Our respiratory system is divided into two main parts: upper and lower respiratory system. The upper respiratory tract consists of the nose, nasal cavity, and pharynx, where the lower respiratory tract is connected to the larynx, trachea, bronchi, and lungs.
Therefore, upper respiratory tract infections often include common colds, tonsillitis, sinus infections, laryngitis, and the flu, which can cause mild symptoms such as sore throat, runny nose, sneezing, headache, and muscle aches.
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On the other hand, lower respiratory tract infections include bronchitis, pneumonia, bronchiolitis, tuberculosis and sometimes even the flu.
The SARs-COV-2 virus has been identified as the cause of both upper and lower respiratory tract infections, depending on which type of Covid-19 variant is infected.