A Preliminary Study of the Biological Control of Strongyles Affecting Equids in a Zoological Park

The main goal in this research was to determine the beneficial effect of incorporating biological procedures in parasite control programs for equids in zoological parks. Two trials were developed for Equus quagga, E asinus , and E africanus asinus. The first trial (September 2010 to August 2011) consisted of chemotherapy only (ivermectin plus praziquantel), and the second trial (September 2011 to September 2012) consisted of administration of chemotherapy and chlamydospores of the nematophagous fungus Arthrobotrys (Duddingtonia) flagrans. The effect of these measures was evaluated by the estimation of the reduction in the fecal egg counts (FECR). In the first trial, 100% FECR values were achieved 15 days after treatment in all the animals. The egg reappearance period (ERP) was 2-3 months for the equids, and all of them were passing strongyle eggs in the feces at 2-4 months after their deworming. In the second experiment, the FECR values were 100% in the three species. ERPs of 3 months in the European donkeys, 4 months in the Africans, and 6 months in the zebras were recorded. All the equids had positive results for the coprological flotation test 4-8 months after anthelmintic administration. This preliminary study demonstrates the incorporation of chlamydospores of nematophagous fungus, as A flagrans appears highly promising for reduction of the infective stages of the strongyles affecting captive animals, but the experimental design precludes true determination of whether the treatment is fully efficacious.