Getting ready to jingle your bells this holiday season? Looking forward to snagging that hottie from Accounting under the mistletoe at the office party? Uh, not so fast there, snuggle-lips. Swap spit with a stranger, and you could end up with a LOT more than just rosy cheeks.

When the spit hits the fan...

Saliva isn't all bad of course...it's essential in helping you speak and eat. In fact, saliva is basically the first step in digestion, as it contains the enzyme amylase which breaks down some starches and starts fat digestion. In addition, it protects your teeth should your body feel the need to vomit. Your barf contains gastric substances which are extremely acidic. If your body is preparing to upchuck, signals are sent from your brain to your salivary glands which increase saliva secretion. As a result, when you're getting ready to blow beets, there is already saliva present to minimize acidity and preserve the tooth structure. And just in case you were wondering, you produce about three-quarters of a liter of spit each day.

Saliva may be essential to your health - but someone else's might be detrimental to yours. Here are 10 reasons to keep your tongue to yourself this season.

 

WARNING: This article contains what may be considered as graphic images.

10. Cold sores - Eeeeuuw. Would you even kiss someone who appeared to have a cold sore? You WOULD? Cold sores are caused by a viral infection that attacks the skin and nervous system which forms small, painful, fluid-filled blisters on the mouth or nose. Cold sores are caused by the virus known as herpes simplex type I (HSV-1). After the first episode, the virus lies dormant in the nerves or skin around the original area until something sets it off into another eruption. Colds, flu, and even stress can cause you to have an outbreak of cold sores. The first symptom of an outbreak may include tingling, burning, or itching in the area around the mouth or nose. Within a few hours or days, the area may become reddened and develop small fluid-filled blisters. Several of these small blisters may even come together and form one large blister. Just for fun.

9. Cytomegalovirus (CMV) - CMV is a common virus that infects most people at some time during their lives but fortunately, rarely causes obvious illness. It is another member of the (disturbingly large) herpes virus family, which includes chickenpox, infectious mononucleosis, fever blisters and genital herpes. Like other herpes viruses, CMV infection can become dormant for a while and may reactivate at a later time. Almost everyone will have been exposed to CMV by the time they reach adulthood. Most adults who are infected with CMV do not develop symptoms, but those who do may have fever, swollen glands and feel tired. Oy.

8. Molluscum contagiosum - Sounds more like a Harry Potter spell for shellfish, but Molluscum contagiosum is a relatively common viral infection of the skin that often affects children (so don't kiss any 8-year-olds under the mistletoe either - just in case you were thinking.) The disease causes firm bumps (papules) which are painless and disappear within a year without treatment. If the papules are scratched or injured, the infection can spread to surrounding skin. In adults, molluscum contagiosum may appear on the genitals and is considered a sexually transmitted disease (STD).

7. Hepatitis B - If you're drinking at the office holiday party, you need a healthy liver. Unfortunately, Hep B stops your liver from functioning effectively. Symptoms include liver inflammation, vomiting, jaundice, and rarely, death. Chronic hepatitis B may eventually cause liver cirrhosis and liver cancer. It's estimated that up to a third of the world's population has been exposed to Hepatitis B, and between 3 and 6% are currently infected. That means, if you kiss 10 people at the party, potentially 6 of them could be infected. Or not.

This female Cambodian patient presented with a distended abdomen due to a hepatoma resulting from chronic hepatitis B infection.

6. Gum Disease - Kissing can pass on up to 500 different species of germs - including the ones that give you gum disease, according to the American Dental Association. Gum disease is the leading cause of tooth loss in adults and is easily transmitted through mouth to mouth contact. It can put you at risk for heart attacks and strokes, and for individuals with diabetes, is associated with poor control of insulin levels. Got a bun in the oven? Be careful! Pregnant women with gum disease are at risk for having premature births and low weight babies.

5. Upper Respiratory Infection - Colds and flu - a URI is any type of infection of the head and chest that is caused by a virus. It can affect your nose, throat, sinuses and ears and also affect your windpipe, voice box and airways. The busy holiday party season is the "perfect" time to get infected while kissing because your risks increase when you are emotionally or physically stressed, tired, you're not eating well, you smoke or you're living (shopping) or working in crowded conditions. But the good news is, a URI generally only lasts one or two weeks.

