Infectious mononucleosis

Some germs make you feel sick.

This sickness is called mono.

Most people get it from spit. You can get it by sharing a toothbrush.

You might also get it from a kiss.

It can make your throat hurt a lot. You might feel very tired too. Some people get a fever.

Your neck might feel puffy.

It is good to rest and drink water. Most people feel better in a few weeks. You can stay well by not sharing cups.

Some people call mono "the kissing disease."

It is a sickness caused by germs. Most cases come from the Epstein–Barr virus, or EBV.

This virus is in the herpesvirus family. It spreads through saliva. You might get it by sharing a toothbrush or a glass.

How you feel depends on your age. Many children have few symptoms. Young adults often feel very sick. They may have a fever for 14 days. A sore throat can hurt for several days. You might also feel very tired. This fatigue can last for many months.

Some people get swollen glands in their neck.

Doctors can check for mono. They look at your throat and neck. They may also use blood tests. These tests look for antibodies. Antibodies are tiny parts of your blood that fight germs. Some people may have a swollen spleen. The spleen is a part inside your body. In very rare cases, the spleen can burst. Most people get better with rest and water.

Infectious mononucleosis is an illness often called "mono."

It is most commonly caused by the Epstein–Barr virus, or EBV. This virus belongs to a group called the herpesvirus family. While EBV is the main cause, other things can cause it too. For example, a tiny living thing called Toxoplasma gondii can cause it. About 5% to 7% of cases come from a different virus called cytomegalovirus.

Knowing about mono is important because it affects many people around the world. Most people will have had an EBV infection by the time they are adults.

The way the virus works starts in the throat. It first grows inside the cells of the pharynx, which is the part of the throat behind the mouth. Later, the virus moves into B cells. These are a type of white blood cell in your body. Your body tries to fight back using special cells called T cells. These T cells attack the infected B cells. This battle causes the cells to change shape and become what doctors call reactive lymphocytes.

This process is what makes you feel sick.

Doctors first described this illness in the 1920s. Since then, people have learned much about how it spreads. It is often called "the kissing disease" because it spreads through saliva. You can catch it by sharing things like toothbrushes or drinking glasses. It can also spread through a cough or a sneeze. A person can even spread the virus weeks before they feel sick.

This makes it hard to know when someone might be contagious.

Many facts help us understand how common mono is. In the United States, about 45 out of every 100,000 people get it each year. It is most common in people aged 15 to 24 years. For people in that age group, it causes about 8% of all sore throats. Symptoms can vary a lot based on how old you are. Children often have very mild symptoms. Young adults might have a fever for 14 days or a sore throat for several days.

Some people may also see small red spots on the roof of their mouth.

Understanding mono helps you stay healthy. You can prevent it by not sharing personal items like glasses or toothbrushes. If you do get sick, the best way to feel better is to rest. Drinking plenty of fluids is also very important. Most people get better in two to four weeks. However, feeling very tired can sometimes last for many months.

In very rare cases, the spleen, which is an organ in your belly, can swell or even burst. Staying careful helps you manage the risks.

Infectious mononucleosis, often called "mono" or glandular fever, is a contagious infection.

It is most commonly caused by the Epstein–Barr virus (EBV), a member of the herpesvirus family. While EBV causes about 90% of cases, other agents can trigger the disease. These include the cytomegalovirus (CMV), which causes 5% to 7% of cases, and the protozoon Toxoplasma gondii, which causes less than 1% of cases. Other rare causes include adenovirus, rubella, and herpes simplex viruses. Understanding mono is vital because nearly 95% of the population is exposed to EBV by age 40.

The biological mechanism of the infection follows a specific sequence. The virus first replicates within the epithelial cells of the pharynx, the tissue in the throat.

This initial replication often leads to pharyngitis, which is a painful sore throat. After this stage, the virus moves to invade B cells, which are a type of white blood cell. The body responds with an immune defense involving cytotoxic T cells. These T cells target the infected B lymphocytes. This interaction results in the creation of enlarged, reactive lymphocytes, also known as Downey cells.

This cellular battle is a primary driver of the symptoms patients experience.

Symptoms of the disease vary significantly depending on a person's age. In children, the illness is often mild and may only produce flu-like symptoms or minor throat infections. Adolescents and young adults typically experience a characteristic triad of symptoms. This includes a fever that usually lasts 14 days, a severe sore throat for 3 to 5 days, and swollen lymph nodes. These swollen glands are often mobile and located around the back of the neck. Young adults also frequently suffer from intense fatigue, headaches, and abdominal pain.

In older adults, the presentation of the disease changes again. They are less likely to experience the classic sore throat or swollen glands. Instead, they often face prolonged fever, fatigue, and body pains. Older adults are also more prone to liver enlargement and jaundice, which is a yellowing of the skin or eyes. People over the age of 40 are more likely to develop a serious illness from the infection. While most people recover within two to four weeks, fatigue can persist for months in about 28% of cases.

Medical history shows that infectious mononucleosis was first described in the 1920s. It earned the nickname "the kissing disease" because it is primarily spread through saliva.

Transmission can occur through kissing, sharing drinking glasses, or using shared toothbrushes. It can also spread through coughing or sneezing. Interestingly, an infected person can spread the virus weeks before they even feel sick. The incubation period, or the time between infection and symptoms, is estimated to be between 33 and 49 days. Some studies suggest people may remain contagious for up to 18 months.

Diagnosis relies on physical exams and specific laboratory tests. Doctors look for swollen lymph nodes and an enlarged spleen to suspect the illness. They may also check for petechiae, which are small reddish-purple spots on the roof of the mouth.

The monospot test, or heterophile antibody test, is one method used, but it has poor accuracy. Because of this, the CDC does not recommend it for general use. Instead, doctors often use serology to detect specific antibodies. They look for Immunoglobulin M (IgM) to identify current infections and Immunoglobulin G (IgG) to identify past infections.

There are several notable complications and side effects to consider. In about 50% of cases, patients may see petechiae in the mouth. A common complication is splenomegaly, which is the enlargement of the spleen.

In less than 1% of cases, the spleen may actually rupture. Some patients may also develop a rash if they take certain medications like amoxicillin while infected. Furthermore, the disease can occasionally lead to secondary cold agglutinin disease, an autoimmune condition affecting red blood cells. In very rare instances, the infection can become chronic and lead to T cell lymphoma.

Managing mono focuses on supporting the body while it fights the virus. There is currently no vaccine for EBV, though research is ongoing. Most cases improve without specific medical treatment. Patients are encouraged to drink plenty of fluids and get sufficient rest. Pain medications like paracetamol or ibuprofen can help reduce discomfort. By avoiding the sharing of personal items, people can help prevent the spread of this common virus.