title: Exploration of the susceptibility of AChE from the poultry red mite Dermanyssus gallinae (Acari: Mesostigmata) to organophosphates in field isolates from France.
abstract: The red fowl mite Dermanyssus gallinae (De Geer, 1778) is a hematophagous mite species, which is very commonly found in layer facilities in Europe. The economic and animal health impact of this parasite is quite important. In laying hen houses, organophosphates are almost the only legally usable chemicals. Detecting a target resistance can be useful in order to limit the emergence of resistant populations. The acetylcholinesterase (AChE) activity and the enzyme sensitivity to paraoxon was investigated in 39 field samples and compared to a susceptible reference strain (SSK). Insensitivity factor values (expressed as IC50 ratio) obtained from field isolates compared to SSK revealed some polymorphism but not exceeding a 6-fold difference. The kinetic characteristics of AChE from some field samples showed some difference in KM values for acetylthiocholine and inhibition kinetics performed with diethyl paraoxon exhibited a 5.5-fold difference in the bimolecular rate constant in one field isolate. Taken together, these data suggested that differences in AChE susceptibility to organophosphates may exist in D. gallinae but no resistant population was found.
authors.affiliation: Ecole Nationale Vétérinaire de Lyon, Laboratoire de parasitologie, Université de Lyon, 69280, Marcy-L'Etoile, France. l.roy@vet-lyon.fr
authors.forename: Lise
authors.initials: L
authors.lastname: Roy
authors.forename: Claude
authors.initials: C
authors.lastname: Chauve
authors.forename: Jean
authors.initials: J
authors.lastname: Delaporte
authors.forename: Gilbert
authors.initials: G
authors.lastname: Inizan
authors.forename: Thierry
authors.initials: T
authors.lastname: Buronfosse
mesh_terms: D000110:Acetylcholinesterase / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000737:chemistry*; D005602:France; D007700:Kinetics; D008925:Mites / Q000201:enzymology* / Q000254:growth & development; D010261:Paraoxon / Q000737:chemistry*
chemical_list: D002800:Cholinesterase Inhibitors; D000110:Acetylcholinesterase; D010261:Paraoxon