Dengue Cases More Than Double in Chennai: Why the Risk Rises After the Monsoon

Dengue cases have been rising rapidly in Chennai, the capital of Tamil Nadu, with a sharp increase reported in September. As of September 23, the number of dengue cases in Tamil Nadu stood at 17,939. This figure includes nine deaths reported during the same period.

The state has been witnessing a continued increase in dengue cases, with 25,585 cases reported in 2025 and around 35,000 cases in 2024. The current trend is linked to seasonal fluctuations in dengue cases, which are typically higher during the monsoon season because the conditions are favourable for the breeding of Aedes mosquitoes.

The Tamil Nadu government has intensified mosquito-control and disease-surveillance measures. It has also deployed more than 25,000 workers across the state to strengthen preventive measures and monitor fever cases in vulnerable districts.

Why are dengue cases rising?

Tamil Nadu, located in the southern part of India, receives significant rainfall, which can leave standing water in many places. This stagnant water can become a breeding ground for mosquitoes.

The warm and humid conditions in the state can also support mosquito breeding. Water collected in tyres, containers, drains and open areas can become breeding sites for mosquitoes.

Even after the monsoon season ends and rainfall decreases, dengue transmission can continue. Stagnant water does not always disappear immediately after the rain stops, allowing mosquitoes to continue breeding. People can also remain exposed to mosquitoes in their homes and neighbourhoods.

How does dengue spread?

Dengue spreads through the bite of infected Aedes mosquitoes. These mosquitoes can bite during the daytime.

Some of the most common symptoms of dengue include high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea, vomiting, skin rashes and extreme tiredness.

However, these symptoms alone cannot confirm a dengue infection. A medical evaluation and appropriate testing may be needed for diagnosis.

There are also warning signs that can indicate a more serious illness, including:

Severe stomach pain

Repeated vomiting

Bleeding from the nose or gums

Blood in vomit or stool

Extreme weakness

Difficulty breathing

Unusual sleepiness or restlessness

If any of these warning signs are noticed, medical help should be sought immediately.

Children, older adults, pregnant women and people with existing health conditions may require additional attention if they develop symptoms and should seek medical advice when necessary.

How can people protect themselves from dengue?

There are several simple steps people can take to reduce the risk of dengue infection:

Do not allow water to collect around the house.

Empty water containers regularly.

Keep water tanks covered.

Clean drains and other areas where water can collect.

Use mosquito repellent.

Wear clothing that covers the arms and legs.

Use mosquito screens or nets where appropriate.

What are health authorities doing?

Health authorities are inspecting areas, removing stagnant water, applying larvicides and using biological control measures to reduce mosquito breeding.

These efforts require coordination between municipal workers, primary health centres and local communities. The aim is to reduce mosquito breeding sites while strengthening long-term prevention and disease surveillance.

Rising pressure on hospitals

Rising dengue cases are also increasing patient inflow, putting pressure on hospital departments and healthcare workers across the state.

Tamil Nadu has recorded between 17,000 and 19,000 dengue cases this year, according to the figures cited above. Districts such as Coimbatore, Salem, Tiruvallur and Chengalpattu have also reported high numbers of fever cases.

Both private and government hospitals have reported crowded outpatient departments and fever wards, with some patients waiting for up to 12 hours for admission.

The rise in cases also creates a need for stronger disease-control measures. Regular collection of fever-case reports from private hospitals adds to the administrative responsibilities of health workers involved in surveillance, monitoring hotspots and coordinating preventive measures.

Dengue prevention is not only about avoiding mosquito bites. It also requires vigilance about stagnant water and awareness of warning signs that need immediate medical attention. People should seek medical advice when symptoms become severe rather than delaying care or trying to manage serious symptoms on their own.