Dengue Cases in Madurai Show Cyclic Epidemic Pattern

A comprehensive study conducted by the health department in Madurai district has established a cyclic pattern in the occurrence of dengue cases, revealing that the disease tends to take an epidemic form once every five to six years. This study, which examined fever surveillance and dengue testing data from 2012 to 2023, offers valuable insights into the trends of dengue outbreaks in both rural and urban areas of Madurai.

Published in the Tamil Nadu Journal of Public Health and Medical Research, the study highlights the following key findings:

• Cyclic Epidemic Pattern: The data indicates high dengue incidence in 2012, 2017, and 2023, with Attack Rates (AR) of 77.14, 125.69, and 63 per 1 lakh population, respectively. In contrast, the AR was consistently below 28 in other years.
• Uniform Trends: Both rural and urban areas showed similar trends in dengue case incidence, with sporadic occurrences throughout the district.
• Seasonal Variation: The analysis of seasonal data from 2013 to 2023 revealed a rise in dengue cases from June to December. This period coincides with the northeast monsoon, which brings more rainfall to Madurai compared to the southwest monsoon.
• Breeding Grounds: The Aedes aegypti mosquito, the primary vector for dengue, breeds in clean water containers, such as drums, barrels, and air coolers. Open water sources significantly contribute to the spread of dengue.

Dr. P Kumaragurubaran, deputy director of health services in Madurai and one of the study's authors, emphasized the importance of chlorination and eliminating mosquito breeding sites to prevent dengue. With the northeast monsoon approaching, health officials are maintaining vigilance, although the current daily average of reported dengue cases remains in single digits.

The study's findings are expected to aid in forecasting potential dengue outbreaks and developing effective control strategies, ensuring better preparedness and response in the future.