Mononucleosis (mono) is an illness most commonly caused by the Epstein-Barr virus.
Mono can be spread through any exchange of saliva — not just from kissing.
The best way to prevent the spread of mono is to avoid situations where you exchange saliva with others, like kissing on the mouth or sharing drinks.
Perhaps you've heard about the “kissing disease.” It’s commonly known as “mono,” which is short for mononucleosis. This illness is usually caused by the Epstein-Barr virus (EBV), and it can make you feel crummy for a month or so. And almost everyone — 90% of adults by age 30 — will get it at some point in their life. But the infamous “kissing disease” isn’t always caused by kissing. No matter how someone gets it, there are steps you can take to avoid spreading it.
Mononucleosis can actually be caused by a few different viruses. But most commonly it’s caused by EBV, which we’ll be referring to for the rest of this article. Other viruses that can cause mono include cytomegalovirus (CMV), HIV, and adenovirus.
If you catch EBV, like after kissing someone else who has it, it infects cells in your mouth, throat, and tonsils. Then it spreads through the rest of your body, and your immune system kicks into gear to fight it off. This immune system response to the virus is what causes you to feel sick.
Once the virus enters your mouth, it starts to gather in your saliva. So, if you kiss another person on the mouth, you can transmit the virus to them through your saliva. But that’s just one of the ways you can get it or spread it.
What if you’ve gotten mono and haven’t kissed anyone over the last few months? Since the virus stays in saliva, sharing drinks and eating utensils, or even sneezing can also spread the virus. But saliva may not be the only way mono can be passed on.
It turns out that EBV may also be present in blood and sexual fluids if you have mono. There have been rare cases where blood transfusions transmitted EBV to people who had an organ transplant. Even though EBV has been found in sexual fluids, whether having sex causes mono isn’t known for sure. Until more science is known about this subject, it’s still a good idea to keep using condoms for protection from EBV and other sexually transmitted diseases.
Are you feeling sick but unsure if it’s mono? One clue is based on your age. Most cases of mono occur before the age of 30, and children as young as 5 years old can get it. But most often mono occurs in healthy individuals between the ages of 15 and 25. If you’re older than age 40 and have symptoms of mono, it’s best to get checked out by your healthcare provider since you may have something else going on.
Swollen lymph nodes
Other symptoms may include headaches, body aches, and a decreased appetite.
Most of the time your healthcare provider can make the diagnosis of mononucleosis based on your symptoms and a physical exam. But in certain cases, to confirm the diagnosis your provider may order blood tests, including:
Antibody tests: Blood tests that detect antibodies — special immune system proteins — against EBV are the most accurate tests for diagnosing EBV-related mono.
Monospot test: Providers used to commonly order this test since it’s quick and can be done in the office. But this test isn’t used much anymore because it isn’t very accurate.
White blood cell count: With mono infections, your lymphocyte count (a type of white blood cell) can be very high.
If your tests don’t show that you have EBV, then your healthcare provider may order tests for other viruses that cause mono, like CMV. They may also test you for other conditions that cause similar symptoms to mono — like strep throat, a bacterial infection of the throat.
Even after you feel better, EBV can linger in your saliva for months. And this can make you contagious long after your symptoms have gone away — up to 6 months or more in some cases.
The best way to prevent spreading mono is to avoid sharing body fluids of any kind if you know you’re sick. But a person can also be contagious without knowing it. So, if you suspect you’ve come into contact with someone with mono or just recovered from an infection in the last few months, there are a few actions you can take to prevent from spreading it:
Avoid sharing your drinks (or utensils like spoons, forks, and knives) with other people.
Avoid kissing people on the mouth.
Use protection, such as a condom, during sexual intercourse.
It turns out that many of us get the “kissing disease” by early adulthood. But some people get it through non-kissing methods of sharing saliva (like sharing drinks) — or possibly even from sexual fluids. With mono you may feel under the weather for a few weeks, and you can still be contagious even when you feel better. You’ll feel better with time though, and you can do your part to help prevent spreading the virus that causes mono (EBV) in the meantime.
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