Dengue
Dengue fever is caused by a virus called Flavivirus and it has 4 serotypes. Main vector for dengue is a mosquito 'Aedes aegypti'. Pakistan had its first dengue outbreak in 2010 and since then the cases have surged in number. Incubation period of infection followed by a mosquito bite is about 2-7 days. Patients presents with prodromal illness of malaise and headache for 2 days followed by "Saddle back fever" which is a fever with break on 4th or 5th day and then recrudescence. Nausea, vomiting, lacrimation are also common complaints. Faint macular rash may develop in 1-2 days followed by maculopapular and morbilliform rash that blanches on pressure appearing from days 3-5. In untreated patients critical phase may occur 3-7 days after onset of fever which shows signs of dengue hemorrhagic fever(DHF). This severe form show signs of thrombocytopenia, hypotension, circulatory failure like pleural effusion and ascites. Diagnosis is made via complete blood count. Confirmatory tests include 4 fold increase in IgG antibody titers and detection of dengue virus RNA by PCR. Treatment is symptomatic because not existing antivirals are effective.