Effects of ivermectin application on the diversity and function of dung and soil fauna: Regulatory and scientific background information

Abstract

The application of veterinary medical products to livestock can impact soil organisms in manure-amended fields or adversely affect organisms that colonize dung pats of treated animals and potentially retard the degradation of dung on pastures. For this reason, the authorization process for veterinary medicinal products in the European Union includes a requirement for higher-tier tests when adverse effects on dung organisms are observed in single-species toxicity tests. However, no guidance documents for the performance of higher-tier tests are available. Hence, an international research project was undertaken to develop and validate a proposed test method under varying field conditions of climate, soil, and endemic coprophilous fauna at Lethbridge (Canada), Montpellier (France), Zurich (Switzerland), and Wageningen (The Netherlands). The specific objectives were to determine if fecal residues of an anthelmintic with known insecticidal activity (ivermectin) showed similar effects across sites on 1) insects breeding in dung of treated animals, 2) coprophilous organisms in the soil beneath the dung, and 3) rates of dung degradation. By evaluating the effects of parasiticides on communities of dung-breeding insects and soil fauna under field conditions, the test method meets the requirements of a higher-tier test as mandated by the European Union. The present study provides contextual information on authorization requirements for veterinary medicinal products and on the structure and function of dung and soil organism communities. It also provides a summary of the main findings. Subsequent studies on this issue provide detailed information on different aspects of this overall project. Environ Toxicol Chem 2016;35:1914-1923. © 2015 SETAC.

Is qualitative and quantitative metabarcoding of dung fauna biodiversity feasible?

“…However, the species richness present and that barcoded do correlate positively (Table ; r = 0.63) and have similar coefficients of variation, so the type II error was roughly similar in all samples. Because biodiversity assessments in the present study and other contexts typically compare various samples across populations or treatments (in the present special section livestock medication levels ), detection of differences between them might therefore not be strongly affected by inflated barcoding richness (assuming no systematic biases). On the other hand, the barcoding diversity index was actually lower than the actual species diversity of the samples when based on the relative abundances of raw reads for all hits, but higher when based on the decadic logarithm of these relative abundances (Table ).…”

Modelling the impact of targeted anthelmintic treatment of cattle on dung fauna

“…The topic is a key area for future work to enable effective assessment and regulation of the use of veterinary medicines, with regards to their impact on all aspects of biodiversity (Adler et al, 2016). Future work should also include economic analysis, in order to balance short-term production gains with longer term environmental impacts.…”

Proposal for a Monitoring Concept for Veterinary Medicinal Products with PBT Properties, Using Parasiticides as a Case Study

“…In this context, several guidance documents describing field methodologies were checked for useful information, e.g., regarding the sampling of soil organisms or the measurement of organic matter degradation [ 19 , 20 ] . Relevant aspects related to the post-authorization of parasiticides were compiled based on personal experience, e.g., from field studies performed with ivermectin [ 21 , 22 ], or information from available literature [ 23 ]. In addition, experiences from other legal frameworks such as the registration of pesticides [ 16 , 24 ], or the environmental risk assessment of genetically modified organisms (GMO) [ 25 ] were considered.…”