Determination Range Susceptibility of Anopheles Stephensi Mamassani Strain in Fars Province to DDT, Malathion and Fenitrothion

Background: An. Stephen's is one of the main malaria vectors in the south of Iran. This anopheles is a kind of resistance to some organophesphorous and organochlorine insecticides. So An. Stephensi is collected in a village called Bekesh Dodangeh in the south of Iran to determine the degree of susceptibility to DDT 4%, malathion 5% and fenitrothion 1% insecticides. Methods: The testing methods were used according to standard WHO. The tests were carried out on blood fed adult females in lots of 25 adults in 4 replicates Results: An. Stephensi touched to malathion 5% and fenitrothion 1% insecticides in 20, 30 and 60 minutes exposure time showed the mortality effect on them as follows: Malathion (86.8%, 84.2% and 98.02%), Fenitrothion (57.1%, 60.3% and 97.02%). The result of the tests showed An. Stephensi is susebtibility to malathion and tolerant to fenitrothion. However, this Anophel had resistance to Malathion in Mamassani; therefore, the reason of this increase susceptibility was not used malathion insecticide in this region. Tolerant cause to fenitrothion was non-used this insecticide in Noorabad Mamassani and little concentration and unsufficient exposure time. Also we tested susceptibility of An. Stephensi to DDT in 20, 30 and 60 minutes. The result of mortality testes were 38.4%, 56.3% and 37.1% degree testes KD were 7.6%, 13.9% and 39.7%. So An. Stephensi is resistant to DDT insecticide. This anopheles has resistant background in Mamassani.