Infectious Mononucleosis (Mono): Symptoms, Spread and Recovery

Infectious mononucleosis — mono — is a contagious disease, most often caused by Epstein-Barr virus (EBV). It's common among teenagers and young adults, especially college students: at least 1 in 4 teens and young adults infected with EBV develops mono. There's no vaccine.

Symptoms

Symptoms usually appear 4 to 6 weeks after infection, and can come on slowly, not all at once:

• extreme fatigue;
• fever;
• sore throat;
• headaches and body aches;
• swollen lymph nodes in the neck and armpits;
• a swollen liver or spleen, or both (less common);
• rash.

Most people get better in 2 to 4 weeks, though some feel tired for several more weeks, and occasionally symptoms last 6 months or longer. The liver or spleen may stay enlarged even after the fatigue ends.

How it spreads

The viruses that cause mono spread mostly through body fluids, especially saliva — and also through blood and semen during sex, blood transfusions and organ transplants. See how EBV spreads.

Besides EBV, mono can be caused by cytomegalovirus (CMV), toxoplasmosis, HIV, rubella, hepatitis A, B or C and adenovirus.

Protect yourself by not kissing someone with mono, or sharing their drinks, food or personal items such as toothbrushes.

Diagnosis

Providers usually diagnose mono from symptoms; lab tests are generally needed only for atypical cases. With EBV mono, blood tests may show:

• more lymphocytes (a type of white blood cell) than normal, some unusual-looking;
• fewer neutrophils or platelets than normal;
• abnormal liver function.

(For labs: EBV testing.)

Treatment and recovery

Ease symptoms by:

• drinking fluids;
• resting;
• taking over-the-counter pain and fever medicine.

Don't take penicillin antibiotics such as ampicillin or amoxicillin if you have mono. Depending on how severe it is, a provider may treat specific organs affected.

Avoid contact sports until you've fully recovered: mono can enlarge your spleen, and strenuous contact can rupture it.

More: MedlinePlus on mono.

Sources

Based on "About Infectious Mononucleosis (Mono)," Centers for Disease Control and Prevention; a work of the United States government in the public domain.