Since the beginning of 2023, the National Dengue Control Unit (NDCU) reported 43,752 dengue cases (by June 13). These figures are around three times higher than the cases reported during the same period in the past two years; the number of dengue cases in the corresponding weeks in 2022 and 2021 being 591 and 2,302 compared to the 2730 (23rd week).
 Dr. Lahiru Kodituwakku |
The Gampaha District reported the highest number of cases last month with 2,167 with Colombo coming in a close second with 2,126. However, surges were seen elsewhere with three MOH areas in Trincomalee, namely Uppuveli, Trincomalee and Kuchchavely, indicating an upward trend of patients, NDCU data showed.
In a proactive move to tackle the ongoing spread of Covid-19 and Dengue in the country, President Ranil Wickremesinghe has established two committees, a Ministerial Committee and an Expert Committee. These committees, formed in accordance with Cabinet decision No. 23/Miscellaneous/026 issued on June 22, 2023, aim to implement urgent measures and seek expert guidance to control the outbreaks.
The Ministerial Committee, led by Prime Minister Dinesh Gunawardene, consists of eight members, including Cabinet and State Ministers. Their primary responsibility is to execute immediate measures targeted at containing the spread of both Covid and Dengue.
Expert committee
Simultaneously, President’s Secretary Saman Ekanayake, acting on President Wickremesinghe’s instructions, has appointed an expert committee comprising 11 members with extensive knowledge in the relevant field. This committee, chaired by Dr. Seetha Arambepola - State Minister of Health, aims to provide invaluable expertise and guidance in the ongoing fight against Covid-19 and Dengue.
To further support the efforts of the Ministerial Committee, an array of experts and officials in relevant fields has been appointed as members of the experts committee.
Recognising the importance of collaboration and coordination at the provincial level, nine Provincial sub-Committees have been established. Chaired by the Chief Secretary of each province, these sub-Committees comprise representatives from key sectors such as education, fisheries, health, Local Government, and the Tri Forces. The aim is to foster synergy and cooperation in the fight against Covid-19 and Dengue at the regional level.
We spoke to Dr. Lahiru Kodituwakku of the NDCU to ask about what is causing the increasing Dengue cases. He said that Sri Lanka usually experiences a surge of Dengue from June to July with the onset of the South-Eastern Monsoon. “But this year due to intermittent rain from February all through March, April and May we had this year, we have started the season with a high baseline. The other reason is most probably is a change in the Dengue serotype, but this is an assumption”.
Dr. Kodituwakku said that the Dengue serotype 3 had become predominant this year while adding that the third factor behind this surge is human behaviour. There are four dengue virus serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. Severe dengue was found to be seven times more frequent among cases of DENV-2 than among those of the other serotypes, one Brazilian study identified.
Control program
We asked Dr. Kodituwakku what is being done to curb the outbreak so far. “We have routine prevention and control program. He said that there also several surveillance programs, which includes a system which updates whenever a new Dengue patient is reported from a MOH area. “There is also a surveillance program called ‘Midnight Surveillance’ which includes 73 large hospitals in Sri Lanka, that gives a count of how many Dengue patients are admitted by midnight; this is done to check whether the capacity of the hospital is exceeding”. Based on this data, prevention and control programs target high-risk MOH areas. He said that these programs work together with local Government and community organisations to curb dengue outbreaks in their areas by the way of cleanups and public awareness campaigns in addition to islandwide programs. “This is a combine effort of Ministry of Defence, Police, Red Cross and other organisations”.
The NDCU also conducts Vector Surveillance by analysing the density of mosquito population in specific areas.
Dr. Kodituwakku said that surveillance and campaigns are just the primitive sector side. “In the puritive sector, we have trained around 400 doctors and 500 nurses on Dengue management to maintain the uniformity of treatment in the country”.
 Uncovered water storage and wells have been causing a surge in Dengue cases in Trincomalee and Batticaloa according to the NDCU |
Regarding the spike in cases in the Trincomalee District, Dr. Kodituwakku said that this is due to regional diversity in Dengue breeding sites. “We found Trincomalee had a lot of breeding sites in wells through our vector surveillance,” he said. There are usually two to three wells per house in Trincomalee, some are used and some are unused and there are also tube wells. “We have programs to cover these wells and introduce some larvae types as well”. Despite the surge, he said that the situation is under control in Trincomalee and Batticaloa.
Common bacteria
The World Mosquito Programme (WMP) introduced their Wolbachia method in 2011 to the world. Wolbachia are extremely common bacteria that occur naturally in 50 percent of insect species, including some mosquitoes, fruit flies, moths, dragonflies and butterflies.
Wolbachia lives inside insect cells and is passed from one generation to the next through an insect’s egg.
Aedes aegypti mosquitoes don’t normally carry Wolbachia, however many other mosquitoes do. In July 2017, the WMP established a research partnership with the Sri Lankan Ministry of Health and Indigenous Medical Services through the NDCU to examine new, more effective ways to protect communities from mosquito-borne diseases. We asked for an update on the Wolbachia from Dr. Kodituwakku.
“We conducted pilot programs in Modera, Mattakkuliya and in Negombo. The monitoring phase takes three to five years to observe the effectiveness of Wolbachia in mosquitos.
We are seeing a reduction of cases in Modera and Mattakkulia,” he said while adding that data collection is ongoing in the monitoring phase and plans are underway to cover the entire Colombo District. Dr. Kodituwakku said that there are no setbacks to the program but rather it takes time to gather evidence according to the routine procedure.
Despite the challenges posed by the increasing dengue cases the proactive measures taken by the Government, including the establishment of committees and the engagement of experts, demonstrate a strong commitment to tackling the outbreaks of both Covid-19 and Dengue.
Efforts such as routine prevention and control programs, surveillance initiatives, and vector surveillance have been implemented to target high-risk areas and ensure a coordinated response. Collaboration between various sectors and organisations underscores the collective determination to combat these diseases.
Pilot programs
Additionally, the promising results observed in pilot programs utilising the Wolbachia method offer hope for effective mosquito-borne disease prevention. The ongoing data collection and plans to expand the program highlight a commitment to evidence-based approaches.
With sustained efforts and continued vigilance, Sri Lanka will successfully control the outbreaks, protect its citizens, and build a healthier and more resilient future.
NDCU data sheet for 13 June