• 500 technical grade litres await Customs clearance 
• PHIs to ascertain efficacy in fogging operations  
• Authorities testing different chemicals for varied needs 
• Dengue cases top 82,000 with 175 high-risk zones identified

India has donated a consignment of the insecticide malathion to Sri Lanka to bolster dengue control efforts after health authorities found that the chemical currently used for mosquito fogging is proving ineffective in some areas, the National Dengue Control Unit (NDCU) said. 

Responding to questions from The Daily Morning yesterday (27), Acting Director of the NDCU, Dr Kapila Kannangara said the request for malathion had been made by the Health Ministry after Public Health Inspectors (PHIs) reported that the chemical currently being used for fogging is not proving sufficiently effective against mosquitoes in some areas. 

“Earlier, they used malathion, but we don’t have malathion at the moment,” Dr Kannangara said. He said that the purpose of obtaining malathion is to test its effectiveness in dengue mosquito control activities, adding that around 500 litres of the chemical is expected to be received within a day or two. 

“It is a donation and we are trying it out to see whether it is effective. They will be sending 500 litres of malathion,” he said. Dr Kannangara explained that malathion had previously been used in mosquito control programmes – especially in Sri Lanka’s battle against malaria, particularly for outdoor spraying activities. However, he said that the current plan is to use different chemicals for different requirements, depending on whether spraying is carried out outdoors or inside premises.

Meanwhile, highly placed sources told The Daily Morning that the Ministry had made a written request to the Indian Government seeking technical malathion for dengue control activities. Sources said that although Sri Lanka had requested assistance in obtaining the chemical, the Indian Government had agreed to provide the required quantity free of charge. 

The consignment had already arrived in Sri Lanka and reached Customs on 26 July, sources said, adding that its release would take some time due to Customs clearance procedures. According to sources, the quantity provided by the Indian Government would be sufficient to support dengue control activities throughout the current dengue season.

The number of dengue cases reported in Sri Lanka so far this year (2026) has continued to rise. A total of 82,011 dengue cases have been reported nationwide to date, while 61 deaths have been attributed to the disease. The Gampaha District has recorded the highest number of cases, with 17,395 infections, followed by the Colombo District with 16,294 cases. 

The Western Province continues to report the highest number of dengue infections among all Provinces, with 43,388 cases recorded so far this year. The Southern Province has reported the second-highest number of cases, with 12,419 infections. A total of 175 high-risk dengue zones have been identified across the island as the disease continues to spread.