Spatial patterns of reinfestation by Triatoma guasayana in a rural community in northwestern Argentina.

VAZQUEZ-PROKOPEC GM; CECERE MC; CANALE MD; GURTLER RE; KITRON U

JOURNAL OF MEDICAL ENTOMOLOGY

Año: 2005 vol. 42 p. 571 - 581

0022-2585

ABSTRACT Triatoma guasayana (Wygodzinsky & Abalos) is a secondary vector of Trypanosomacruzi (Chagas), the etiologic agent of Chagas disease, in the Chaco region of Argentina, Bolivia, andParaguay. The spatial distribution of T. guasayana in a rural community in northwestern Argentina isdescribed and analyzed using very high spatial resolution satellite imagery, geographic informationsystems, and spatial statistics. Since a 1992 residual spraying with insecticides of all houses, site-speciÞcdomestic and peridomestic reinfestations by triatomine bugs were monitored using various methodssemiannually from 1993 to 2002. The reinfestation by T. guasayana started with Þnding of only adultbugs in a few sites. Bug abundance was signiÞcantly clustered and predominantly peridomestic in thesouthern and northern extremes of the community. The identiÞed source of reinfestation in thenorthern cluster was a colonized wood pile, whereas no potential peridomestic source was found forthe southern cluster. The spatial distribution of T. guasayana was positively associated with theabundance and spatial distribution of goats. Active dispersal from the hypothesized source and thesurrounding sylvatic environment, and passive transport of bugs in wood piles seems to be themost likely mechanisms underlying the observed spatial pattern of T. guasayana. The absence ofdomestic colonization indicates that, to date, there is no trend toward increased local domiciliationof T. guasayana. The clustering zones can be considered “hot spots” where bug invasion from othersources is expected to be higher and where eventually, introduction of sylvatic T. cruzi to suitable hostsmay occur.