When you have chicken pox, the varicella-zoster virus that caused it remains in your system but lies dormant for years. When the virus reactivates, for any number of reasons, it appears as a localized rash called herpes zoster, or shingles.

Human viruses cause a variety of maladies, depending on the virus type and the tissues infected. All humans contract multiple viruses throughout the course of life. The severity of viral illnesses ranges from mild to lethal.

The stomach flu, medically known as viral gastroenteritis, is an infection of the intestines. Although most people catch the stomach flu by ingesting contaminated food or water, you also can pick up this infection by coming into contact with an infected person.

Adults who suffer from a cough can choose from many over-the-counter medications to ease symptoms. But when an infant gets a cough, different rules apply. Since over-the-counter cough medications are not recommended in young children, it’s challenging to find a quick and effective remedy to manage symptoms.

Epstein-Barr Virus (EBV) is a common virus: According to Dr. John Sullivan, writing in the medical database UpToDate, it is estimated that 90 to 95 percent of adults have evidence of being infected by the virus at some time. It commonly causes mononucleosis--infamously known as the "kissing disease"

Mumps is an infectious disease that can be prevented by vaccination. The American Academy of Pediatrics recommends that children receive their first dose of the measles, mumps and rubella (MMR) vaccine between the ages of 12 and 15 months and a second dose between ages 4 and 6.

Many doctors and medical experts recommend that individuals over six months of age receive the flu vaccine annually to reduce the risk of contracting the flu virus. Flu shots normally begin appearing at doctor’s offices, hospitals, clinics and pharmacies beginning in September and extending through the winter months.

Whether you have a cough due to a cold, the flu, allergies or dry winter air, the array of cough medicine options can be confusing. Upper-respiratory infections, like a cold or the flu, are the most common cause of cough.

Although nasal sprays can reduce the symptoms of allergies and nasal congestion, they are not always the best solution. Using a decongestant nasal spray, for example, can cause rebound congestion and a reduction in efficacy after three days, according to the Mayo Clinic website.

Candida is a yeast, also classified as a fungus, that is commonly found on the skin, in the digestive tract and on the genitals of humans.

Candida albicans can cause a myriad of problems -- oral thrush, canker sores, skin rashes and even athlete's foot. Bacteria such as candida can thrive in dark moist areas such as locker rooms and inside your shoes.

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