This image depicts staff members Nik Khairol Reza Mohd Yazin, and Mohd Hafiz Abdullah, in the process of looking for Aedes spp. larvae in these roof gutters, while in the Kota Bharu district of Kelantan, Malaysia, in February, 2014. The investigation was part of an effort to reduce the number of Dengue fever cases in the country.
Dengue virus is a leading cause of illness and death in the tropics and subtropics. As many as 400 million people are infected yearly. There are not yet any vaccines to prevent infection with Dengue virus and the most effective protective measures are those that avoid mosquito bites. When infected, early recognition and prompt supportive treatment can substantially lower the risk of medical complications and death.
For more on the subject of Dengue fever, see the link below.