This is the most common disease showing lymphocytosis. it is caused by the Epstein-Barr Virus, which enters through the oral route and infects B lymphocytes, in turn, normal lymphocytes become infected and transform into reactive lymphocytes. Patient's Lymph nodes are usually enlarged and hepatosplenomegaly is also present, the peripheral smear usually shows a reactive lymphocytosis with 10 to 60% reactive lymphocytosis.
a. Human Monocytic Ehrlichiosis
b. Infectious Mononucleosis
c. Malaria
d. Human Granulocytic Anaplasmosis