Potential Use of Neem Leaf Slurry as a Sustainable Dry Season Management Strategy to Control the Malaria Vector <I>Anopheles gambiae</I> (Diptera: Culicidae) in West African Villages

Abstract

Larval management of the malaria vector, Anopheles gambiae Giles s.s., has been successful in reducing disease transmission. However, pesticides are not affordable to farmers in remote villages in Mali, and in other material resource poor countries. Insect resistance to insecticides and nontarget toxicity pose additional problems. Neem (Azadirachta indica A. Juss) is a tree with many beneficial, insect bioactive compounds, such as azadirachtin. We tested the hypothesis that neem leaf slurry is a sustainable, natural product, anopheline larvicide. A field study conducted in Sanambele (Mali) in 2010 demonstrated neem leaf slurry can work with only the available tools and resources in the village. Laboratory bioassays were conducted with third instar An. gambiae and village methods were used to prepare the leaf slurry. Experimental concentration ranges were 1,061-21,224 mg/L pulverized neem leaves in distilled water. The 50 and 90% lethal concentrations at 72 h were 8,825 mg/L and 15,212 mg/L, respectively. LC concentrations were higher than for other parts of the neem tree when compared with previous published studies because leaf slurry preparation was simplified by omitting removal of fibrous plant tissue. Using storytelling as a medium of knowledge transfer, villagers combined available resources to manage anopheline larvae. Preparation of neem leaf slurries is a sustainable approach which allows villagers to proactively reduce mosquito larval density within their community as part of an integrated management system.

Application of loop analysis for evaluation of malaria control interventions

“…However, several limitations have been reported. They include disturbance to local ecosystems such as predator–prey relationships [a4,3(−) x a8,4(−) = mosquitoes(+)] [41,53], mosquitoes’ resistance to larvicides [a7,3(+) x a3,7(−) x a8,3(−) = mosquitoes(+)] [54-56] and ineffectiveness in extensive water bodies [24,57]. In addition, Bti lacked inherent residual activity outside of potable container habitats, especially in habitats with turbid water or high organic loading [58].…”

Neem Extract

“…A variety of preparations made from different parts of neem exhibit antimicrobial (antibacterial, antiviral, and antifungal), antimalarial, antioxidant, antimutagenic, anticarcinogenic, anti-inflammatory, contraceptive, and antiulcer activities. The hormone-mimicking action of neem extracts causes interference with the parasitic life cycle, thereby inhibiting their nutrition intake as well as the hatching of eggs (Kusamran et al, 1998;Mahmoudi et al, 2002;Kumar and Navaratnam, 2013;Luong et al, 2012). Neem bark and roots are excellent bio-insecticides for the control of ectoparasites like fleas and ticks, as well as for treating skin infections such as acne, scabies, psoriasis, and eczema (Abdel-Ghaffar et al, 2012).…”

Women’s perceptions of health, quality of life, and malaria management in Kakamega County, Western Province, Kenya

“…For example, commercial repellent lotions would be difficult to distribute in Kakamega County because residents consider them too expensive. Interestingly, the neem tree, Azadirachta indica which grows in this area, is an insect growth regulator (prevents adult development) for anopheline mosquitoes (Luong et al 2012) and is a repellent for adult mosquitoes (Dunkel 2015). Using neem leaf slurry as a repellent dip for cloths, clothes, or even bed nets or in homemade soap are potential local solutions that do Fig.…”

“…In these Malian communities where bio-cycle storytelling was developed by Dunkel et al, stagnant water disappeared, larvae were monitored, and villagers readily learned to use neem leaves, Azadirachta indica from local trees to create an insect growth regulator safe to use in semi-permanent stagnant water (Luong et al 2012). When significantly less malaria was locally observed and documented, villagers conveyed the bio-cycle stories to nearby villages in part to help other communities facing high rates of malaria and in part to prevent the reintroduction of the malaria protozoan back into their own community.…”