Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Ebola virus disease wikipedia , lookup
Plant virus wikipedia , lookup
Introduction to viruses wikipedia , lookup
Oncolytic virus wikipedia , lookup
Social history of viruses wikipedia , lookup
Viral phylodynamics wikipedia , lookup
Virus quantification wikipedia , lookup
History of virology wikipedia , lookup
Avian influenza wikipedia , lookup
Respiratory Virus Medically important members RNA Orthomyxoviridae Virus Paramyxoviridae Togaviridae Picornaviridae Coronaviridae Reoviridae DNA Adenoviridae Virus Influenza virus Measles virus Mumps virus Respiratory syncytial virus Parainfluenza virus Rubella virus Rhinovirus Coronavirus, SARS Cov Reovirus Adenovirus Influenza Virus Avian Influenza • Orthomyxovirdae • 3 types H9N2 Russian Influenza H5N1 H7N7 H5N1 H1N1 Spanish Influenza H1N1 1918 Asian Influenza H2N2 H3N2 Hong Kong Influenza 1957 1968 1977 1997 2003/4 1998/9 2005 Type A Type B Type C Human + + + Animal reservoir Antigenic drift Antigenic shift Human epidemics Human pandemics + + - + + - + - - + + - + - - Biological properties • Size and Shape – highly pleomorphic • mostly spherical: 80 - 120nm • long filamentous particles – Structure • nucleocapsid • Envelop NA • Function – Hemagglutination – Attachment and penetration – Antigenicity NA • Function – Release – Antigenicity Replication 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 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. Emergency hospital during 1918 influenza epidemic What is avian influenza (bird flu)? 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? Resistance • Weak – Sensitivity • • • • • Heat Drying Ultraviolet Acid formalin – Resistance • Cold Pathogenicity • Source – Patients • transmission – Aerosols or droplets • Pathogenesis – surface infection without entering blood generally. Clinical findings • Uncomplicated influenza – – – – – Fever (38 - 40℃) myalgia (or muscle ache) Headache photophobia, tears Dry cough, nasal discharge • Complications – Pneumonia – Reye’s syndrome Immunity • short and re-infection – No viremia – Many subtypes – High variation Microbiologic diagnosis • haemagglutination inhibition test Prevention and treatment • Prevention – inactivate (most) – live attenuated (new) • Treatment – Rimantadine金刚乙胺 and amantadine金刚烷 胺 – Oseltamivir达菲 II. Paramyxoviridae Morbillivirus: measles virus cause systemic symptoms Paramyxovirus: mumps virus parainfluenza virus Pneumovirus: cause infant & young respiratory syncytial virus children local LRT infections (RSV) 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 1. Measles virus About 10d incubation period V→ respiratory epithelial cells → replicate in LC regional lymphoid → Blood (first Viremia) tissue ↓ 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 Main complications encephalitis; pneumonia; SSPE (subacute sclerosing panencephalitis). B. Immunity: lifelong C. Treatment and prevention: live attenuated vaccine; Immunoglobulin-γ/placenta immunoglobulin for emergency; Presence of viremia Types of Ag Ag stability Influenza V No viremia Labile Measles V Two viremia Many subtypes Single type Stable Infectious characteris tic Local mucosa systemic 2. Mumps virus A patient with parotitis 2. Mumps virus V respiratory epithelial cells facial lymph nodes blood viremia parotid glands, the other tissues Disease manifestation: Typical symptom: unilateral or bilateral non-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. 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. 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. Ⅲ.Other respiratory viruses 2. Coronaviridae: Coronavirus: ~10-30% common cold; bronchitis and pneumonia. o SARS-CoV: 80-140nm osymptom: high fever, cough, headache, general malaise and aches, dry cough, dyspnea; Respiratory distress cause death