A student at the All India Institute of Medical Sciences (AIIMS) died of dengue today taking the toll from the deadly disease in the national capital to 11.Kamal Raj Kiran, a seventh-semester student at AIIMS, was being treated at the ICU of the hospital since Thursday.Kiran, who hailed from Hyderabad, became the eleventh victim of the disease, which has affected over 300 Delhiites so far this year.As many as 15 cases have been reported in the past five days from AIIMS.While six are resident doctors and medical students, five are AIIMS staffers, and the remaining three are relatives of hospital staff.In view of the spurt in dengue cases, AIIMS authorities have begun a drive to check all water coolers in the hospital premises. Stagnant water in the coolers are the chief breeding grounds of the Aedes mosquito, the dengue vector.