Respiratory Virus

1. Respiratory Virus

2. Medically important members RNA Orthomyxoviridae Influenza virus Virus Paramyxoviridae Measles virus Mumps virus Respiratory syncytial virus Parainfluenza virus Togaviridae Rubella virus Picornaviridae Rhinovirus CoronaviridaeCoronavirus, SARS Cov Reoviridae Reovirus DNA Adenoviridae Adenovirus Virus

3. Influenza Virus • Orthomyxovirdae • 3 types Avian Influenza H9N2 H7N7 H5N1 H5N1 Russian Influenza H1N1 Asian Influenza H3N2 Spanish Influenza Hong Kong Influenza H2N2 H1N1 1918 1957 1968 1977 1997 2003/4 2005 1998/9

4. Type A Type B Type C Human + + + Animal reservoir + + - Antigenic drift + + - Antigenic shift + - - Human epidemics + + - Human pandemics + - -

5. Biological properties • Size and Shape • highly pleomorphic • mostly spherical: 80 - 120nm • long filamentous particles • Structure • nucleocapsid • Envelop

9. NA • Function • Hemagglutination • Attachment and penetration • Antigenicity

10. NA • Function • Release • Antigenicity

11. Replication

13. Typing and Variation • Typing • NP, M1, and M2: type A, B, and C • HA and NA: subtypes only in type A • Influenza A viruses: H1-H15, N1-N9 • Avian: H1~H15, N1~N9 • Human: H1, H2, H3, H5 and N1, N2

14. Typing and Variation • Variation • Antigenic drift抗原漂移: minor antigenic changes of HA and NA due to point mutations, belonging to quantitative changes, causing annual epidemics of influenza viruses. • Antigenic shift抗原转变: major antigenic changes of HA and NA due to genetic reassortment between human and animal influenza viruses, belonging to qualitative changes, resulting in new subtype and may causing periodic pandemics.

16. Emergency hospital during 1918 influenza epidemic

17. What is avian influenza (bird flu)?

20. Avian influenza • What is the avian influenza A (H5N1) virus • How do people become infected with avian influenza viruses? • Does the current seasonal influenza vaccine protect me from avian influenza? • Is there a vaccine to protect humans from H5N1 virus? • Is there a risk for becoming infected with avian influenza by eating poultry? • What changes are needed for H5N1 or another avian influenza virus to cause a pandemic?

21. Resistance • Weak • Sensitivity • Heat • Drying • Ultraviolet • Acid • formalin • Resistance • Cold

22. Pathogenicity • Source • Patients • transmission • Aerosols or droplets • Pathogenesis • surface infection without entering blood generally.

23. Clinical findings • Uncomplicated influenza • Fever (38 - 40℃) • myalgia (or muscle ache) • Headache • photophobia, tears • Dry cough, nasal discharge • Complications • Pneumonia • Reye’s syndrome

24. Immunity • short and re-infection • No viremia • Many subtypes • High variation

25. Microbiologic diagnosis • haemagglutination inhibition test

26. Prevention and treatment • Prevention • inactivate (most) • live attenuated (new) • Treatment • Rimantadine金刚乙胺 and amantadine金刚烷胺 • Oseltamivir达菲

27. II. Paramyxoviridae • Morbillivirus: measles virus cause systemic symptoms • Paramyxovirus: mumps virus • parainfluenza virus cause infant & young • Pneumovirus: respiratory syncytial virus children local LRT infections (RSV)

28. II. Paramyxoviridae Common properties: Size: 150~300nm in diameter. Shape: spherical or pleomorphic. Structure: enveloped; -ssRNA non-segmented; genetically stable spikes: fusion protein; attachment protein

29. 1. Measles virus

30. About 10d incubation period replicate in LC respiratory epithelial cells → → → regional lymphoid tissue Blood (first Viremia) V reticuloendothelial system ↓ Blood (second Viremia) ↓ epithelial surface of body ↓ respiratory tract, eye conjunctiva, mouth, skin, small blood vessels, etc Typical symptoms ↓ high fever, photophobia, rhinitis, cough, Koplik’s spots, maculopapular skin rash eye conjunctivitis (diagnostic signification) prodrome

31. Presence of viremia Types of Ag Ag stability Infectious characteristic Influenza V No viremia Many subtypes Labile Local mucosa Measles V Two viremia Single type Stable systemic Main complications encephalitis; pneumonia; SSPE (subacute sclerosing panencephalitis). B. Immunity: lifelong C. Treatment and prevention: live attenuated vaccine; Immunoglobulin-γ/placenta immunoglobulin for emergency;

32. 2. Mumps virus A patient with parotitis

33. 2. Mumps virus V respiratory epithelial cells facial lymph nodes blood viremia parotid glands, the other tissues Disease manifestation: Typical symptom: unilateral or bilateralnon-suppurative parotitis, fever Severe complications: testitis, ovaritis, pancreatitis, aseptic meningitis Immunity: permanent Prevention: live attenuated vaccine MMR(Measles-Mumps-Rubella) is used in US; Monovalent form (only attenuated mumps virus S97) --program of immunization.

34. 3. Respiratory syncytial virus(RSV) The most important cause of LRT infection in infants and young children. Diseases: Infants:bronchiolitis(50%), pneumonia(25%); Young children & adults: common cold, rhinitis. Immunity: not strong & long, re-infection. Ab cannot prevent babies from RSV, aggravate disease.

35. Ⅲ.Other respiratory viruses 1. Rhinovirus the most important virus that cause common cold) Picornaviridae. Spherical, 28-30nm in diameter; +ssRNA many serotypes(>100); Diseases: mild URT infection, bronchitis and pneumonia.

36. Ⅲ.Other respiratory viruses 2. Coronaviridae: • Coronavirus: • ~10-30% common cold; • bronchitis and pneumonia. • SARS-CoV: • 80-140nm • symptom: high fever, cough, headache, • general malaise and aches, dry cough, • dyspnea; • Respiratory distress cause death