Urban wild boar: drivers of presence, phenotypic responses and health concerns
- Autores: Raquel Castillo Contreras
- Directores de la Tesis: Jorge R. López Olvera (dir. tes.), Gregorio Mentaberre García (dir. tes.), Santiago Lavín González (dir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2019
- Idioma: español
- Materias:
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- Resumen
There are wildlife species able to exploit the resources offered by urban environments. Wild boars can explore urban and peri-urban areas, but their presence in these areas is a nuisance and poses a risk for public health and safety. Interactions between wild boars and people are expected to continue rising in Europe owing to increasing wild boar and human population trends, particularly in urban settings. This thesis determines the drivers of wild boar presence in the urban area of Barcelona, addresses the phenotypic changes shown by urban individuals with respect to non-urban ones, and identifies wild boar related public health concerns in an urban environment.
Wild boar presence in the city of Barcelona was positively correlated to proximity to streams in the bordering Collserola natural space, higher landscape fragmentation and the presence of both urban green areas and stray cat colonies. The presence was also more frequent in spring and summer, which could be related to births leading to a higher group size and increased energetic needs, juvenile and yearling dispersal and lower availability of food resources in the warm seasons in Mediterranean regions. Moreover, urban wild boars used more anthropogenic food resources, showed higher body mass and grew faster than non-urban ones. Urban female wild boars started reproducing earlier than non-urban ones, probably as a result of achieving the required body mass earlier. However, urban wild boars died at a younger age than non-urban wild boars, indicating a possible cost of exploring the urban area for the wild boar in Barcelona.
This thesis also describes the presence of zoonotic tick-borne and food-borne pathogens carried by ticks parasitizing wild boars and wild boars, respectively. Wild boars in the Metropolitan Area of Barcelona (MAB) carried ticks belonging to species Hyalomma lusitanicum, Dermacentor marginatus, Rhipicephalus sanguineus sensu lato and, anecdotally, Rhipicephalus bursa. Screening of tick pools revealed the presence of three emerging zoonotic Rickettsia species (R. massiliae, R. slovaca and R. raoultii), whereas wild boar spleen samples yielded negative results. Therefore, despite wild boars do not seem to act as reservoirs of Rickettsia spp. in the MAB, they could be favouring tick dispersion and promoting Rickettsia spp. circulation among ticks by sustaining abundant tick populations and facilitating the transmission via co-feeding.
Wild boars in the MAB also carried Campylobacter spp., C. lanienae being more prevalent than C. coli, and different serovars of Salmonella enterica subsp. enterica. There was a high genetic diversity among Campylobacter isolates, some of which showed a high virulence potential. None of the Campylobacter isolates were susceptible to all the antimicrobials tested, and nearly 60% of C. coli isolates and one Salmonella isolate were multiresistant, the latter being a monophasic S. Typhimurium clone of public health concern in Europe. These results provide further evidence on the role of wild boars as reservoirs of zoonotic thermophilic Campylobacter species, and show that they can carry and spread these food-borne zoonotic bacteria into urban and peri-urban areas in the MAB.
Results from this thesis have management and public health implications, and several management measures derived from these results are currently being applied and scientifically evaluated in Barcelona. This thesis contributes to improve the incipient knowledge of wild boars in urban and peri-urban areas from an ecological, epidemiological and applied management approach.
