Assessment of the impact of the biological larvicide VectoMax G: Combination of Bacillus thuringiensis and Lysinibacillus sphaericus on non-target aquatic organisms in Yaoundé-Cameroon
Djepand-Ngognouak Thierry,
Landre Djamouko-Djonkam,
Foko Dadji Gisèle,
Mayi Marie Paul Audrey,
Tchuinkam Timoléon,
Zébazé-Togouet Serge Hubert,
Wondji Charles Sinclair,
Antonio-Nkondjio Christophe
Affiliations
Djepand-Ngognouak Thierry
Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
Landre Djamouko-Djonkam
Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, P.O. Box 067, Dschang, Cameroon
Foko Dadji Gisèle
Laboratory of Zoology, Higher Teacher Training College, University of Yaoundé I, P.O. Box 47, Yaoundé, Cameroon
Mayi Marie Paul Audrey
Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, P.O. Box 067, Dschang, Cameroon
Tchuinkam Timoléon
Vector Borne Diseases Laboratory of the Applied Biology and Ecology Research Unit (VBID-URBEA), Department of Animal Biology, Faculty of Sciences of the University of Dschang, P.O. Box 067, Dschang, Cameroon
Zébazé-Togouet Serge Hubert
Faculty of Science, University of Yaoundé I, P.O. Box 337, Yaoundé, Cameroon
Wondji Charles Sinclair
Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK; Centre for Research in Infectious Disease (CRID), Yaoundé, P.O. Box 13591, Cameroon
Antonio-Nkondjio Christophe
Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon; Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, L3 5QA, Liverpool, UK; Corresponding author. Malaria Research Laboratory, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), P.O. Box 288, Yaoundé, Cameroon.
There has been a renewed interest for larviciding during the recent decade. Although biological larvicides are considered not to be harmful to non-target organisms, there is still not sufficient data on the effect of new long-lasting larvicide formulations such as VectoMax G combining Bacillus thuringiensis israelensis and Lysinibacullus sphaericus on the environment especially on non-target organisms. The present study aimed to assess the possible influence of VectoMax G on the diversity and abundance of the aquatic fauna cohabiting with mosquito larvae in breeding habitats during a larviciding trial in the city of Yaoundé.Twelve districts of the city of Yaoundé divided into 6 intervention and 6 control sites were chosen for the study. In each district 4 semi-permanent or permanent aquatic habitats were followed. VectoMax G application was done once every two weeks during 6 months and aquatic organisms were collected 48 h after each treatment. All collected organisms were brought to the laboratory for identification. Physico-chemical parameters were recorded as well.A high diversity of the zooplankton was recorded in the intervention areas with 28 species collected against 14 species in the control areas. Cladocerans were the most represented group in both sites while Ostracods were found only in control sites. A total of 19 macro-invertebrates species were recorded in the control areas vs 16 species in the intervention areas. Gasteropods were the most represented groups of macro-invertebrates. Vertebrates such as larvivorous fishes and amphibians larvae were also found in approximately similar densities in both sites.The study indicated no significant influence of larviciding with VectoMax G on the diversity and abundance of the non-target aquatic fauna in the city of Yaoundé.
