A motorized vehicle-mounted sprayer as a new tool for Chagas disease vector control

Abstract

Residual insecticide spraying still is the main tool used to suppress house infestations with Chagas disease vectors. While manual compression sprayers (MCS) have traditionally been used in Latin America, Mendoza's vector control program from Argentina introduced the use of a modified motorized vehicle-mounted sprayer (VMS) with apparent advantages over MCS. We conducted a randomized intervention trial to evaluate the effectiveness and selected components of the performance of MCS and VMS. We assessed house infestation by Triatoma infestans in 76 previously-infested houses at 0, 1, 4 and 12 months postintervention. Infestations were reduced substantially, with no significant differences between treatments. End-point infestations were restricted to peridomiciles. Although VMS required less time to complete the house spraying than MCS, both treatments had similar performance and did not suppress infestations completely. The main relative advantages of VMS were a reduced physical effort, especially under harsh field conditions, and potential gains in spray coverage per unit of time.

Urban vectors of Chagas disease in the American continent: A systematic review of epidemiological surveys

“…As a consequence, the urban environment implies a strong, novel and atypical challenge for control programs. Protocols and methodologies for vector control and evaluation, which were standardized in the 1960s, established the use of manual and/or automatic pumps for the application of insecticide [ 71 , 72 ]. In rural areas with an infestation rate <5%, the insecticide is applied following the selective methodology, whereas in those with an infestation rate >5%, the insecticide is applied following the attack methodology [ 73 ].…”

The eco-epidemiology of Triatoma infestans in the temperate Monte Desert ecoregion of mid-western Argentina

“…A large fraction of houses with infested domiciles also harboured a peridomestic focus, mainly in goat corrals. Recently, two alternative control methods to reduce domestic triatomine populations have been trailed in Argentina: a motorised vehicle-mounted sprayer for insecticide application, which restricted end-point infestations to peridomiciles ( Carbajal-de-la-Fuente et al 2017 ), and modification of traditional goat corrals, which increased goat productivity and likely enhanced the detectability of low-density infestations ( Gorla et al 2013 ). A combination of environmental management and improved chemical vector control may be needed to suppress peridomestic infestations.…”

“…Study design and vector survey - As part of a randomised intervention trial evaluating the efficiency and effectiveness of insecticide spraying operations, an exploratory survey of house infestation was undertaken in April 2013 ( Carbajal-de-la-Fuente et al 2017 ). Experienced field personnel of the National Vector Control Program (NVCP) from Mendoza inspected 198 houses for evidence of current or past infestation (i.e., live triatomines, eggs and faeces).…”

“…Houses where evidence of infestation was found (n = 76) were included in the current study and re-inspected in May 2013 before spraying operations began. All of the 198 houses were sprayed with pyrethroid insecticides during May-June 2013 ( Carbajal-de-la-Fuente et al 2017 ). The 76 houses included in this study were scattered over 1,400 km 2 , with distances between houses ranging from a few hundred meters up to 50 km.…”

“…In an effort to improve vector control activities, we conducted a randomised intervention trial to evaluate the efficiency and effectiveness of insecticide spraying operations in Lavalle Department ( Carbajal-de-la-Fuente et al 2017 ) as part of a wider study on the eco-epidemiology and control of T. infestans in the region. The aims of the current study were to assess the environmental and socio-demographic determinants of house infestation with T. infestans , bug abundance, vector infection with T. cruzi and its host-feeding patterns in a well-defined rural area of Lavalle Department.…”