Viruses upper respiratory tract infection

Considerable data is available suggesting thatmild-to-moderate immunosuppression can lead to an increase in infectious disease. The types of infections that occur tend to result from either common pathogens (e.g., causing upper respiratory tract infections) or latent viruses (e.g., herpes cold sores), rather than opportunistic organisms such as Pnuemocyctis carinii. These are usually not life-threatening, except in certain susceptible populations, such as the elderly. Opportunistic infections, in contrast, are more prevalent in individuals where severe forms of immunosuppression are present, such as primary immunodeficiency diseases or HIV/AIDS. 

Respiratory syncytial virus (RSV) infection is a major cause of bronchiolitis in infants, whereas influenza A infection usually manifests as an upper respiratory tract infection. The immunological responses of infants to RSV infection and influenza A infection are different. In our studies of the cytokine responses during these infections, we found that the serum concentrations of IL-4, IL-5, RANTES, and soluble intercellular adhesion molecule-1 (sICAM-1) in infants with RSV infection were significantly higher than those with influenza A infection (S8). The concentration of TNF-a in nasopharyngeal aspirates was significantly lower in infants with RSV infection. Therefore, a predominant T helper cell type 2 (Th2) cytokine and related immunological response was observed in infants with RSV infection, whereas a predominantly proinflammatory cytokine response was observed in infants with influenza A infection. This may explain the different clinical manifestations of the two viral infections in infants (S8). 

Viral infections are primarily responsible for exacerbations of asthma. Viral upper respiratory tract infections are a major precipitant of acute asthma in children, being involved in up to 20% to 40% of acute episodes. Infants are particularly susceptible to airways obstruction and wheezing with viral infections because of their small airways. The most common cause of exacerbations in both children and adults is the common rhinovirus." Other viruses isolated include respiratory syncytial virus (RSV), parainfluenza virus, coronavirus, and influenza viruses. The inflammatory response to viral infection is thought to be associated directly with the increasing BHR. Certain viruses (RSV and parainfluenza virus) are capable of inducing spe-... 

Influenza virus sialidase, one of two major antigenic glycoproteins (the other is hemagglutinin) on the surface of influenza virus, is undoubtedly the most comprehensively studied sialidase to date [3-5], Influenza is a highly contagious upper respiratory tract infection that, in addition to humans, infects mammals such as seals, whales, horses, and pigs, and many bird species [6], There are three distinct types of... 

Human viruses will cause disease in other animals. Some are capable of infecting only a few closely related primate species, others will infect a wide range of mammals. Under the conditions of natural infection vimses generally exhibit a considerable degree of tissue specificity. The influenza vims, for example, replicates only in the cells lining the upper respiratory tract. 

The severity of the symptoms of measles is greater in adolescents and adults than in children. The incubation period is 10 to 12 days and during this period there is virtually no outward sign of illness. During this period the virus first causes a local infection of the upper respiratory tract then spreads to other parts of the body. The virus is then disseminated throughout by bloodstream causing a primary disease. 

Palase P, Schulman JL. Inhibitors of viral neuraminidase as potential antiviral drugs. In Chemoprophylaxis and virus infections of the upper respiratory tract, vol. 1. Boca Raton, Florida CRC Press, 1977 189-205. 

Poliomyelitis is a contagious viral infection that usually causes asymptomatic infection but in its serious form causes acute flaccid paralysis. Poliovirus is spread via the fecal-oral route. The virus replicates in the upper respiratory tract, gastrointestinal tract, and local lymphatics. The vast majority of polio infections are subclinical and asymptomatic. Indigenous polio has been absent from the United States since 1979, and the last case in the Americas was reported in 1991. Global eradication efforts are entering the final stages, and the eradication of polio should be accomplished in the next few years. 

Pharyngitis is caused by a virus (viral pharyngitis) or by bacteria (bacteria pharyngitis) such as the beta-hemolytic streptococci. Patients know this as strep throat. A throat culture is taken to mle out beta-hemolytic streptococcal infection. Sometimes patients experience acute pharyngitis along with other upper respiratory tract disease such as a cold, rhinitis, or acute sinusitis. 

Binding of influenza viruses to the human cell surface is mediated by the hemagglutinin (HA) proteins. The attachment initiates the uptake of the virus particle into the host cell. Influenza HAs bind to carbohydrates bearing sialic acids (A-acetylneuraminic acid). The human influenza virus HA proteins preferentially bind to a2-6-linked sialic acids (Fig. 8A) that are found in the upper respiratory tract of humans. In contrast, avian HA proteins preferentially bind to a2-3-hnked sialic acid (Fig. 8B) (61-63). Glycans of this type occur in the respiratory tract and intestine of birds. This way, species specificity of the influenza strains is generated and a barrier exists for avian strains infecting humans, as the sialic acid with an a2-3 linkage is rare on the cell surface of human epithelial cells in the readily accessible upper respiratory tract (61,64). 

Marin, J., Jeler-Kacar, D., Levstek, V., and Macek, V. (2000). Persistence of viruses in upper respiratory tract of children with asthma. J. Infect. 41, 69. 

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). 

Wu H, Pfarr DS, Johnson S, et al. Development of Motavizumab, an ultra-potent antibody for the prevention of respiratory syncytial virus infection in the upper and lower respiratory tract. / Mol Biol 2007 368 652-665. 

The virus attacks the ciliated respiratory epithelium of the airways, with necrosis of the epithelium. Usually, these changes affect mainly the upper conducting airways, but in severe and fatal cases, they extend down to the level of the terminal bronchioles, and the alveoli become filled with protein-containing edema fiuid, red cells, and desquamated alveolar epithelial cells. Following alveolar epithelial cell necrosis, hyaline membranes are often prominent. With recovery from initial infection, the respiratory epithelium regenerates. During this period, however, the mucociliary defense mechanism is defective, and the respiratory tract is particularly prone to attack by secondary invaders. 

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