Efficacy of neem oil, <i>Zanthoxylum zanthoxyloides</i> and <i>Vernomia colorata</i> extracts on ticks and multi-resistant bacteria isolated from milk in the dairy value chain in Northern Côte d’Ivoire

Abstract

Livestock diseases are a major constraint to farmers in sub-Saharan Africa. However, an inadequate use of acaracides and antibiotics for animal diseases control leads to multi-resistance. Research on medicinal plants can be an alternative. The aim of this study was to assess the efficacy of three plant extracts on cattle ticks and multi-resistant bacteria isolated in milk from the Korhogo dairy basin. A cross- sectional survey was conducted from March to August 2023 in 24 farms in northern Côte d’Ivoire. Rhipicephalus (Boophilus) microplus and Amblyomma variegatum female adult ticks were sampled. A questionnaire was administrated to farmers on their knowledge and practices on diseases control. Three plant extracts (Azadirachta indica, Vernomia colorata and Zanthoxylum zanthoxyloides) were screened for bio-acaricide and anti-bacterial activities using adult immersion test and disc-diffusion assay respectively. At 5000 parts per million (ppm), neem oil and hydroalcoholic extract of the stem bark of Z. zanthoxyloides were effective on A. variegatum while only neem oil at 5000 ppm was active on R. (B) microplus. The three plant extracts at 5000 ppm showed no antibacterial activity on multiresistant isolates of Escherichia coli and Staphylococcus aureus. Neem oil can be used for plant-based bioacaricide development to control the resistant cattle tick R. (B) microplus in Côte d’Ivoire.