????.

36
Jonas Salk

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  ????"? ????? ??? ??? ?????.
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  ?? ???? ??????.
• ????, ???? ???????? ????? ????? ???? ???????.

37
Jonas Salk

• The success of the vaccination effort won Jonas
  Salk unsought fame.
• He had applied the findings of others in a
  successful bid to prevent disease.
• Other researchers and doctors grumbled that he
  hadn't found anything new he had just applied
  what was there.

38
Jonas Salk

• But the timing of his successful vaccine at the
  peak of polio's devastation made the public blind
  to that.

39
Jonas Salk

• Salk's vaccine was soon replaced by a variation
  developed by Albert Sabin that could be taken
  orally.
• There were pros and cons to each, but the oral
  vaccination won out.
• Jonas Salk died of congestive heart failure in
  1995.

40
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  ????????? ???-??? ?????.

41
Sabin, Albert Bruce 1906-1993
American physician and microbiologist, b.
Bialystock, Russia, grad. New York Univ. (B.S.,
1928 M.D., 1931). He emigrated to the United
States in 1921 and was naturalized in 1930. He
conducted research on viral and other infectious
diseases and developed (c.1959) a live-virus
vaccine for immunization against poliomyelitis.
The Sabin vaccine may be taken orally and
provides longer immunity than the killed-virus
vaccine. Also, the killed-virus vaccine protects
only against paralysis, whereas the live vaccine
guards against both paralysis and infection.
42
Dr. Sabin's Vaccine

• In 1957 the World Health Organization (WHO)
  decided Dr. Sabin's vaccine deserved world-wide
  testing.
• He was invited to administer the vaccine to large
  groups of children in parts of Russia, Holland,
  Mexico, Chile, Sweden, and Japan.

43
Dr. Sabin's Vaccine

• But at home in the United States, he had a hard
  time convincing the Poliomyelitis Foundation and
  the U.S. Public Health Service his method was any
  better than Jonas Salk's "killed" vaccine method.

44
Advantage of Dr. Sabin's Vaccine

• An advantage of Dr. Sabin's oral vaccine,
  especially in less developed countries, is ease
  of administration no shots.
• But two other pluses are even more important.

45
Advantage of Dr. Sabin's Vaccine

• First, the live vaccine gives both intestinal and
  bodily immunity the killed vaccine gives only
  bodily immunity and allows the immune person to
  still serve as a carrier or transmitter.
• Second, the Sabin vaccine produces lifelong
  immunity without the need for a booster shot or
  vaccination.