The analysis revealed that dengue cases begin rising in July, peak from August to October, and decline by December.
Published Aug 26, 2025 | 7:00 AM ⚊ Updated Aug 26, 2025 | 7:00 AM
Representative image of a mosquito
Nearly one out of every three fever cases in South India during the August-October period can be attributed to dengue, according to laboratory data from PharmEasy’s diagnostic network.
Three southern states experienced a significant dengue outbreak, with Karnataka recording 32,886 cases in 2024, Tamil Nadu reporting 27,378 instances, and Kerala documenting 20,674 cases, along with 128 fatalities — the highest death toll among all states in 2024.
The data showed that dengue comprised 27.7 percent of all fever tests conducted during the peak season, indicating the substantial burden this mosquito-borne disease places on healthcare systems across these three southern states.
The analysis revealed that dengue cases begin rising in July, peak from August to October, and decline by December. This consistent yearly pattern aligns with monsoon conditions that create ideal breeding environments for the Aedes mosquito responsible for dengue transmission.
Weather conditions above 27°C, combined with humidity levels between 60-78 percent and steady rainfall, create perfect breeding conditions for mosquitoes in stagnant water found in pots, puddles, tanks, and tires. The complete mosquito lifecycle requires seven to 10 days in these stagnant water conditions.
Interestingly, the data noted that very heavy rainfall can sometimes reduce mosquito numbers by washing away their larvae, but moderate, steady rain provides the ideal conditions for mosquito proliferation.
PharmEasy Labs data demonstrateed that individuals aged 11-30 have the highest dengue positivity rates compared to other age groups. Over 50 percent of dengue cases occur in the 11-30 age group, with this trend reflecting increased outdoor activity and exposure.
“Children most often play outside in fields, exposing themselves to risk; likewise, individuals of the working age (18 to 60 years) who do physical work for a living, especially in outdoor settings, also get exposed, thus increasing their risk of infection,” explained Dr Nayana Shetty, MBBS, MD.
The data revealed that people are now getting tested earlier in the season, with dengue test bookings rising as early as May in 2024, compared to June in previous years.
This shift toward proactive testing has contributed to a steadily decreasing dengue positivity rate, suggesting increased public awareness is leading to more preventive testing.
The laboratory analysis revealed distinct gender-based patterns in dengue infection. Men under 50 years of age show a higher likelihood of testing positive for dengue compared to women in the same age group. The data indicated that more men are infected with dengue than women overall.
However, women over 50 face a different scenario. In this demographic, females demonstrated higher positivity rates than males and showed greater disease severity.
Laboratory data indicated that women over 50 not only test positive more often but also experience more severe platelet depletion, falling into “Emergency,” “High Risk,” and “Risky” platelet count categories at significantly higher rates.
“In my practice, I notice gender differences in dengue severity. Younger men often come late due to work and ignore early signs, leading to issues like low platelets and dehydration. Postmenopausal women over 50, even when diagnosed early, tend to have sharper platelet drops and liver changes likely due to age and immune changes after menopause. These patients need closer monitoring, even if their vitals look fine initially,” noted Dr Vishesh Bharucha, MBBS, MD Medicine.
Over 40 regions across India reported dengue cases in 2024, but the concentration in southern states is particularly striking. Karnataka leads with 32,886 cases in 2024, making it the state with the highest case count nationally.
Tamil Nadu follows with 27,378 cases in 2024, while Kerala, despite having 20,674 cases in 2024, recorded the highest number of deaths at 128 fatalities.
The geographic analysis showed that while dengue is widespread across India, the most severe cases are concentrated in parts of South and West India.
Maharashtra also reported significant numbers with 19,385 cases in 2024, while Uttar Pradesh recorded 15,868 cases and Delhi documented 10,585 cases in 2024.
Southern states, including Karnataka, Tamil Nadu, and Kerala, showed high impact levels, while northeastern states reported fewer than 100 cases per state, demonstrating the regional concentration of the outbreak.
The crisis is mirrored in digital behaviour patterns. Analysis of Google search data revealed over 770,000 searches for the top 10 dengue-related keywords during peak season.
The most searched terms include “dengue symptoms,” “dengue,” “dengue mosquito,” “dengue fever,” and “dengue treatment.”
Google searches for dengue spiked sharply during the August-October period, showing a strong correlation between real cases and public concern.
This pattern contrasts with other fever-causing conditions such as typhoid, malaria, and influenza, which showed significantly lower and more consistent search volumes without noticeable seasonal spikes.
The data revealed concerning patterns in disease severity. While most people recover after a short illness, some experience severe complications due to plasma leakage, bleeding, and drops in blood pressure.
Serious cases can progress to dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), thrombocytopenia, or plasma leakage if not managed promptly in hospital settings.
The risk status often depends on platelet count and clinical condition, which healthcare providers determine based on individual patient assessment.
Laboratory data showed that platelet risk categories vary significantly, with emergency cases showing the highest percentages among different demographic groups.
The laboratory analysis explained why mosquito populations surge during the monsoon season. The complete Aedes mosquito lifecycle from egg to adult mosquito takes seven to 10 days in stagnant water conditions. The lifecycle progresses through distinct stages: Laying eggs, eggs developing into larvae, larvae transforming into pupae, and finally emerging as adult mosquitoes.
“In India, we observe a significant surge in dengue cases during the monsoon season (June to September), primarily due to stagnant water becoming breeding grounds for mosquitoes. People must be particularly careful in this weather to avoid contact with the female Aedes mosquito responsible for dengue, which can be identified by the distinct white lines it has on its legs and thorax,” explained Dr Shetty.
The data emphasised several key prevention approaches. Using mosquito repellents provides daily protection during the peak season when mosquitoes thrive. Eliminating breeding spots by clearing stagnant water from coolers, flower pots, and trays helps stop mosquito reproduction at the source.
Additional protective measures include wearing full-sleeved clothing to minimise exposure, keeping doors and windows closed during evening hours, and installing screens to prevent mosquitoes from entering homes.
The analysis stresses that early detection represents the most effective intervention strategy. Getting tested promptly when fever symptoms appear can prevent progression to severe complications. The data showed that dismissing early symptoms or self-medicating can lead to serious complications, especially when platelet levels or blood pressure begin dropping.
Recognition of early signs, including sudden high fever, severe fatigue, joint pain, and body aches, enables timely medical intervention. Healthcare providers emphasise that following prescribed treatment protocols significantly improves patient outcomes.
Laboratory data revealed clear shifts in dengue testing patterns over recent years. The total number of dengue tests has increased annually, with people seeking testing earlier in the season.
The 2024 data showed notable increases in dengue test bookings beginning in May, representing a shift from the traditional June timeframe of previous years.
This earlier testing pattern, combined with increased awareness, contributed to a steadily decreasing positivity rate even as absolute case numbers remain concerning in affected regions.
(Edited by Muhammed Fazil.)
