Infectious lung diseases are defined as pathogen-caused illnesses that can be transmitted from person to person. They range in severity from mild to deadly, and while some are very common, others are quite rare. Vaccinations have all but eradicated many of the once epidemic infectious lung diseases, but others mutate too quickly to allow for effective vaccination. Almost all lung diseases share the symptoms of coughing, difficulty breathing, and excessive production of mucus.
Influenza
While many people, when they come down with a wintertime bug, claim to have the "flu," in fact, true flu is a specific infection by an influenza type virus. According to the National Institutes of Health (NIH), while either the flu or a cold can cause aches, coughing, and sore throat, true influenza comes on much quicker than a cold, and the symptoms are far more severe. It also commonly causes intense headache and high fever, neither of which are typical cold symptoms. While influenza can be deadly for the very young, the elderly, and the immunosuppressed, most people require only palliative treatment and recover well over a period of several weeks.
Pneumonia
Pneumonia is not caused by a single pathogen, but can instead be brought on by bacteria, viruses, or even fungi. It is most common in patients with underlying respiratory weakness, including the very young, the elderly, and asthmatics. It's also an opportunistic disease, often occurring in tandem with influenza or other infections, notes the Mayo Clinic. Symptoms include coughing, wheezing, and shortness of breath as well as fever, malaise, chills, and pain. Fungal and bacterial pneumonias can be treated with antibiotics, but viruses don't respond to such drugs, and as such, these pneumonias simply warrant patient support and comfort measures.
Tuberculosis
A bacterial disease, tuberculosis is rarely contracted by healthy adults. Instead, it's more common in the immunosuppressed and medical professionals, who may be exposed to tuberculosis by their patients. The Centers for Disease Control and Prevention (CDC) note that symptoms of tuberculosis are initially similar to those of other infectious lung diseases, but that they may be limited to the lungs and may persist for long periods of time. In particular, tuberculosis can cause an infected patient to cough up blood or large amounts of sputum. Several months' worth of drug therapy can usually clear up cases of tuberculosis.
Pertussis
Also called whooping cough, pertussis is not nearly as common as it once was, owing to the effectiveness of vaccines. These days, babies who have not yet been vaccinated sufficiently to have developed immunity are the most susceptible members of the population. Initial whooping cough symptoms are similar to those of the common cold, including stuffy nose, a dry cough, and sneezing. Instead of clearing up over time, however, as cold symptoms do, pertussis symptoms worsen. The cough deepens and develops into a rasping sound that ends with a high-pitched "whoop" as the patient struggles to pull air into the lungs. Untreated, pertussis can be fatal, but it responds well to antibiotics, notes the Mayo Clinic.
