Hydrophilic Nanosilica as a New Larvicidal and Molluscicidal Agent for Controlling of Major Infectious Diseases in Egypt

Aim: This research was conducted to evaluate the molluscicidal and mosquitocidal efficacy of silica nanoparticles in the eradication of the larvae and pupa of malaria and filariasis vector as well as vectors of rift-valley fever virus (Culex pipiens); Schistosoma mansoni vector (Biomphlaria alexandrina (snail and egg masses)).
Materials and Methods: Hydrophilic nanosilica particles (NSPs) were characterized using transmission electron microscope during the preliminary part of the study; the stages were exposed to upgrade concentrations of NSP from 50 to 1200 ppm each for 24-36 h exposure time. The highly effective concentrations were re-evaluated at lower exposure time as 3, 6, and 12 h.
Results: Lethal concentration (LC₅₀) and LC₉₀ versus mosquito larvae were (350 ppm/24 h and 1400 ppm/24 h, respectively). C. pipiens pupae proved slight high tolerance versus the effect of these nanoparticles as the two previous doses increased to 680 ppm/6 h and 1300 ppm/24 h. The LC₅₀ and LC₉₀ versus B. alexandrina were increased to 590 ppm/6 h and 980 ppm/48 h, respectively. Moreover, the embryonated snail egg masses appear more susceptible to the toxic effect of these nanoparticles than the non-embryonated eggs as the LC₅₀ and LC₉₀ were increased to 1450 ppm/12 h and 1250 ppm/48 h, respectively, for embryonated eggs, and it was 1400 ppm/24 h and 1890 ppm/48 h, respectively, for non-embryonated one.
Conclusion: The results open a new field for controlling the infectious diseases through eradication of their vectors by the way that avoids the resistance recorded from the successive chemical application in this field.