Question

Can someone explain the pathogenesis of H1N1 virus (Spanish Influenza)?

Answer 1

Swine influenza virus is common throughout pig populations worldwide. Transmission of the virus from pigs to humans is not common and does not always lead to human influenza, often resulting only in the production of antibodies in the blood. If transmission does cause human influenza, it is called zoonotic swine flu or a variant virus. People with regular exposure to pigs are at increased risk of swine flu infection. The meat of an infected animal poses no risk of infection when properly cooked.

• H1N1 swine flu is an acute disease that infects the upper respiratory tract and can cause inflammation of the upper respiratory passages, trachea, and possibly the lower respiratory tract.
• The known incubation period for H1N1 swine flu ranges from 1 to 4 days, with the average around 2 days in most individuals, but some individuals, it may be as long as 7 days.
• The contagious period for adults starts about 1 day before symptoms develop and lasts around 5 to 7 days after the person develops symptoms.
• The contagious period may be longer in individuals with weakened immune systems and children (e.g., 10 to 14 days).
• The acute symptoms of uncomplicated infections persist for three to seven days, and the disease is mostly self-limited in healthy individuals, but malaise and cough can persist for up to 2 weeks in some patients.
• Patients with more severe disease may require hospitalization, and this may increase the time of infection to around 9 to 10 days.
• The body's immune reaction to the virus and the interferon response are the causes of the viral syndrome which includes high fever, coryza, and myalgia. Patients with chronic lung diseases, cardiac disease and who are currently pregnant are at higher risk of severe complications such as viral pneumonia, superimposed bacterial pneumonia, hemorrhagic bronchitis, and possibly death.
• These complications can potentially develop within 48 hours from the onset of symptoms.
• The replication of the virus occurs primarily in the upper and lower respiratory tract passages from the time of inoculation and peaks around 48 hours in most patients.
• The recommended time of isolation of the infected patient is around 5 days.