Doctors have warned Hyderabadis of the spread of viral fevers, especially dengue. Increasing cases of dengue fevers are being reported in Fever Hospital and other hospitals in the city. Dengue is caused by the Aegis Egypt, female mosquito, also called Tiger mosquito that is active during the daytime. There is no cure for dengue and treatment is given only for the fever, doctors said. Normally the disease is controlled within three days. But fever continues for upto a week, blood tests should be done, they added.