Influenza A Viral Infection

This presentation provides an overview of Influenza A viral infection, including its signs and symptoms, pathophysiology, and pharmacology. It also discusses the relevance of nursing practice in reducing the spread of the virus. The presentation concludes with information about the effectiveness of Tamiflu as a treatment option.

INFLUENZA A VIRAL INFECTION
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Definition
Influenza A, according to the World Health Organization, is
a contagious and viral infection that affects the respiratory
system leading to fever, headache and fatigue.
The disease is caused by an RNA viruses of the family
orthomyxoviridae.

Signs and symptoms
Fever above 38 degree Celsius
Aching muscles
Chills and sweats
Headache
Dry, persistent cough
Fatigue
Weakness
Nasal congestions
Sore throat.

Physiology and Homeostasis
The human respiratory system is responsible for gaseous
exchange in the human body.
Flu viruses travel through the air or through drips when
someone with the infection coughs.
However, this is not the case in Influenza A infection since
the virus is attached to the epithelial cells of the airways
and as the immune system responds, there is inflammation
and secretion of mucus and that is why the patient
experience soar throat, persistent cough to clear the
mucus, fatigue and weakness.

Pathophysiology
Influenza virus is found in body fluids such as saliva and mucous. It is transmitted
through tiny, air-born droplets created through sneezing and coughing.
The primary target of influenza virus is the upper respiratory tract and the
symptom that the virus exerts in this area is severe inflammation and in the
trachea and upper respiratory tract location.
Upon entrance of the virus in the body, the human immune system starts reacting
and develops high immune reaction against the foreign protein. in this situation
airway inflammation occurs due to which epithelial cells and endothelial cells are
completely disrupted.
One of the mechanisms through which, influenza is believed to affect humans is
the inhibition of adrenocorticotropic hormone (ACTH) that results in lowering the
cortisol levelsupon understanding which genes that are carried by a particular
strain of influenza could help to predict to the degree it will infect humans and the
severity this infection will be.

Depending on temperature of the environment, the influenza
virus can remain infectious for up to one month.
Glycoproteins, specifically hemagglutinin (HA) found on the
surface membranes of the virus bind with specific proteins of
the epithelial cells and this leads to endocytosis of the virus.
Within the host cells, the viral RNA and the Neuraminidase
tetramers are released into the cell that cleave the sialic acid
leading to replication of the virus and symptoms in the host
organism.
Pathophysiology (contd.)

Pharmacology-pharmacodynamics
Oseltamivir (Tamiflu) is the licensed drug for treating influenza A viral
infection.
It is known as a prodrug which is provided to the patients as
phosphates
Upon administration into the body, it develops the form of hydrolyzing
ethers that increases the number of active metabolites in the human
liver.
Further due to its lower affinity to bind to bodily proteins, it exerts
higher affinity for the foreign virus in the body.
Oseltamivir is normally hydrolyzed in the liver to form oseltamivir
carboxylase which hinder the action of neuraminidase enzymes of the virus.
Since it is neuraminidase that leads to viral replication, stopping its action
effectively prevents the infection.

Pharmacology-pharmacokinetics
Gastrointestinal tract is the primary organ where the absorption of
Oseltamivir occurs and within this, it is converted into heparases that
increases the ability of this disorder.
It is proven that more than 75% of oseltamivir reach the systemic
circulation as oseltamivir carboxylase active metabolite when administered
orally.
Further, it is possible to estimate the serum concentration of oseltamivir
carboxylase once it is administered. Furthermore, it is the enzyme hepatic
esterase that metabolize oseltamivir to oseltamivir carboxylase in the liver.
Finally, the Oseltamivir carboxylase is normally excreted through urine after
glomerular filtration and tubular secretion.
Further, Plasma concentrations of both pro-drug and active metabolite are
proportional to dose and are unaffected by co-administration with food.

Pharmacology-Tamiflu(Oseltamivir)
The most effective drug administration route of Tamiflu (Oseltamivir) is oral
route and the through the primary mode of action of Tamiflu, it prevents the
neuraminidase enzyme that is expressed on the surface of the influenza
virus.
There are several side effects that affects the patients who are consuming
the medications for their influenza related condition. Within these the
critical symptom, the fatigue, headache , dizziness, insomnia, nausea,
vomiting and diarrhea.
Tamiflu should not be used in people that are hypersensitive to the drug and
should be cautiously used among patients with chronic cardiac and
respiratory diseases.

Relevance to Nursing Practice
Nurses may play a important role in the reduction of spread
of influenza in the community.
It will enhance the ‘Herd Immunity’ of the community as well.
Attitude and knowledge of the nurses can be a barrier for the
uptake of influenza vaccination.
Nurses can help increase the vaccination of influenza.

Conclusion
Influenza A virus continues to affect people globally.
Studies have shown Tamiflu to be an effective drug in
treating the contagious since it impairs viral replication by
inhibiting the action of neuraminidase enzyme. However,
the drug is not recommended to people who are
hypersensitive and should be used cautiously among
patients with chronic cardiac and respiratory diseases.