EBV is a member of the herpes virus family and is transmitted through saliva. EBV causes glandular fever in up to 50% of infected people. After initial exposure to the virus, there is an incubation period of several weeks. EBV then causes a primary infection, followed by resolution and dormancy. Symptoms of glandular fever include a very high temperature, a severe sore throat, swollen glands, and extreme fatigue.