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. 2013 Apr 10;7(1):56-65.
Print 2013.

Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae) to Temephos in Malarious Areas of Irana

Aboozar Soltani  1 , Hassan Vatandoost, Mohammad Ali Oshaghi, Ahmad Ali Enayati, Ahmad Raeisi, Mohammad Reza Eshraghian, Mohammad Mehdi Soltan-Dallal, Ahmad Ali Hanafi-Bojd, Mohammad Reza Abai, Fatemeh Rafi
Affiliations

Baseline Susceptibility of Different Geographical Strains of Anopheles stephensi (Diptera: Culicidae) to Temephos in Malarious Areas of Irana

Aboozar Soltani et al. J Arthropod Borne Dis. .

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%).

Conclusion: 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.

Keywords: Anopheles stephensi; Iran; Larvicide resistance; Susceptibility; Temephos.

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Figures

Fig. 1
Fig. 1
Location of Anopheles stephensi collection sites from malarious areas of Iran, 2011
Fig. 2
Fig. 2
temephos resistance ratio pattern in An. stephensi field strains from southern Iran, 2011
Fig. 3
Fig. 3
Regression lines of eight strains of An. stephensi and susceptible Beech-Lab strain, 2011
See this image and copyright information in PMC

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