The abomasal trichostrongyle, Haemonchus spp., is a health concern in ruminants (domestic and exotic) in the southeastern U.S. and abroad.1-3 Non-chemical alternatives are now being integrated in strategic control programs in exotic species to reduce drug selection pressures and address resistance issues in zoological settings. The nematophagous fungus, Duddingtonia flagrans, has shown promise for environmental control of the infective third-stage larvae (L3) in the feces in the environment.3 Short- and long-term clinical trials were conducted to evaluate this product for controlling Haemonchus spp. in exotic artiodactyls at Disney’s Animal Kingdom® and Disney’s Animal Kingdom Lodge®. The trials involved feeding spores of the nematode-trapping fungus to select species in order to reduce L3 survival/development in feces and, thus, reduce exhibit forage contamination. The fungal spores were fed daily at 250,000 spores/kg BW for five days, a lower-dosage trial of 30,000 spores/kg BW for five days, and then a long-term trial at 30,000 spores/kg BW for three months. Feces were collected from control and treatment animals before, during, and after the treatment course to look at fecal egg counts (FEC) and L3 culture survival rates. Savannah grass samples were collected during the three-month trial to evaluate pasture L3 counts (PLC) during the treatment period. Both doses showed successful reduction in survival of L3 in vitro, implying that daily dosing of 30,000 spores/kg BW may be an effective tool for environmental control of Haemonchus spp. in exotic artiodactyls. Fecal egg count and PLC were reduced during the long-term treatment. Based on these data, the use of Duddingtonia flagrans has been strategically integrated into the parasite management program based on savannah PLC trends. The program now includes giving 30,000 spores/kg BW daily for three months to high FEC shedding species at Disney’s Animal Kingdom® and Disney’s Animal Kingdom Lodge®.
The authors would like to thank the animal health technicians and animal care teams at Disney’s Animal Kingdom® and Disney’s Animal Kingdom Lodge® for their tireless hours of fecal collection and processing to make these investigations possible, as well as the technical support team at Louisiana State University and International Animal Health Products (Huntington, NSW, Australia) for sample processing and fungus supply, respectively.
1. Fontenot DK, Miller JE. Alternatives for gastrointestinal parasite control in exotic ruminants. In: Fowler ME, Miller RE, eds. Zoo and Wild Animal Medicine. 7th ed. Philadelphia, PA: WB Saunders Co.; 2010:581–588.
2. Fontenot M, Miller M, Peña M, Larsen M, Gillespie A. Efficiency of feeding Duddingtonia flagrans chlamydospores to grazing ewes on reducing availability of parasitic nematode larvae on pasture. Vet Parasitol. 2003;118:203–213.
3. Terrill T, Larsen M, Samples O, Husted S, Miller J, Kaplan R, Gelaye S. Capability of the nematode-trapping fungus Duddingtonia flagrans to reduce infective larvae of gastrointestinal nematodes in goat feces in the southeastern United States: dose titration and dose time interval studies. Vet Parasitol. 2004;120:285–296.