Relative Efficacy of Different Synthetic Pyrethroid Impregnated Fabrics (ITNs) on Knock Down Time of Anopheles Stephensi

Faeze Shamspour Hassan Vatandoost Mohammad Reza Abai


We aimed to evaluate the efficacy of different fibers of bednets impregnated with various pyrethroids and the efficacy of LD50,LD90 and diagnostic dose of pyrethroids on median knock down time of susceptible strain of An.stephensi . The other aim of the present study was to determine distribution of knock down time values (Standard Division). Bioassey test was carried out with simple netting apparatus under laboratory condition  using a new method of WHO proposed by Curtis. 11 female mosquitoes were released into net apparatus and median knock down time of them were calculated for each type of pyrethroids and fabrics. their  standard division ( SD ) and  Standard error ( SE ) were  calculated  exactly by Probit analysis of Finney.  Results  showed Median knock down time in 10 mg.m-2 dosage of lambdacyhalothrin on polyester, nylon and cotton net was calculated as 3.1, 3.5 and 6.3 minutes respectively. It was calculated in 20 mg.m-2 dosage of deltamethrin on polyester , nylon and cotton net, as 6.6, 8.7 and 21.7 minutes respectively. In 40 mg.m-2 dosage of cyfluthrinon on polyester , nylon and cotton net, It was calculated as 6.3, 7.5 and 19.9 minutes respectively . Finally in 200 mg.m-2  dosage of etophenprox on polyester , nylon and cotton net, It was calculated as 10.6, 12.5 and 7.4 minutes. It was seen direct relationship between LD50, LD90 and diagnostic dose of pyrethroids and median knock down time. Lambdacyhalothrin had the least value of LD50 (10 mg.m-2 ), LD90 and D.D, created the least value of knock down time in comparison with other pyrethroids.  Etophenprox had the highest value of LD50 (200 mg.m-2), LD90 and D.D, created the highest value  of knock down time.  Deltamethrin and cyfluthrin had intermediate values. Also there was  a reverse  relationship between dosage of pyrethroids and median knock down time.  Polyester net need the least concentration of pyrethroid, shown the least values of knock down time and the least LD50, LD90 and diagnostic dose. So it is the best  suitable net for impregnation. In all doses of all pyrethroids on all type of nets,  median knock down time was similar to the knock down time of the 6th mosquito ( mode ).  These values were the closest value to the KDT50.

Full Text:



Curtis CF., Myamba J. and Wilkes TJ. 1996. Comparison of different insecticides and fabrics for anti-mosquito bednets and curtains. Med.Vet. Entomol.,1996; 10: 1-11.

Curtis CF. 2005. Insecticide treatment bednets to prevent malaria . Sci .Dev . November 2005 .

Zaim M., Aitio M. and Nakashima N. 2000. Safety of pyrethroid-treated mosquito nets . Medical & Veterinary Entomology. 2000; 14 : 1-5.

Vatandoost H., Golizadeh S., Abai M.R. and Djavadian E. 2006. Laboratory Efficacy of Protection Rate of Torn Nets Treated With Pyrethroids, Cyfluthrin, Deltamethrin, nd Permethrin Against Anopheles stephensi (Diptera: Culicidae). Journal of Biological Sciences. 2006, 6(2): 331-336.

Ladonni, H. & Townson, H. 1998. A major gene conferring permethrin resistance in the larvae of the malaria vector Anopheles stephensi. Bull. Entomol. Res.

Vatandoost, H., Mc.Caffery, A. & Townson, H. 1998. An electro-physiological investigation of target-site insensitivity in permethrin-resistant and permethrin-susceptible strains of Anopheles stephensi. Iranian Journal of Arthropod-Borne Diseases. 1998 ; 27(3-4) : 29-44.

Moosa-Kazemi SH., Vatandoost H., Raeisi A. and Akbarzadeh K. 2007. Deltamethrin Impregnated Bed Nets in a Malaria Control Program in Chabahar, Southeast Baluchistan, I.R. Iran. Iranian J. Arthropod-Borne Dis. 2007; 1(1): 43–51

Hanafi-Bojd AA, Vatandoost H., Philip E., Stepanova E., Abdi A., Safari R., Mohseni GH., Bruhi MI., Peter A., Abdulrazag SH. And Mangal G. 2010. Malaria Situation Analysis and Stratification in Bandar Abbas County, Southern Iran, 2004–2008. Iranian J. Arthropod-Borne Dis, 2010; 4(1): 31–41.

Vatandoost H., Dehaki M., Djavadian E. and Abai MR., 2005. Comparative performance of torn impregnated nets by bifenthrin, lambdacyhalothrin and DEET against malaria vector An.stephensi in Iran using tunnel test. Medicine and Health in the Tropics, Marseille, 11-15 September 2005; France.

