Project Lead(s): Thiery Alavo
The intensive use of chemical insecticides against mosquitoes has led to widespread insecticide resistance in Benin.
There is an urgent need for malaria control programs to adopt integrated mosquito management approaches that include sustainable, non-chemical solutions.
One strategy is the use of the insect parasitic roundworm, Romanomermis iyengari, a parasite that develops inside mosquito larvae that die when the parasite emerges.
However, use of these nematodes in west Africa has been hampered by low yields from rearing using coarse sand, which is the common substrate used in North America for this approach.
The objective of the project was to develop a simple and cost-effective procedure for large-scale production of Romanomermis iyengari, to be used for mosquito control in pilot areas to significantly reduce malaria transmission.
The innovative approach was to rear the nematodes using coconut coir fibres as a substrate in the breeding tank, instead of coarse sand.
Coconut coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut. It is a by-product of coconut processing, and is cheaply and widely available in Benin.
Using this rearing method, yields of the nematodes were increased and were sufficient to be used in biological control-targeting larvae of malaria-transmitting mosquitoes in Benin.
This method of rearing the nematodes has the potential to facilitate wider distribution of these nematodes for use against malaria vectors in West Africa. Engagement of institutions (such as the World Health Organisation (WHO) and Ministries of Health in Sub-Saharan malaria-endemic countries) will be critical for this.
Since the simple rearing facility has been installed, three technical personnel can produce up to 150 million nematodes monthly. This amount is sufficient to suppress malaria vectors in about 75,000 square meters of breeding site monthly.
Several press conferences have been held to announce the study findings, which have been featured on national and international television stations. A 16-minute documentary on the project was also prepared for World Malaria Day in 2014.