This chapter provides detail description of infections. Chapter has 18 well illustrated diagrams and pictures. Typhoid in children, tuberculosis in children, viral hepatitis in children, hepatitis A, hepatitis B, dosage schedule for immunization, hepatitis C, hepatitis D, hepatitis E, dengue fever, virus transmission into the human host from the vector and the extent of viremia are described in detail. 8 boxes are included to depict interpretation of Widal test, tuberculin test and indications of use of steroids. 67 references are included at the end of the chapter to facilitate further reading.