Influenza

Abstract

Virus Influenza virus is the only human-pathogenic member of orthomyxovirus, which during evolution acquired the capability to infect the cells of various mammals and birds. Besides man common hosts are domestic animals as horse, swine, cat and poultry, among the birds especially goose and duck, and nearly all mammals living in water. The influenza virus A and B genome is segmented, when two different viruses infect one cell whole genome-segments can be exchanged ( reassortment). This capability leads to a high variability of the envelope surface proteins H (haemagglutinin) and N (neuraminidase), as well as the polymerase inside the virus particle. An influenza virus equipped with epitopes on its surface that are unknown by the human and animal immune system has the potential to initiate a new epidemic. Transmission for influenza virus main route is aerogene, especially by small droplets while coughing and sneezing and by smear infection, mostly by direct contact. Incubation time is usually 24 to 48 hours. Early clinical symptoms are fever, all signs of inflammation in the upper respiratory tract with sore throat, nasal secretion, conjunctivitis that are associated with myalgia, chills and malaise. Prevention important is the distance from the infected, to avoid aerosol formation, and within care units disinfection of hands and utensils as from stethoscope to door handle. Essential for prevention of disease is the annual vaccination against the seasonal strains influenza virus A-H1N1, A-H3N2 and influenza virus B. Treatment unspecific by anti-inflammatory drugs and reduction of symptoms by therapy of bacterial superinfection with antibiotics. Specific: by application of neuraminidase inhibitors as oseltamivir (Tamiflu®) and zanamavir (Relenza®) within 48 hours after onset of the symptoms.