Bohomolets Microbiology Lecture #13


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By Ms. Kostiuk from Microbiology department

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Bohomolets Microbiology Lecture #13

  1. 1. Picornaviruses Enteroviruses
  2. 2. Family - Picornaviridae <ul><li>Pico – small , RNA – ribonucleic acid </li></ul><ul><ul><li>P – polioviruses </li></ul></ul><ul><ul><li>I – insensitivity to ether </li></ul></ul><ul><ul><li>C – coxsackie </li></ul></ul><ul><ul><li>O – orphan </li></ul></ul><ul><ul><li>R – RNA </li></ul></ul><ul><ul><li>N – new types </li></ul></ul><ul><ul><li>A - animal </li></ul></ul>
  3. 3. Virions of picornaviruses
  4. 4. Family Picornaviridae (modern classification, 2003 р. ) <ul><li>Genus: </li></ul><ul><li>Enterovirus </li></ul><ul><li>Rhinovirus </li></ul><ul><li>Cardiovirus </li></ul><ul><li>Aphthovirus </li></ul><ul><li>Hepatovirus </li></ul><ul><li>Parechovirus </li></ul><ul><li>Erbovirus </li></ul><ul><li>Cobuvirus </li></ul><ul><li>Common host </li></ul><ul><li>Human </li></ul><ul><li>Human </li></ul><ul><li>Animal </li></ul><ul><li>Animal </li></ul><ul><li>Human </li></ul><ul><li>Human </li></ul><ul><li>Animal </li></ul><ul><li>Human </li></ul>
  5. 5. Picornaviruses <ul><li>Icosahedral </li></ul><ul><li>Nonenveloped viruses </li></ul><ul><li>Small - diameter 20-30 nm </li></ul><ul><li>Cubical type of symmetry </li></ul><ul><li>Genome – single-stranded linear RNA </li></ul><ul><li>RNA has positive polarity </li></ul><ul><li>5’ end of RNA has a protein that serves as a primer for transcription by RNA polymerase </li></ul>Coxsackievirus virions
  6. 6. Structure of picornaviruses ( scheme ) <ul><li>60 capsomers (protomers) </li></ul><ul><li>5 virus proteins: </li></ul><ul><ul><li>( VP1, VP2, VP3, VP4 are contained in capsomers ), </li></ul></ul><ul><ul><li>VPg is bound with virus RNA </li></ul></ul>
  7. 7. Capsomer of picornavirus
  8. 8. Scheme of virus proteins formation
  9. 9. Scheme of RNA replication
  10. 10. Assembly of the picornaviral virion Formation and assembly of capsid proteins Procapsid Viral RNA Provirion Finishing of virion proteins formation Matured virion
  11. 11. Different properties of enteroviruses, hepatoviruses and rhinoviruses Rhinitis, respiratory infection No 33 0 C Upper respiratory tract Rhino-viruses Hepatitis A Diseases Yes Yes Stableness under acid conditions (pH3-5) 37 O C 37 O C Optimal temperature of replication Enteric tract Enteric tract Primarily infected tissue Hepato-virus Entero-viruses Property
  12. 12. Modern classification of enteroviruses Enterovirus 68,70 Human enterovirus D (HEV-D) Coxsackie А types 1, 11, 13, 15, 17-22, 24 Human enterovirus C (HEV-C) Coxsackie А-9, Coxsackie В types 1-6, ЕСНО types 1-7,9,11-21,24-27, 29-33; Enterovirus 69 Human enterovirus B (HEV-B) Coxsackie А types 2-8, 10, 12, 14, 16; Enterovirus 71 Human enterovirus A (HEV-A) Polioviruses 1, 2, 3 types Polienterovirus (PEV) Past name Species
  13. 13. Polioviruses
  14. 14. Polioviruses
  15. 15. Diseases caused by enteroviruses Fever, chest pain, and signs of congestive failure Myocarditis, pericarditis Vesicular rash on the hands and feet and ulceration in the mouth Hand-foot-and- mouth disease Aseptic meningitis, mild paresis and transient paralysis. Upper respiratory infections and minor febrile illness with or without rash. Both CAV and CBV Fever and severe pleuritic-type chest pain Pleurodynia Coxsackie-viruses B (CBV) Fever, sore throat and tender vesicles in the oropharynx Herpangina Coxsackie-viruses A (CAV) Paralysis Poliomyelitis Polioviruses Symptoms Disease Viruses
  16. 16. Poliomyelitis in an ancient civilization Poliomyelitis is an acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis.
  17. 17. Characteristic of poliovirus infections <ul><li>Inapparent (asymptomatic) infection. 99% cases </li></ul><ul><li>Abortive poliomyelitis. Mild, febrile illness with headache, sore throat, nausea, and vomiting. </li></ul><ul><li>Nonparalytic poliomyetitis. Aseptic meningitis with fever, headache, and a stiff neck. </li></ul><ul><li>Paralytic poliomyelitis. Flaccid paralysis is the predominant finding but brain stem involvement can lead to life-threatening respiratory paralysis. Painful muscle spasms occurs. The motor nerve damage is permanent. </li></ul>
  18. 18. Clinical findings of poliomyelitis
  19. 19. Clinical findings of poliomyelitis
  20. 20. Viruses ЕСНО <ul><li>Е – enteric </li></ul><ul><li>C – cytopatogenic </li></ul><ul><li>H – human </li></ul><ul><li>O - orphan </li></ul><ul><li>Disease: </li></ul><ul><li>Aseptic meningitis </li></ul><ul><li>Upper respiratory infection </li></ul><ul><li>Febrile illness with and without rash </li></ul><ul><li>Infantile diarrhea </li></ul><ul><li>Hemorrhagic conjunctivitis </li></ul>
