Influenza Virus Characteristics
The influenza virus, conversationally called the flu, is an illness that's highly contagious and causes a number of different symptoms. There are many different types, or strains, of the influenza virus, including the seasonal flu virus and the H1N1 influenza virus (commonly called swine flu).
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
More severe than the common cold, flu symptoms can cause serious complications like pneumonia and other infections in some people -- especially those with a weakened immune system, including the elderly, the very young and pregnant women.
Respiratory Symptoms
The most common symptoms of the influenza virus are respiratory--a bad cough is common. Congestion in the chest and in the nose (having a stuffy nose) are also common symptoms of the flu, says the American Academy of Family Physicians 1. Your nose may also run, and a sore throat is also common, says the U.S. Centers for Disease Control and Prevention.
Fever and Body Aches
Flu Symptoms Without Nausea or Vomiting
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The flu is often characterized by running a high fever--typically 102 degrees or higher, says the AAFP. That fever is generally accompanied by sweating and the chills, and aches and pains all over the body. Aching muscles and body pains are often felt in the legs, arms and back, but may occur anywhere. A headache may also commonly occur along with these symptoms.
- The flu is often characterized by running a high fever--typically 102 degrees or higher, says the AAFP.
- Aching muscles and body pains are often felt in the legs, arms and back, but may occur anywhere.
Gastrointestinal Symptoms
The flu virus may also cause gastrointestinal symptoms, like vomiting, nausea or diarrhea. But, these gastrointestinal symptoms strike more often in children with the flu rather than adults, says the CDC.
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References
- American Academy of Family Physicians-Colds and the flu
- InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Flu: Overview. 2013 Dec 18 [Updated 2019 Nov 7]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279459/
- Boktor SW, Hafner JW. Influenza. [Updated 2019 Dec 5]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459363/
- Kalarikkal SM, Jaishankar GB. Influenza Vaccine. [Updated 2019 Oct 8]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537197/
- Dynasty: Influenza Virus in 1918 and Today. NIH News 29 June 09. National Institute of Allergy and Infectious Diseases. National Institutes of Health.
- Centers for Disease Control and Prevention. About Flu. Updated September 5, 2019. cdc.gov
- Newman LP, Bhat N, Fleming JA, Neuzil KM. Global influenza seasonality to inform country-level vaccine programs: An analysis of WHO FluNet influenza surveillance data between 2011 and 2016. PLoS One. 2018;13(2):e0193263. Published 2018 Feb 21. doi:10.1371/journal.pone.0193263
- Centers for Disease Control and Prevention. Key Facts About Influenza (Flu). Updated September 13, 2019. cdc.gov
- InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Flu: Overview. 2013 Dec 18 [Updated 2019 Nov 7].
- Zhang N, Li Y. Transmission of Influenza A in a Student Office Based on Realistic Person-to-Person Contact and Surface Touch Behaviour. Int J Environ Res Public Health. 2018;15(8):1699. Published 2018 Aug 9. doi:10.3390/ijerph15081699
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- US Food & Drub Administration. Influenza A (H5N1) Virus Monovalent Vaccine, Adjuvanted. November 14, 2019. fda.gov
- Shao W, Li X, Goraya MU, Wang S, Chen JL. Evolution of Influenza A Virus by Mutation and Re-Assortment. Int J Mol Sci. 2017;18(8):1650. Published 2017 Aug 7. doi:10.3390/ijms18081650
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- Arbeitskreis Blut, Untergruppe «Bewertung Blutassoziierter Krankheitserreger». Influenza Virus. Transfus Med Hemother. 2009;36(1):32–39. doi:10.1159/000197314
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- Caini S, Kroneman M, Wiegers T, El Guerche-Séblain C, Paget J. Clinical characteristics and severity of influenza infections by virus type, subtype, and lineage: A systematic literature review. Influenza Other Respir Viruses. 2018;12(6):780–792. doi:10.1111/irv.12575
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Diana Rodriguez is a Louisville, Kentucky-based full-time freelance writer who specializes in health and real-estate writing. Since 2008 her numerous articles have appeared on various news and health websites. She also specializes in custom Web content for a variety of businesses. She has degrees in journalism and French from Miami University of Ohio.