Are insecticide-impregnated dog collars a feasible alternative to dog culling as a strategy for controlling canine visceral leishmaniasis in Brazil?

In a zoonotic visceral leishmaniasis (ZVL)-endemic area in Brazil, deltamethrin-impregnated collars (DMC) were fitted to 136 dogs for 5 months and significantly reduced the odds of increasing their anti-Leishmania antibody titer during this period by 50% (95% confidence interval 29-87%, P=0.01), as compared with a population of 97 uncollared dogs with pre-intervention prevalence within the same town. Mathematical modeling suggests that under typical Brazilian ZVL-endemic conditions, the epidemiological impact of community-wide DMC application should be greater than the currently practiced dog culling strategy, but that its impact will be dependent on collar coverage and loss rate. Both interventions should have a higher proportional impact in regions of lower endemicity, but the relative advantage of DMC over culling increases with transmission rate. Sensitivity analyses indicate that the impact of either intervention is not significantly affected by variation in the biology of the sandfly vector, but is greatly influenced by variation in dog mortality and serorecovery rates.