Oral dosing with papaya latex is an effective anthelmintic treatment for sheep infected with Haemonchus contortus

Abstract

BackgroundThe cysteine proteinases in papaya latex have been shown to have potent anthelmintic properties in monogastric hosts such as rodents, pigs and humans, but this has not been demonstrated in ruminants.MethodsIn two experiments, sheep were infected concurrently with 5,000 infective larvae of Haemonchus contortus and 10,000 infective larvae of Trichostrongylus colubriformis and were then treated with the supernatant from a suspension of papaya latex from day 28 to day 32 post-infection. Faecal egg counts were monitored from a week before treatment until the end of the experiment and worm burdens were assessed on day 35 post-infection.ResultsWe found that the soluble fraction of papaya latex had a potent in vivo effect on the abomasal nematode H. contortus, but not on the small intestinal nematode T. colubriformis. This effect was dose-dependent and at tolerated levels of gavage with papaya latex (117 μmol of active papaya latex supernatant for 4 days), the H. contortus worm burdens were reduced by 98%. Repeated treatment, daily for 4 days, was more effective than a single dose, but efficacy was not enhanced by concurrent treatment with the antacid cimetidine.ConclusionsOur results provide support for the idea that cysteine proteinases derived from papaya latex may be developed into novel anthelmintics for the treatment of lumenal stages of gastro-intestinal nematode infections in sheep, particularly those parasitizing the abomasum.

A cysteine protease from the latex of Ficus benjamina has in vitro anthelmintic activity against Haemonchus contortus

“…Regarding pH stability, FbP could remain active in the abomasum of ruminants, which is the H. contortus habitat. The abomasum corresponds to the glandular stomach of ruminants; under normal conditions, the abomasum has an acidic pH (2-3), but H. contortus infection can raise the abomasal pH to values close to neutral (6-7) (NICHOLLS & LEE, 1989;BUTTLE et al, 2011), which is the optimal range of FbP performance (Figure 2A). Moreover, FbP has the potential to display anthelmintic activity against other nematodes.…”

Anthelmintic activity of Leucaena leucocephala protein extracts on Haemonchus contortus

“…Controlling these parasites consists primarily of using synthetic anthelmintics (OLIVEIRA et al, 2011), but inappropriate use of anthelmintics has led to an increase in resistant nematode strains . As such, certain plant compounds have been considered as an alternative for the control of these parasites (EGUALE et al, 2007;BUTTLE et al, 2011).…”

In Vitro Evaluation of Anthelmintic Efficacy of Some Plant Species Possessing Proteinases and/or Other Nitrogenous Compounds in Small Ruminants

“…The primary anthelmintic bioactive phytochemical in the above crude extract is proteases in nature, and similar to that of some plant species in the current study [44]. Cysteine proteinases from papaya latex administered to sheep infected with Haemonchus contortus and Trichostrongylus colubriformis, also exhibited dose dependent anthelmintic activity [45]. Additionally, aqueous extracts of pineapple skin and bromelain exhibited dose-dependent in vitro inhibition on Haemonchus contortus egg-hatch and larval development in sheep [46].…”