(HealthDayNews) -- While it can affect people of all ages, mononucleosis is most common among teens and young adults.

It's estimated that 50 percent of students have had mono by the time they start university or college. But, in many cases, the symptoms are so mild that the condition goes undiagnosed. Fatigue, fever, sore throat, appetite loss, headache and swollen lymph glands in the neck are among the most common symptoms.

Mono is caused by the Epstein-Barr virus. There are no vaccines to prevent mono. Acetaminophen, steroids to reduce inflammation, and refraining from drinking alcohol are among the treatment approaches, the University of Toronto Health Services says.

In most cases, mono runs its course within a few weeks and causes no serious complications. Only about 1 percent to 2 percent of people with mono will continue to experience intermittent fatigue for months.