Can a person have mononucleosis more than once? Will monospot or heterophile antibody tests stay positive for life? — David Cooper, PA-C, Fayetteville, Pa.

Mononucleosis is caused by Epstein-Barr virus (EBV), a human herpesvirus (HHV4). Like all HHV infections, mononucleosis consists of a primary phase, latency and reactivation. Most infections with EBV are asymptomatic (95% of young adults will test positive for exposure to EBV).

The monospot test is a nonspecific test for heterophile antibodies and is used for initial screening in suspect individuals. If an individual is negative for monospot, more specific testing for EBV is required. False-positive monospot results occur in cytomegalovirus and varicella-zoster virus infections, leukemia, lymphoma, hepatitis, influenza, rubella and autoimmune disorders (namely systemic lupus erythematosus).

Up to 85% of patients with infectious mononucleosis will have positive monospot results, although they may be delayed for up to two weeks. Patients are typically well within one to two months, but the virus remains inactive in a few cells for life. Periodically, the virus can reactivate, usually without symptoms. The likelihood of infection is increased by the presence of immunoglobulin M antibodies or a fourfold increase in immunoglobulin G over four weeks. — Claire Babcock O’Connell, MPH, PA-C (182-2)