Vatandoost H., Dehakia M., Djavadian E., Abai MR. & Duchon S., 2006. Comparative study on the efficacy of lambdacyhalothrin and bifenthrin on torn nets against the malaria vector, Anopheles stephensi as assessed by tunnel test method. J. Vec. Borne Dis. 43 September 2006, PP.133-135.

WHO, 2002. Malaria vector control, decision making criteria and procedyres for judicious use of insecticides. Najera NJ. and Zaim M. (Eds). WHO/CDS/WHOPES/2002.

Rafinejada J., Vatandoosta H., Nikpoora F., Abaia M.R., Shaeghia M., Duchenb S. and Rafia F. 2008. Effect of washing on the bioefficacy of insecticide-treated nets (ITNs) and long-lasting insecticidal nets (LLINs) against main malaria vector Anopheles stephensi by three bioassay methods J. Vector Borne Dis. 45, June 2008; PP: 143–150.

Vatandoost H., Ramin E., Rassi Y. 2009. Stability and Wash Resistance of Local Made Mosquito Bednets and Detergents Treated with Pyrethroids against Anopheles stephensi . Iranian Journal of Arthropod-Borne Diseases. 2009;3(1) : 19-28.

Kayedi M.H., lines JD., Haghdoost A.A., Vatandoost MH. Eassi Y. and Khamisabadi K. 2008. Evaluation of the effects of repeated hand washing, sunlight, smoke and dirt on the persistence of deltamethrin on insecticide-treated nets. Transactions of Royal Society of Tropical Medicine and Hygiene. 2008; 102(8): 811-816 .

WHO, 2009. World malaria report 2009. WHO Press, World Health Organization, Geneva. 66 pages.

WHO, 1997. The impact of permethrin and deltamethrin resistance in Anopheles gambiae S.S on the efficacy of insecticide-treated mosquito nets. Darriet F., Guillet P., N'Guessan RN., Doannio JMC., Koffi AA., Carnevale P. WHO/MAL/99.1088. WHO/VBC/99.1002 / 1997.

Vulule J., Beach JM., Atieli FK., Mount DL., Roberts JM. & Mwangi RW. 1996. Long term use of permethrin-impregnated nets does not increase Anopheles gambiae tolerance. Med.Vet. Entomol. 10: 71-79.

Singh OP., Raghavendra K. , Nanda N., Mittal PK. and Subbarao SK. 2002. pyrethroid resistance in Anopheles Culicifacies in Surat district, Gujarat,west India . Research Communications current science . 2002; 82 (5): P:47-550.

Jingjiang X Li Z, Banquan L., Taihua Z. and Mingxin L. 1987. Mosquito nets im¬preg¬nated whit deltamethrin against ma¬laria vectors in China. WHO/VBC/87-93/1987.

Kang W., Gao B., Jiang H., Wang H., Yu T., Yu P., Xu B. and Curtis CF. 1995. Tests for possible e¡ects of selection by domestic pyrethroids for resistance in culicine and anopheline mosquitoes in Sichuan and Hubei. China. Ann. Trop. Med. Parasitol.1995; 89: 677- 84.

Sharma S.K., Upadhyay AK., Haque MK., Padhan K., Tyagi PK., Batra CP., Adak T., Dash AP. and Subbarao SK. 2005. Village-Scale evaluation of mosquitoe nets treated with a tablet formulation of deltamethrin against malaria vector. med. Vet. Entomol., 2005; 19: 286-292.

Vatandoost H., Ramin E., Rassi Y. 2009. Stability and Wash Resistance of Local Made Mosquito Bednets and Detergents Treated with Pyrethroids against Anopheles stephensi . Iranian Journal of Arthropod-Borne Diseases. 2009;3(1) : 19-28.

Frances SP, Watson K, Constable BG. Comparative Toxicity of permethrin and bifenthrin-treated cloth fabric for Anopheles farauti and Aedes aegypti. J Am. Mosq Control Assoc. 2003; 9(3): 275–8.

Hougard JM , Duchon st., Darrie , Fredric et al., 20003. Comparative Performances,under laboratory conditions, of seven pyrethroids used for impregnation of mosquitoe nets. Bull World Health Organ. 2003; 81 (5) , P:324-333.

Rohani A , Saadiyah I., Walgun A. and Lee HL. 2007. Laboratory study on the effect of Deltamethrin WG and WP formulations against An.maculatus on rough and smooth surface of bamboo wall . Tropical Biomedicine. 2007; 24(2) : 77-82.



  • There are currently no refbacks.

Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.