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. 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 host of the parasite,
roe deer (Capreolus capreolus ) is also an intermediate host in
Spain (Arnal et al., 2017) and specific antibodies against B.
besnoiti have been also described in wild ruminants (roe deer and red
deer [Cervus elaphus ]) in North Eastern Spain, regions where
bovine besnoitiosis is endemic (Gutiérrez-Expósito et al., 2013, 2016);
despite this fact, their role in the epidemiology of bovine besnoitiosis
is of scarce importance (Gutiérrez-Expósito et al., 2016). In contrast,
specific antibodies were not detected in small ruminants
(Gutiérrez-Expósito et al., 2017). Similarly, the lack of antibodies
against Besnoitia spp. in wild carnivore species from Spain in
which results provided no evidence to support the idea that within the
geographical regions covered by the analysis wild carnivores were
implicated in the epidemiology of B. besnoiti (Millán et al.,
2012).
Domestic and wild felines have
been suggested as definitive hosts for B. besnoiti , however,
experimental infections in these 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.