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

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

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

Picornaviridae Enterovirus Rhinovirus types 1 to 100+ Cardiovirus 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

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

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

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

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)

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

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.

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

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%

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)

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

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

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

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

PeV Respiratory infections Gastrointestinal infections

Enteroviruses/Laboratory Diagnosis Nükleic acit detection Isolation Serology: Antibody

Enteroviruses/Treatment Pleconaril new antiviral drug

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)

'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.

Iron lung

Polio sekeli

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”

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

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

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