Assessing the potential effects of selected Kenyan medicinal plants on longevity of Phlebotomus duboscqi (Diptera: Psychodidae)

Abstract

Phlebotomus duboscqi (Diptera: Psychodidae) has been incriminated as the vector of Leishmania major, the causative agent of zoonotic cutaneous leishmaniasis (ZCL) in various parts of the world. This study sought to describe the influence of Tarchonanthus camphoratus (Asteraceae), Acalypha fruticosa (Euphorbiaceae) and Tagetes minuta (Asteraceae) crude extracts on longevity of Phlebotomus duboscqi. These medicinal plants were prepared from the dried aerial parts followed by grinding into a fine powder and then soaking the plant materials in methanol and ethyl acetate solvents for 48 hours. After 48 hours, the materials were filtered and dried out using a rotary evaporation at 30-35°C. The extracts obtained were later prepared into appropriate concentrations for bioassay. Groups of ten female sand flies were aspirated into vials where they were fed on a mixture of the plant extracts and sucrose solution. The crude extracts reduced the survival time of P. duboscqi significantly (P<0.05). It was found out that P. duboscqi flies that 
had fed on A. fruticosa extract had a life span of 7 days, T. minuta 7 days and T. camphoratus 9 days as compared to a life span of 12 
days in P. duboscqi flies that formed the control group. The observation that A. fruticosa, T. minuta andT. camphoratus have effect on longevity of P. duboscqiimplies that these plants can be used as a natural means of reducing transmission of leishmaniasis by reducing the life span of Phlebotomus duboscqi eventually killing them.