4. Meningitis - This potentially deadly disease is the inflammation of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis may develop in response to a number of causes, including infectious agents, physical injury, cancer, or certain drugs. While some forms of meningitis are mild and disappear on their own, meningitis is a potentially serious condition because the inflammation is so close to the brain and spinal cord. The potential for serious neurological damage or even death necessitates prompt medical attention and evaluation. Infectious meningitis, the most common form, is typically treated with antibiotics and requires close observation. If untreated, the disease can progress rapidly and can lead to shock and death.

Symptoms include fever, vomiting, severe headache, stiff neck, aversion to bright lights, delirium, seizures and rash. The rash consists of tiny red or brown pin-prick marks which can change into larger red or purple blotches or blood blisters. If you suspect Meningitis, the "Tumbler Test" may help your diagnosis. Press a glass tumbler against the rash. With meningitis, the marks will not fade, and you'll be able to see them through the glass. The largest epidemic outbreak was in 1996, when over 250,000 cases occurred and 25,000 people died as a consequence of the disease. But the majority of cases occur in the "Meningitis Belt" - an area in sub-Saharan Africa which stretches from Senegal in the west to Ethiopia in the east. If you get a party invitation there, graciously decline.

IMAGE: Pneumococcal meningitis in an alcoholic. Head opened at autopsy revealing purulent inflammation of leptomeninges beneath reflected dura.

3. Mononucleosis - Known as mono, glandular fever or "kissing disease," mononucleosis is caused by the Epstein-Barr virus (see below), and is most common in adolescents and young adults.

Mononucleosis usually isn't very serious, but the virus remains in your body for life. Treatment mostly involves bed rest and getting adequate fluids. Symptom include fatigue, weakness, sore throat, fever, swollen lymph nodes or tonsils, night sweats and swollen spleen.

2. Epstein-Barr virus - According to the Center for Disease Control Epstein-Barr virus, frequently referred to as EBV, is a member of the herpes virus family and one of the most common human viruses. The virus occurs worldwide, and most people become infected with EBV sometime during their lives. In the United States, as many as 95% of adults between 35 and 40 years of age have been infected. When infection with EBV occurs during adolescence or young adulthood, it causes infectious mononucleosis 35% to 50% of the time.

Although the symptoms of infectious mononucleosis usually resolve in 1 or 2 months, EBV remains dormant or latent in a few cells in the throat and blood for the rest of your life. (One kiss is worth THAT? I think not!) Periodically, the virus can reactivate and is commonly found in the saliva of infected persons. EBV also establishes a lifelong dormant infection in some cells of the body's immune system and appears to play an important role in Burkitt's lymphoma and nasopharyngeal carcinoma, two rare cancers.

1. Polio – Ok, it’s rare these days, but polio or poliomyelitis, is a disease that can damage the nervous system and cause paralysis. Since polio immunization has become widespread in the United States, cases of polio are rare, but it remains a problem in many parts of the world. The greatest risk is now in the Indian subcontinent and, to a lesser extent, in West and Central Africa. The polio virus attacks the nerve cells that control muscle movements, but many people infected with the virus have few or no symptoms. Others have short-term symptoms, such as headache, tiredness, fever, stiff neck and back, and muscle pain. However, more serious problems occur when the virus invades nerves in the brain and causes paralysis of the muscles used in swallowing and breathing. Invasion of the nerves in the spinal cord can cause paralysis of the arms, legs, or trunk.

In very rare cases, the vaccine used to prevent polio can cause polio paralysis in persons who are vaccinated (1 in every 8.1 million doses - you see, it's REALLY rare) and in people who are close contacts of a vaccinated person (1 in every 5 million doses). Only about 8 to 9 cases of paralytic polio caused by the oral vaccine have been reported in the United States yearly, and to date this year, only 790 cases of polio have been reported around the world, significantly down from 1997 cases in 2006 - mostly in Africa.