Challenges of copro-parasitological surveys in wild Iberian ibex (Capra pyrenaica) populations addressed through a combination of molecular and statistical tools

Copro-parasitological surveys in wildlife face challenges due to the
secretive nature of many species and the unknown performance of the
diagnostic tests employed. To overcome these issues, we used a combination
of hierarchical models (site-occupancy and N-mixture models) applied to
copro-parasitological data obtained from faecal samples assigned to the
host species by molecular methods in the Iberian ibex in north-western
Iberian Peninsula. The aims were to compare the performance of four
diagnostic tests (Mini-FLOTAC, McMaster, Willis flotation, and natural
sedimentation) and to use this methodological approach (molecular analysis
with hierarchical models) to better estimate positivity proportion and
shedding intensity in a wild ibex population. Pooled faecal samples were
collected, and those confirmed by molecular analyses to be the host
species in question were included in the study. Hierarchical models
confirmed different performances of each diagnostic test, with Mini-FLOTAC
showing higher sensitivity for eimeriid coccidia, Willis flotation (for
proportion positive) and McMaster (for shedding intensity) in
gastrointestinal Strongylida, and equal performance of MiniFlotac/Willis
flotation (for proportion positive) and MiniFlotac/McMaster (for shedding
intensity) in Moniezia spp. This study employed a combination of molecular
and statistical methods that improved the estimates of prevalence and
shedding intensity and allowed us to compare the performance of four
diagnostic tests while assessing the effect of covariates. Such
improvements are critical to enhancing inference in non-invasive wildlife
copro-parasitological studies.