Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 May;72(3):269-283.
doi: 10.1111/zph.13202. Epub 2024 Dec 8.

Free-Ranging Wolves (Canis lupus) are Natural Reservoirs of Intestinal Microeukaryotes of Public Health Significance in Southwestern Europe

Sheila Ortega  1 , Ana M Figueiredo  2 , Barbara Moroni  3 , Nadia Abarca  1   4 , Alejandro Dashti  1 , Pamela C Köster  1   5   6 , Begoña Bailo  1 , David Cano-Terriza  7   8 , Moisés Gonzálvez  7   9 , Manena Fayos  10 , Álvaro Oleaga  11 , Carlos Martínez-Carrasco  9 , Roser Velarde  12 , Rita T Torres  2 , Eduardo Ferreira  2 , Dário Hipólito  2   13 , Tânia Barros  2 , Ana Lino  2 , Serena Robetto  3   14 , Luca Rossi  15 , Gemma J Muñoz-de-Mier  5 , Gabriel Ávalos  1 , Rafael Calero-Bernal  16 , David González-Barrio  1 , Sergio Sánchez  1 , Ignacio García-Bocanegra  7   8 , David Carmena  1   8
Affiliations

Free-Ranging Wolves (Canis lupus) are Natural Reservoirs of Intestinal Microeukaryotes of Public Health Significance in Southwestern Europe

Sheila Ortega et al. Zoonoses Public Health. 2025 May.

Abstract

Introduction: Intestinal microeukaryote parasites are major contributors to the burden of diarrhoea in humans and domestic animals, but their epidemiology in wildlife is not fully understood. We investigated the frequency, genetic diversity and zoonotic potential of protists of animal and public health significance in free-ranging grey wolf (Canis lupus) populations in south-western Europe.

Methods: Individually formed faecal samples collected from necropsied wolves or scat trails in Italy (n = 47), Portugal (n = 43) and Spain (n = 225) during the period 2011-2023 were retrospectively analysed using molecular (PCR and Sanger sequencing) methods. Complementary epidemiological data were gathered when available.

Results: Giardia duodenalis was the most frequent microeukaryote found (40.3%, 127/315; 95% CI: 34.9-46.0), followed by Cryptosporidium spp. (3.5%, 11/315; 95% CI: 1.8-6.2), Enterocytozoon bieneusi and Encephalitozoon spp. (1.6%, 5/315; 95% CI: 0.5-3.7 each). Blastocystis was not identified in any of the faecal samples analysed. Sequence analyses confirmed the presence of canine-adapted assemblage D within G. duodenalis (n = 7). Three Cryptosporidium species were identified, namely canine-adapted C. canis (n = 9), zoonotic C. parvum (n = 1) and primarily anthroponotic C.hominis (n = 1). Genotyping tools enabled the identification of subtype family XXe2 within C. canis. Among microsporidia, the canine-adapted genotype PtEb IX was identified within E. bieneusi. Two samples were confirmed as Enc. intestinalis and three more as Enc. cuniculi genotype IV. This is the first record of Enc. intestinalis and Enc. cuniculi in the grey wolf globally.

Conclusions: Silent carriage of intestinal microeukaryotes seems common in free-ranging grey wolves in southwestern Europe. Wolves can contribute to environmental contamination through the transmission stages (cysts, oocysts, spores) of species/genotypes potentially infective to humans. Individuals in close contact with wolf carcasses or their faecal material may be at potential risk of infection by microeukaryotic pathogens.

Keywords: Cryptosporidium; Giardia; epidemiology; genotyping; microsporidia; zoonoses.

PubMed Disclaimer

References

    1. Adriana, G., K. Zsuzsa, D. Mirabela Oana, G. C. Mircea, and M. Viorica. 2016. “ Giardia duodenalis Genotypes in Domestic and Wild Animals From Romania Identified by PCR‐RFLP Targeting the gdh Gene.” Veterinary Parasitology 217: 71–75. https://doi.org/10.1016/j.vetpar.2015.10.017.
    1. Appelbee, A. J., L. M. Frederick, T. L. Heitman, and M. E. Olson. 2003. “Prevalence and Genotyping of Giardia duodenalis From Beef Calves in Alberta, Canada.” Veterinary Parasitology 112: 289–294. https://doi.org/10.1016/s0304‐4017(02)00422‐3.
    1. Barrera, J. P., D. Carmena, E. Rodríguez, et al. 2020. “The Red Fox ( Vulpes vulpes ) as a Potential Natural Reservoir of Human Cryptosporidiosis by Cryptosporidium hominis in Northwest Spain.” Transboundary and Emerging Diseases 67: 2172–2182. https://doi.org/10.1111/tbed.13569.
    1. Beck, R., H. Sprong, S. Lucinger, E. Pozio, and S. M. Cacciò. 2011. “A Large Survey of Croatian Wild Mammals for Giardia duodenalis Reveals a Low Prevalence and Limited Zoonotic Potential.” Vector Borne and Zoonotic Diseases 11: 1049–1055. https://doi.org/10.1089/vbz.2010.0113.
    1. Boitani, L. 2000. “Action Plan for the Conservation of the Wolves ( Canis lupus ) in Europe.” Nature and Environment, Council of Europe Publishing 113: 1–86.

Publication types

MeSH terms

Associated data

LinkOut - more resources