Contagious or Not? Are You at Risk?

10. Gastroenteritis
Gastroenteritis is an inflammation, or irritation, of the gastrointestinal tract, which includes the stomach and intestines.

Stomach Flu

Stomach flu, or the norovirus, is a form of gastroenteritis and is very contagious. Young children can die of dehydration caused by excessive vomiting or diarrhea, so make sure to consult your doctor or local emergency room if you see these symptoms. Essential electrolytes and fluids can be replenished with medications, intravenous (IV) fluids, and small doses (a teaspoon or so) of liquids.
Abdominal pain


Food Poisoning
Food poisoning is another form of gastroenteritis and occurs when people eat food contaminated with bacteria such as E. coli and salmonella. Symptoms will appear within hours of ingesting the contaminated food but will pass in a matter of days. Food poisoning is not contagious.


Stomach cramping
Low-grade fever


9. Meningitis
Meningitis is an inflammation, or infection, of the spinal cord fluid that bathes and surrounds the brain. A dangerous and potentially deadly condition, meningitis is very contagious and can spread like wildfire. Doctors perform spinal fluid tests to determine whether meningitis is viral or bacterial.

Viral Meningitis
There is no vaccine for viral meningitis, and treatment is limited to rest and drinking plenty of fluids. Sometimes people can have viral meningitis and not have any symptoms.


High fever
Stiff neck

Bacterial Meningitis

A vaccine can help prevent bacterial meningitis, which is treated with antibiotics.


High fever

Stiff neck

8. Hay Fever
Hay fever, a type of allergy, affects 20 percent of Americans. An allergic reaction occurs when the body mistakenly attacks allergens, and the immune system springs into action. Allergens are harmless compounds such as pollens, dust, molds and animal dander, but the body identifies them as foreign and therefore harmful, and launches a full attack on them.

The body forms antibodies, which histamines that attack the allergens. Excessive histamines in the body cause irritations like sneezing, coughing, runny nose and other allergy symptoms. Antihistamines, over-the-counter and prescription drugs are commonly used to treat hay fever. Allergies are not contagious.


Irritated eyes
Runny or stuffed nose

Indoor Allergens

Household dust
Pet dander

Outdoor Allergens


7. Mono
By age 40, more than 95 percent of adults have caught a virus known as mononucleosis, or mono, which is also known as kissing disease. The Epstein-Barr virus (EBV) causes mono, and most commonly affects school-age children.

Many of those infected with EBV will never show signs or symptoms, but will carry the virus for the rest of their lives. Mono is highly contagious and commonly spread through saliva, so take care not to share food, utensils, glasses or toothbrushes. Symptoms of mono usually appear four to seven weeks after infection.


High fever
Severe sore throat
Swollen glands and tonsils
Swollen spleen
Abdominal pain

Constant fatigue

6. Fifth Disease
Fifth disease is caused by an infection of human parvovirus B19. There is another parvovirus found in animals, but it is different than the human form, and cannot be transmitted to humans and vice versa.

Fifth disease often masquerades as a harmless rash but can develop into something much more serious if not treated. Forty to 60 percent of children between the ages of 5 and 15 have already caught the highly contagious virus, and outbreaks tend to happen in spring and winter.

The infection usually starts with a red rash on the face, which then spreads to the torso, arms and legs. Fifth disease is contagious, but usually before the rash appears. Once a child is infected, he or she develops immunity and doesn’t run the risk of re-infection.


Low-grade fever
Stuffy/ runny nose

5. Trichomoniasis
Trichomoniasis, or trich, is the most common non-viral sexually transmitted disease. Caused by a single-celled protozoan parasite, Trichomonas vaginalis, the symptoms of trich are more commonly seen in women than men and usually appear within five to 28 days after contact with an infected partner. Trich can be cured with oral medication, but both partners should be treated at the same time to effectively eliminate the parasite.


In women:
Frothy, yellow-green vaginal discharge with a strong odor
Discomfort during intercourse
Discomfort during urination

Irritation and itching of the genital area

In men:
Most men with trichomoniasis do not have symptoms, but if they do, symptoms include:
Irritation inside the penis
Mild discharge
Slight burning after urination or ejaculation

4. Bladder Infection
A bladder infection, or cystitis, is an inflammation of the bladder.

Bladder  Infection

Dr. Lisa explains what happens when you have a bladder infection. Learn more.

A bladder infection is treated with antibiotics, but patients should see their doctor to ensure the infection doesn’t spread to their kidneys, which has serious consequences. If a woman is pregnant, immediate medical treatment is imperative, as the infection can be deadly. Although women frequently develop bladder infections after intercourse, they are not sexually transmitted or contagious.


Frequent need to urinate

Painful urination

3. Cellulitis
Cellulitis is a common but potentially serious bacterial skin infection. The two most common causes of cellulitus are streptococcus and staphylococcus bacteria, which are treated with antibiotics.

When a person is infected with cellulitis, the skin on the lower legs or feet becomes red and swollen, feels hot to the touch, and spreads rapidly. Cellulitis can occur anywhere on the face or body, but the lower legs are the most commonly affected area. If left untreated, the infection can quickly become life-threatening, so make sure to seek immediate medical care.
Red or swollen skin
Tender skin

Skin warm to the touch

Possible symptoms
Red spots
Small blisters

2. Gout
Gout is a disease caused by a build-up of uric acid in the body. It is an extremely painful ailment that often comes on without warning but is not contagious. Uric acid is a by-product of the body’s metabolism of foods that contain purines, which can be found in some types of fish, beans, peas, beer, wine and red meat.

Excessive levels of uric acid form urate crystals in tissues and joints, causing inflammation, arthritis, kidney stones and decreased kidney function. Gout is treated with anti-inflammatories.


Intense joint pain


Though eating certain foods and alcohol may contribute to gout, they don’t cause the condition.
Foods to Keep Uric Acid Levels in Check

1. Gum Disease
Gum disease, or periodontal disease, is an infection of the tissues and bone that surround and support the teeth. Gum disease is caused by the buildup of plaque, a layer of germs that forms on the teeth. The plaque contains bacteria that, over time, irritate and break down the tissue.

Although gum disease is not contagious, bacteria can be spread in saliva. The best way to prevent gum disease is to brush and floss your teeth daily and get regular dental check-ups.