Author: Alison Shieh

Editor: Helia Mansouri Dana


Influenza, otherwise known as the flu, is a respiratory disease caused by the influenza virus that affects approximately 5 to 15% of the global population every year (Dangi & Jain, 2012) and is transmitted through the inhalation of respiratory droplets (Yamauchi, 2018). The major influenza viruses that affect humans are influenza A and B, with influenza A virus infecting humans more commonly and severely, and each having their own subtypes that transmit among humans (Peteranderl et al., 2016).

Through mutations that cause minor changes in their genetic information (Ghebrehewet et al., 2016; Peteranderl et al., 2016), influenza A viruses are thereby able to avoid attacks by the human immune system, resulting in seasonal epidemics each year generally occurring during the winter seasons (Dangi & Jain, 2012). 


What causes Influenza?

The flu is caused by influenza viruses, namely influenza A and influenza B (Ghebrehewet et al., 2016). The virus is transmitted through respiratory droplets and infects different locations along the respiratory tract, which leads to some of the common symptoms including sore throats and coughs (Ghebrehewet et al., 2016)



  • Headache
  • Sore throat
  • Aching muscles
  • Fatigue
  • Fever
  • Nausea
  • Vomiting
  • Diarrhea 

(Minodier et al., 2015)


Risk Factors

  • children of ages 2 and younger
  • adults over the age of 65
  • heart or lung disease
  • diabetes

(Dangi & Jain, 2012)


How is Influenza diagnosed?

Influenza is typically diagnosed clinically through tests on respiratory samples (Ghebrehewet et al., 2016). Individuals suffering from flu-like symptoms including fever, cough, or sore throat, or battling acute pneumonia, especially those residing in a place where a flu outbreak is prevalent, should be tested for carrying the influenza virus (Jilani, Jamil & Siddiqui, 2020; Soleimani & Akbarpour, 2011).


Patients may be treated with antiviral drugs; however, antiviral therapies are only effective during the very early stages of the illness, and the ability of the virus to change genetically makes treatment difficult (Peteranderl et al., 2016). 

Reducing the Spread of Influenza 

Non-pharmaceutical methods available to reduce infection include community health education about the importance of social distance, and personal hygiene ( Sharma et al.2019). Biosecurity measures, regular disease surveillance and monitoring program, farm management practice including washing hands (Khanna et al. 2012, Itolikar et al. 2015, Singh et al. 2011, Scolaro et al. 2017), follow the disinfection and sanitary practices, isolating people with flu from the public places.

It is important to follow biosafety standards, such as using face masks, covering nostrils and mouth while sneezing or coughing (Dhama et al. 2012), following infection control practices, distributing correct information, and having Education and Communication (IEC) material in hospitals and schools (Mahesh et al. 2014).



Vaccination has been found to be the most effective method of preventing influenza, though the composition of influenza vaccines need to be altered every year to account for the changing nature of the virus (Peteranderl et al., 2016).



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