a comparative study on the susceptibility of geographical populations of main malaria vector, anopheles stephensi with plasmodium berghei

anopheles stephensi is one of the main vectors of malaria in the world including south of iran. three geographical populations for an. stephensi have been defined, based on egg morphology. the aim of the current study is determining the ability of different geographical populations of an. stephensi in the transmission of plasmodium berghei using anka strain of this parasite. four geographical populations of an. stephensi from bandar-abbas, iranshahr, kazeroun and beach (native of india) were colonized. p. berghei strain anka was used to infect mice. then the starved female mosquitoes of each population artificially fed on the infected blood of mice. in order to determine oocyst and sporozoite development, mosquitoes were dissected at several time-points after infection. the populations of beach and kazeroun showed the highest infection rate as well as the highest density to oocyst development while the lowest oocyst infection was observed in bandar-abbas strain. oocyst infection of iranshahr strain was significantly higher than bandar-abbas but less than beach and kazeroun strains. the ratio of sporozoite infection in salivary glands of four populations followed the same order as oocyst infection. the highest salivary glands infection was observed in beach population followed by kazeroun population but bandar-abbas group showed the lowest salivary glands infection. it seems that geographical and ecological separation of mosquito vectors not only cause some morphological, physiological and genetical changes but also affect the sensitivity of the vector to plasmodium. therefore impacts of each environment crucially affect plasmodium/anopheles interaction. so these findings may explain the transmission ability of some anopheles in only a particular area. also, the results may give basic evidence on the mechanism of plasmodium adaptation to their mosquitos' vectors.