Background: Research has shown that the classical Stegomyia indices (or ‘‘larval indices’’) of the dengue
vector Aedes aegypti reflect the absence or presence of the vector but do not provide accurate measures
of adult mosquito density. In contrast, pupal indices as collected in pupal productivity surveys are a much
better proxy indicator for adult vector abundance. However, it is unknown when it is most optimal to
conduct pupal productivity surveys, in the wet or in the dry season or in both, to inform control services
about the most productive water container types and if this pattern varies among different ecological
settings.
Methods: A multi-country study in randomly selected twelve to twenty urban and peri-urban neighborhoods
(‘‘clusters’’) of six Asian countries, in which all water holding containers were examined for larvae and
pupae of Aedes aegypti during the dry season and the wet season and their productivity was characterized
by water container types. In addition, meteorological data and information on reported dengue cases were
collected.
Findings: The study reconfirmed the association between rainfall and dengue cases (‘‘dengue season’’)
and underlined the importance of determining through pupal productivity surveys the ‘‘most productive
containers types’’, responsible for the majority (.70%) of adult dengue vectors. The variety of productive
container types was greater during the wet than during the dry season, but included practically all
container types productive in the dry season. Container types producing pupae were usually different from
those infested by larvae indicating that containers with larval infestations do not necessarily foster pupal
development and thus the production of adult Aedes mosquitoes.
Conclusion: Pupal productivity surveys conducted during the wet season will identify almost all of the most
productive container types for both the dry and wet seasons and will therefore facilitate cost-effective
targeted interventions