PhD in Veterinary Sciences for Animal Health and Food Safety

Contacts

Supervisor

Ezio Ferroglio

Curriculum vitae

Curriculum Vitae

Phd thesis

1) Background

The concern towards shared pathogens at the wildlife-domestic animal interface has increased with the awareness of their impact on human, public health and economy (1). Global and local (glocal) factors (human management of the environment and land use, climatic changes) are remodelling the interactions among wildlife, domestic animals and people, intensifying pathogen transmission and reshaping diseases’ epidemiology (1).

This may affect several pathogens through different paths. Tick-borne zoonoses, together with their vectors, are changing their geographical distribution and prevalence in response to global warming and its consequences: disease cases are appearing where not present before (2,3).  The prevalence of several pathogens, Toxoplasma gondii among those, is increasing in response to human landscape modifications (4), while changes in wild species population dynamics (as the reintroduction of wolves in the alps) may impact related pathogens, as it is the case of Neospora caninum (5).

In this changing scenario, to manage diseases at a population level, good data quality is required. Thus, gathering reliable wildlife population data, from density to space use, is a crucial part not only for animal management, but also to complete information for epidemiological studies, thus improving risk assessment, disease control and prevention, remarking the benefits of an integrated wildlife monitoring to address the One Health concept (6,7).

2) Specific aims of the project and methods

The general aim of the project is to shed light on the risk for people to be exposed to zoonotic pathogens in the natural environment, focusing on how wildlife and the habitat influence pathogen circulation.

Specific aims (SA) include:

SA1. Identify the impact of wildlife temporal occupancy on questing ticks’ abundance.

Comparing different study areas (lowland, alpine and Apennine), I modelled (GAM (8)) questing tick abundance (collected with dragging transects) on wild ungulates and mesocarnivores temporal occurrence (extracted from camera trap pictures), biotic and abiotic environmental drivers.

SA2. Describe the variation of tick abundance at a gradient distance from human pathways.

A descriptive analysis was performed of distribution for ticks collected with dragging transects at 0, 1, 2 and 4 m distance from human pathways.

SA3. Identify main factors affecting tick-borne zoonotic presence in questing ticks.

TBZ prevalences (from SA1 ticks) were related (Random Forest and GAM) to habitat fragmentation characteristics and to wildlife individuals count (from camera trap pictures of SA1).

SA4. Apply a holistic approach to identify exposure risk to TBZ in humans.

In the alpine study area, in addition to collected ticks (SA1) and wildlife spleen, in collaboration with Ospedale Amedeo di Savoia, we sampled a tick exposed group of people and their dogs, also surveying their habits in the natural environment that may expose or protect them from TBZ. Serological and PCR diagnostic will be performed for same pathogens as in SA3.

SA5. T. gondii seroprevalence in wildlife related to human presence.

In two study areas, collected sera from culled wildlife have been serologically screened for T. gondii and will be related to human density (GLM) as an indirect proxy of cats’ presence.

3) Preliminary results

SA1. Collected ticks were mostly Ixodes ricinus, followed by Haemaphisalys punctata, while wildlife temporal occupancy corresponds to estimated wildlife density. Wildlife temporal occupancy models show an additive effect on questing ticks for species that are habitual hosts and a negligible one for other hosts, however affected by habitat factors and wildlife population distribution.

SA2. Peaks of abundance varied regarding to habitat type (grass or forest) and tick stages. In general, a peak is recorded at points were suitable ticks’ microhabitats and wild host passage combine (1m and 4m).

SA3. Preliminary analysis suggests an important impact of habitat fragmentation on TBZ prevalence, while models (Rickettsia SFG only) show an additive impact for the tick abundance and mesocarnivores (probably as an indicator for micromammals presence) and a dilutive effect of wild ruminants presence and variety of species.

SA4. Preliminary results remark the importance to contextualize the analysis in the light of survey information and TBZ ecology.

SA5. T. gondii antibodies were mainly found in wild boar. No relationship was found with human density, but analysis is still to be completed for the second study area.

References:

1. Gortázar C, Ferroglio E, Höfle U, Frölich K, Vicente J. Diseases shared between wildlife and livestock: a European perspective. Eur J Wildl Res. 2007;53(4):241–56.
2. Martello E, Mannelli A, Ragagli C, Ambrogi C, Selmi M, Ceballos LA, et al. Range expansion of Ixodes ricinus to higher altitude, and co-infestation of small rodents with Dermacentor marginatus in the Northern Apennines, Italy. Ticks Tick Borne Dis. 2014;5(6):970–4.
3. Jongejan F, Ringenier M, Putting M, Berger L, Burgers S, Kortekaas R, et al. Novel foci of Dermacentor reticulatus ticks infected with Babesia canis and Babesia caballi in the Netherlands and in Belgium. Parasit Vectors. 2015;8(1):1–10.
4. Brearley G, Rhodes J, Bradley A, Baxter G, Seabrook L, Lunney D, et al. Wildlife disease prevalence in human‐modified landscapes. Biol Rev. 2013;88(2):427–42.
5. Sobrino R, Dubey JP, Pabón M, Linarez N, Kwok OC, Millán J, et al. Neospora caninum antibodies in wild carnivores from Spain. Vet Parasitol. 2008;155(3–4):190–7.
6. ENETWILD‐consortium, Pascual R, Acevedo P, Apollonio M, Blanco‐Aguiar JA, Body G, et al. Report of the 2nd Annual General Meeting of ENETWILD 5‐6th October 2021. EFSA Support Publ. 2021;18(12):7053E.
7. Cardoso B, García-Bocanegra I, Acevedo P, Cáceres G, Alves PC, Gortázar C. Stepping up from wildlife disease surveillance to integrated wildlife monitoring in Europe. Res Vet Sci. 2021;
8. Rowcliffe JM, Field J, Turvey ST, Carbone C. Estimating animal density using camera traps without the need for individual recognition. J Appl Ecol. 2008;1228–36.
9. Battisti E, Zanet S, Khalili S, Trisciuoglio A, Hertel B, Ferroglio E. Molecular Survey on Vector-Borne Pathogens in Alpine Wild Carnivorans. Front Vet Sci. 2020;7(January):1–9.
10. Zanet S, Trisciuoglio A, Bottero E, De Mera IGF, Gortazar C, Carpignano MG, et al. Piroplasmosis in wildlife: Babesia and Theileria affecting free-ranging ungulates and carnivores in the Italian Alps. Parasit Vectors. 2014;7(1):1–7.

Research activities

My research focuses on an holistic approach to study the circulation of parasites and tick-borne diseases at the human-wildlife-livestock interface, with a particular focus regarding disease ecology.

Publications

All of my research products