Prevalence, Phytochemical Investigation, and In Vitro Acaricidal Efficacy Evaluation of Dodonaea angustifolia, Eucalyptus globulus, Millettia ferruginea, and Euphorbia abyssinica against Sarcoptic Mange of Camel, Babile District, Ethiopia

Abstract

The present study was designed to determine the prevalence of sarcoptic mange from camels; evaluate the presence of secondary metabolites in the methanolic leaf extracts of D. angustifolia M. ferruginea, E. abyssinica, and E. globulus essential oil; and also evaluate their in vitro acaricidal efficacy against camel sarcoptic mange in the Babile District, Ethiopia. Each plant was subjected to qualitative phytochemical screening for the presence or absence of secondary metabolites. The in vitro application of each plant extracts was carried out against clinical mange mites with positive and negative controls. Accordingly, a total of 384 camels were examined for the presence of Sarcoptes scabiei var. cameli. The study revealed that an overall prevalence of 67(15.9%) animals was infested by mange mites. The study showed that a higher prevalence was observed in female camel than in male camel with no statistically significant difference ( $P>0.05$ ). However, statistically higher prevalence ( $P<0.05$ ) was recorded in young camel (28.2%) than adult (10.95%). The study also revealed that statistically higher prevalence ( $P<0.05$ ) was observed in poor body conditioned camel (26.3%) than medium (13.5%) and good body condition camels (5.4%). For the in vitro evaluation of the efficacy of plant extracts, essential oils and crude extracts of four medicinal plant extracts were diluted at different concentrations from 200 mg/mL to 6.25 mg/mL and added to Petri dishes containing the adult stage of Sarcoptes scabiei. The efficacy of each plant was determined by comparing the mortality of mites treated with plant extracts with those of mites in nontreated (2% Tween 80) and treated (diazinon) control plates. After 3 h of contact, all concentrations of E. globulus, D. angustifolia, M. ferruginea, and E. abyssinica showed good in vitro acaricidal efficacy compared to controls nontreated control ( $P<0.05$ ). After 3 h of exposure to the methanolic extract of D. angustifolia and the essential oil of E. globulus, comparable acaricidal efficacy in causing mites mortality at concentrations of 200 mg/mL has been recorded when compared to reference drugs. The crude extract of E. abyssinica showed a lower acaricidal efficacy compared to reference drugs. The present plant extracts studied showed comparable acaricidal efficacy to reference drugs at concentrations of 200 mg/mL. Therefore, further epidemiological and in vivo acaricidal studies as well as toxicity of the plants should be conducted in area to use these plants as alternative treatment option to substitute the use of synthetic drugs for which most of mites developed resistance and control impacts Sarcoptes scabiei on camel.