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 PDF Version
A Review of Entomological
Sampling Methods and Indicators for Dengue Vectors
Dana A. Focks
Infectious Disease Analysis, Gainsville, Florida,
USA
TDR / IDE / Den / 03.1
This review was developed in response to a recommendation of the WHO Informal
Consultation on Strengthening Implementation of the Global Strategy for
Dengue Fever/ Dengue Haemorrhagic Fever Prevention
and Control, held in October of 1999, urging “the refinement of existing
entomological indicators and/or the development of new indicators that better
reflect transmission potential.” The Consultation “recommended that such
indicators should provide clear, meaningful information for communities as
well as for programme managers and policy-makers.” Whereas the traditional Stegomyia indices (the House, Container, and Breteau indices, and various related derivations) are of
some operational value for measuring the entomological impact of larval
control interventions against the mosquito vectors of dengue virus, they are
not proxies for adult vector abundance. Neither are they useful for assessing
transmission risk because they do not take into consideration the
epidemiologically important variables, including adult vector and human
abundance, temperature, and sero-conversion rates
in the human population.
The document reviews and critiques current methods, focusing especially
on sampling methods that provide information on (1) the risk of transmission
as a function of vector abundance, and (2) the relative or absolute
importance of the various types of containers in the environment. This second
aspect is essential when considering a suppression strategy designed to
minimize costs or to improve sustainability by targeting only a subset of the
breeding containers for control or elimination – specifically those container
types that are responsible for the majority of adult production. In reviewing
current and generally-used sampling methods, each is discussed with respect
to transmission risk assessment and evaluated in terms of being useful for
either “research or special studies” or as a practical operational tool
providing useful information for planning and management of vector control programmes.
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