An estimated 5 percent of the population of the United States has a thyroid gland that functions poorly, a condition called hypothyroidism, the National Endocrine and Metabolic Diseases Information Services reports.

Typhoid fever is an infectious disease caused by the bacteria Salmonella typhi. The Centers for Disease Control and Prevention, or CDC, estimates a worldwide incidence of 22 million cases and 200,000 deaths annually. It occurs less commonly in the United States, with a yearly estimate of only 400 cases.

One of the most commonly used ways to diagnose shingles is by looking for its fairly unique symptoms. Shingles usually starts by causing a very severe burning or tingling pain that is limited to one side of the body or face. After the pain begins, a rash develops on the affected parts of the body.

Coughing is the body’s way of expelling an irritant in the throat and airways, and can be caused by many factors, including allergies, asthma, pneumonia, flu, colds and postnasal drip.

The flu is a respiratory illness that is caused by a virus known as the influenza virus. The flu isn’t the same viral illness as a cold, but they share some of the same symptoms.

The Epstein-Barr virus is very common and affects nearly all individuals in the United States at one point or another during their lifetime. It can be either acute or chronic, and although there isn’t a cure, lifestyle changes — including your diet — can help relieve symptoms and promote healing.

Your nails say a lot about how you take care of yourself. Peeling fingernails can be caused by harsh products, nail hygiene or the manner in which you are using your nails. According to Nia Terezakis, M.D.

Leg spasms and muscle cramps can be symptoms of certain infections such as the flu. If your sickness is causing diarrhea or vomiting, you could also suffer from an electrolyte imbalance which can cause leg spasms.

Saline nasal spray has several advantages over steroid nasal sprays and over no treatment at all. Saline sprays can be used to moisturize dry sinus cavities, loosen nasal congestion, and remove debris or pollens from the nose. Water and salt or sodium comprise the spray.

If you get flu-like symptoms, such as vomiting and diarrhea, after eating chicken, it's likely that the chicken was undercooked and was infected with either salmonella or campylobacter.

The influenza virus, usually referred to simply as the flu, is common and profoundly contagious. It can cause serious complications in infected individuals, especially children.

Chills accompanied by cold feet can result from a number of conditions ranging from chronic diseases such as Raynaud's disease or anemia to environmental factors or illnesses.