Green-synthesized metal nanoparticles for mosquito control: A systematic review about their toxicity on non-target organisms.

Studies capturing the high efficiency of green-synthesized metal nanoparticles (NPs) in targeting mosquito vectors of the world's main infectious diseases suggest the NPs' possible utilization as bio-insecticides. However, it is necessary to confirm that these potential bio-insecticides are not harmful to non-target organisms that are often sympatric and natural enemies of the vectors of these diseases. In this systematic review, we comprehensively analyse the content of 56 publications focused on the potentially deleterious effects of NPs on these non-target organisms. Current research on biosynthesised NPs, characterization, and impact on mosquito vectors and non-target larvivorous organisms is reviewed and critically discussed. Finally, we pinpoint some major challenges that merit future investigation. Plants (87.5%) were mainly used for synthesizing NPs in the studies. NPs were found to be spherical or mainly spherical in shape with a large distribution size. In most of the included studies, NPs showed interesting mosquitocidal activity (LC50 < 50 ppm). Some plant families (e.g., Meliaceae, Poaceae, Lamiaceae) have produced NPs with a particularly high larvicidal and pupicidal activity (LC50 < 10 ppm). Regarding non-target organisms, most of the studies concluded that NPs were safe to them, with boosted predatory activity in NP-treated milieu. In contrast, some studies reported NP-elicited adverse effects (i.e., genotoxic, nuclear, and enzymatic effects) on these non-target organisms. This review outlines the promising mosquitocidal effects of biosynthesized NPs, recognizing that NPs' potential usage is currently limited by the harm NPs are thought pose to non-target organism. It is of utmost importance to investigate green NPs to determine whether laboratory findings have applications in the real world.

Malaria Transmission around the Memve'ele Hydroelectric Dam in South Cameroon: A Combined Retrospective and Prospective Study, 2000⁻2016.

Dam constructions are considered a great concern for public health. The current study aimed to investigate malaria transmission in the Nyabessan village around the Memve'ele dam in South Cameroon. Adult mosquitoes were captured by human landing catches in Nyabessan before and during dam construction in 2000-2006 and 2014-2016 respectively, as well as in the Olama village, which was selected as a control. Malaria vectors were morphologically identified and analyzed for Plasmodium falciparum circumsporozoite protein detection and molecular identification of Anopheles (A.) gambiae species. Overall, ten malaria vector species were identified among 12,189 Anopheles specimens from Nyabessan (N = 6127) and Olama (N = 6062), including A. gambiae Giles (1902), A. coluzzii Coetzee (2013), A. moucheti Evans (1925), A. ovengensis Awono (2004), A. nili Theobald (1903), A. paludis Theobald (1900), A. zieanni, A. marshallii Theobald (1903), A. coustani Laveran (1900), and A. obscurus Grünberg (1905). In Nyabessan, A. moucheti and A. ovengensis were the main vector species before dam construction (16-50 bites/person/night-b/p/n, 0.26-0.71 infective bites/person/night-ib/p/n) that experienced a reduction of their role in disease transmission in 2016 (3-35 b/p/n, 0-0.5 ib/p/n) (p < 0.005). By contrast, the role of A. gambiae s.l. and A. paludis increased (11-38 b/p/n, 0.75-1.2 ib/p/n) (p < 0.01). In Olama, A. moucheti remained the main malaria vector species throughout the study period (p = 0.5). These findings highlight the need for a strong vector-borne disease surveillance and control system around the Memve'ele dam.