what is the natural History of Influenza virus?

Topic 1 Influenza

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Natural History of Influenzas

The influenza virus was once called the Spanish Flu. This was because at the end of May 1918, the King of Spain, King Alfonso XIII, was the first to openly admit that a new disease had emerged in their country (Mamelund, 2017). But the disease did not originate in Spain. Other countries during that period throughout Europe including the United States were experiencing the so called “Spanish” Flu. Since World War I, much has changed in terms of understanding the flu and the origination of infectious disease. It is now known that the Flu is caused by a virus. Statistical studies since 2000 have found that higher mortality rates occur among the poor in comparison to the more affluent (Mamelund, 2017). People who are more susceptible to influenza are those who have poor nutrition, live in overcrowded areas, have secondary infections like pneumonia and other diseases (Mamelund, 2017).

Presenting Symptoms of Influenza

According to the Centers for Disease Control and Prevention (CDC), Influenza is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and even cause death (Influenza, 2018).

• Fever or feeling feverish/chills
• Cough
• Sore throat
• Runny or stuffy nose
• Muscle or body aches
• Headaches
• Fatigue
• Some people may have vomiting and diarrhea (More common in children than adults)

Outbreak characteristics

According to the CDC, people who have the flu are most contagious in the first 3 to 4 days after infection. People who are healthy can start infecting others, 1 day before symptoms develop and up to 5 to 7 days after getting sick (Influenza, 2018). In addition, some people can have the virus, have no symptoms and spread it to others.

The World Health Organization’s Global Influenza Surveillance and Response System was established in 1952 (Influenza, 2018). The purpose is to reduce the spread of infection by vaccines.  Based on the surveillance system, Influenza activity in the United States remains low throughout the summer months and early October. Outpatient illness surveillance: The proportion of outpatient visits for influenza-like illness remained low and was 1.4% which is below the national baseline of 2.2%