Picornaviruses

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Picornaviruses
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Picornaviruses

• Small (pico)
• RNA
• Naked capsid
• gt230 members
• 5 genera

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Picornaviruses

• 5 genera
• Enterovirus Rhinovirus Heparnavirus
• Cardiovirus Aphtovirus

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Picornaviruses

• Enteroviruses
• At least 72 serotypes
• Polioviruses
• Coxsackieviruses
• Echoviruses

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International Virus Taxonomi committee

• Enterovirus genus (EV)
• Poliovirus
• and EV A, B, C and D.
• Parechovirus cinsi (PeV) echovirus 22 ve 23

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Picornaviruses

• Enteroviruses (EV)
• At least 72 serotypes
• Polioviruses
• Coxsackieviruses
• Echoviruses
• Human parechoviruses 1-3 (HPeV)

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Picornaviridae

• Enterovirus
• Poliovirus type 1, 2, and 3
• Coxsackie A virus types 1 to 22 and 24
• Coxsackie B virus types 1 to 6
• Echovirus (ECHO virus) types 1 to 9, 11 to 27,
  and 29 to 34
• Enterovirus 68 to 71
• Rhinovirus types 1 to 100
• Cardiovirus
• Aphtovirus
• Heparnavirus
• HAV

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Picornaviruses

• Enteroviruses
• Capsid very resistant facilitates transmission by
  the fecal-oral route
• Infection initiated in the gastrointestinal tract
• Rarely cause enteric disease
• Infections are usually asymptomatic

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Picornaviruses/Replication

• The specifity of the picornavirus interaction for
  cellular receptors is the major determinant of
  the target tissue tropism and disease
• VP1 and canyon
• 80 of rhinoviruses and several serotypes of of
  coxsackieviruses recognize ICAM-1
• polio a different molecule

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Enteroviruses/PathogenesisImmunity

• The diseases produced by the enteroviruses are
  determined mainly by differences in tissue
  tropism and cytolytic capacity of the virus
• Poliovirus with the narrowest tissue
  tropism recognize a receptor expressed on
  anterior horn cells of the spinal cord, dorsal
  root ganglia, motor neurons, skeletal muscle
  cells, and few other cells

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Enteroviruses/PathogenesisImmunity

• Portal of entry
• URT
• Oropharynx
• Intestinal tract
• Most enteroviruses are cytolytic
• Excp HAV
• Viral shedding
• From oropharynx
• From the intestine (gt 30 days)

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Enteroviruses/PathogenesisImmunity

• Antibody is the major protective immune response
  to the enteroviruses

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Enteroviruses/Epidemiology

• The enteroviruses are exclusively human
  pathogenes
• Spread by the fecal-oral route
• Asymptomatic shedding can occur
• Poor sanitation and crowded living conditions
  foster transmission of the viruses
• Enterovirus epidemics sewage contamination of
  water supplies
• Outbreaks in schools day care centers (summer)
• Spread via resp. tract coxsackie echov.

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Enteroviruses/Epidemiology

• Poliovirus has been eliminated from the Western
  Hemisphere, but
• not from the world
• Polio cause more severe disease in late
  childhood, the adolescent years, or adulthood
• Coxsackie A mor severe in adults than children
• Coxsackie B some echos can be particularly
  harmful to infants

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Enteroviruses/Clinical syndromes

• Poliovirus infections
• Asymptomatic illness (90)
• Abortive poliomyelitis (minor illness)
• Nonspecific febrile illness (5)
• Nonparalytic poliomyelitis or aseptic meningitis
• 1 to 2, symptomes of the minor illness CNS sm
• Paralytic polio, the major illness
• 0.1 to 2.0

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Enteroviruses/Clinical syndromes

• Poliovirus infections
• Paralytic poliomyelitis
• Asymmetrical flaccid paralysis with no sensory
  loss
• Poliovirus type 1 is responsible for 85 of cases
• Vaccine-associated disease (reversion of type
  23)
• Recovery, within 6 months to 2 years
• Bulbar poliomyelitis
• More severe, 75 death, iron lungs (1950s)
• Postpolio syndrome (30-40 years later) in 20-80
  of the original victims)

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Enteroviruses/Clinical syndromes

• Coxsackievirus and echovirus infections
• Herpangina
• Several types of Coxsackie A
• Hand-foot-and-mouth disease ( a vesicular
  exanthem)
• Usually caused by coxsackievirus A16
• Pleurodynia (Bornholms disease)(Devils grip)
• Fever unilateral low thoracic, pleuritic chest
  pain
• Coxsackie B

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Enteroviruses/Clinical syndromes

• Coxsackievirus and echovirus infections
• Myocardial and pericardial infections
• Coxsackie B
• Occur sporadically in older children and adults
• Most threatening in newborns
• Febrile illness, sudden unexplained onset of
  heart failure high mortality

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Enteroviruses/Clinical syndromes

• Coxsackievirus and echovirus infections
• Viral (aseptic meningitis)
• Acute febrile illness CNS symptoms
• Petechia or a rash
• Summer and autumn outbreaks with Echo 11
• Fever, rash and common cold-like symptoms
• Other diseases
• Acute hemorrhagic conjunctivitis
• Enterovirus 70 and coxsackie A24

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Enteroviruses/Clinical syndromes

• Coxsackievirus and echovirus infections
• Other diseases
• Acute hemorrhagic conjunctivitis
• Enterovirus 70 and coxsackie A24
• transplacental infection
• Insulin-dependent diabetes
• Coxsackie B

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PeV

• Respiratory infections
• Gastrointestinal infections

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Enteroviruses/Laboratory Diagnosis

• Nükleic acit detection
• Isolation
• Serology Antibody

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Enteroviruses/Treatment

• Pleconaril new antiviral drug

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Enteroviruses/ Prevention control

• The prevention of paralytic polyomyelitis is one
  of the triumphs of modern medicine
• Poliovirus vaccines
• IPV, developed by Jonas Salk
• OPV, developed by Albert Sabin (live attenuated)

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'Poliosuz Ülke Sertifikasi

• Rutin asilama çalismalarina ek olarak Ulusal Asi
  Günleri (UAG) ve Mop-up gibi destek asilamalar
  düzenlemesi gerekmistir.
• 1998 yilinda tip 1 poliovirüse bagli son çocuk
  felci vakasi Agri ilinde saptanmistir.
• Bu vaka ayni zamanda DSÖ Avrupa bölgesinin de
  son polio vakasi olmustur.
• Türkiye, Dünya Saglik Örgütü Avrupa bölgesi ile
  birlikte 21 haziran 2002 tarihinde çocuk felci
  hastaligindan (polio) arindirilmis olarak
  sertifikalandirilmistir.

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Iron lung
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Polio sekeli
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Rhinoviruses

• Most important cause of the common cold and URTI
• ICAM-1
• Unable to replicate in the GIT
• Labile to pH
• Grow best _at_ 33oC
• Infection can be initiated by as little as 1
  (one) infectious viral particle
• Runny nose

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Rhinoviruses

• Most important cause of URTI 50
• Common cold
• Enteroviruses
• Coronaviruses
• Adenoviruses
• Parainfluenza viruses

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Rhinoviruses

• Common cold symptoms
• Sneezing
• Rhinorrhea nasal obstruction
• Mild sore throat
• Headache
• Malaise
• Cough
• Fever rigors

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Rhinoviruses

• The clinical syndrome of the common cold is
  usually so characteristic that laboratory
  diagnosis is unnecessary!!