doi:10.1038/nindia.2016.3 Published online 12 January 2016
Researchers have discovered that silver and carbon nanoparticles can separately kill the larvae and pupae of Culex quinquefasciatus — mosquitoes that transmit lymphatic-filariasis-causing parasites to humans1. These nanoparticles could potentially be useful for checking the spread of filariasis in humans.
Lymphatic filariasis, also known as elephantiasis, causes painful and disfiguring swelling of legs and genitalia, and it afflicts millions in urban and semi-urban areas of Asia. Anti-filarial drugs can treat the disease but are unable to cure chronic infection.
To find an alternative way to combat lymphatic filariasis, the researchers converted silver nitrate solutions into silver nanoparticles using seed extracts of a medicinal plant and also synthesized carbon nanoparticles from citric acid and urea.
The silver and carbon nanoparticles were found to be toxic to Cx. quinquefasciatus larvae and pupae. The water bug Lethocerus indicus, which lives in the same habitat as the mosquitoes, naturally devours the larvae and pupae. Treating the water bug with the nanoparticles increased their efficiency in killing the larvae and pupae. The scientists found that low doses of the silver nanoparticles reduced the motility of the mosquito larvae and pupae, allowing the water bug to devour them more efficiently.
The nanoparticles did not detrimentally affect the behaviour of other aquatic animals living in the same environment, suggesting that they could be used to reduce the larval and pupal populations of filariasis-spreading mosquitoes, the researchers say.
1. Murugan, K. et al. Carbon and silver nanoparticles in the fight against the filariasis vector Culex quinquefasciatus: genotoxicity and impact on behavioral traits of non-target aquatic organisms. Parasitol. Res. (2016) doi: 10.1007/s00436-015-4837-9