PicornavirusesPicornaviruses

Enteroviruses Enteroviruses

Family -Family - PicornaviridaePicornaviridae

Pico – small Pico – small , , RNA – ribonucleic acid RNA – ribonucleic acid

P – polioviruses P – polioviruses I – insensitivity to etherI – insensitivity to ether C – coxsackieC – coxsackie O – orphan O – orphan R – RNA R – RNA N – new typesN – new types A - animalA - animal

Virions of picornavirusesVirions of picornaviruses

Family Family Picornaviridae Picornaviridae (modern classification, (modern classification, 2003 р.2003 р.))

Genus:Genus:

EnterovirusEnterovirus

Rhinovirus Rhinovirus

Cardiovirus Cardiovirus

Aphthovirus Aphthovirus

HepatovirusHepatovirus

Parechovirus Parechovirus

Erbovirus Erbovirus

Cobuvirus Cobuvirus

Common hostCommon host

Human Human

Human Human

Animal Animal

Animal Animal

HumanHuman

Human Human

Animal Animal

Human Human

Picornaviruses Picornaviruses

Icosahedral

Nonenveloped viruses

Small - diameter 20-30 nm

Cubical type of symmetry

Genome – single-stranded linear RNA

RNA has positive polarity

5’ end of RNA has a protein that serves as a primer for transcription by RNA polymerase

Coxsackievirus virions Coxsackievirus virions

Structure of picornavirusesStructure of picornaviruses ((schemescheme))

60 capsomers (protomers) 5 virus proteins:

(VP1, VP2, VP3, VP4 are contained in capsomers),

VPg is bound with virus RNA

Capsomer of picornavirusCapsomer of picornavirus

Scheme of virus proteins formationScheme of virus proteins formation

Scheme of RNA replication Scheme of RNA replication

Assembly of the picornaviral virionAssembly of the picornaviral virion

Formation and assembly of capsid proteins

Procapsid

Viral RNA

Provirion

Finishing of virion proteins formation

Matured virion

Different properties of enteroviruses, Different properties of enteroviruses, hepatoviruses and rhinoviruseshepatoviruses and rhinoviruses

Property Property Entero-Entero-viruses viruses

Hepato-Hepato-virusvirus

Rhino-Rhino-virusesviruses

Primarily infected Primarily infected tissue tissue

Enteric Enteric tract tract

Enteric Enteric tract tract

Upper Upper respiratory respiratory tract tract

Optimal temperature Optimal temperature of replication of replication

3737OOCC 3737OOCC 333300CC

Stableness under acid Stableness under acid conditions (pH3-5)conditions (pH3-5)

Yes Yes Yes Yes No No

Diseases Diseases Hepatitis Hepatitis AA

Rhinitis, Rhinitis, respiratory respiratory infection infection

Modern classification of Modern classification of enteroviruses enteroviruses

Species Species Past name Past name

Polienterovirus (PEV)Polienterovirus (PEV) Polioviruses 1, 2, 3 typesPolioviruses 1, 2, 3 types

Human enterovirus A Human enterovirus A (HEV-A)(HEV-A)

CoxsackieCoxsackie А А typestypes 2-8, 10, 12, 14, 16; 2-8, 10, 12, 14, 16;

Enterovirus Enterovirus 71 71

Human enterovirus BHuman enterovirus B (HEV-B)(HEV-B)

CoxsackieCoxsackie А-9, А-9, CoxsackieCoxsackie В В typestypes 1-6, 1-6,

ЕСНО ЕСНО typestypes 1-7,9,11-21,24-27, 29-33; 1-7,9,11-21,24-27, 29-33; Enterovirus 69 Enterovirus 69

Human enterovirus CHuman enterovirus C (HEV-C)(HEV-C)

CoxsackieCoxsackie А А typestypes 1,1, 11,11, 13,13, 15,15, 17-22, 17-22, 24 24

Human enterovirus DHuman enterovirus D (HEV-D)(HEV-D)

EnterovirusEnterovirus 68,70 68,70

Polioviruses Polioviruses

Polioviruses Polioviruses

Diseases caused by enterovirusesDiseases caused by enteroviruses

Viruses Viruses Disease Disease Symptoms Symptoms

Polioviruses Polioviruses PoliomyelitisPoliomyelitis Paralysis Paralysis

Coxsackie-Coxsackie-viruses A viruses A (CAV)(CAV)

HerpanginaHerpangina Fever, sore throat and tender Fever, sore throat and tender vesicles in the oropharynxvesicles in the oropharynx

