Since mono is spread from person to person, avoiding close personal contact with infected individuals and practicing excellent hygienic practices can help prevent transmission of the virus. This includes avoiding sharing contaminated utensils like toothbrushes and drinking glasses. However, since periodic reactivations of the virus infection seem to occur in healthy individuals and because many infected people who may transmit the virus to others will not have symptoms of the condition, prevention is extremely difficult. In fact, these individuals without symptoms are believed to be the primary source of transmission of the virus. The fact that up to 95% of adults have antibodies to EBV suggests that prevention of the infection is difficult if not impossible. It is not known why some people develop the symptoms of mono while others appear to acquire the EBV infection without having symptoms. It is possible that many infections occur and produce mild symptoms and are not recognized as mono, while other infections may not produce symptoms at all.