Cost-Effectiveness of Chagas Disease Vector Control Strategies in Northwestern Argentina

Abstract

BackgroundControl and prevention of Chagas disease rely mostly on residual spraying of insecticides. In Argentina, vector control shifted from a vertical to a fully horizontal strategy based on community participation between 1992 and 2004. The effects of such strategy on Triatoma infestans, the main domestic vector, and on disease transmission have not been assessed.Methods and FindingsBased on retrospective (1993–2004) records from the Argentinean Ministry of Health for the Moreno Department, Northwestern Argentina, we performed a cost-effectiveness (CE) analysis and compared the observed CE of the fully horizontal vector control strategy with the expected CE for a vertical or a mixed (i.e., vertical attack phase followed by horizontal surveillance) strategy. Total direct costs (in 2004 US$) of the horizontal and mixed strategies were, respectively, 3.3 and 1.7 times lower than the costs of the vertical strategy, due to reductions in personnel costs. The estimated CE ratios for the vertical, mixed and horizontal strategies were US$132, US$82 and US$45 per averted human case, respectively. When per diems were excluded from the costs (i.e., simulating the decentralization of control activities), the CE of vertical, mixed and horizontal strategies was reduced to US$60, US$42 and US$32 per averted case, respectively.Conclusions and SignificanceThe mixed strategy would have averted between 1.6 and 4.0 times more human cases than the fully horizontal strategy, and would have been the most cost-effective option to interrupt parasite transmission in the Department. In rural and dispersed areas where waning vertical vector programs cannot accomplish full insecticide coverage, alternative strategies need to be developed. If properly implemented, community participation represents not only the most appealing but also the most cost-effective alternative to accomplish such objectives.

Comparative Field Trial of Alternative Vector Control Strategies for Non-Domiciliated Triatoma dimidiata

“…Insecticide spraying had a cost within the lower range of that reported in other studies ($7-48/house). 26,[36][37][38][39][40] However, it should be noted that we did not include transportation costs in our estimate. Impregnated curtains and insect screens had a higher cost, as do most housing improvement strategies, 26,35 but their sustainability would likely make them more cost-effective in the long term.…”

Potential for entomopathogenic fungi to control Triatoma dimidiata (Hemiptera: Reduviidae), a vector of Chagas disease in Mexico

“…These interventions include improvements in housing conditions and vector control through indoor insecticide spraying 15 using several synthetic carbamates, organophosphates and pyrethroids [16][17][18] . However, in addition to adverse environmental effects of these substances, an increase in the numbers of fi eld vector populations resistant…”

Toxicity of non-pyrethroid insecticides against Triatoma infestans (Hemiptera: Reduviidae)

“…However, in the Gran Chaco ecoregion, T. infestans numbers have not been reduced and this area is considered to represent the last main barrier to be conquered (Gürtler 2009). The lack of efficacy in this area may be attributable to several factors, such as incomplete insecticide coverage and entomological surveillance, interruption of local control programs due to economic problems and harsh environmental working conditions, such as temperatures ranging from -10-50ºC and the increasing desertification of some areas (Porcasi et al 2006, Gürtler 2009, Vazquez-Prokopec et al 2009). As noted by Gürtler et al (2004), peridomestic populations of T. infestans in the Gran Chaco ecoregion may exhibit a high rate of survival after chemical control actions, leading to a low efficacy of these treatments.…”