  21. 21. Scheme of enterovirus pathogenesis
  22. 22. Diagnosis of enteroviral infection <ul><li>Isolation the viruses in cell culture and suckling mice (for Coxsackie A viruses) and identification in neutralization test with specific antiserum </li></ul><ul><li>Testing serum samples (from patient) for observing a rise in titer of antiviral antibody </li></ul>
  23. 23. CPE caused by polioviruses Native Vero cells CPE – full destruction of cell monolayer after virus multiplication
  24. 24. Differentiation of enteroviruses - + ЕСНО + ( spastic ) + Coxsackie В + ( flaccid ) + Coxsackie А + + Polioviruses Paralysis in newborn mice CPE in cell culture Virus
  25. 25. Diagnosis of Coxsackievirus 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
  26. 26. Prevention of poliomyelitis <ul><li>IPV - inactivated (killed) vaccine (made by Salk in 1954). </li></ul><ul><li>IPV is inactivated by formalin </li></ul><ul><li>OPV – attenuated (live), oral vaccine (made by Sabin in 1955-1958). </li></ul><ul><li>OPV is made using selection technology </li></ul><ul><li>Both OPV and IPV contain 3 serologic types . </li></ul>
  27. 27. Important features of poliovirus vaccines Yes No Affords secondary protection by spread to others Yes No Induces local intestinal immunity (IgA) Yes Yes Induces humoral immunity (IgG) Yes No Interrupts transmission Yes Yes Prevents disease Live (Sabin) Killed (Salk) Attribute
  28. 28. Important features of poliovirus vaccines Longer Shorter Duration of immunity Yes No Requires refrigeration Oral Injection Route of administration Yes No Can cause disease in the immunocompromised Yes No Reverts to virulence Yes No Interferes with replication of virulent virus in gut Live (Sabin) Killed (Salk) Attribute
  29. 29. Spread of virulent polioviruses in 1988
  30. 30. Spread of virulent polioviruses in 1998
  31. 31. Methods of laboratory diagnosis of infectious disease
  32. 32. Laboratory diagnosis . Goals : <ul><li>Diagnostics of disease – definition of infection disease etiology </li></ul><ul><li>Control of disease development </li></ul><ul><li>Choosing of adequate individual therapy </li></ul><ul><li>Estimation of effectiveness of treatment </li></ul><ul><li>Detection of donor blood or organ contamination </li></ul><ul><li>Control of epidemic development </li></ul>
  33. 33. Materials for laboratory diagnosis <ul><li>Blood – influenza, AIDS </li></ul><ul><li>Spinal liquid – viral and bacterial meningitis </li></ul><ul><li>Urine – genitourinary infections </li></ul><ul><li>Feces – enteroviral infection, cholera </li></ul><ul><li>Material from wound, pus </li></ul><ul><li>Sputum – respiratory infections (rhinoviral infection) </li></ul>
  34. 34. Methods of laboratory diagnostic <ul><li>Direct – to reveal presence of agent (microorganism) or its components in patient organism : </li></ul><ul><li>Microscopy </li></ul><ul><li>Cultivating method </li></ul><ul><li>Biological method </li></ul><ul><li>Indication of microbial antigens </li></ul><ul><li>Gen diagnosis </li></ul><ul><li>Indirect – to detect response of human organism to agent (microorganism) : </li></ul><ul><li>Serological diagnosis </li></ul><ul><li>Histological assay </li></ul><ul><li>Allergic assay </li></ul>
  35. 35. Microscopy <ul><li>Negative </li></ul><ul><li>Only presumptive diagnose </li></ul><ul><li>Non universal </li></ul><ul><li>Low sensibility </li></ul><ul><li>Positive: </li></ul><ul><li>Rapid </li></ul><ul><li>In early stage of disease </li></ul><ul><li>Simple </li></ul>Based on microscopic identification the morphological and structural features of microorganisms directly in the specimen from patient
  36. 36. Some disease that can be diagnosed by microscopy <ul><li>Acute gonorrhea </li></ul><ul><li>Meningococcal meningitis </li></ul><ul><li>Primery syphilis </li></ul><ul><li>Первинного сифілісу </li></ul><ul><li>Rotaviral infection </li></ul><ul><li>Relapsing fever </li></ul>
  37. 37. Microscopy diagnosis of relapsing fever Blood, stained with Romanowsky-Giemsa method
  38. 38. Microscopy diagnosis of rotaviral infection <ul><li>Electron microscopy </li></ul>
  39. 39. Microbiologic diagnosis ( cultural method ) <ul><li>Method is based on obtaining a pure culture of microorganisms from the patient material and next identification the culture to species </li></ul><ul><li>The most exact, permit to make final diagnosis </li></ul><ul><li>In early stage of disease </li></ul><ul><li>Give possibility to choose antimicrobial treatment </li></ul><ul><li>May be used different system for cultivation of microorganisms (for instance, nutrient medium for bacteria and cell culture for viruses) </li></ul><ul><li>Some microorganisms can not be cultivated and isolated in pure culture </li></ul><ul><li>Long time for examination and making the diagnosis </li></ul>