What is it about?
**Simple Explanation (Under 250 Words)** Dengue is a common illness in cities like Surat and spreads through mosquito bites. We studied dengue cases and mosquito levels from 2016 to 2020 to understand where the risk is highest and who is most affected. We found that reported dengue cases decreased over time, especially in 2020. However, mosquitoes were still present in large numbers in many areas. This means the risk of dengue continues even when fewer cases are reported. The drop in 2020 may also be linked to COVID-19, when fewer people visited hospitals or cases were not reported. Most dengue cases occurred after the monsoon season. Teenagers and young adults, especially men, were the most affected. Some areas of the city, particularly the South and South-East zones, repeatedly showed higher numbers of cases, making them high-risk areas. We also observed that most cases were reported by government hospitals, while private hospitals reported fewer cases. This suggests that many dengue cases may not be officially recorded. Overall, our study shows that counting mosquitoes alone is not enough to predict dengue risk. To better control dengue, efforts should focus on high-risk areas, improve reporting from all hospitals, and increase public awareness—especially among young people—about preventing mosquito bites.
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Why is it important?
**Why is this important? (Precise, simple technical explanation)** This is important because it shows that dengue risk in Surat remains high despite a decline in reported cases. High mosquito levels and repeated post-monsoon increases indicate ongoing transmission risk. Relying only on reported cases can be misleading, especially when many cases from private hospitals are not reported. This can result in underestimating the true burden and weakening control efforts. The findings also identify high-risk areas (South and South-East zones) and vulnerable groups (adolescents and young adults), allowing for more focused and effective interventions. In addition, the weak link between mosquito indices and dengue cases shows that a single indicator is not enough for accurate surveillance or prediction. Overall, this evidence supports the need for better reporting, targeted vector control, and improved surveillance to prevent future dengue outbreaks.
Perspectives
This study demonstrates that in urban Surat, declining reported dengue cases do not necessarily reflect reduced transmission risk. Despite lower case numbers, persistently high larval indices and clear post-monsoon peaks indicate ongoing and spatially clustered transmission, particularly in the South and South-East zones. A key finding is the mismatch between entomological indicators and actual disease trends, showing that larval indices alone are insufficient for reliable outbreak prediction in dense urban environments. The observed moderate model performance (AUC = 0.687) further confirms that dengue risk is driven by multiple interacting factors beyond vector density alone. The study also highlights important surveillance gaps, including probable underreporting from private healthcare facilities and a higher disease burden among adolescents and young adults. Overall, these findings emphasize that effective dengue control requires integrated surveillance, zone-specific vector control, and improved reporting systems rather than reliance on single-indicator monitoring.
JIGNA GOHIL
Read the Original
This page is a summary of: Spatiotemporal patterns and entomological predictors of dengue transmission in Urban Surat, India (2016–2020): A surveillance-based risk modelling study, PLOS Global Public Health, March 2026, PLOS,
DOI: 10.1371/journal.pgph.0006086.
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