Influenza type A virus

Liu C, Eichelberger MC, Compans RW, Air GM. Influenza type A virus neuraminidase does not play a role in viral entry, replication, assembly, or budding. J Virol 1995 69 1099-1106. 

Mozdzanowska, K., Feng, J., Eid, M et al. (2003) Induction of influenza type A virus-specific resistance by immunization of mice with a synthetic multiple antigenic peptide vaccine that contains ectodomains of matrix protein 2. Vaccine 21, 2616-2626. 

Zharikova, D., Mozdzanowska, K., Feng, J., Zhang, M., and Gerhard, W. (2005) Influenza type A virus escape mutants emerge in vivo in the presence of antibodies to the ectodomain of matrix protein 2. J. Virol. 79, 6644-6654. 

The drug is found to inhibit the replication phenomenon of the influenza type A viruses specifically at low concentrations. The above admantanamine essentially possesses two vital mechanisms, namely ... 

Most samples were sent at the request of the College of American Pathologists, which helps laboratories do proficiency testing. A private company. Meridian Bioscience Inc. of Cincinnati, Ohio, is paid to prepare the samples. The firm was told to pick an influenza type A virus sample and chose from its stockpile the deadly 1957 H2N2 strain. The reason for choosing this past, mighty strain, and not a current strain, remains unclear [88]. Still, some other test kit providers besides the college also used the 1957 pandemic strain in samples sent to laboratories in the United States. 

Shoham D (1993). Biotic-abiotic mechanisms for long-term preservation and reemergence of influenza type A virus genes. Prog. Med. Virol. 40 178-192. 

Menna H, Barnett JB, Soderberg LSF. 1985. Influenza Type A virus infection of mice exposed in utero to chlordane survival and antibody studies. Toxicol Lett 24 45-52. 

Viral respiratory tract infections for which treatments exist include those of influenza types A and B, and respiratory syncytial virus (RSV). [Note Immunization against influenza A is the preferred approach. However, antiviral agents are employed when patients are allergic to the vaccine or when the outbreak is due to an immunologic variant of the virus not covered by vaccines, or when outbreaks occur among unvaccinated individuals at risk who are in closed settings, for example, in a nursing home.]... 

Influenza is an infection of the respiratory tract caused by the influenzavirus. Compared with most other viral respiratory infections, such as the common cold, influenza infection often causes a more severe illness. In an average year, influenza is associated with more than 20,000 deaths nationwide and more than 100,000 hospitalizations. Influenza-viruses are divided into three types designated A, B, and C. Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter and are often associated with increased rates for hospitalization and death. Type C infection usually causes either a mild respiratory illness or no symptoms at all [16]. 

Compound 28, named zanamivir, was selected for clinical studies for the prophylaxis and treatment of influenza virus. Zanamivir was found to be suitable as a drug because it is highly selective for influenza type A and B viruses, which it inhibits with high potency... 

Unlabeled u.ses of ribavirin include aerosol treatment of influenza types A and B and oral treatment of hepatitis, genital herpes, and Lassa fever. Ribavirin does not protect cells again.st the cytotoxic effects of the AIDS virus. 

Influenza viruses belong to the orthomyxoviridae family. There are three types of influenza virus, named A, B and C (from the chronological order of their characterization). A multitude of subtypes have been characterized for type A virus. These have arisen from the antigenic cross-reactivities of the surface glycoproteins (see below). No subtypes have been identified for types B and C. Influenza type C virus is significantly different to the other two and in this work only influenza viruses A and B are discussed. Influenza virus particles are spherical in shape, approximately 100 nm in diameter. A schematic diagram of the virus is shown in Fig. 1. 

Ribavirin is a synthetic guanosine analogue, with in vitro activity against a broad spectrum of DNA and RNA viruses, and retroviruses, including HIV. Ribavirin has been used for treatment of a variety of viral infections, including respiratory syncytial virus bronchiolitis and pneumonia, measles, influenza types A and B, Lassa fever, hemorrhagic fever with renal syndrome (Hantaviruses), hepatitis C, and HIV infection. It is used commonly now along with interferon alpha for treatment of hepatitis C infection. There is no known direct nephrotoxicity of ribavirin. 

