Respiratory syncitial virus

Infants with SCID have profound immunodehciency and present with frequent episodes of diarrhea, pneumonia, otitis, sepsis, and cutaneous infections. Persistent infections with opportunistic organisms such as Pneumocystis carinii, Epstein-Barr virus, Candida albicans, cytomegalovirus, parainhuenzae 3 virus, respiratory syncitial virus, adenovirus, varicella, and bacille Calmette-Guerin (BCG) lead to death within the hrst or second year of life. ADA dehciency also occurs in adults, but with a much later onset and nhlder, but clinically discernible, immunodehciency [3,5]. 

Virus infections Viral cholangiopathy, sometimes with concomitant destruction of the intrahepatic bile ducts, has been reported to derive from several species of viruses, e.g. HIV, cytomegaly, rotaviruses, respiratory syncitial virus (RS), hepatitis C, congenital rubella and reovirus 1 Bacteria may, however, also be the cause of disease, as is the case with congenital syphilis. 

About two-thirds of colds are caused by rhinoviruses - members of the picomavirus group (as are the polio viruses), and all of them are RNA-(+)-viruses. These have an icosahedral (20-sided, near-spherical) shape and their protein coat is made from four different proteins with widely differing amino acid compositions. It is not therefore surprising that there are more than 90 serotypes hence, there is little possibility of a useful vaccine, and none of us has much chance of becoming immune to all forms of the common cold. Other viruses that produce the symptoms of a cold include coronaviruses, adenoviruses, coxsackie viruses, orthomyxoviruses, paramyxoviruses, respiratory syncitial viruses, echoviruses and enteroviruses. 

As with influenza, the brevity of the incubation period and the fact that by the time the first symptoms appear, the virus will already be present in large amounts, means that prophylaxis and treatment are difficult. Add to this the fact that the cold may be due to another type of virus, for example, an adenovirus (a DNA virus) or a respiratory syncitial virus, and the problems appear insuperable. And indeed, at present, no drugs have reached the marketplace. The rhinoviruses are RNA-(+)-viruses and have two principal viral enzymes an RNA polymerase and a protease, but although a number of potential enzyme inhibitory drugs have been evaluated in clinical trials, none has reached the marketplace. 

Respiratory virus infections (respiratory syncitial virus [RSV], parainfuenza viruses, influenza viruses and adenoviruses) are all highly contagious and symptomatic individuals should be isolated before virologic confirmation is available. To prevent progression of RSV from the upper to the lower respiratory tract, aerosolized ribavirin may be used alone or in combination with RSV-specific antibodies or palivizumab, an RSV-specific monoclonal antibody (Boeckh et al., 2001). 

Shepherd NE, Hoang HN, Desai VS et al (2006) Modular a-helical mimetics with antiviral activity against respiratory syncitial virus. J Am Chem Soc 128 13284—13289... 

Tripp RA, Jones L, Anderson LJ, Brown MP. CD40 ligand (CD 154) enhances the Thl and antibody responses to respiratory syncitial virus in the BALB/c mouse. J Immunol 2000 164(11) 5913-5921. 

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