In this article, we will discuss about the Pathogenesis of Influenza virus. So, let’s get started.
Pathogenesis of Influenza virus
The incubation period is about 2 days but ranges somewhere between 1-4 days. The route of transmission is Airborne (Aerosol) causing acute respiratory tract infection. The virus adheres to the epithelial cells and replicates for 4-6 hours. It progressively infects surrounding epithelial cells which are then subjected to apoptosis and in result causes local inflammatory response and associated symptoms (detailed flow chart is shown below). The generalized symptoms such as fever, headache, malaise, fatigue, etc relieve within a week whereas cough can persist for 2 or more weeks. Influenza A (H1N1) is proved to be more pathogenic than the seasonal influenza virus; however, the pathogenicity of H5N1 still remains higher, humans occasionally get infected with it. The high-risk group includes pregnant women, children under 5 years of age, industrial and health care workers, elderly individuals (above 65 years age), individuals with chronic medical conditions such as diabetes mellitus or chronic pulmonary, renal diseases, etc, and individuals on immunosuppressive agents. The seasonal influenza virus spreads rapidly in a crowded area such as schools, nursing homes, offices, etc. Seasonal influenza virus infection usually occurs in the winter season.
World wide annual epidemics of influenza virus infection ranges about 3-5 million cases of severe illness and about 290,000-650,000 annual deaths due to respiratory complications.
For prevention, individuals should cover the mouth and nose while coughing or sneezing in order to minimize possible transmission and should wear a mask when outside.