Which organ system is affected by influenza?

The respiratory system is affected by influenza because the virus primarily attacks the cells of the respiratory tract, leading to inflammation and symptoms such as coughing, sore throat, and difficulty breathing. Influenza virus is known to enter the body through the nose or mouth and replicate in the epithelial cells lining the respiratory system. The immune response to this infection can further exacerbate symptoms, making it a condition closely linked to respiratory health.

The digestive system, while it might experience symptoms like nausea in some cases of viral infections, is not the primary organ system involved in influenza. The nervous system might experience indirect effects, such as fatigue or malaise, but it is not directly targeted by the influenza virus. The circulatory system can also be impacted due to secondary complications, but again, it is the respiratory system that is directly affected by the influenza virus itself.