Assessing Red Fox (Vulpes vulpes) Demographics to Monitor Wildlife Diseases: A Spotlight on Echinococcus multilocularis

Abstract

The assessment of red fox population density is considered relevant to the surveillance of zoonotic agents vectored by this species. However, density is difficult to estimate reliably, since the ecological plasticity and elusive behavior of this carnivore hinder classic methods of inference. In this study, red fox population density was estimated using a non-invasive molecular spatial capture-recapture (SCR) approach in two study areas: one in a known hotspot of the zoonotic cestode Echinococcus multilocularis, and another naïve to the parasite. Parasitological investigations on collected samples confirmed the presence of the parasite exclusively in the former area; the SCR results indicated a higher fox population density in the control area than in the hotspot, suggesting either that the relationship between fox density and parasite prevalence is not linear and/or the existence of other latent factors supporting the parasitic cycle in the known focus. In addition, fox spotlight count data for the two study areas were used to estimate the index of kilometric abundance (IKA). Although this method is cheaper and less time-consuming than SCR, IKA values were the highest in the areas with the lower molecular SCR density estimates, confirming that IKA should be regarded as a relative index only.

Multiscale ecological drivers of Echinococcus multilocularis spatial distribution in wild hosts: A systematic review

“…They found that definitive host species richness showed a negative relationship with E. multilocularis suitability and that the proportion of definitive hosts in the community of carnivores was positively related with E. multilocularis suitability ( Botero-Cañola et al, 2019 ). Finally, the feeding behaviour of definitive hosts might mediate the effect of their density on parasite transmission, as a reduction of feeding on non-competent hosts when alternative resources are available might explain why in some instances the density of definitive hosts is negatively related to parasite transmission ( Celva et al, 2023 ).…”

Global and local drivers of Echinococcus multilocularis infection in the western Balkan region

“…Neither types of hosts have direct data on population size within the study area. In the case of carnivores, hunting bag data can be used as an indicator of trends in population change 34 – 36 . The data collected in a national database show an explicit increase during the previous decade (Supplementary Table S1 ).…”

“…The loss of landscape heterogeneity resulted in vole dominance both in the habitat and in the pellets 42 . In the Alps, an opposite phenomenon is observed as habitat fragmentation enhances the population expansion of Alpine rodent species resulting in exacerbation of E. multilocularis epizootic 34 .…”

“…This conjecture was strengthened in a telemetry study, using autocorrelated kernel density estimation (AKDE), wherein was found that golden jackals’ average home range size proved 2.39 km 2 (50% AKDE) and 11.17 km 2 (90% AKDE) in southern Hungary and northern Serbia 59 . For foxes, diverse home range sizes were determined in different regions of Europe 34 – 36 . For comparability of data from different host species, we used a uniform grid for both hosts.…”

Confirmed Autochthonous Case of Human Alveolar Echinococcosis, Italy, 2023

“…In Europe, the historical endemic areas are Austria, France, Germany, and Switzerland, and that range has expanded to include Eastern and Northern Europe ( 3 ). In Italy, infected foxes have been reported over the past 20 years in the Trentino-Alto Adige region ( 4 – 7 ). Autochthonous animal transmission might occur in the area ( 8 ), and prevalence in foxes seems to be increasing ( 9 ).…”