A. ALLERGIC DISEASE: In an allergy, the body mistakenly identifies a harmless substance as dangerous. The body's immune system responds accordingly, which can result in inflammation, fever, respiratory distress, even shock and death.
"Farmer's Lung," a particular allergy, is more accurately called "Hypersensitivity pneumonitis" — an inflammation in the lungs caused by exposure to a foreign substance, usually organic dust. This dust may come from animal dander, molds or plants. Its symptoms are cough, fever and shortness of breath.
B. PARASITE: A parasite is a living organism that survives by robbing the host organism of food and shelter. Parasites can live in the digestive tract, the cardiac system or the respiratory system, among others — examples are liver flukes, giardia or tapeworms. Rarely, they can cause pneumonia, although most pneumonias are caused by bacteria or viruses.
C. GENETIC DISEASE: A genetic disease is inherited from parents and involves a mutation in the DNA — the "chemical blueprints" that build our bodies. Genetic diseases vary widely, from immune system disorders to cardiac problems, from tendencies to various cancers to mental disorders.
D. FOOD POISONING: Food poisoning occurs when we eat something that is poisonous to our system. Symptoms usually include nausea, vomiting, stomach pain and dehydration. The very young and the very old are most affected, and their symptoms may last the longest. Some types of food poisoning have different symptoms, including weakness, numbness or confusion.