All of the following are true about dengue fever except:

Ans: b (Thrombocytosis) Ref: Harrison's, 16th ed, p. 1164; 17th ed, p. 1230In dengue fever thrombocytosis is not seen, thrombocytopenia is seen.Dengue feverDengue is also known as breakbone feverIncubation period: 2-7 daysIt is transmitted by Aedes aegyptiiSecond infection with a serotype of dengue virus different from that involved in the primary infection leads to dengue hemorrhagic fever.Diagnosis by IgM - ELISACriteria for clinical diagnosis of DHF:1) High grade continuous fever lasting 2- 7 days2) Haemorrhagic manifestations including atleast a positive tourniquet test.3) HepatomegalyLab diagnosis1) Thrombocytopenia (100.000/mm3 or less)2) Haemoconcentration: Haematocrit increased by 20%The first two clinical criteria plus thrombocytopenia and haemoconcentration or a rising haematocrit are sufficient to establish diagnosis of DHF.Dengue shock syndrome (DSS)1) All the above criteria plusShock manifested by rapid and weak pulse and narrowing of pulse pressure or hypotension with cold clammy skinManagement:Symptomatic and supportiveImportant incubation periodsDengue: 2-7 daysDiphtheria: 2-6 daysPertussis: 7-14 daysTetanus: 6-10 daysMeasles: 10 daysMumps: 2-3 weeks (18 days)Rubella: 2-3 weeks (18 days)Chicken pox: 14-16 daysJapanese encephalitis: 5-15 daysKyasanur forest disease: 3-8 days