Experimental samples were obtained from 20 pig heads

purchased at butcher shops that traded fresh pork for human consumption at the wholesale produce market of Ilheus, Bahia, Brazil, from September 2009 to February 2010. The heads were individually placed in refrigerated UMI-77 containers and taken to the Veterinary Parasitology Laboratory of State University of Santa Cruz, Brazil; the brains were then removed. Peptic digestion of samples was performed according to the protocol established by Dubey (1998) with several modifications. Briefly, each brain was ground in a blender. While grinding, a minimum volume of PBS was added to facilitate the procedure. The jar of the device was properly washed with a solution of 2.5% sodium hypochlorite and neutral detergent between each organ to prevent contamination between samples. For each sample, 40 g of homogenate was removed and placed in a 250 mL Erlenmeyer flask; next, an acid pepsin solution (pH 1.1–1.2) was added until see more a final volume of 200 mL was reached. Homogenate digestions were incubated in an orbital shaker at a temperature of 37 °C for 1 h. The digested materials were then strained in a sieve with double cheesecloth and centrifuged twice at 1200 × g for 10 min. Supernatants were discarded, and the sediments were resuspended in a neutralizing solution of 1.2% sodium bicarbonate (pH 8.3) and centrifuged at 1200 × g

for 20 min. Supernatants were again discarded, and the sediments were resuspended in 5 mL of an antibiotic solution that contained 1000 IU of penicillin and 100 μg streptomycin per mL of PBS. This product was subcutaneously inoculated in three Swiss Webster mice (25–35 g) at a dose of 1 mL per mouse; mice were given a second identical injection 24 h after the first inoculation. For each group, an additional

mouse was inoculated with sterile PBS as control. The mice were observed for 42 days and sacrificed at the end of this period for brain retrieval. The virulence analysis of the samples was realized according to previous report (Bezerra et al., Linifanib (ABT-869) 2012). Following brain removal, 100 mg fragments were frozen in liquid nitrogen and macerated using a mortar and pestle. DNA extraction was performed using Easy-DNA® Kits (Invitrogen) according to Protocol 3 of the manufacturer. PCR amplifications were performed using two sets of primers that amplified a 529 bp fragment: Tox4 Forward, CGCTGCAGGGAGGAAGACGAAAGTTG and Tox5 Reverse, CGCTGCAGACACAGTGCATCTGGATT (Homan et al., 2000). Each 50 μL PCR mixture contained 10 μL of sample DNA, 0.2 mM of sense and antisense primers, 100 mM dNTPs (Invitrogen), 60 mM Tris–HCl (pH 9.0), 2.5 mM MgCl2 and 2 U of Taq DNA polymerase (Invitrogen). The amplification 37 cycle consisted of an initial denaturation step of 5 min at 94 °C, followed by 35 cycles of 1 min at 94 °C, 1 min at 58 °C and 1 min at 72 °C with a final extension step of 10 min at 72 °C.