Introduction
Besnoitia besnoiti (Apicomplexa) is the aetiological agent of a
chronic and debilitating disease of cattle called bovine besnoitiosis
characterized by a low body score, non-specific systemic clinical signs
and skin lesions. Reproductive failure is a major concern since males
may develop infertility, sterility or even may die during the acute
phase of the infection (González-Barrio et al., 2020).
Bovine besnoitiosis causes
considerable economic losses in many countries in Africa, the Middle
East and Europe. In these regions, the disease has been increasingly
spreading over the last two decades (EFSA, 2010; Álvarez-García et al.,
2013), mainly due to control drawbacks including the absence of vaccines
and therapeutical tools, also pre-movement of cattle testing may be
insufficient and contribute to the spread of the disease. Several
surveys confirmed the increased prevalence and geographical expansion of
this disease in cattle, in areas of Western and Northern Europe
(Álvarez-García et al., 2016). A few studies carried out in Spain
reported high seroprevalence rates in beef cattle herds, ranging from 36
to 87% in Urbasa Andía mountains and the Pyrenees in North Spain
(Cortes et al., 2014; Álvarez-García et al., 2014; Gutiérrez-Expósito et
al., 2014).
Despite the fact that its biological cycle is not fully known, it is
assumed that B. besnoiti might have an indirect life cycle with a
carnivore as definitive host able to shed oocysts after ingestion of
tissues harbouring mature cysts (Jaquiet et al., 2010; Cortes et al.,
2014). Although domestic cattle act as intermediate hosts of the
parasite, specific antibodies against B. besnoiti were also
described in roe deer (Capreolus capreolus ) (Arnal et al., 2017)
and red deer (Cervus elaphus ) in North Easter Spain, regions
where bovine besnoitiosis is endemic, showing that these wild ruminant
species are also intermediate host (Gutiérrez-Expósito et al., 2013,
2016). Despite this fact, their role in the epidemiology of bovine
besnoitiosis seems to be of scarce importance (Gutiérrez-Expósito et
al., 2016). In contrast, specific antibodies were not detected in small
ruminants (Gutiérrez-Expósito et al., 2017). Similarly, a serosurvey onBesnoitia spp. in wild carnivore species from Spain provided no
evidence to support that wild carnivores are implicated in the
epidemiology of B. besnoiti within the geographical regions
covered by the analysis (Millán et al., 2012).
Domestic and wild felines have
been suggested as definitive hosts for B. besnoiti , however,
experimental infections in several felid species failed to confirm their
suitability as potential definitive hosts (Diesing et al., 1988; Basso
et al., 2011). The putative role of a sylvatic life cycle, involving
other Carnivora species, in the epidemiology of the disease has not been
fully elucidated (see Table 1).
The aim of the present survey is
to assess the presence of Besnoitia spp. DNA in faeces from wild
mesocarnivores in Spain as a first step to determine which species might
be considered as potential definitive host candidates in further
investigations.