The human lung is a common site for viral infections, particularly during the fall and winter months. This is because when it's cold outside, people remain in close proximity, sneezing and coughing indoors, which facilitates the viruses' transmission from person to person. Most viruses then cause an upper respiratory infection before entering the lungs and causing disease.
Bronchiolitis
Bronchiolitis is an illness caused by several viruses, particularly the respiratory syncytial virus, or RSV, and the influenza or flu virus. It usually affects infants and young children. Although it initially causes upper respiratory symptoms like a runny and congested nose the virus can then affect the lungs, causing the symptoms of bronchiolitis. These include raspy cough; wheezing (a high-pitched noise on expiration of air); rapid breathing; retractions (pulling in of abdominal muscles in an attempt to bring in more air); and hypoxia, or low oxygen content in the blood stream. The treatment for bronchiolitis involves supportive care, which includes administration of intravenous fluids if dehydrated and oxygen support for hypoxia. The illnesses can last for a couple of days to, in severe cases, two weeks.
Pneumonia
Pneumonia is an inflammation of the lungs usually caused by infectious agents like viruses. Viral pneumonia is usually milder than its counterpart bacterial pneumonia, but it can predispose the lungs to infection by bacteria and worsening of symptoms. Pneumonia symptoms include cough, usually accompanied by phlegm, fever or chills, shortness of breath with rapid breathing and retractions, pain on inspiration, or pleurisy, muscle aches and fatigue. If the viral pneumonia leads to bacterial pneumonia, worsening symptoms of shortness of breath and hypoxia can ensue, and the patient can have a pleural effusion, an accumulation of fluid in the lungs, which may need to be surgically drained.
Interstitial Lung Disease
Interstitial lung disease, or ILD, is a group of lung diseases that affect the interstitium, the tissue and space around the air sacs of the lungs. These conditions usually lead to scarring of the lung tissue, affecting its ability to deliver oxygen to the blood. Symptoms include dry cough, feeling of breathlessness, chest pain and wheezing. These symptoms worsen over time, slowly affecting regular activities of daily living. One of the causes of ILD is cytomegalovirus. You are susceptible to it especially if you have a weak immune system, as in patients with cancer or HIV.
