Transcript 슬라이드 1
Paramyxoviruses 미생물학교실 권 형 주 Paramyxoviruses (from Greek para-, beyond, -myxo-, mucus or slime, plus virus, from Latin poison, slime) Genus Human Pathogen Mobillivirus Measles virus (rubeola, 홍역 – maculopapular rash) Paramyxovirus Parainfluenza viruses 1 to 4 Mumps virus Pneumovirus Respiratory syncytial virus –upper respiratory tract infection Metapneumovirus - Live vaccine •Measles viruses •Mumps viruses • only one serotype - Cell-cell fusion • Syncytia formation • Multinucleated giant cells - New group • Zoonosis-causing viruses • Nipah virus • Hendra virus STRUCTURE and REPLICATION - Negative-sense, single-stranded RNA - Envelope - the order of the protein-coding regions differs for each genus - orthomyxoviruses : segmented genome Replication of paramyxoviruses Measles Virus (홍역바이러스) Family : Paramyxoviridae Genus : Mobillivirus - Measles is still one of the most prominent causes of disease (45 million cases per year) and death (1 to 2 million per year) worldwide in unvaccinated populations Pathogenesis and Immunity - Host – only human - cell fusion, giant cells - cell-to-cell spread escape antibody control - Hemagglutinin(+), Neuraminidase (-) - Highly contagious - respiratory droplets - Maculopapular measles rash : T cells targeted to measles-infected endothelial cells lining small blood vessels rash (lifelong immunity) - Encephalitis 1) direct infection of neurons 2) a postinfectious encephalitis : immune mediated 3) SSPE – a defective variant of measles - Time course of measles virus infection. - 초 기 증 상 : cough, conjunctivitis, coryza, and photophobia (CCC and P) - Koplik’s spots, rash - SSPE (subacute sclerosing panencephalitis, 아급 성경화범뇌염)-rare Epidemiology - Development of effective vaccine programs Clinical Syndromes - Incubation periods : 7-13 days - 초기증상 (발진전) : High fever, CCC and p - After 2 days of illness : Koplik spots - A typical mucous membrane lesions - first day or two after the rash appears - mouth, conjunctivae, vagina - 발진 (exanthem of measles) : starts belows the ears and spreads over the body : maculopapular rash - Complications : Pneumonia, bacterial superinfection Prevention Parainfluenza Virus - Respiratory viruses : mild cold-like symptoms, serious respiratory tract disease - Human pathogens : four serotypes Clinical Syndromes - Types 1, 2, 3 : respiratory tract syndromes - mild cold-like upper respiratory tract infection (coryza, pharyngitis, mild bronchitis, wheezing, fever) - Bronchiolitis - Pneumonia - Croup (laryngotracheobronchitis) Laboratory Diagnosis - Isolated from nasal washing and respiratory secretion Grow well in primary monkey kidney cells Hemagglutination Serotype (antibody) ; hemagglutination inhibition RT-PCR Treatment, Prevention, and Control - Administration of nebulized cold or hot steam No specific antiviral agents Killed vaccine : ineffective No live attenuated vaccine Mumps Virus - 볼거리, 볼치기 (귀밑샘염) Parotitis (이하선염) : painful swelling of the salivary glands Isolated in embryonated eggs in 1945 Cell culture in 1955 Human pathogen : One serotype - Recovered from saliva, urine, pharynx, stensen duct, cerebrospinal fluid - Grow well in monkey kidney cells - Formation of multinucleated giant cells - Hemadsorption of guinea pig erythrocytes: hemagglutinin - MMR vaccine - Antiviral agents are not available Respiratory Syncytial Virus (RSV) 호흡기세포융합바이러스 Family : Paramyxoviridae Genus : Pneumovirus Subgroups : A and B - Fatal acute respiratory tract infection - Infants, young children RSV Virion, Genome and Proteins envelope spikes plasma membrane G F SH budding virion attachment fusion unknown Neutralization targets inner envelope face M assembly ribonucleocapsid 150 nm (EM by Tony Kalica, LID/NIAID) nonstructural NS1 NS2 M2-2 inhibit host type I interferon response NS2 NS1 unassigned N regulation of RNA synthesis N RNA-binding P L phosphoprotein polymerase M2-1 transcription processivity factor P M SH G F M21 M2-2 L 3´ 5´ Single-stranded negative-sense RNA, 15.2 kb RSV –syncytium formation • Symptom : bronchiolitis, pneumonia, mechanical ventilation, and respiratory failure in infants. - Virus infections almost always occur in the winter. Infants : lower respiratory infection (bronchiolitis and pneumonia) Children : mild to pneumonia Adults : mild symptoms Laboratory Diagnosis - RT-PCR - Immunofluorescence and enzyme immunoassay test Treatment, Prevention, and Control - Ribavirin (제한적) : inhalation(nebulization) Passive immunization :anti-RSV Ig (제한적) No vaccine is currently available Inactivated vaccine : severe RSV disease : heightened immunologic response (Th2 immune response ?)