Name of Microorganism: Influenza Virus
Description of Influenza virus
Influenza virus as stated in the name is a virus. The influenza virion is roughly spherical and enveloped (the outer layer is a lipid membrane which is taken from the host cell in the which the virus multiplies. (Racanilello, 2009) Under the lipid membrane is a viral protein called M1 (matrix protein). (Racanilello, 2009)The M1 protein gives strength and rigidity to the lipid envelope. Within the virion are the viral RNAs (the genetic material for the virus). (Racanilello, 2009) In order to see an influenza virus an electron microscope must be used.
Virulence factors are molecules that aid in infecting host cells. In the case of influenza virus A, one of the virulence factors includes hemagglutinin (HA). (Kanazawa University, 2019) HA is required for binding the virus to the cell receptor and for fusion of host endosomal membrane with the virus. (Fislova, Kostolansky, 2005) HA virulence factor produces a new subtype virus complete with new HA and/or Neurminidase (N), which leaves people without antibody protection. (Upchurch, N.d.)
Influenza A and B posses a virulence factor called “antigenic drift”, meaning that the virus induces small changes slowly but continually to become a new strain so the existing antibodies cannot recognize the new strain. (Upchurch, N.d.)
Innate immune response- body’s first line of defense against a virus. During this first stage once the body recognizes it has been infected, it starts the synthesis of cytokines. Cytokines elicit symptoms typical of a viral infection. (fever, sleepiness, lethargy, muscle pain, and nausea.) (Racanilello, 2009)
Inflammatory response- once the cytokines have been brought into circulation, they allow white blood cells to be easily brought to the site of infection. A series of signals is initiated that leads to cell death, as an attempt to prevent spread of the infection. (Racanilello, 2009) During this time is when the inflammatory response is seen in 4 typical ways. (this is due to increased blood flow and capillary permeability, influx of phagocytes, and tissue damage) These 4 ways include: redness, heat, swelling and pain) (Racanilello, 2009)
Adaptive immune response- The adaptive defense consists of antibodies and lymphocytes (humeral response and cell mediated response). (Racanilello, 2009) Vaccines are used as a way to create immune memory. Memory is maintained by B and T lymphocytes.
The respiratory tract is the most common route of viral entry. Foreign particles and aerosolized droplets (containing virions) are introduced into the respiratory tract. (Racanilello, 2009) Should one of the virions introduced into the body be a strain of influenza, a host would then have the potential to become infected with a strain of influenza virus, which causes “the flu”.
Most of the symptoms that are associated with an infection of an influenza virus are a result of the body attempting to attack it. (Maldarelli, 2018) If the body did not react in such a way the influenza virus would continue to replicate and slowly destroy the lining of the respiratory tract causing death (if pneumonia did not kill the host first). (Maldarelli, 2018) There would be no symptoms typically associated with influenza without immune response, meaning there would be no coughing, fever, and pains.
Influenza virus is mainly categorized as an acute infection. An acute infection is one that is short term and typically does not cause long term infections.
Hypothetical patient: 65-year-old Caucasian woman. Patient has a history of hypertension, but no other serious health issues. Patient is a grandmother of 2 young children that she sees on a regular basis. Children attend daycare and preschool. Patient presents with the following symptoms: fever (101.0), body aches, persistent cough, and headache. Patient has not received a flu injection this year.
- Patient presents with classic influenza symptoms: bloodwork should not be needed unless the condition persists longer than a 2 week period.
- Patient may have contracted the virus via the grandchildren, she spends time with them on a regular basis. Daycare and preschool are known to be an area of frequent illness.
- Patient also did not receive a yearly flu injection.
- Influenza is known to affect the young and elderly more so than middle age adults.
- Patient is not immune compromised as her history includes hypertension, which is not an immunosuppressing condition.
An annual influenza vaccine is the best way to prevent influenza illness. (CDC, 2018) The seasonal influenza vaccine is created each year with strains that research has shown to be the most common during the upcoming season. (CDC, 2018) CDC either inactivated influenza or live attenuated influenza, no preference is expressed for one over the other. (CDC, 2018) Inactivated vaccine- pathogen that has been grown in a culture and has lost disease producing capacity. Live attenuated vaccine- contains a viable pathogen, but has been altered to become harmless or less virulent. Vaccines train the immune system to recognize a pathogen, with memory cells the immune system is able to find and destroy pathogens quickly resulting in the host not becoming infected.
CDC recommends the following:
- Everyone over the age of 6 months and older should receive a vaccine
- Vaccine should be given before flu begins spreading in a community
- It takes 2 weeks for antibodies to protect against influenza after vaccine is given
- Influenza vaccine is a yearly need due to the body’s immune response to the vaccination declines over time, and influenza strains are constantly changing
- Influenza vaccine can reduce the risk of flu-associated hospitalization
- Influenza vaccine can be life saving for children.
Treatment usually consists of bed rest and fluids. In some cases, a doctor may prescribe an antiviral medication (Tamiflu or Relenza). (Mayo Clinic Staff, 2019) Antivirals must be taken shortly after symptoms are noticed. Antiviral drugs bind to an enzyme of the influenza virus so that the infectious part of the virus (virions) cannot be released. (Bowers, 2013)
Influenza is primarily a community-based infection. (CDC, 2019) Those that become infected with influenza seek medical care in ambulatory healthcare settings. (CDC, 2019) Health- care associated influenza infections can occur in any healthcare setting and are most common in tandem with an outbreak in the community. (CDC, 2019) It is recommended supplement measures be taken during flu season for facilities such as, nursing homes, assisted living, long-term care facilities, rehabilitation centers, and hospitals. (CDC, 2019) Those most at risk include:
Elderly people, children under 6 months old, pregnant women, and people with chronic conditions, and the immunosuppressed individuals (HIV/AIDS patients, those undergoing chemotherapy, post-transplant patients, etc.)