In the second edition of Dengue haemorrhagic fever: diagnosis, treatment, prevention and control, the World Health Organization' (WHO), dengue fever (DF) is defined as "an acute viral febrile disease frequently presenting with headaches, bone or joint and muscular pains, rash and leukopenia as symptoms,"while dengue haemorrhagic fever (DHF) is said to be characterized by four major clinical manifestations: high fever, haemorrhagic phenomena, often with hepatomegaly, and, in severe cases, signs of circulatory failure." Patients with DHF may develop dengue shock syndrome (DSS) which is a hypovolaemic shock due to plasma leakage.