Can dengue mosquitoes breed in clean or dirty water?

Dengue Mosquitoes Breed in Clean Water, Not Dirty Water

Dengue mosquitoes (Aedes aegypti and Aedes albopictus) primarily breed in clean, stagnant water found in man-made containers rather than dirty water sources. 1, 2

Breeding Habitat Preferences

Water Quality Requirements

• Aedes mosquitoes prefer clean, stagnant water with specific characteristics:
  • Temperature range: 25.3-39.8°C 3
  • pH preferences:
    • Aedes aegypti: Alkaline water (pH 7.5-8.5)
    • Aedes albopictus: Slightly acidic to neutral water (pH 6.5-7.5) 3
  • Both species prefer water with low turbidity and low total dissolved solids (TDS) 3
  • Optimal TDS levels: 250-350 ppm 3
  • Mean dissolved oxygen level: 6.9 ± 0.7 mg/L 3

Common Breeding Sites

• Man-made containers are the primary breeding sites:
  • Water storage containers (jars, tanks, drums) 2, 4
  • Discarded receptacles (tires, pots) 2
  • Flower vases 1
  • Unused toilets and bathtubs
  • Rain gutters and plant saucers
  • Any container that can hold stagnant water for several days

Risk Factors for Dengue Transmission

Environmental Factors

• Stagnant water around villages significantly increases dengue risk (AOR = 3.61) 5
• Unplanned urbanization with poor drainage systems and inadequate garbage collection 2
• Climate change driving water storage behaviors:
  • Water shortages lead households to store more water in containers 2
  • Warmer climates increase water storage practices 2

Human Behavioral Factors

• Water storage practices:
  • Cultural practice in many endemic regions 4
  • Often driven by concerns about water scarcity and high water rates 4
  • Associated with specific demographic groups (e.g., housewives have 2.6 times higher odds of storing water) 4
• Non-use of bed nets increases dengue risk (AOR = 2.74) 5
• Close contact with dengue patients increases risk (AOR = 5.36) 5

Prevention Strategies

Vector Control Approaches

• Environmental management:

  • Drain or cover water containers 5
  • Use long-lasting insecticidal covers for water storage containers 6
  • Regular cleaning and emptying of water containers
  • Proper waste disposal to eliminate potential breeding sites

• Biological control:

  • Introduction of larvivorous fish (guppies) in water containers 2
  • After implementation in Cambodia and Laos, Aedes larvae infestation reduced from 40% to 3% 2

Integrated Vector Management

• Combining multiple approaches:
  • Environmental management
  • Biological control
  • Chemical control (when necessary)
  • Community education and participation 2
  • Intersectoral collaboration between health, environment, and urban planning sectors 2

Community-Based Interventions

• Education about dengue transmission and breeding sites
• Community mobilization for regular container inspection and cleaning
• Promotion of proper water storage practices:
  • Using sealed containers
  • Regular emptying and cleaning of containers
  • Using larvicides in water storage containers when appropriate

Practical Implications

• In regions with unreliable water supply, focus on covering water storage containers rather than eliminating them 4
• Target specific water containers based on local usage patterns:
  • In some regions, cement basins (albercas) are used for domestic cleaning
  • Plastic containers are often used for cooking water 4
• Climate vulnerability increases risk of vector persistence in tropical regions compared to subtropical/temperate areas 7

Understanding that dengue mosquitoes breed in clean water is essential for effective prevention strategies. This knowledge allows for targeted interventions focusing on proper water storage practices and elimination of clean water breeding sites around homes and communities.