TITLE:
Climatic and Physiographic Variables to Evaluate Culex pipiens s.l. Risk and Habitat
AUTHORS:
Maria da Conceição Proença, Maria João Alves, Maria Teresa Rebelo
KEYWORDS:
Vector-Borne Diseases, Transmission Risk, Culex pipiens s.l., GIS, Global Changes
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.10 No.8,
August
4,
2022
ABSTRACT: Using a geographic information system (GIS), the relations between a
georeferenced data set of Culex pipiens s.l. collected in
Portugal mainland during seven years (2006-2012) and meteorological and
physiographic parameters are evaluated. This work is one of the results of a
long-term surveillance program of pernicious insects that act as vectors of
various diseases; its focus is on the possibility of prevention that can be
achieved with abundance data. The focus on Culex pipiens is justified by
its abundance and its competence as a vector
for numerous health issues. The cumulative distribution of monthly captures by each meteorological parameter allows to compute thresholds corresponding
to mosquito massive presence related to 90% of the captures. Using the weather parameters measured in the network
of weather stations across the
country, a monthly average of each parameter of interest (temperature, humidity,
etc.) is computed and an interpolation of the results is made to produce raster maps corresponding to each
month. The previously obtained thresholds
are applied to each map, producing spatial masks with the relevant zones
for each parameter. The intersection of the various masks for each month shows
the most densely populated area of Culex, and the ensemble allows us to observe
the evolution of mosquito presence through the critical season, which is from
May to October at these latitudes. In parallel, mosquito abundance data are
related to physiographic parameters. The relative distribution of female
mosquitoes across land cover types in each month allows identifying which
classes and seasons are most relevant. Orthometric altitude related to the
presence of 90% of the catches shows the limits reached by mosquitoes in each
month. The results are applied to the previously obtained climate envelopes,
delimiting critical areas where the level of risk of transmission of the
pathogens for which Culex pipiens is a competent vector is high and
countermeasures should be concentrated, allowing its planning, and targeting on
a monthly basis. The described procedure can be used with other relevant
vectors in any region of the world, whenever abundance data is available.