Disease surveillance is a main strategy in disease prevention and control. The Epidemiology Unit of the Ministry of Health is the leading institution which carries out epidemiological surveillance and coordinates dengue related disease activities with the National Dengue Control Unit.

Surveillance and Notification goes together. All Medical Practitioners (in Government and private medical institutions) who attend to patients with a tentative diagnosis of the dengue illness should notify the disease to the proper authority. The disease should be notified immediately at the time of first suspicion without waiting for laboratory Confirmation.

Surveillance Case definition:

In Children : An Acute Febrile illness of 2-7 days duration with 2 or more of the following: headache, retro-orbital pain, myalgia, arthralgia, flushed extremities tender hepatomegaly, rash, leucopenia and haemorrhagic manifestation.

In adults : An acute febrile illness of 2-7 days duration with 2 or more of following; headache, retro-orbital pain, myalgia with one of the following - leucopenia, thrombocytopenia or haemorrhagic manifestations.

There are three types of surveillance when dengue is concern;

• Passive Surveillance: The notification card H-544 should be filled with patient’s residential address and sent to Medical Officer of Health (MOH) where the patient is residing.
• Sentinel Site Surveillance: Details of patients who are suspected of having dengue illness will be entered to the web-based system called “DenSys” by the hospital Infection Control Nursing Officer (ICNO) or by an assigned officer. This will reduce the undue delay of H-544
• Special Surveillance: This surveillance is used to identify the dynamics of Dengue Fever and dengue Haemorrhagic Fever.

Main tasks of NDCU is to monitor the disease trends in all MOH areas and advise on relevant control activities. The NDCU in cooperation with the Epidemiology unit, Regional Epidemiologists and Medical Officers of Health (MOOH) is carrying out dengue fever surveillance activities in the country.