Effect of the Filamentous Fungus Mucor circinelloides On The Development of Eggs of the Rumen Fluke Calicophoron daubneyi (Paramphistomidae)

This study screened for anthelmintic and/or antitumour bioactive compounds from Thai indigenous plants and evaluated effectiveness against three different worm species and two cancer cell lines. Methylene chloride and methanol extracts of 32 plant species were screened for in vitro anthelmintic activity against three species of worms, the nematode Caenorhabditis elegans, the digeneans Paramphistomum epiclitum and Schistosoma mansoni (cercariae). Cytotoxicity of the extracts was evaluated against two cancer cell lines: human amelanotic melanoma (C32) and human cervical carcinoma (HeLa) by the SRB assay. Anthelmintic and anticancer activities were evaluated by the inhibiting concentration at 50% death (IC(50)) and the selectivity index (SI) relative to human fibroblasts. None of the extracts were active against Paramphistomum epiclitum. Plumbagin, a pure compound from Plumbago indica, had the strongest activity against Caenorhabditis elegans. The methylene chloride extract of Piper chaba fruits had the strongest activity against schistosome cercariae. Strong cytotoxicity was shown by the methylene chloride extract of Michelia champaca bark and the methanol extract of Curcuma longa rhizome against C32 and HeLa, respectively. These extracts had higher SI (>100) than positive controls in relation to either the worms or the cell lines. The methanol extract of Bouea burmanica had a slightly lower activity towards C32 cells than did Michelia champaca but had a much higher SI (>27,000). The plant species screened in this research was recorded by several indigenous medicinal practitioners as antiparasitic, anticancer and/or related activities to the human major organ system.

Recently, sharp increases in the prevalence of rumen fluke infections have been recorded throughout Western Europe. However, scarce information is available on the diagnosis, pathogenic importance and control of this parasite. We undertook 3 pilot studies to gain more insights into these aspects of rumen fluke biology in cattle. First, we evaluated the diagnostic performance of mini-FLOTAC to detect adult rumen fluke infections based on faecal egg count in an abattoir survey and found high sensitivity (0.94) and specificity (0.98). Moreover, there was an association between ruminal fluke burden (assessed by visual scoring) and faecal egg count and a cut-off of 200 eggs per gram is proposed to detect highly infected animals (>200 flukes present in the rumen and/or reticulum). There was also a significant association between ruminal fluke burden and faecal consistency. However, in a second study, we performed a case-control field survey to investigate the association between rumen fluke infection and herd-level problems with diarrhoea and no association was found. Finally, we evaluated the use of closantel (Flukiver(®), Elanco Animal Health, subcutaneous administration at 10mg/kg) to treat rumen fluke infection on 3 herds, but no significant reduction in egg output post-treatment was found. Because this result is in contrast with a previous study using an oral dose of closantel, more research is required into the effect of administration route on the efficacy of closantel on rumen fluke.