Extinction of experimental Triatoma infestans populations following continuous exposure to dogs wearing deltamethrin-treated collars

REITHINGER R; CEBALLOS L; STARIOLO R; DAVIES CR; GURTLER RE

AMERICAN JOURNAL OF TROPICAL MEDICINE AND HYGIENE

Año: 2006 vol. 74 p. 766 - 771

0002-9637

Dogs are domestic reservoir hosts of Trypanosoma cruzi, the etiological agent of Chagas disease. Weevaluated the effect of deltamethrin-treated dog collars (DTDCs) over time on the population dynamics of Triatomainfestans, a main T. cruzi vector. Forty founder bugs of mixed life stages were allowed to colonize mud-thatchedexperimental huts and exposed continuously to either uncollared control dogs (N
3) or dogs wearing DTDCs (N
7) for a period of up to 196 days. When compared with bugs exposed to control dogs, bugs exposed to collared dogs wereshown to have reduced feeding success (odds ratio [OR]
0.40; 95% confidence interval [CI], 0.26–0.63; P < 0.001) andlower survival (OR
0.15; 95% CI, 0.08–0.29; P < 0.001); in fact, all of the bug populations exposed to collared dogsbecame extinct 77–196 days after study initiation. Bugs exposed to DTDC-wearing dogs were also shown to have a lowerfecundity (i.e., number of eggs produced per live female bug: OR
0.64; 95% CI, 0.51–0.81; P < 0.001) and molting rateto first-instar nymphs (OR
0.32; 95% CI, 0.13–0.75; P < 0.01) than those bugs exposed to control dogs. DTDCs couldrepresent a novel tool to prevent and control canine and (hence) human Chagas disease.