Spatio-temporal patterns of reinfestation by Triatoma guasayana (Hemiptera: Reduviidae) in a rural community of north-western Argentina.

VAZQUEZ-PROKOPEC GM, CECERE MC, CANALE DM, GÜRTLER RE, KITRON U.

Nevada-USA

Congreso; 5. VI International Congress of the Society for Vector Ecology (SOVE).; 2005

Triatoma guasayana is a secondary vector of Trypanosoma cruzi, the etiologic agent of Chagas disease, in the Chaco region of Argentina, Bolivia and Paraguay. The spatial distribution of T. guasayana in a rural community in northwest Argentina is described and analyzed using very high spatial resolution satellite imagery, Geographic Information Systems and spatial statistics. Since the 1992 residual spraying of all houses with pyrethroid insecticides, site-specific domestic and peridomestic reinfestations by triatomine bugs were monitored using various methods semi annually from 1993 to 2002. Bug abundance was significantly clustered in the southern and northern extremes of the community, and positively associated with the abundance and spatial distribution of goats. Further bug searches in natural habitats around houses (bromeliads and dry cacti) confirmed this pattern of clustering of T. guasayana. Active dispersal from an identified peridomestic source and from the surrounding sylvatic environment and passive transport of bugs in wood piles appear to be the most likely mechanisms underlying the observed spatial pattern of T. guasayana. The clustering zones can be considered ‘hotspots’ into which bug invasion from other sources is expected to be higher and where eventually, introduction of sylvatic T. cruzi to suitable hosts may occur.