What causes upper respiratory infections

Inflammation of the upper respiratory tract due to many different causes, may be due to an allergy to the weather, with different types of allergens (antigens) in the air, the effects of dust or chemicals, cigarette smoke ( smoking or inhaling secondhand smoke, pipe tobacco by others released) or by pathogenic microorganisms (fungi, bacteria, viruses). In this article, we mentioned pathogens are bacteria.
 
By the research and scientific experiments, it was found mostly cause upper respiratory tract infections are viral.
In addition, we may encounter other causes such as bacteria, fungi, dust and gases. May include here some typical virus: Rhino virus, corona, Asian influenza parainfluenza, adeno, respiratory syncytial virus RSV. Some bacteria are also common in the upper respiratory tract infection is haemolytic streptococci group A, pneumococcus, Haemophilus influenzae, some mushrooms ... Some common parasitic bacteria in the respiratory tract on as they cocci, in which special attention is the pneumococcus bacteria (Streptococcus pneumoniae); streptococcus, especially streptococcus group A (Streptoccocus pyogenes); Hemophilus influenzae, B. catarrhalis, spirochetes Vencent, a number of bacteria such as E. coli intestinal bacteria, Enterobacter, Citrobacter, even with the blue pus bacillus (Ps.aeruginosa), S. aureus (S. aureus). In addition there are bacteria Candida albicans fungus as well common respiratory pathogens on, most notably the tongue thrush.
Group pathogenic viruses by residents in the mucus lining of the nose and throat. We will be in it, penetrate the mucosal cells, replication and cell damage and spread to neighboring cells. The body will resist with IgA antibodies available and army protection leukemia. Usually there will be some respiratory mucosa cells vulnerable to viruses and destruction, but after about two weeks of classes with new cells grow and push virus. But in some cases, the body does not effectively kill the virus from the respiratory tract in duplicate and penetrate down to the lower respiratory tract into the blood and cause disease variants.
In the case of bacterial etiology is rarely pathogenic bacteria alone that they are often triggered by infection and inflammation of the virus earlier. A high incidence of hemolytic streptococci of group A. This is the leading bacterial cause complications glomerulonephritis in children from a common sore throat.