There is not just one type of respiratory infection, but several infections that can reach the respiratory tract, some lighter and some more severe. Some of the most common causes of respiratory infections include:
Common Cold or Flu: It is an infection caused by viruses, causing cough, runny nose, sneezing and nasal obstruction. In influenza, there is infection with influenza viruses, which cause more intense symptoms such as body pain and fever.Sinusitis: is the infection caused in the bones of the face and can cause headache, facial pain, nasal discharge, cough and fever, caused by viruses, bacteria or fungi;Pharyngitis: There is infection of the throat region, causing local inflammation, as well as runny nose and cough, most often caused by viruses;Tonsillitis: pharyngitis may be accompanied by tonsil infections, causing intense inflammation, being more intense when there is infection by bacteria, which can produce pus in the region;Bronchitis: is the inflammation of the bronchi, already considered a low respiratory infection, since it already reaches the lungs. It causes coughing and shortness of breath and may have both allergic and infectious causes from viruses or bacteria.Pneumonia: It is the infection of the lungs and pulmonary alveoli, which can cause intense secretion, cough, shortness of breath and fever. It is usually caused by bacteria, it can also be caused by viruses or fungi;Tuberculosis: This is a type of lung infection caused by the bacterium of Koch bacillus, which causes chronic, gradual inflammation with cough, fever, weight loss and weakness, which can become severe if treatment is not done promptly.
  These infections can be classified as acute when they appear suddenly and rapidly worsen, or as chronic when they have a long lasting, sluggish course and difficult to treat, which often happens in certain cases of sinusitis, bronchitis or tuberculosis. , for example.
