Parasitology

Research Article

Efficacy of the cyclooctadepsipeptide PF1022A against Heligmosomoides bakeri in vitro and in vivo

UZOMA NWOSUa1a2, MIREILLE VARGASa1a2, ACHIM HARDERa3 and JENNIFER KEISERa1a2 c1

a1 Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland

a2 University of Basel, P.O. Box, CH-4003 Basel, Switzerland

a3 Bayer Animal Health GmbH, Building 6700, 51368 Leverkusen, Germany

SUMMARY

The cyclooctadepsipeptide PF1022A derived from the fungus, Mycelia sterilia, is characterized by a broad spectrum of activity against different parasitic gastrointestinal nematodes of livestock. In the present work the anthelmintic activity of PF1022A against Heligmosomoides bakeri, a widely used laboratory model was studied. Albendazole, ivermectin and levamisole served as reference. In vitro, PF1022A showed low activity on embryonation but significantly inhibited egg hatch (10 and 100 μg/ml), whereas albendazole (10 and 100 μg/ml) revealed statistically significant inhibitions of both embryonation and egg hatch. PF1022A (1–100 μg/ml) completely inhibited larval movement at most examination points. Comparable significant anthelmintic activity on the larval stages of H. bakeri was observed with levamisole (48–100%), while slightly lower activities were observed with ivermectin (20–92%) and albendazole (0–87%) at 1–100 μg/ml. PF1022A and levamisole significantly inhibited motility and egg release of adult worms, while albendazole and ivermectin failed to demonstrate activity. Significant worm burden reductions were achieved with PF1022A, levamisole and ivermectin in vivo. For example, at 0·125 mg/kg PF1022A a worm burden reduction of 91·8% was observed. The use of drug combinations did not further enhance the in vitro and in vivo activity of PF1022A. In conclusion, further investigations are warranted with PF1022A, as the drug is characterized by significant larvicidal and nematocidal activity in vitro and in vivo.

(Received January 13 2011)

(Revised April 07 2011)

(Accepted April 20 2011)

(Online publication July 15 2011)

Correspondence:

c1 Corresponding author: Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel, Switzerland. Tel: +41 61 284 8218. Fax: +41 61 284 8105. E-mail: jennifer.keiser@unibas.ch

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