How Do You Get Mono? Causes And Spread Explained

Mono, short for mononucleosis, is caused by the Epstein-Barr virus (EBV). The virus spreads mainly through saliva, which is why it is often called the “kissing disease.” You can get mono by coming into contact with the saliva of someone who has the virus, even if they do not have symptoms yet.

How Do You Get Mono? Causes and Spread Explained

Mono happens when you get infected with EBV. The virus lives in saliva and can spread through kissing, sharing drinks or food, using the same toothbrush, or touching surfaces contaminated with saliva and then touching your mouth. EBV is very common — most people in the United States get it at some point in their lives. Many do not even know they had it.

What Causes Mono?

The Epstein-Barr virus is the main cause of mono. It belongs to the herpes virus family. Once you get EBV, it stays in your body for life, usually in a dormant state. Less commonly, other viruses like cytomegalovirus (CMV) can cause mono-like symptoms. But EBV is responsible for more than 90% of mono cases in adolescents and young adults.

Who Is at Risk for Mono?

Anyone can get mono, but it is most common in teens and young adults between 15 and 30 years old. Children who get EBV often have mild symptoms or none at all. Young adults are more likely to develop the classic symptoms of mono, such as severe fatigue, sore throat, and swollen lymph nodes. People who live in crowded spaces or share close quarters — like college dorms or military barracks — are at higher risk because the virus spreads easily through saliva.

What Are the Symptoms of Mono?

Symptoms of mono usually appear about four to six weeks after you are exposed to the virus. The most common symptoms include extreme fatigue, fever, sore throat, and swollen lymph nodes in the neck and armpits. Some people also have an enlarged spleen or liver, headaches, muscle aches, or a skin rash. The fatigue can last for several weeks or even months.

How Long Is Mono Contagious?

You can spread EBV even before you have symptoms. The virus is present in your saliva during the incubation period and for up to 18 months after the initial infection. However, the highest risk of spreading mono is during the first few weeks when symptoms are at their peak. After that, you can still shed the virus in saliva, but the amount decreases. A small number of people continue to shed the virus at low levels for years without knowing it.

How Is Mono Diagnosed?

Doctors usually diagnose mono based on your symptoms and a physical exam. They check for swollen lymph nodes, a red throat, and an enlarged spleen. A blood test can confirm the diagnosis. The most common test is the monospot test, which checks for antibodies that appear during an active EBV infection. However, the monospot test can sometimes be negative early in the illness. A more specific EBV antibody panel can give a clearer picture.

How Is Mono Treated?

There is no specific antiviral treatment for mono. The illness is managed with rest, plenty of fluids, and over-the-counter pain relievers for fever and sore throat. Corticosteroids are sometimes used if the throat swelling is severe enough to block breathing, but they are not given routinely. Because mono can enlarge the spleen, doctors advise avoiding contact sports or heavy lifting for at least four weeks after symptoms start to reduce the risk of spleen rupture. Most people recover fully within two to four weeks, but fatigue can linger.

Can Mono Be Prevented?

There is no vaccine for EBV. The best way to reduce your chance of getting mono is to avoid sharing personal items that touch saliva, such as toothbrushes, utensils, and drinking glasses. Kissing someone who has mono or is recovering from it also increases your risk. Simple hand washing — especially after touching shared surfaces — helps reduce the spread of many viruses, including EBV.