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ORTHOMYXOVIRUS PARAMYXOVIRUS

ORTHOMYXOVIRUS PARAMYXOVIRUS. Ma. Rosario L. Lacandula, MD, MPH Department of Microbiology & Parasitology College of Medicine Our Lady of Fatima University. Orthomyxovirus. Influenza virus Influenza A- pandemics and epidemics; humans and animals Influenza B- epidemics; human virus

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ORTHOMYXOVIRUS PARAMYXOVIRUS

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  1. ORTHOMYXOVIRUS PARAMYXOVIRUS Ma. Rosario L. Lacandula, MD, MPH Department of Microbiology & Parasitology College of Medicine Our Lady of Fatima University

  2. Orthomyxovirus • Influenza virus • Influenza A- pandemics and epidemics; humans and animals • Influenza B- epidemics; human virus • Influenza C- mild respiratory tract infection

  3. Morphology: • Segmented, ss genome,helical nucleocapsid with outer lipoprotein envelope • Envelope contain 2 spikes • Hemagglutinin • Binds to cell surface receptors( neuraminic acid/sialic acid • Neuramidase • Enzymatic activity • Internal antigens- M1 & NP proteins- type specific, shows cross reactivity

  4. Antigenic Variations • Antigenic shift • Undergoes reassortment • Results in changes of the H and N antigen • Pandemics and epidemics • Occurs with influenza A only • Antigenic drift • Change in the amino acid sequence of the H ag • Occur both in A & B

  5. MOT: airborne respiratory droplets ( less than 10 um) • Survive for short period on surfaces • I.P. 18-72 hours • Virus concentration in nasal and tracheal secretions remains high for 24 to 48 hours • Site of infection- epithelial cells of the respiratory tract • Recovery- interferons and CMI • Humoral Immunity- ( IgG & IgA)protection against reinfection, antibody against HA is important

  6. Symptoms and complications • 1. Uncomplicated influenza • Fever ( 38-40 C) • Myalgias, headache • Ocular symptoms- photophobia, tears, ache • Dry cough, nasal d/c • 2. Pulmonary complications/sequelae • Croup( acute larygotracheobronchitis) • Primary influenza pneumonia • Secondary bacterial infection

  7. 3 Non pulmonary complications • Myositis • Cardiac complications • Encephalopathy • Reyes syndrome • Guillen-Barre syndrome

  8. Diagnosis • 1. virus isolation • Monkey kidney cell etc. • No CPE • 2.serology • Hemadsorption • PCR

  9. Chemotherapy • Rimantadine and amantadine • Zanamavir and oseltamivir • Rest, liquids and anti febrile agents

  10. PROPERTIES OF ORTHOMYXOVIRUS AND PARAMYXOVIRUS

  11. Envelope spikes

  12. Paramyxovirus • Non segmented, ss genome; helical capsid with outer lipoprotein envelope • Envelope spikes: H & N and fusion protein

  13. MEASLES VIRUS • Single serotype • H- target of neutralizing Ab • Humans are the natural host

  14. Pathogenesis • Receptor: CD46 on surface of macrophages • Rash-cytotoxic T cells attacking the virus infected vascular endothelial cells in the skin • CMI- neutralizing the virus during viremic phase • MOT: droplet inhalation • Hematogenous transplacental

  15. Clinical • IP 7-13 days • Prodrome- high fever, 3C & P- infectious • Koplick’s spots- buccal mucosa across the molars- grains of salt surrounded by red halo • Rashes appears-starts below the ears and spread throughout the body undergoes brawny desquamation

  16. Complications • Encephalitis • Bacterial pneumonia • Giant cell pneumonia- defective CMI • Atypical measles- older inactivated mealses • SSPE-subacute sclerosing panencephalitis

  17. Mumps virus • H and N + fusion protein on envelope spikes • Internal nucleocapsid protein- S Antigen- detected in complement fixation test • Humans are the natural host • thermolabile

  18. Mumps • Nasal or URT epithelial cells- blood-salivary glands, testes,ovaries, pancreas, meninges and kidneys • Shed in the saliva 2 days before to 9 days after the onset of salivary gland swelling • (+) virus in urine up to 14 days after onset of symptoms

  19. Clinical • 1/3 of patients subclinical • 50% with swelling of the salivary glands • Pain and anorexia • Complications • Orchitis-postpubertal-unilateral, bilateral-sterility • aseptic meningitis • Oophoritis-5% • Pancreatitis- 4%

  20. Immunity • Ab vs HN glycoprotein- correlate with immunity • Ab vs S Ag- appear earliest, gone w/in 6 months • Passive immunity from mother to offspring- protection during 1st 6 months of life

  21. Diagnosis • 1. cell culture • Specimen-saliva, spinal fluid or urine • Monkey kidney cell • CPE- cell rounding and giant syncytia formation • 2. serology- 4 fold rise in Ab titer in HI or CF • Ab vs S antigen- current infection • Ab Vs V antigen- past infection • Prevention: vaccine, attenuated vaccine

  22. Respiratory Syncytical Virus • Most important cause of pneumonia and bronchiolitis in infants • Fusion proteins- syncytia formation • Humans and chimpanzees- natural host • 2 serotype: A & B • MOT: respiratory droplet

  23. Clinical • 1. infants- bronchiolitis, pneumonia • 2. young children- otitis media • 3. older children and adults- common cold • Diagnosis: immunofluorescence • Isolation in cell culture- + CPE • serology

  24. Treatment • Aerosolized Ribavirin • Ribavirin + hyperimmune globulins • Prevention • NO VACCINE • Palivizumab-prophylaxis, monoclonal ab vs. fusion protein

  25. Parainfluenza Virus • Surface spikes: H & N same spike, fusion on different spike • Both humans and animals infected • Four serotypes: 1, 2, 3 & 4 • MOT: respiratory droplet

  26. No viremia • Clinical: • 1&2- major cause of croup; children < 6 y/o • Laryngitis • Pneumonia • Common cold- 4 • Pharyngitis • Otitis media

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