Spatial Re-Establishment Dynamics of Local Populations of Vectors of Chagas Disease.

HEINRICH ZU DOHNA; MARı´A CARLA CECERE; RICARDO E. GU¨ RTLER; URIEL KITRON; JOEL E. COHEN

PLOS NEGLECTED TROPICAL DISEASES

PUBLIC LIBRARY SCIENCE

Año: 2009 p. 490 - 501

1935-2735

Background: Prevention of Chagas disease depends mainly on control of the insect vectors that transmit infection.Unfortunately, the vectors have been resurgent in some areas. It is important to understand the dynamics of reinfestationwhere it occurs. Here we show how continuous- and discrete-time models fitted to patch-level infestation states canelucidate different aspects of re-establishment. Triatoma infestans, the main vector of Chagas disease, reinfested sites inthree villages in northwest Argentina after community-wide insecticide spraying in October 1992.Methodology/Principal Findings: Different methods of estimating the probabilities of bug establishment on each site werecompared. The results confirmed previous results showing a 6-month time lag between detection of a new infestation anddispersal events. The analysis showed that more new bug populations become established from May to November thanfrom November to May. This seasonal increase in bug establishment coincides with a seasonal increase in dispersal distance.In the fitted models, the probability of new bug establishment increases with increasing time since last detected infestation.Conclusions/Significance: These effects of season and previous infestation on bug establishment challenge our currentunderstanding of T. infestans ecology and highlight important gaps in knowledge. Experiments necessary to close thesegaps are discussed.