Part Description
LP14239-5 Influenza virus A
Influenza viruses, from the family Orthomyxoviridae, are enveloped negative-strand RNA viruses with segmented genomes containing seven to eight gene segments. Of the five genera in the family, only influenza A virus (IAV), influenza B and C are medically relevant to humans. Aquatic birds harboring avian IAV are the likely natural reservoir for all known IAV subtypes and are probably the original source of all human pandemic IAV strains. IAV maintained in wild birds have been associated with stable host switch events to novel hosts, including most often to domestic poultry but also to horses, swine, toothed whales and humans. The influenza virus life cycle begins with the binding of viral HA to host cell receptors. Endocytosis and HA-mediated fusion of the viral and cellular membranes occurs. Viral ribonucleoprotein complexes are released into the cytoplasm, travel to the nucleus, then are replicated and transcribed by the viral polymerase complex. The new viruses are formed and bud when the newly formed ribonucleicprotein complexes and structural proteins reach the plasma membrane. Further research is needed to better understand how IAVs switch hosts and the viral genetic changes that underlie human adaptation. IAV causes respiratory infections in humans ranging from asymptomatic to fatal. Pandemics are attributed to "novel" viruses which possess a viral hemagglutinin (HA) to which humans do not have immunity. PMID: 20542248 ] PMID: 25812763
Influenza viruses A and B are single-stranded RNA enveloped viruses belonging to the Orthomyxoviridae family. The symptoms of infection of Influenza A and B include fever, cough, sore throat, rhinorrhea, nasal congestion, headache, myalgia and malaise. Some patients may experience gastrointestinal symptoms including watery diarrhea, vomiting and abdominal pain. The influenza viruses spread rapidly in enclosed spaces with a documented rate of infection of 70% following a common source of exposure. Infection occurs in the respiratory epithelium in both the upper and lower respiratory tract, and the virus can be found in many specimen types, including nasal aspirates, nasal or nasopharyngeal swabs, throat swabs, sputum and tracheal aspirates. When infection rates reach epidemic proportions, hospitalization of children and elderly patients rises as does the mortality rates of elderly patients.(Manual of Clinical Microbiology, 11th edition, James H. Jorgensen; Karen C. Carroll; Guido Funke; Michael A Pfaller; Marie Louise Landry; Sandra S. Richter; David W. Warnock)
Source: Regenstrief LOINC