case18-influenza

case18-influenza - Lydyard, Peter; Cole, Michael; Holton,...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
1. What is the causative agent, how does it enter the body and how does it spread a) within the body and b) from person to person? Causative agent Influenza A virus belongs to the Orthomyxoviridae virus family (myxo = affin- ity for mucin). The viral genome consists of 8 segments of negative single- strand RNA (i.e. RNA that cannot be translated directly on the ribosome, but has to be first copied into its complementary, positive, strand), which collectively encode 10 (or possibly 11) viral proteins (Figure 1). Each RNA segment is closely associated with the nucleoprotein, to form a helical Case 18 Influenza virus A 59-year-old woman went to see her doctor, as she had been unwell for the past 3 days. She initially noticed a nonproductive cough, and then she became abruptly worse with a marked fever, headache, and shivering. Since then she had developed muscle aches all over her body, especially in the legs, and her eyes had become watery and painful to move. She was a nonsmoker, previously fit and well, and on no regular medication. On examination, she was febrile (38.2 C), and had difficulty in breathing through her nose, but there were no other abnormal physical signs. A throat swab was taken, broken off into viral transport medium, and sent to the laboratory. Immunofluorescent staining with a monoclonal antibody against influenza A virus was positive, confirming a diagnosis of acute influenza virus infection. lipid bilayer PB2 PB1 PA HA hemagglutinin NP nucleocapsid NA neuraminidase M 1 matrix protein M 2 ion channel NS 1 multi-functional infected-cell protein NS 2 NS2/NEP protein matrix protein hemagglutinin neuraminidase RNA and nucleoprotein ion channel 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 transcriptase complex Figure 1. Schematic diagram of an influenza virus. The eight segments of RNA are enclosed within a nucleocapsid, which is in turn surrounded by a lipid envelope into which are inserted two surface glycoproteins, the hemagglutinin and neuraminidase. The helical nucleocapsid contains eight segments of ssRNA each coated with nucleoprotein. This is surrounded by a layer of M1 (membrane or matrix) protein, which in turn is surrounded by a lipid envelope into which are inserted two viral glycoproteins (hemagglutinin and neuraminidase) and a small amount of the M2 ion channel protein. © Lydyard, Peter; Cole, Michael; Holton, John; Irving, Will; Porakishvili, Nino; Venkatesan, Pradhib; Ward, Kate, Jan 01, 201 Garland Science, Hoboken, ISBN: 9780203856871
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
ribonucleoprotein (RNP), or nucleocapsid . The RNPs are in turn sur- rounded by a matrix protein and then a lipid envelope , which contains two viral glycoproteins, hemagglutinin (H or HA) and neuraminidase (N or NA), and also small amounts of the nonglycosylated M2 ion channel pro- tein. Influenza viruses are grouped into types on the basis of the nature of the NP, which occurs in one of three antigenic forms, hence types A, B, or C influenza viruses. Influenza type A viruses are widespread in nature,
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/14/2011 for the course PHARM mb taught by Professor Staff during the Spring '11 term at UCSD.

Page1 / 14

case18-influenza - Lydyard, Peter; Cole, Michael; Holton,...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online