Baseline susceptibility to alpha-cypermethrin in Lutzomyia longipalpis (Lutz & Neiva, 1912) from Lapinha Cave (Brazil)

Abstract

BackgroundGiven the increase in cases of visceral leishmaniasis in recent years, associated with the socio-economic impact of this disease, as well as the wide distribution of Lutzomyia longipalpis in Brazil and the likelihood that this vector may develop resistance to insecticides used for control, the Ministry of Health considers as crucial the creation of a network in order to study and monitor the resistance of this vector to insecticides used for control. In this sense, this study aimed: 1) to characterize the susceptibility of L. longipalpis from Lapinha Cave (Lagoa Santa, MG - Brazil) to Alfateck SC200 in field bioassays, and 2) to define the susceptibility baseline to alpha-cypermethrin in laboratory bioassays, checking the possibility of using it as susceptibility reference lineage (SRL).FindingsThe field bioassays revealed that the tested population was highly susceptible to alpha-cypermethrin in all time periods with high mortality (~100 %) in all treated surfaces before six months after spraying. In the laboratory bioassays, the studied population presented LD50, LD95 and LD99 to 0.78013, 10.5580 and 31.067 mg/m2, respectively. The slope was 1.454121.ConclusionsThe studied population of L. longipalpis was considered as adequate for SRL according criterion recommended by Pan-American Health Organization and has proven susceptibility to tested insecticide in the field. One cannot rule out the possibility of finding populations of L. longipalpis more susceptible to alpha-cypermethrin; therefore, further research is necessary on other populations with potential use as a SRL.

Susceptibility of wild-caught Lutzomyia longipalpis (Diptera: Psychodidae) sand flies to insecticide after an extended period of exposure in western São Paulo, Brazil

“…longipalpis, with most, but not all [ 27 , 44 , 45 ] of these studies on Lu. longipalpis from Brazil and in particular from Minas Gerais State [ 20 , 21 , 28 , 46 ].…”

“…(i) the discriminating concentrations and baseline susceptibility times to different insecticides for Lu. longipalpis colonies have not been fully established [ 21 , 24 , 46 ]. Although it is reasonable to use those from similar genera, they cannot be extrapolated from other insect groups such as Anopheles mosquitoes [ 26 , 39 , 49 ].…”

Chemical control and insecticide resistance status of sand fly vectors worldwide

“…Last but not least, a number of WHO/CDC dose–response bioassay studies have been conducted in Brazil, Peru, Venezuela, and Colombia, in order to define the LC values (LC 50 , LC 95 , or LC 99 ) for L . longipalpis [ 93 ], Lutzomyia evansi [ 94 , 95 ], and Lutzomyia peruensis [ 96 ] field populations against commonly used insecticides. The respective test values are given in S1 Table .…”

Susceptibility of phlebotomine sandflies (Diptera: Psychodidae) collected in the field, to alpha-cypermethrin in four municipalities endemic to leishmaniasis

“…This was the first record of an insecticide tolerance of sandfly species in South America. Pessoa et al 14 after testing sandflies from Gruta da Lapinha indicated this population as a susceptible reference lineage, as it complies with the requirements of The Pan American Health Organization 14 . More recently, González et al 15 tested populations of Lu.…”