1 / 33

Picornaviruses

Picornaviruses. Picornaviruses. Small ( pico ) RNA Naked capsid >230 members 5 genera. Picornaviruses. 5 genera Enterovirus Rhinovirus Heparnavirus Cardiovirus Aphtovirus. Picornaviruses. Enteroviruses At least 72 serotypes Polioviruses Coxsackieviruses Echoviruses.

rbancroft
Download Presentation

Picornaviruses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Picornaviruses

  2. Picornaviruses • Small (pico) • RNA • Naked capsid • >230 members • 5 genera

  3. Picornaviruses • 5 genera Enterovirus Rhinovirus Heparnavirus Cardiovirus Aphtovirus

  4. Picornaviruses • Enteroviruses At least 72 serotypes • Polioviruses • Coxsackieviruses • Echoviruses

  5. International Virus Taxonomi committee • Enterovirus genus (EV): Poliovirus and EV A, B, C and D. • Parechovirus cinsi (PeV): echovirus 22 ve 23

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

  7. 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

  8. 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

  9. 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

  10. Enteroviruses/Pathogenesis&Immunity • 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

  11. Enteroviruses/Pathogenesis&Immunity • Portal of entry: • URT • Oropharynx • Intestinal tract • Most enteroviruses are cytolytic • Excp: HAV • Viral shedding • From oropharynx • From the intestine (> 30 days)

  12. Enteroviruses/Pathogenesis&Immunity • “Antibody is the major protective immune response to the enteroviruses”

  13. 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.

  14. 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 echo“s” can be particularly harmful to infants

  15. 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%

  16. 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 2&3) • Recovery, within 6 months to 2 years • Bulbar poliomyelitis • More severe, 75% death, iron lungs (1950’s) • Postpolio syndrome (30-40 years later) in 20-80% of the original victims)

  17. 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 (Bornholm’s disease)(Devil’s grip) • Fever + unilateral low thoracic, pleuritic chest pain • Coxsackie B

  18. 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

  19. 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

  20. Enteroviruses/Clinical syndromes Coxsackievirus and echovirus infections • Other diseases • Acute hemorrhagic conjunctivitis • Enterovirus 70 and coxsackie A24 • transplacental infection • Insulin-dependent diabetes • Coxsackie B

  21. PeV • Respiratory infections • Gastrointestinal infections

  22. Enteroviruses/Laboratory Diagnosis • Nükleic acit detection • Isolation • Serology: Antibody

  23. Enteroviruses/Treatment • Pleconaril new antiviral drug

  24. 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)

  25. 'Poliosuz Ülke Sertifikası’ • Rutin aşılama çalışmalarına ek olarak Ulusal Aşı Günleri (UAG) ve Mop-up gibi destek aşılamalar düzenlemesi gerekmiştir. • 1998 yılında tip 1 poliovirüse bağlı son çocuk felci vakası Ağrı ilinde saptanmıştır. • Bu vaka aynı zamanda DSÖ Avrupa bölgesi’nin de son polio vakası olmuştur. • Türkiye, Dünya Sağlık Örgütü Avrupa bölgesi ile birlikte 21 haziran 2002 tarihinde çocuk felci hastalığından (polio) arındırılmış olarak sertifikalandırılmıştır.

  26. Iron lung

  27. Polio sekeli

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

  29. Rhinoviruses • Most important cause of URTI ~ 50% • Common cold: • Enteroviruses • Coronaviruses • Adenoviruses • Parainfluenza viruses

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

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

More Related