Evaluation of anthelmintic properties of ethnoveterinary plant preparations used as livestock dewormers by pastoralists and small holder farmers in Kenya

Parasitic nematodes, especially Haemonchus contortus, are among the most common and economically important causes of infectious diseases of sheep and goats owned by pastoralists and small holder farm ers in East Africa. In Kenya, control of these infections mainly relies on the use of anthelmintic dr ugs. However, ethnoveteri nary medicine (EVM) preparations are widely used by pastoralists and small holder farmers (SHF) for treatment of their livestock agains t helminth parasites. This thesis covers the evaluation of the anth elmintic efficacy of some EVM preparations used by pastoralists and SHF in Kenya. The plant species selected, and prepared for animal dosing with the help of traditional healers (THs) were: Aframomum sanguineum, Albizia anthelmintica, Ananas comosus, Annona s quamosa, Azadirachta indica, Dodonaea angustifolia, Hagenia abyssinica, Hildebrandtia sepalosa, Myrsine africana, Olea europaea var. africana , and Rapanea melanophloeos . Evaluation was carried out in two in vivo infection models, namely H. contortus in sheep and Heligmosomoides polygyrus in mice. The anthelmintic efficacy of the EVM preparations was monitored through faecal egg count (FEC) reduction, at regular intervals fo r a period of 2 – 3 weeks post treatment in sheep. Monitoring in mice was done through FE C and total worm counts (TWC) one week after treatment. An a priori cut-off value of 70% reduction of FEC and TWC, to denote useful anthelmintic efficacy, was used for both sheep and mice. Of the ten plant species tested in sheep, the largest decrease of 34% in FEC was measured from a bark preparation of A. anthelmintica collected from the Samburu District. None of the other plant species had a significant effect on FEC. Similarly, the seven plant species and some of their related active constituents evaluated in mice did not significantly reduce FEC or remove parasites. Preparations of A. anthelmintica at doses above 0.5 g per mouse were toxic. In conclusion, no reduction of FEC or TWC greater than the a priori value of 70% was observed in sheep or in mice. Therefore, the plants evaluated were ineffective as anthelmintics in the preparations and forms that were used. Keywords : Ethnoveterinary preparations, sheep, mice, Haemonchus contortus , Heligmosomoides polygyrus, anthelmintic efficacy, pastoralists, smallholder farmers, Kenya