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Long‐term use of permethrin‐impregnated nets does not increase Anopheles gambiae permethrin tolerance
Author(s) -
VULULE J. M.,
BEACH R. F.,
ATIELI F. K.,
MOUNT D. L.,
ROBERTS J. M.,
MWANGI R. W.
Publication year - 1996
Publication title -
medical and veterinary entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 82
eISSN - 1365-2915
pISSN - 0269-283X
DOI - 10.1111/j.1365-2915.1996.tb00084.x
Subject(s) - permethrin , biology , anopheles gambiae , term (time) , toxicology , zoology , ecology , pesticide , malaria , immunology , physics , quantum mechanics
. Previous use of permethrin‐impregnated bednets (mosquito nets) and curtains in four Kenyan villages for one year, 1990‐91, raised the permethrin LT 50 of Anopheles gambiae to 2.4‐fold above its baseline value, designated permethrin tolerance (PT), as measured by exposure to 0.25% permethrin‐impregnated papers in W.H.O. test‐kits. During 1992‐93, with ongoing use of permethrin‐impregnated nets and curtains, PT regressed slightly compared with the contemporary susceptibility level of An. gambiae from non‐intervention villages, to 1.8‐fold in 1992 and only 1.6‐fold in 1993. Thus the selection pressure of impregnated nets for PT in Angambiae appears to be minimal in our study villages, although the impact of permethrin was demonstrated by a significantly lower parous‐rate of Angambiae females in the intervention (63–66%) than in non‐intervention (79%) villages, and by reduced malaria transmission (reported elsewhere). In a selected stock of An. gambiae from the study area, PT did not affect the susceptibility to deltamethrin, fenitrothion, propoxur or DDT. Bioassays described herein provide easy procedures for field‐monitoring of mosquito susceptibility/tolerance/resistance to insecticides used for net impregnation in operational programmes.