title: Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae) to Temephos in Malarious Areas of Irana.
abstract: BACKGROUND
  Malaria still remains a public health problem in Iran. There are different vector control interventions such as insecticide spraying. The present study was carried out to determine the susceptibility status of Anopheles stephensi larvae to temephos as a national plan for monitoring and mapping of insecticide resistance.
  
  
  METHODS
  Eight different localities in two main malarious provinces were determined as field collecting sites. Mosquitoes were collected from the field and reared in an insectray. Susceptibility assays were carried out according to the WHO method. The laboratory reared susceptible Beech-Lab strain was used for comparison. Data were analyzed using Probit analysis to determine LC50 and LC90 values.
  
  
  RESULTS
  Susceptibility of An. stephensi to temephos indicated that the LC50 ranged from 0.0022 mg/l to 0.0141 mg/l. Although all field strains were susceptible to temephos, considerable variations in temephos resistance ratios of field strains were noticed from all the localities studied in comparison with the susceptible strain. A low level of resistance ratio was noticed in An. stephensi populations except for the Chabahar strain (RR= 4.27 fold). All field-collected An. stephensi populations exhibited homogeneity to the larvicide except for Bandar Abbas and Hormoodar village strains (P> 0.05%).
  
  
  CONCLUSIONS
  Due to intensive use of temephos in the neighboring countries and occurrence of resistant to this insecticide in the main malaria vector in the region, insecticide resistance gene may evolve in the populations of An. stephensi. If temephos be applied as a larvicide it should be used judiciously for resistance management, as rotation strategy.
authors.affiliation: Department of Medical Entomology and Vector Control, School of Public Health and National Institute of Health Research, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Aboozar
authors.initials: A
authors.lastname: Soltani
authors.forename: Hassan
authors.initials: H
authors.lastname: Vatandoost
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Oshaghi
authors.forename: Ahmad Ali
authors.initials: AA
authors.lastname: Enayati
authors.forename: Ahmad
authors.initials: A
authors.lastname: Raeisi
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Eshraghian
authors.forename: Mohammad Mehdi
authors.initials: MM
authors.lastname: Soltan-Dallal
authors.forename: Ahmad Ali
authors.initials: AA
authors.lastname: Hanafi-Bojd
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Abai
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Rafi
keywords: Anopheles stephensi; Iran; Larvicide resistance; Susceptibility; Temephos