According to the Centers for Disease Control and Prevention, over 1 million people are infected by the human immunodeficiency virus -- HIV -- in the United States. Early on, symptoms of this disease may mimic other illnesses, such as the flu.

Known among mountaineers as “dex,” dexamethasone is a steroid used to treat high-altitude cerebral edema. Every year about 2 percent of mountain climbers suffer from this life-threatening condition, according to Ken Kamler’s 2005 article, “Steroids on Everest” on the National Geographic website.

Body aches and fatigue are common symptoms of a variety of illnesses and conditions. While both terms are somewhat vague, body ache usually refers to soreness in the muscles, while fatigue is another word for lack of energy or exhaustion.

Bloating is often described as a feeling of fullness or pressure in the abdomen that results in a physical swelling or distention of the abdomen. Occasional bloating in women is normal and usually occurs as a result of improper digestion of gas-forming foods or as a regular symptom of the reproductive cycle.

Grapefruit is a popular and wholesome breakfast food. According to the U.S. Department of Agriculture, grapefruit is the second leading citrus fruit consumed per capita in the United States. Grapefruits are rich in vitamin A, ascorbic acid, folic acid, potassium, fiber and flavonoids.

Whether it is spring or fall, if you suffer from allergies, you run the risk of becoming sick. For some sufferers, allergies cause nasal congestion, headache and cough. For others, if their bodies react strongly enough, their symptoms may include a low-grade fever and fatigue.

Most people associate black caviar with swanky parties and champagne, but it's much more than just a cocktail party cracker topping. Black caviar is simply sturgeon roe -- or fish eggs -- tiny little balls that contain contain vitamins and minerals that nourish the unborn fish.

Chronic inflammatory polyneuropathy, or CIDP, is an autoimmune disorder that involves nerve swelling and irritation. The cause of CIDP is usually not known, and it may occur with other chronic conditions, such as hepatitis, diabetes, HIV and lupus. Treatment often involves medication to treat the symptoms.

When the immune system works perfectly, antibodies travel throughout our body to kill off germs and other foreign substances. Usually this system knows the difference between good and bad, killing off only the bad particles.

Finding out you have HIV doesn't mean a death sentence. However, if you are infected with HIV and don’t get treatment, HIV will eventually overwhelm your immune system. This will lead to your being diagnosed with Acquired Immune Deficiency Syndrome (AIDS).

The lymph nodes are small glands distributed throughout the body that play an important role in immunity. They frequently swell in response to an infection, but may also swell for other reasons. Often a baby develops swollen lymph nodes in her neck.

Human papillomavirus, or HPV, is a virus that causes warts. The most common kind is genital HPV, and at least half of sexually active men and women contract it at some point in their lives, says the Center for Disease Control and Prevention.