Spatial patterns of high Aedes aegypti oviposition activity in northwestern Argentina.
BACKGROUND
In Argentina, dengue has affected mainly the Northern provinces, including Salta. The objective of this study was to analyze the spatial patterns of high Aedes aegypti oviposition activity in San Ramón de la Nueva Orán, northwestern Argentina. The location of clusters as hot spot areas should help control programs to identify priority areas and allocate their resources more effectively.


METHODS
Oviposition activity was detected in Orán City (Salta province) using ovitraps, weekly replaced (October 2005-2007). Spatial autocorrelation was measured with Moran's Index and depicted through cluster maps to identify hot spots. Total egg numbers were spatially interpolated and a classified map with Ae. aegypti high oviposition activity areas was performed. Potential breeding and resting (PBR) sites were geo-referenced. A logistic regression analysis of interpolated egg numbers and PBR location was performed to generate a predictive mapping of mosquito oviposition activity.


RESULTS
Both cluster maps and predictive map were consistent, identifying in central and southern areas of the city high Ae. aegypti oviposition activity. A logistic regression model was successfully developed to predict Ae. aegypti oviposition activity based on distance to PBR sites, with tire dumps having the strongest association with mosquito oviposition activity. A predictive map reflecting probability of oviposition activity was produced. The predictive map delimitated an area of maximum probability of Ae. aegypti oviposition activity in the south of Orán city where tire dumps predominate. The overall fit of the model was acceptable (ROC=0.77), obtaining 99% of sensitivity and 75.29% of specificity.


CONCLUSIONS
Distance to tire dumps is inversely associated with high mosquito activity, allowing us to identify hot spots. These methodologies are useful for prevention, surveillance, and control of tropical vector borne diseases and might assist National Health Ministry to focus resources more effectively.
Centro de Investigaciones Entomológicas de Córdoba, Instituto de Investigaciones Biológicas y Tecnológicas CONICET-Universidad Nacional de Córdoba, Facultad de Ciencias Exactas, Físicas y Naturales-Ciudad Universitaria, Córdoba, Argentina. eelizabet@gmail.com
Elizabet Lilia
EL
Estallo
Guillermo
G
Más
Carolina
C
Vergara-Cid
Mario Alberto
MA
Lanfri
Francisco
F
Ludueña-Almeida
Carlos Marcelo
CM
Scavuzzo
María Virginia
MV
Introini
Mario
M
Zaidenberg
Walter Ricardo
WR
Almirón
D000330:Aedes / Q000502:physiology*; D000818:Animals; D001118:Argentina; D001947:Breeding; D002452:Cell Count; D002947:Cities; D003715:Dengue / Q000517:prevention & control / Q000635:transmission; D005260:Female; D062305:Geographic Mapping; D005843:Geography; D007303:Insect Vectors / Q000502:physiology*; D016015:Logistic Models; D008297:Male; D009032:Mosquito Control / Q000379:methods / Q000706:statistics & numerical data; D010058:Oviposition / Q000502:physiology*; D010063:Ovum / Q000166:cytology; D012621:Seasons; D062206:Spatial Analysis