The efficacy of a combined larvicide–adulticide in ultralow volume and fumigant canister formulations in controlling the dengue vector Aedes aegypti (Diptera: Culicidae) in Northwest of Argentina

Abstract

The efficacy of an ultralow volume formulation (ULV) and fumigant canister, containing both permethrin and pyriproxyfen, was compared with that of standard permethrin applications in a field assay conducted in Banda del Río Salí, Tucumán (north-western Argentina). Five treatment areas were established: first area was sprayed with a ULV formulation of 10 % permethrin, a second area was treated using a fumigant canister containing 10 % permethrin and 3 % pyriproxyfen, the third area was sprayed with a ULV formulation of 10 % permethrin and 3 % pyriproxyfen, the fourth area with ULV formulation of 10 % permethrin using a portable aerosol generator and the fifth area was a left untreated area. Immature and adult Aedes aegypti individuals placed in containers and sentinel cages were positioned within the treated and control areas. The effects of treatment and time on larval, pupal and adult survival were tested. We also investigated the effects of treatment and time on the numbers of larval and pupal deaths, on the proportion of larvae that metamorphosed into pupae and adults, and on the proportion of dead adults. Larval A. aegypti survivorship in 250 mL containers revealed a significant treatment effect and significant treatment × time interaction 2 and 24 h after the application of the ULV treatment with 10 % permethrin using the portable aerosol generator. The number of dead larvae in 20 L containers differed significantly by treatment and by time. ULV treatment with 10 % permethrin and 10 % permethrin plus 3 % pyriproxyfen using the cold fogger truck mount ULV resulted in the greatest numbers of dead larvae; most larvae died 2 weeks after application. Adult A. aegypti mortality in all treatments did not differ significantly 2 and 24 h after application. In addition, we found no significant differences in adult mortality between cages exposed at 3 m and those at 6 m from the ULV application line. However, there was a significant difference in adult mortality between the 10 % permethrin treatment applied with cold fogger truck mount ULV and that applied using the portable aerosol generator (P < 0.001). The larval index known as Breteau index (BI) was higher before treatment than after treatment in different areas. After the treatments, the lowest value of BI was observed in the area treated with the fumigant canister formulation, and a long-lasting effect was observed with the formulation of 10 % permethrin and 3 % pyriproxyfen.

Community effectiveness of pyriproxyfen as a dengue vector control method: A systematic review

“…One was in Thai the others in English. Seven of the studies were conducted in Central or South America (four in Argentina [ 21 , 22 , 23 , 24 ], one in Colombia [ 25 ], two in Peru [ 26 , 27 ]; four in Southeast Asia (one in Cambodia [ 28 ], two in Thailand [ 29 , 30 ], one in Vietnam [ 31 ]); two in the USA [ 32 , 33 ], two in Martinique [ 34 , 35 ], and two in Europe (Italy [ 36 ], Netherlands [ 38 ]).…”

“…While all included studies had a CE element, some also examined the efficacy of pyriproxyfen [ 25 , 27 ], or resistance [ 35 ]. Others looked at different application forms, including auto dissemination [ 26 , 27 , 33 , 36 , 37 ], fumigation [ 22 ], ULV application [ 21 , 32 ], long-lasting materials [ 24 , 31 ], and controlled-release application [ 28 , 31 ]. Some tested the combination of pyriproxyfen with another active ingredient; seven of the eight CE studies used it either in combination with another product—permethrin [ 22 , 23 , 31 ], Beauveria bassiana [ 37 ]—or compared it to other products [ 21 , 29 ].…”

“…Various methods of pyriproxyfen application were used and information on sampling and reporting of sample size was often limited, making comparisons between the studies difficult. The largest study included communities with a total of 97,262 people [ 25 ], followed by 64,591 people [ 21 ]. Both studies were conducted in urban settings, facilitating a high coverage.…”

“…The reported outcome measures differed depending on the respective research question and intervention ( Table 3 ). The most widely used outcome measure, reported by 11 of the 17 studies, was per cent adult emergence inhibition (EI) [ 21 , 22 , 23 , 24 , 26 , 28 , 32 , 33 , 34 , 35 , 37 ].…”

“…Regarding entomological indices, three studies reported Breteau Index (BI) only [ 21 , 22 , 25 ] and one BI and Container Index (CI) [ 23 ]. Pupae per person (PPP), currently considered the most highly associated with the density of adult vectors (36), was only reported by one study [ 23 ].…”