Larval Indices of Aedes Mosquitoes in Selected Military Units of the Kathmandu Valley

Abstract

Introduction
Aedes aegypti usually breeds in water-holding containers around human homes. Dengue is an increasing public health concern in Nepal; however, vector breeding in military settings remains unexplored. This study aimed to assess vector breeding sites and calculate the Container Index and Maya Index in military units of Kathmandu Valley, Nepal.

Methods
A cross-sectional entomological study was conducted in ten military units of Kathmandu Valley, Nepal, from August to October 2022. Every water-holding containers indoors and outdoors, were classified by controllability. Larvae collected in the field were reared to adulthood and Container Index (CI) and Maya Index (MI) were calculated for each unit. Data were analyzed using SPSS v25.

Results
Total 696 containers were examined, of which 436 held water and out of these 106 (24.31%) were positive for Aedes larvae. Aedes larval positivity ranged from 3.70% to 49.52%. Tires, 49/75 (65.33%), and half-cut mineral water bottles, 16/16 (100%), were the most productive containers, followed by broken flower pots, 6/6 (100%), and water tanks, 11/65 (16.92%). Container Index ranged from 3.7% to 60%, with four Units above 40%.  On Maya Index 4/10 units were low risk and 6/10 were medium risk; two units reached the highest risk category on both Breeding Risk Index and Hygiene Risk Index.

Conclusions
Aedes larvae were present in all military units, mainly in discarded tires, indicating a need for targeted container management and hygiene interventions despite the absence of high-risk MI units.