Table 1. Operational definitions used in this study ^{3, 13, 18}.

Variable		Definition
Ecological regions	Delta and low land	Heavy rainfall more than 2500 mm. Includes Ayeyarwady, Yangon, and Bago regions; Mon and Kayin states
	Hills	Moderate to heavy rainfall. Includes Kachin, Kayah, Chin, and Shan states
	Coastal	Heavy rainfall more than 2500 mm. Includes Rakhine state and Taninthayi regions
	Plains	Uneven topography and rainfall less than 1000 mm. Includes Magway, Mandalay, Sagaing, and Nay Pyi Taw regions
Dengue Grading	Dengue Fever	Fever with two of the following•     Headache. •     Retro-orbital pain. •     Myalgia. •     Arthralgia/bone pain. •     Rash. •     Haemorrhagic manifestations Hess* test + > 70% •     No evidence of plasma leakage
	DHF Grade I	Fever and haemorrhagic manifestation Hess test + > 90% Evidence of plasma leakage
	DHF Grade II	As in Grade I plus spontaneous bleeding.
	DHF Grade III	As in Grade I or II plus circulatory failure (weak pulse, narrow pulse pressure (≤20 mmHg), hypotension, restlessness).
	DSS (Hypotensive shock)	As in Grade III plus profound shock with undetectable blood pressure and pulse
	Expanded Dengue Syndrome	Complications of severe profound shock or associated with underlying host conditions/ diseases or coinfections. Central nervous system manifestations including convulsions, spasticity, changes in consciousness and transient paresis have been observed.

DHF, dengue hemorrhagic fever; DSS, dengue shock syndrome.