Trichinellosis survey in the wild boar from the Toledo mountains in south-western Spain (2007–2008): molecular characterization of Trichinella isolates by ISSR-PCR

Abstract

In Spain, trichinellosis represents a public health problem, with an average of five outbreaks per year, wild boar meat being the main source of infection. A trichinellosis survey (2007-2008 hunting campaign) was carried out on wild boars in the Toledo Mountains (south-western Spain, EU) in the context of a surveillance programme on wildlife diseases. A total of 2216 wild boars from different locations of the region were examined. The examination was carried out by veterinarians in the local abattoir (Matadero Municipal de Toledo). The positive samples were sent to the Department of Parasitology (Facultad de Farmacia, UCM) for experimental isolation and specific identification by inter-simple sequence repeat-polymerase chain reaction (ISSR-PCR). Using this technique we identified 17 isolates as Trichinella spiralis with an electrophoretic profile indistinguishable from the T. spiralis reference strain (ISS48). We confirmed that ISSR-PCR is a robust technique for the molecular identification of Trichinella isolates. According to our results, the prevalence of T. spiralis in wild boars from the Toledo Mountains (>800 m above sea level) during the hunting season was approximately 0.77%. The prevalence of T. spiralis (100% of our observations) is a good example of the persistence of this species in sylvatic conditions (coming from the domestic cycle), if a good wild host is abundant. Our observations confirm the major prevalence of T. spiralis over T. britovi in this region, as well as the risk to human health represented by the consumption of uninspected wild boar meat.

Serosurveillance of Trichinella sp. in wild boar and Iberian domestic suids in Mediterranean ecosystems of southwestern Spain

“…In previous reports (2016–2020), the results were quite similar: prevalence in pigs was under 0.001% in the last 5 years and prevalence in wild boar ranged between 0.20 (2018) and 0.36 (2019), with an average of 0.29%. A recent regional study, in northeast Spain, detected 0.34% positivity in wild boar with a light ascending trend over four hunting seasons (Díaz et al., 2021); some previous reports described higher prevalence, reaching 0.77% (García‐Sánchez et al., 2009). The same situation can be observed worldwide: data obtained by artificial digestion during meat inspection results in lower prevalence values in comparison with those obtained by serology.…”

“…Prevalence of Trichinella sp. in wild boar (0.2%–0.77%) is higher than in domestic pigs (reported number of positive/tested in fattening pigs not raised under controlled housing conditions in Spain during 2020: 3/52,910,207; <0.001%) (Díaz et al., 2021; EFSA‐ECDC Report, 2021; García‐Sánchez et al., 2009), being most of human outbreaks related to consumption of meat products from wild boar (Moral et al., 2022). Moreover, wild boar population has been growing in Spain, as it is in many areas of Europe, for more than a decade, expanding not only in natural habitats, but also successfully occupying human‐generated habitats, such as agricultural and peri‐urban areas (Barasona et al., 2021).…”

From wildlife to humans: The global distribution of Trichinella species and genotypes in wildlife and wildlife-associated human trichinellosis

“…vulpes ) 1/70 (1.4%) Spain Southwest Spain Wild boar ( S . scrofa) ISSR-PCR 17/2216 (0.8%) Garcia-Sanchez et al (2009) Spain Iberian peninsula Wild boar ( S . scrofa ) Multiplex-PCR 225/692,678 (0.03%) Zamora et al (2015) Spain Northeast Wild boar ( S .…”