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

5. Antigenic Variations Antigenic shift Antigenic drift
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

6. MOT: airborne respiratory droplets ( less than 10 um)
Survive for short period on surfaces
I.P 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

7. Symptoms and complications
1. Uncomplicated influenza
Fever ( 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

8. 3 Non pulmonary complications
Myositis
Cardiac complications
Encephalopathy
Reyes syndrome
Guillen-Barre syndrome

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

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

11. PROPERTIES OF ORTHOMYXOVIRUS AND PARAMYXOVIRUS
Property
orthomyxovirus
paramyxovirus
viruses
Influenza A,B,C
Measles,mumps, RSV,& parainfluenza
genome
Segmented
Non segmented
Virion RNA polymerase
yes
Capsid
helical
Envelope
size
Smaller(110 nm)
Larger( 150 nm)
Surface spikes
H&N diff. spikes
H&N same spikes
Giant cell formation no

13. Envelope spikes Virus H N Fusion protein Measles virus + - mumps RSV
Parainfluenza

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

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

16. 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

17. 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

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

19. 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

20. 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

21. 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%

22. 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

23. 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

24. 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

25. 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

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

27. 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

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