The Prophylactic Effect of Ivermectin Treatments on Nematode Infections of Mammals in a Faunistic Park (Northern Italy)

Abstract

Nematode infections of mammals can spread in zoos and faunistic parks and lead to disease in humans and animals. Group treatment strategies with anthelminthic drugs are common. Still, their effectiveness should be verified by sensitive and specific copromicroscopic analyses. This study assessed longitudinal parasitological monitoring, by FLOTAC^® dual technique, in mammals housed in an Italian faunistic park, in order to verify the effectiveness of the two adopted ivermectin prophylactic treatments. Twenty-one species of herbivorous mammals from ten families were treated twice per year with ivermectin in an in-feed formulation (medicated feed containing 1.7 g/ton ivermectin daily, for 30 days in March and November), while 13 species of carnivores and primates from five families were treated once a month with oral or subcutaneous administrations of ivermectin (200 μg/kg body weight (b.w.), from March to November). Fecal samples were collected in June-July and October 2019 (late spring-early summer and autumn sampling groups, respectively). All nematode infections, sustained by Nematodirus spp., Capillaria spp., Trichuris spp., Parascaris spp. and Strongylida, were detected in samples collected from herbivores, presenting prevalence rates of infection of 17.3% (9/52), 15.4% (8/52), 15.4% (8/52), 5.8% (3/52), and 3.8% (2/52), respectively. All carnivores and primates tested negative. The general linear mixed model showed that nematode eggs' excretion in herbivores were influenced by sampling and sampling-host family interaction. Results showed that frequency and dose of prophylactic treatments in herbivores should be improved according to host and parasite taxonomic groups. The treatment adopted in carnivores and primates, together with hygienic management, was effective in nematode control.

Keywords: FLOTAC; endoparasites; ivermectin; nematode infections; parasitological monitoring; zoo mammals.

Figure 1

Estimated nematode Log(EPG+1), by time of sampling, in herbivores housed in the studied faunistic park obtained by a generalized linear mixed model. Vertical bars: 95% confidence intervals; horizontal black bar: pairwise comparison between nematode eggs excretion in the two sampling points.

Figure 2

Estimated nematode Log(EPG+1) by host family and time of sampling in herbivores housed in the studied faunistic park, obtained by a generalized linear mixed model. Vertical bars: 95% confidence intervals; horizontal black bar: significant pairwise comparison between nematode eggs excretion in the two samplings by family; n.s.: not significant.