Dengue pandemic in Sri Lanka

Dengue pandemic in Sri Lanka
Map of confirmed cases
Disease	Dengue fever
Virus strain	Dengue virus
Location	Sri Lanka
Date	1989 (1989) – present (34 years)
Confirmed cases	31,162 (2020)
Deaths	35 (2020)
Fatality rate	0.11% (2020)
Government website
www.epid.gov.lk

The dengue pandemic in Sri Lanka is part of the tropical disease dengue fever pandemic. Dengue fever is caused by Dengue virus, first recorded in the 1960s. It is not a native disease in this island. Present-day dengue has become a major public health problem. Aedes aegypti and Aedes albopictus are both mosquito species native to Sri Lanka. However, the disease did not emerge until the early 1960s. Dengue was first serologically confirmed in the country in 1962. A Chikungunya outbreak followed in 1965. In the early 1970s two type of dengue dominated in Sri Lanka: DENV-1 type1 and DENV-2 type 2. A total of 51 cases and 15 deaths were reported in 1965–1968. From 1989 onward, dengue fever has become endemic in Sri Lanka.

Status of outbreak

Dengue cases by region

Region		Cases
Provinces	Districts	2021	2020
Western	Colombo	1,027	4,257
	Gampaha	525	2,666
	Kalutara	346	1,810
	Total	1,898	8,733
Central	Kandy	252	3,443
	Matale	34	595
	Nuwara Eliya	23	168
	Total	309	4,206
Southern	Galle	90	1,671
	Matara	147	545
	Hambantota	126	368
	Total	363	2,584
North Western	Kurunegala	382	969
	Puttalam	165	500
	Total	547	1,469
Sabaragamuwa	Kegalle	173	865
	Ratnapura	211	2,014
	Total	384	2,879
Eastern	Trincomalee	80	2,296
	Batticaloa	2,818	3,717
	Ampara	134	1,298
	Total	3,032	5,015
North Central	Anuradhapura	55	433
	Polonnaruwa	23	251
	Total	78	684
Northern	Jaffna	94	2,157
	Kilinochchi	20	135
	Mannar	19	137
	Mullaitivu	3	90
	Vavuniya	24	252
	Total	160	2,771
Uva	Badulla	31	525
	Monaragala	39	0
	Total	70	525

History

Dengue outbreaks started to emerge in Sri Lanka in the 1960s, with the Ministry of Health first serologically confirming the disease in Sri Lanka in 1962. However, unofficial British Ceylon clinical studies recorded dengue-like cases in Sri Lanka in the early 20th century. The first outbreak was confirmed in 1965 and was associated with DEN types 1 and 2, with 51 cases of 15 deaths between 1965 and 1968. Since 1989 dengue has become a major problem in Sri Lanka. From 1970 to 1990, multiple outbreaks with endemic were reported in Western Province urban areas. In 1990 dengue cases rose 1,350 of 54 deaths. In the early 1990s, annual dengue cases were reported as being up to 1,000. In 2002 the largest outbreak in recent years was recorded, with 8,931 cases and 64 deaths. The following year, 2003, was one of relatively low endemicity, with only 4,749 suspected cases and 32 deaths reported. In 2004 there were 15,463 suspected cases and 88 deaths reported to the Epidemiological Unit of the Ministry of Health. During the year 2005, 5,211 cases of suspected cases of DF/DHF and 26 deaths were reported to the Epidemiological Unit.

Most dengue cases reported dominated in Western Province. Outbreaks from 2005 to 2008 were attributed to a new mutation DEN type 3. Almost all the districts in Sri Lanka have reported cases and posed a threat to the health of the people. Colombo, Gampaha, Kalutara and Kandy districts have recorded highest number of cases.

Background

Sri Lanka is a tropical and warm country. Mean temperatures range from 28 °C. The rainfall pattern is influenced by monsoon winds from the Indian Ocean and Bay of Bengal. Average rain at 800 to 1,200 mm per year. Average humidity from 75% during different seasons and in the different regions of the country. Tropical region humidity ranges from 75% to 90%. Sri Lanka is a tropical country with two monsoons: the northeast monsoon (December to March) and the southwest monsoon (May to September). Two annual peaks have been identified in the occurrence of dengue cases in the country in association with the monsoon rain.

See also

• Dengue fever
• Mosquito-borne disease
• Tropical disease