title: Laboratory evaluation of repellents against Leptotrombidium deliense, vector of scrub typhus.
abstract: OBJECTIVE
  Scrub typhus, a rickettsial disease transmitted by larvae of Leptotrombidium deliense, is of special importance to the Armed Forces personnel, due to the heightened risk to this disease during movement in mite endemic areas during exercise/war. The disease is best prevented by the use of personal protective measures including repellents. Studies were undertaken to determine the relative efficacy of repellents: diethyl toulamide (DEET), dibutyl phthalate (DBP) with an indigenously developed repellent diethyl phenyl acetamide (DEPA) against the larval trombiculid mite.
  
  
  METHODS
  The repellents were tested for persistence on impregnated cloth prior to washing, post washing and ironing by means of a specially fabricated testing kit. Acaricidal efficacy estimation was performed on the treated fabrics and topical application efficacy of repellents on mice was evaluated by a novel animal testing model.
  
  
  RESULTS
  DEET and DEPA were found to provide maximum protection (repellence and acaricidal efficacy), could withstand two launderings of the impregnated uniform and also had superior efficacy on topical application (8 h). Ironing was found to significantly reduce the repellence of DEET and DBP.
  
  
  CONCLUSIONS
  The findings of this study point towards the superiority of DEPA and DEET for impregnation of the uniform cloth as well as for topical application for the prevention of scrub typhus amongst the troops.
authors.affiliation: Department of Preventive & Social Medicine, Armed Forces Medical College, Pune 411040, India.
authors.forename: R
authors.initials: R
authors.lastname: Tilak
authors.forename: V W
authors.initials: VW
authors.lastname: Tilak
authors.forename: J D
authors.initials: JD
authors.lastname: Yadav
mesh_terms: D000818:Animals; D006801:Humans; D007302:Insect Repellents; D007303:Insect Vectors; D008925:Mites / Q000382:microbiology*; D012285:Orientia tsutsugamushi / Q000302:isolation & purification*; D012612:Scrub Typhus / Q000517:prevention & control* / Q000635:transmission
chemical_list: D007302:Insect Repellents