Cross-Sectional Study of Anti-Trichinella Antibody Prevalence in Domestic Pigs and Hunted Wild Boars in Estonia

Abstract

Trichinella spp. are relevant zoonotic pathogens in Estonia. The aim of this nationwide cross-sectional study was to estimate the seroprevalence of Trichinella spp. in domestic pigs (Sus scrofa domestica) and hunted wild boars (Sus scrofa). Serum samples from 374 pigs, originating from 14 farms, and meat juice samples from 470 wild boars were tested for immunoglobulin G antibodies against Trichinella excretory/secretory antigens using a commercial enzyme-linked immunosorbent assay (ELISA). Antibodies against Trichinella were not detected in the domestic pigs, indicating effective parasite control strategies in the farms. By contrast, 42.1% of the wild boars tested positive, indicating substantial infection pressure in the sylvatic cycle. Further analysis of a subset of the wild boar samples, using another ELISA and Western blot, yielded a confirmed seroprevalence estimate of 17.4%. A substantial proportion of wild boars in Estonia had evidence of exposure to Trichinella spp. and may have carried infective larvae. Undercooked Estonian wild boar meat is a potential source of Trichinella spp. infections to humans and other hosts.

Serological Evidence of Exposure to Globally Relevant Zoonotic Parasites in the Estonian Population

“…Trichinella spp. merit higher awareness as relevant zoonotic parasites in Estonia, in animal hosts particularly in the sylvatic cycle [ 17 ].…”

“…Recent research confirms that several zoonotic parasites are common and endemic in Estonia, which is located in north-eastern Europe [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. We designed a cross-sectional serological study to investigate the exposure to Ascaris spp., Echinococcus spp., Taenia solium , Toxocara canis , Toxoplasma gondii , and Trichinella spiralis in the Estonian population and its four subgroups: children aged 14–18, animal caretakers, hunters, and veterinarians.…”

Wild Boar: A Reservoir of Foodborne Zoonoses

“…Wild boar meat is currently the second most important source of human trichinellosis, and has been responsible for several human outbreaks (Table 3). Examining wild boar meat for the presence of Trichinella before processing and marketing in Europe has been mandatory since 1992; however, wild boar meat intended for private use in not necessarily tested (Kärssin et al, 2016, Messiaen et al, 2016. Trichinella spiralis, Trichinella britovi, Trichinella nativa, and Trichinella pseudospiralis have been identified in wild boars (Bilska-Zajac et al, 2016, Bilska-Zajac et al, 2017, Pozio, 2015, Rostami et al, 2017a.…”

“…In most of the countries (Australia, Greece, South Korea and the USA) the seroprevalence was between 3% and 13% (Cuttell et al, 2014, Hill et al, 2014, Kim et al, 2015, Lee et al, 2015, Pedersen et al, 2017b, Touloudi et al, 2015. A high seroprevalence of 42% and 17% in Estonian wild boars was reported using ELISA and Western blot, respectively (Kärssin et al, 2016). In Italy, the seroprevalence was 22% and 10% using ELISA and Western blot, respectively (Gómez-Morales et al, 2014).…”

“…Contact between wild boars and domestic animals, especially pigs, should be prevented (Madeira et al, 2017). Controlled housing conditions in pig herds decreases the exposure risk to infections from wild boars (Kärssin et al, 2016). However, outdoor farming may increase due to public demand for more ethical and natural animal production and higher quality meat products (Jori et al, 2017, Murrell, 2016.…”