Hand-foot-and- Hand-foot-and- mouth diseasemouth disease

Vesicular rash on the hands Vesicular rash on the hands and feet and ulceration in the and feet and ulceration in the mouthmouth

Coxsackie-Coxsackie-viruses B viruses B (CBV)(CBV)

Pleurodynia Pleurodynia Fever and severe pleuritic-Fever and severe pleuritic-type chest paintype chest pain

Myocarditis, Myocarditis, pericarditispericarditis

Fever, chest pain, and signs Fever, chest pain, and signs of congestive failureof congestive failure

Both CAV and Both CAV and CBVCBV

Aseptic meningitis, mild paresis and Aseptic meningitis, mild paresis and transient paralysis. Upper respiratory transient paralysis. Upper respiratory infections and minor febrile illness with or infections and minor febrile illness with or without rash.without rash.

Poliomyelitis in an ancient Poliomyelitis in an ancient civilizationcivilization

Poliomyelitis is an acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis.

Characteristic of poliovirus Characteristic of poliovirus infectionsinfections

Inapparent (asymptomatic) infection.Inapparent (asymptomatic) infection. 99% 99% cases cases

Abortive poliomyelitis.Abortive poliomyelitis. Mild, febrile illness with Mild, febrile illness with headache, sore throat, nausea, and vomiting.headache, sore throat, nausea, and vomiting.

Nonparalytic poliomyetitis. Nonparalytic poliomyetitis. Aseptic meningitis with Aseptic meningitis with fever, headache, and a stiff neck.fever, headache, and a stiff neck.

Paralytic poliomyelitis.Paralytic poliomyelitis. Flaccid paralysis is the Flaccid paralysis is the predominant finding but brain stem involvement can lead predominant finding but brain stem involvement can lead to life-threatening respiratory paralysis. Painful muscle to life-threatening respiratory paralysis. Painful muscle spasms occurs. The motor nerve damage is permanent.spasms occurs. The motor nerve damage is permanent.

Clinical findings of poliomyelitis Clinical findings of poliomyelitis

Clinical findings of poliomyelitisClinical findings of poliomyelitis

Viruses Viruses ЕСНО ЕСНО Е – Е – entericenteric C – cytopatogenicC – cytopatogenic H – humanH – human O - orphanO - orphan

Disease:

Aseptic meningitis

Upper respiratory infection

Febrile illness with and without rash

Infantile diarrhea

Hemorrhagic conjunctivitis

Scheme of enterovirus Scheme of enterovirus pathogenesispathogenesis

Diagnosis of enteroviral infectionDiagnosis of enteroviral infection

Isolation the viruses in cell culture Isolation the viruses in cell culture and suckling mice (for Coxsackie A and suckling mice (for Coxsackie A viruses) and identification in viruses) and identification in neutralization test with specific neutralization test with specific antiserum antiserum

Testing serum samples (from Testing serum samples (from patient) for observing a rise in titer of patient) for observing a rise in titer of antiviral antibodyantiviral antibody

CPE caused by polioviruses CPE caused by polioviruses

Native Vero cells CPE – full destruction of cell monolayer after virus multiplication

Differentiation of enteroviruses Differentiation of enteroviruses

Virus Virus CPE in cell CPE in cell culture culture

Paralysis in Paralysis in newborn micenewborn mice

Polioviruses Polioviruses ++ ++

CoxsackieCoxsackie А А ++ + (+ (flaccidflaccid))

CoxsackieCoxsackie В В ++ + (+ (spastic spastic ))

ЕСНОЕСНО ++ --

Diagnosis of CoxsackievirusDiagnosis of Coxsackievirus infection infection

Native suckling mice

Mouse with flaccid paralysis of back extremities

Mice is affected by virus

Flaccid paralysis in newborn mice caused by Coxsackievirus A 10

Prevention of poliomyelitisPrevention of poliomyelitis

IPVIPV - inactivated (killed) vaccine - inactivated (killed) vaccine (made by Salk in 1954). (made by Salk in 1954).

IPV is inactivated by formalin IPV is inactivated by formalin

OPV OPV – attenuated (live), oral vaccine – attenuated (live), oral vaccine (made by Sabin in 1955-1958).(made by Sabin in 1955-1958).

OPV is made using selection technology OPV is made using selection technology

Both OPV and IPV Both OPV and IPV contain 3 serologic contain 3 serologic typestypes. .

