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

Abstract

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