Project Lead(s): Johnson Swai, Thomas Mascari
Malaria is the most serious and costly of the insect-borne diseases, causing about 660,000 deaths annually, mostly in children under the age of five. In Tanzania, the prevalence of malaria is as high as 26% in some regions.
Insect-borne diseases (such as malaria) are among the most complex of all infectious diseases to prevent and control, and are best combatted through a combination of vector control (use of public health insecticides on bed nets or by spraying), medicines and vaccines.
The overall aim of the project was to develop and test a low-cost CO2 source from yeast-molasses fermentation, to be used as an attractant in surveillance and control of vector-borne diseases, and also for soil enrichment in household vegetable gardens.
Disease-transmitting mosquitoes rely on their olfactory cues, including CO2 output, to find their hosts.
In the project, the efficacy of yeast-molasses fermentation as an alternative source of carbon dioxide was tested against yeast sugar fermentation and industrial carbon dioxide sources.
Experiments were conducted in Lupiro Village, Ulanga District, in southeast Tanzania.
Four odour-baited stations (OBS) were placed 30 meters apart and baited with CO2 generated from either yeast-sugar fermentation, yeast-molasses fermentation, industrial CO2 or a control trap (D) that was un-baited.
The trap baited with industrial CO2 (250 ml/min) caught the most mosquitoes, followed by the trap baited with CO2 generated by molasses (from a mixture of 40g of dry yeast, 0.25L of molasses and 1.5L of tap water in each 1.5L bottle), the trap with CO2 generated by yeast-sugar and the unbaited trap.
Micro-garden plots were then established to test whether yeast-molasses fermentation residues could be used to enrich vegetable gardens.
Even though the yeast-molasses fermentation is not as efficient as the industrial CO2 gas, the fact that all the materials required are locally available makes it a more convenient and cheap alternative to industrial, yeast-sugar fermentation and ice sources of carbon dioxide.
The study also found that yeast-molasses fermentation residue can act as a soil-enriching agent for vegetable micro gardens. Results showed that seeds treated with molasses fermentation residues germinated and sprouted faster than those in the urea treated and control chambers. Vegetable production was also enhanced in gardens treated with the residue.
However, more tests are required to confirm that yeast-molasses fermentation residues enrich soil and improve plant health.
The project team intends to apply for Transition To Scale (TTS) funding, to conduct further tests on yeast-molasses residues.