Important features of poliovirus Important features of poliovirus vaccinesvaccines

Attribute Attribute Killed Killed (Salk)(Salk)

Live Live (Sabin)(Sabin)

Prevents diseasePrevents disease Yes Yes Yes Yes

Interrupts transmission Interrupts transmission No No Yes Yes

Induces humoral immunity (IgG)Induces humoral immunity (IgG) Yes Yes Yes Yes

Induces local intestinal immunity Induces local intestinal immunity (IgA)(IgA)

No No Yes Yes

Affords secondary protection by Affords secondary protection by spread to othersspread to others

No No Yes Yes

Important features of poliovirus Important features of poliovirus vaccinesvaccines

Attribute Attribute Killed Killed (Salk)(Salk)

Live Live (Sabin)(Sabin)

Interferes with replication of Interferes with replication of virulent virus in gutvirulent virus in gut

No No Yes Yes

Reverts to virulence Reverts to virulence No No Yes Yes

Can cause disease in the Can cause disease in the immunocompromisedimmunocompromised

No No Yes Yes

Route of administration Route of administration Injection Injection Oral Oral

Requires refrigerationRequires refrigeration No No Yes Yes

Duration of immunityDuration of immunity Shorter Shorter Longer Longer

Spread of virulent polioviruses in Spread of virulent polioviruses in 19881988

Spread of virulent polioviruses in Spread of virulent polioviruses in 19981998

Methods of laboratory Methods of laboratory diagnosis of infectious diagnosis of infectious

diseasedisease

Laboratory diagnosisLaboratory diagnosis. . GoalsGoals::

Diagnostics of disease – definition of Diagnostics of disease – definition of infection disease etiology infection disease etiology

Control of disease development Control of disease development Choosing of adequate individual therapy Choosing of adequate individual therapy Estimation of effectiveness of treatment Estimation of effectiveness of treatment Detection of donor blood or organ Detection of donor blood or organ

contamination contamination Control of epidemic development Control of epidemic development

Materials for laboratory Materials for laboratory diagnosisdiagnosis

Blood Blood –– influenza, AIDS influenza, AIDS

Spinal liquid Spinal liquid – – viral and bacterial viral and bacterial meningitis meningitis

UrineUrine – – genitourinary infections genitourinary infections

Feces Feces – – enteroviral infection, choleraenteroviral infection, cholera

Material from wound, pus Material from wound, pus

Sputum Sputum – – respiratory infections respiratory infections (rhinoviral infection) (rhinoviral infection)

Methods of laboratory Methods of laboratory diagnosticdiagnostic

Direct Direct – – to reveal to reveal presence of agent presence of agent (microorganism) or (microorganism) or its components in its components in patient organismpatient organism::

Microscopy Microscopy Cultivating methodCultivating method Biological method Biological method Indication of microbial Indication of microbial

antigens antigens Gen diagnosisGen diagnosis

Indirect Indirect – – to detect to detect response of human response of human organism to agent organism to agent (microorganism) (microorganism) ::

Serological diagnosis Serological diagnosis Histological assay Histological assay Allergic assay Allergic assay

Microscopy Microscopy

NegativeNegative Only presumptive Only presumptive diagnose diagnose

Non universal Non universal

Low sensibility Low sensibility

Positive:

Rapid

In early stage of disease

Simple

Based on microscopic identification the morphological and structural features of microorganisms directly in the specimen from patient

Some disease that can be Some disease that can be diagnosed by microscopydiagnosed by microscopy

Acute gonorrhea Acute gonorrhea Meningococcal meningitis Meningococcal meningitis Primery syphilis Primery syphilis Первинного сифілісуПервинного сифілісуRotaviral infectionRotaviral infectionRelapsing feverRelapsing fever

Microscopy diagnosis of Microscopy diagnosis of relapsing fever relapsing fever

Blood, stained with Romanowsky-Giemsa method

Microscopy diagnosis of Microscopy diagnosis of rotaviral infectionrotaviral infection

• Electron Electron microscopymicroscopy

Microbiologic diagnosis Microbiologic diagnosis ((cultural methodcultural method))

Method is based on obtaining a pure culture of Method is based on obtaining a pure culture of microorganisms from the patient material and microorganisms from the patient material and next identification the culture to speciesnext identification the culture to species

The most exact, permit to make final diagnosis

In early stage of disease Give possibility to choose

antimicrobial treatment

May be used different system for cultivation of microorganisms (for instance, nutrient medium for bacteria and cell culture for viruses)

Some microorganisms can not be cultivated and isolated in pure culture

Long time for examination and making the diagnosis