A preliminary analysis on the effect of copper on Anopheles coluzzii insecticide resistance in vegetable farms in Benin.

The use of agrochemicals in vegetable production could influence the selection for insecticide resistance in malaria vectors. Unfortunately, there is a dearth of information on the potential contribution of agrochemicals to insecticide resistance in Anopheles mosquitoes breeding on vegetable farms in southern Benin. A Knowledge, Attitudes and Practices study was conducted with 75 vegetable farmers from Houeyiho and Seme to determine the main agrochemicals used in vegetable production, and the concentration and frequency of application, among other details. Mosquitoes and breeding water were sampled from the farms for analysis. Bioassays were conducted on mosquitoes, while breeding water was screened for heavy metal and pesticide residue contamination. Lambda-cyhalothrin was the main insecticide (97.5%) used by farmers, and Anopheles coluzzii was the main mosquito identified. This mosquito species was resistant (30-63% mortality rate) to λ-cyhalothrin. It was also observed that 16.7% of the examined breeding sites were contaminated with λ-cyhalothrin residues. Furthermore, copper contamination detected in mosquito breeding sites showed a positive correlation (r = 0.81; P = 0.0017) with mosquito resistance to λ-cyhalothrin. The presence of copper in λ-cyhalothrin-free breeding sites, where mosquitoes have developed resistance to λ-cyhalothrin, suggests the involvement of copper in the insecticide resistance of malaria vectors; this, however, needs further investigation

Metazoan parasite communities of catfishes (Teleostei: Siluridae) in Benin (West Africa).

International audienceThe need for more precise information on the effect of dry season on fish parasite communities in Benin lead us to undergo a focus during this season in one of the major sites of collection fry by fish farmers.Metazoan parasites were then inventoried in 166 specimens of catfishes which constituted of C larias gariepinus, Clarias ebriensis, Synodontis schall, Synodontis nigrita, and Chrysichthys nigrodigitatus (Teleostei: Siluridae). Those fishes were collected from fishermen of Agonlin-Lowé at the side of Oueme River in south Benin from November 2011 to March 2012. In total, 12 parasite species were listed comprising three Monogena (Gyrodactylus sp., Synodontella sp., and Protoancylodiscoides chrysichthes), three Cestoda (Stoeksia pujehuni, Lytocestus sp., and Cestode indeterminate), five Nematoda (Paracamallanus cyathopharynx, Procamallanus laevionchus, Cithariniella petterae, Synodontisia thelastomoides, and nematode indeterminate), and one indeterminated Copepod species. Total infestation rate varied between 83.87 and 100% for the different fish species. This was high but independent of fish sex (χ(2) = 1.669, df = 4, nonsignificant). The highest mean intensity and mean abundance were, respectively, 44 and 13.33. Monogenea and Nematoda have elevated frequency of dominance, and their presence in the host is significantly correlated (r = -0.999; p < 0.05). Clariids were highly infected by Nematoda. Except for P. laevionchus and Proteoancylodiscoides, respectively, in C. gariepinus and in C. nigrodigitatus, the parasites showed clumped distribution. The component community diversity, as measured by the Shannon index (H'), revealed that S. schall had the most parasite diversit

A preliminary analysis on the effect of copper on Anopheles coluzzii insecticide resistance in vegetable farms in Benin

Open Access Journal; Published online: 14 April 2020The use of agrochemicals in vegetable production could influence the selection for insecticide resistance in malaria vectors. Unfortunately, there is a dearth of information on the potential contribution of agrochemicals to insecticide resistance in Anopheles mosquitoes breeding on vegetable farms in southern Benin. A Knowledge, Attitudes and Practices study was conducted with 75 vegetable farmers from Houeyiho and Seme to determine the main agrochemicals used in vegetable production, and the concentration and frequency of application, among other details. Mosquitoes and breeding water were sampled from the farms for analysis. Bioassays were conducted on mosquitoes, while breeding water was screened for heavy metal and pesticide residue contamination. Lambda-cyhalothrin was the main insecticide (97.5%) used by farmers, and Anopheles coluzzii was the main mosquito identified. This mosquito species was resistant (30–63% mortality rate) to λ-cyhalothrin. It was also observed that 16.7% of the examined breeding sites were contaminated with λ-cyhalothrin residues. Furthermore, copper contamination detected in mosquito breeding sites showed a positive correlation (r = 0.81; P = 0.0017) with mosquito resistance to λ-cyhalothrin. The presence of copper in λ-cyhalothrin-free breeding sites, where mosquitoes have developed resistance to λ-cyhalothrin, suggests the involvement of copper in the insecticide resistance of malaria vectors; this, however, needs further investigation