Susceptibility of Anopheles stephensi (Diptera: Culicidae) to Dirofilaria immitis (Spirurida: Onchocercidae)

Dirofilaria immitis is endemic in the southern parts of Iran where there is a favourable environment for the development of Anopheles stephensi. The aim of the present study was to evaluate the susceptibility of A. stephensi as D. immitis vector under laboratory conditions. Anticoagulated dog blood containing 1,500 microfilariae was artificially administered to 140 mosquitoes of the test group (T group), while 94 mosquitoes were left as a control (C group). Blood-fed mosquitoes of the T group were dissected for morphological and molecular analyses at pre-set time points to observe the developmental stage of D. immitis. The results showed that the average number of the microfilariae ingested per female in T group was 9.6. At the end of the study, 16 mosquitoes developed infective third stage larvae of D. immitis, and 49 mosquitoes survived at end of incubation period, giving an estimated infection rate of 32.6% and the vector efficiency index of 17%. The infection rate and vector efficiency index suggested that A. stephensi could be considered as a potential vector of D. immitis.