Insight into Trichinella britovi Infection in Pigs: Effect of Various Infectious Doses on Larvae Density and Spatial Larvae Distribution in Carcasses and Comparison of the Detection of Anti-T. britovi IgG of Three Different Commercial ELISA Tests and Immunoblot Assay

There is limited information available on the Trichinella britovi (T. britovi) muscle larvae (ML) distribution in pig muscle and the humoral immune response of pigs infected with moderate doses of this parasite; therefore, this study investigated the infectivity of a Polish strain of T. britovi for pigs, the antibody response of this host to various doses of T. britovi, and the efficiency of three different commercial ELISA kits and an immunoblot assay at detecting anti-T. britovi IgG. No significant differences in terms of the infection level of particular muscles or of whole carcasses between pigs infected with 3000 and those infected with 5000 ML of T. britovi were observed. The highest intensity of T. britovi infection was reported in the diaphragm pillars. The larvae of T. britovi showed homogeneous distribution with respect to the muscle side. Statistically, specific IgG antibodies against excretory–secretory (ES) antigens of Trichinella ML were first detected by all ELISA protocols on day 36 post infection; however, individual pig results showed some differences between the three tests applied. A significant increase in the level of anti-T. britovi IgG was observed between days 36 and 41 post infection, and from day 45 until day 62 after T. britovi infection, production of these antibodies reached its plateau phase. No positive correlation was found between the anti-T. britovi IgG level and the larvae density in 15 different muscles. Sera of T. britovi-infected pigs showed reactivity with T. britovi ML ES antigens of 62, 55, and 52 kDa. The results provide novel information on spatial larvae distribution in muscles and the humoral immune response of pigs exposed to two different doses of a Polish strain of T. britovi, extend knowledge on serological diagnostic tools which may be introduced in veterinary practice for the detection of T. britovi infections in pig production, and offer practical solutions for meat hygiene inspectors in the field at sampling sites when examining pig carcasses for Trichinella.