Viral Infection of the Respiratory Track

A viral infection of the respiratory track is one of the most frequent acute illnesses throughout the world. There are over 200 subtypes of viruses that can infect the respiratory tract. Because there are so many types of respiratory viruses, it is common to contract an infection of the respiratory tract several times throughout the year.

Causes
Viral infections of the respiratory tract are very common, as the viruses spread easily from person to person. The virus is spread from coughing or sneezing. The virus also can remain alive on the skin, and so can be spread through shaking hands or touching objects and surfaces.

Signs and Symptoms
The common cold is a mild viral infection of the upper respiratory tract. It can be caused by many different viruses. Symptoms usually include a cough, runny nose and sneezing. There may also be a sore throat. The symptoms usually resolve after two to five days.

Other respiratory viruses can cause more severe infections. The most common is the influenza virus (commonly known as the flu). The patient with influenza is likely to have some of the above symptoms, but also has fever, fatigue, muscle ache and sometimes headaches. The symptoms usually resolve after three to five days, although sometimes longer. Weakness and fatigue may persist for several weeks.

Investigations
The diagnosis is made based on the symptoms and physical examination. Unless other symptoms are present, no investigations are required. If pneumonia is suspected then the appropriate investigations will be required. 

Treatment
An upper respiratory tract infection does not usually require treatment. Some over the counter medications may help ease symptoms, such as throat lozenges for sore throat, cough syrup for nagging cough, or decongestants for nose congestion. Antibiotics are not required, however may be given if an additional bacterial infection develops, such as an ear infection.

Influenza also does not usually require treatment. Symptoms generally resolve after resting at home. They should be advised to maintaining adequate hydration. Analgesia can be given for headaches and muscle aches. However, patients that
might require admission into hospital are those that have impairment of the immune system, such as the elderly, malnourished or those with diabetes, chronic kidney disease or immunodeficiency virus (HIV) infection.  These people may need to be admitted into hospital, as influenza can cause these people to become very unwell. The most common complication in these people is pneumonia.

Avian Influenza
Avian influenza (commonly known as bird flu) is a strain of the influenza virus. The strain that causes most concern is called H5N1. It is very rare, however, it is also very life threatening. The virus originally only infected birds, including chickens. In recent
times the virus has spread from bird to human. Nearly all the humans who have become infected had direct contact with sick or dead birds, or had contact with secretions or excrement from infected birds. Human to human spread is unlikely. However, there is international concern that the virus might mutate to become more like the human influenza virus. If this happened then it would be easily transmitted amongst humans, which would lead to huge mortality rates.