Efficacy of Allium Sativum, Allium Cepa and Jatropha Curcas on Common Natural Gastrointestinal Helminths in Dogs
Prevalence of animal diseases is one of the major livestock production constraints in Kenya with high impacts on livelihoods due to related economic losses affecting food security in the country. The use of synthetic drugs for disease management has challenges; this makes the use of medicinal plants for treatment a rational alternative. Resistance to drugs that are used for the treatment of infections caused by parasitic helminths is an inevitable consequence that could be attributed to excessive treatment frequency, under-dosing and the use of long-acting formulations that decline in activity over time. Helminths of zoonotic importance in dogs in Kenya include Toxocara canis, Ancylostoma caninum and Dipylidium caninum which are commonly found in intestines of dogs and can cause infestation in human beings. The purpose of this study was to investigate the In vitro and in-vivo efficacy of aqueous and ethanol extracts from bulbs of Allium cepa and Allium sativum as well as leaves of Jatropha curcas against common gastrointestinal helminths of dogs. Six extracts from the three plants were selected for in vitro anthelmintic screening by measuring ability to inhibit egg hatching, egg development and survival of larvae. For in vivo efficacy, fifteen puppies of mixed sexes, aged between 8 and 10 weeks, with an average weight of 2.2 kg were grouped into three with five animals in each group; Group 1 was treated with the extract, group 2 was given the recommended dose of a commercial anthelmintic while group 3 was given distilled water, all as single treatments. Fecal samples were obtained from each puppy a day before treatment (day 0) and on days 1, 3, 5, 7, 10 and 14 post treatment for determination of Eggs Per Gram (EPG). The anthelmintic effects were established by computing the percentage reduction of eggs shed in feces (fecal egg count reduction %FECR) using the pretreatment and post treatment EPG counts. Whole blood was collected from each puppy on days 0, 7 and 14 to determine changes in the hematological parameters. Two puppies from each group were then randomly selected and sacrificed for postmortem examination and for collection of intestinal contents for total worm counts and identification. The ethanol extracts of A. cepa inhibited hatching of 100% of eggs of A. caninum between 10,000 ug/ml and 2,500 ug/ml and 100% of eggs of T. canis between 10,000 ug/ml and 1,250 ug/ml while that of A. sativum inhibited hatching of 100% of A. caninum eggs between 10,000 ug/ml and 5,000 ug/ml. However the ethanol extract of A. sativum did not have similar effect on the development of T. canis eggs at these concentrations. The ethanol extracts of both A. cepa and A. sativum affected the survival of 100% of A. caninum larvae at a concentration of 156 ug/ml and higher. The aqueous extracts of the three plants had moderate effects on the eggs and the larvae of both parasites. Ethanol extract of A. cepa was found to be the most effective in vitro and therefore was tested for in vivo efficacy. When tested in vivo at a dose of 6 mg/kg of body weight, the ethanol extract of A. cepa produced a percentage fecal egg count reduction of 47% for strongyle eggs. A significant drop in WBC (p=0.035) was observed 7 days after treatment and a significant increase in RBC (p=0.04) and HGB (p=0.001) 14 days after treatment. The changes in hematological parameters when compared among the control and treatment groups were found to be significant (p<0.05) 7 days after treatment for WBC, RBC, HGB and HCT, and 14 days after treatment for MCHC. No toxicity signs were observed following oral treatment with the ethanol of A. cepa extract at 6 mg/kg. On post mortem examination, the sacrificed animals were anemic with foci of congestion and hemorrhages on intestinal mucosa. Adult ascarids, hookworms and whip worms were isolated from their intestinal content although fewer in animals from the positive control group. The results indicate that the ethanol extracts of A. cepa and A. sativum have anthelmintic properties which can be investigated further to support the ethnoveterinary use of the plants as anthelmintic drugs for control and treatment of worm infestation in dogs. The 47% efficacy against hookworms observed in treated puppies was due to the anthelmintic properties of the crude ethanol extract of A. cepa. This was supported by the hematological changes which occurred as a result of administration of the extract.
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