Examples of model viruses selected for various characteristics are medium-to-large DNA/enveloped (Herpes Simplex I, pseudorabies), small/DNA/nonenveloped (Simian virus SV-40), small/RNA/nonenveloped (Sabin Type I Polio, animal parvovirus), medium-to-large RNA/enveloped (Influenza Type A, parainfluenza virus, Sinbis virus 1), and retrovirus/RNA/enveloped for murine hybridomas (Moloney murine leukemia) [3, 51], Preference in the selection of speciflc model viruses is given to those viruses with signiflcant resistance to physical removal/ chemical agents [47, 49, 51]. 

The most studied sialidase is the influenza virus neuraminidase, whose structure was reported over 15 years ago [9], and which has been the target of highly successful rational drug design [10-12]. Influenza type A and B viruses have two surface proteins, hemagglutinin (HA) which attaches the virus to host cells by recognizing sialic... 

Taylor NR, Cleasby A, Singh O, Skarzynski T, Wonacott AJ, Smith PW, Sollis SL, Howes PD, Cherry PC, Bethel R, Colman P, Varghese J (1998) Dihydropyrancarboxamides related to zanamivir a new series of inhibitors of influenza virus sialidases. Crystallographic and molecular modeling study of complexes of 4-amino-4//-pyran-6-carboxamides and sialidase from influenza virus types A and B. J Med Chem 41 798-807... 

Many enveloped viruses share a common mechanism of fusion, mediated by a virus-encoded glycoprotein that contains heptad repeats in its extraceUnlar domain. Dnring the fnsion process, these domains rearrange to form highly structured and thermodynamically stable coiled-coils. Viruses encoding fusion proteins that have these domains inclnde members of the paramyxovirus family (e.g., respiratory syncytial virus, metapneumovirus, and measles virus), ebola virus, influenza, and members of the retroviridae (e.g., human T cell lenkemia virus type-1 and human immunodeficiency virus type-1, HlV-1). Peptide inhibitors of fusion that disrupt the... 

TEZUKA M, SUZUKI H, SUZUKI Y, KARA H and OKADA s (1997) Inactivation effect of tea leaf catechins on human type-A influenza virus , Jpn J Toxicol Environ Health, 43 (5), 311-15. 

Influenza viruses A and B can cause pneumonia in pediatric and adult patients. Amantidine and rimantidine are available oral agents with activity against influenza virus type A. If started within 48 hours of the onset of the first symptoms, they reduce the duration of the illness by about 1.3 days. Oseltamivir and zanamivir also are oral agents and are active against both type A and B viruses. These agents also reduce the duration of the illness by about 1.3 days if initiated within 40 to 48 hours of the first symptoms.29 For active infection beyond the first 48 hours, none of these agents is effective in treating the infection, and supportive care is the best treatment for these patients. 

D. J. Bucher, A. Mikhail, S. Popple, P. Graves, G. Meiklejohn, D. S. Hodes, K. Johansson, andP. E. Halonen, Rapid detection of Type A Influenza viruses with monoclonal antibodies to the M protein (Ml) by enzyme-linked immunosorbent assay and time-resolved fluoroimmunoassay, J. Clin. Microbiol. 29, 2484-2488 (1991). 

Let s conclude this discussion of life with a short consideration of viruses. Viruses cause all sorts of problems for living organisms. The problems are the consequence of their ability to infect, and ultimately kiU, many types of cells— bacterial, animal, and plant—though each virus is quite specific in terms of the type of cell that it infects. There are many types of viruses. In people, they cause measles, mumps, influenza, AIDS, polio, potentially fatal diarrhea in infants and very young children, herpes, chicken pox, shingles, the common cold, and many other diseases, that may be fatal, serious, and not so serious. In other animals, viruses also cause any number of diseases, as they do in plants. Much effort has been, and continues to be, devoted to the prevention, diagnosis, and treatment of viral diseases. 

Amantadine is 70% to 90% effective in preventing illnesses caused by type A influenza viruses. 

Other illnesses There is no evidence for efficacy of oseltamivir in any illness caused by agents other than influenza viruses Types A and B. 

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