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Influenza virus

Also known as: Flu

Industry of interest: Healthcare

Classification: Virus

Microbiology: Influenza is a family of RNA enveloped viruses that affect birds and mammals. There are three influenza types: A, B and C. A is the most important in human infection. Influenza is a huge public health concern that occurs in seasonal epidemics and has caused pandemic level infections as recently as 2009 with influenza A strain H1N1 (Monto, 2010).


Habitat and transmission: Influenza spreads in seasonal epidemics worldwide, particularly in the cooler winter months. The virus can be spread in droplet nuclei produced by aerosolization for example when coughing or sneezing (Brankston, 2007). It has also been shown that these droplet nuclei can be spread in air currents. Airborne virus particles can either be inhaled or can settle on surfaces, serving as a secondary reservoir of infection. Direct contact with infected individuals is another common mode of transmission (Brankston, 2007). Some strains of the virus can be contracted from close contact with animals such as birds and pigs.

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Treatment: The general guidelines for influenza treatment include plenty of rest, rehydration and, if necessary, over-the-counter flu medications and pain killers can be taken. The most commonly used drugs include paracetemol and pseudophedrine to reduce fever, pain and nasal congestion. Antiviral drugs are used in severe cases of influenza infection.

Prevention and control: The best methods for prevention include regular hand-hygiene with soap and water or alcohol gels, good personal hygiene for example using a handkerchief when coughing or sneezing and regular environmental decontamination and cleaning regimes. N95 masks and/or N95 respirators are also recommended for healthcare workers treating potentially H1N1 infected patients or other pandemic influenza strains to minimize the spread of infection. There is also a seasonal influenza vaccine available for high risk groups (Brankston, 2007). The vaccine protects against the strains of influenza that research has shown to be the most abundant in the upcoming winter season. Some researchers suggest that the influenza vaccine coverage should be expanded to cover more of the population (Monto, 2010).

Disease and symptoms: The most common influenza symptoms include fever, chills, sore throat, muscle/joint pain, malaise, headache, nasal congestion, coughing and fatigue. However influenza can also cause viral pneumonia and is associated with secondary bacterial pneumonia, which result in significant morbidity and mortality in at risk groups such as the elderly, pregnant, asthmatics, those with chronic lung disease and other serious underlying diseases.


Brankston G, Gitterman L, Hirji Z, Lemieux C and Gardam M. (2007) Transmission of influenza A in human beings. The Lancet Infectious Diseases. 7(4): 257-265.

Monto A.S. (2010) Seasonal influenza and vaccination coverage. Vaccine. 28(Suppl 4): D33-D44.

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