| Autor: |
Huang, Juan, Walker, Edward D., Vulule, John, Miller, James R. |
| Předmět: |
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| Zdroj: |
Malaria Journal; 2006, Vol. 5, p1-9, 9p, 2 Charts, 5 Graphs |
| Abstrakt: |
Background: Anopheles gambiae eggs are more frequently found on soil around puddle habitats of the larvae, than on the water surface itself in Western Kenya. Thus, eggs can experience temperatures more wide-ranging and lethal than those experienced by larvae or pupae confined within puddles. Methods: Small batches of eggs from house-collected An. gambiae as well as from the Kisumu laboratory strain were bathed for defined times in water whose temperature was precisely controlled. Daily temperature profiles were recorded by an infrared thermometer on seven different days in and around three types of typical An. gambiae larval habitats at Kisian. Results: For wild eggs, significant mortality occurred upon brief heating between 42 - 44°C. Few eggs hatched after 10 min at 45ଌ and none hatched above this temperature. A similar pattern occurred for eggs of the Kisumu strain, except it was shifted downwards by 1ଌ. Egg mortality was time-dependent above 40ଌ. Temperatures of water in the three types of larval habitats never exceeded 35ଌ. Wet or damp mud rarely and only briefly exceeded 40ଌ thus, water and mud would be highly conducive to egg survival and development. However, dry soils frequently reached 40 - 50ଌ for several h. Eggs stranded on dry surfaces would experience substantial mortality on hot, sunny days. Conclusion: Moist mud around puddles constitutes suitable habitat for An. gambiae eggs; however, eggs on the surface of dry soil under direct sunlight are unlikely to survive for more than a few hours. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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