The Centre has asked states to tighten dengue surveillance and step up mosquito control as the monsoon creates favourable conditions for mosquito breeding, with health authorities also warning that developing El Niño conditions could increase the risk of vector-borne disease transmission, according to two officials and a health ministry communication seen by Mint.
Data from the National Centre for Vector Borne Diseases Control (NCVBDC) shows 13,336 dengue cases and 12 deaths have been reported so far this year. Against that backdrop, the ministry has instructed states to expand laboratory testing using ELISA-based NS1 and IgM kits, submit daily reports through its online portal, and intensify larval source management.
The warning follows several years of heavy dengue transmission. India reported 121,824 dengue cases and 131 deaths in 2025, after 233,519 cases and 297 deaths in 2024, and 289,235 cases and 485 deaths in 2023. The country has also recently approved Takeda's dengue vaccine, which is expected to reach the market next year.
“Dengue fever remains a major public health concern, with transmission patterns increasingly influenced by climate variability. Every year during monsoon and post monsoon period an increased number of cases are reported due to the conducive situation for proliferation of Aedes mosquito,” the health ministry said in its communication to states and Union territories.
Tamil Nadu has reported the highest number of cases this year, with 4,973 infections and two deaths. It is followed by Maharashtra with 1,525 cases, Kerala with 1,403 cases and 10 deaths, Karnataka with 978 cases, and Andhra Pradesh and West Bengal with 770 cases each.
Sharper surveillance
The ministry has asked states to review their action plans to prevent a spike in infections during the rainy season by strengthening surveillance, testing capacity and digital reporting.
“Enhance epidemiological surveillance for early detection of dengue cases. Ensure functioning of all identified laboratories for diagnosis and surveillance. For timely detection with both ELISA based NS1 (first 5 days) and IgM test kits should be made available. The data entered on IHIP-VBD portal to be analysed for any early warning signal to detect any surge of cases. All the reporting units to be instructed for timely entering their data. States/UTs have to be completely onboard on IHIP-VBD for paperless digital reporting,” the ministry said.
The communication also directs hospitals to prepare contingency plans and equip rapid response teams with vehicles and supplies for outbreak areas.
States have been asked to procure ELISA-based NS1 kits in time to ensure uninterrupted availability across laboratories and hospitals. “Ensure all equipment is functional and maintain optimum stocks of insecticides at all levels.”
Primary care centres, including Ayushman Arogya Mandir facilities, have also been instructed to provide blood testing and clinical evaluation for patients with suspected dengue. The ministry said measures to curb mosquito breeding would also help reduce the spread of chikungunya and Zika virus.
Queries sent to the health ministry's spokesperson on Saturday remained unanswered till press time.
Dr. Souradeep Chowdhury, associate consultant of internal medicine at Medanta, Noida, said the monsoon creates ideal breeding conditions for the Aedes mosquito.
“The short periods of water stagnation in coolers, pots, buckets, and construction sites create ideal breeding grounds for daytime-biting Aedes mosquitoes. The early diagnosis via NS1 antigen testing in initial stages and IgM antibody testing later allows clinicians to distinguish dengue from other seasonal viral illnesses and initiate proper management.”
He said dengue is not defined solely by low platelet counts and that most patients recover with hydration, rest and supportive care.
“Critical monitoring is required between the third and seventh day of illness when fever subsides, as severe dengue can cause plasma leakage, bleeding, or organ involvement. Warning signs requiring urgent medical care include severe abdominal pain, persistent vomiting, mucosal bleeding, drowsiness, breathing difficulty, or reduced urine output," Chowdhury added.
He advised patients to avoid self-medication with anti-inflammatory drugs because of the risk of bleeding and to seek treatment under medical supervision.