Genetic characterization of Toxoplasma gondii isolates from pigs intended for human consumption in Brazil

Abstract

This study genetically Toxoplasma gondii isolates obtained from pigs intended for human consumption in northeastern Brazil; multilocus PCR-RFLP and sequencing techniques were utilized. Bioassays were conducted using the brain and tongue of 20 pig heads purchased at butcher shops in the city of Ilheus, Bahia, Brazil. Overall, 11 T. gondii isolates designated TgPgBr06-16 were identified. Application of multilocus PCR-RFLP with seven molecular markers (SAG1, SAG2, SAG3, BTUB, C22-8, PK1 and Apico) identified six different genotypes. Isolates TgPgBr 06, 08, 11, 12, 14 and 15 were indistinguishable by this technique, forming a single genotype; the remaining isolates were characterized as distinct genotypes. However, when five genetic markers (SAG1, SAG2, SAG3, BTUB and c22-8) were employed in multilocus PCR-sequencing, all eleven strains of T. gondii were shown to be different. All isolates differed from Type I, II and III clonal genotypes using both genotyping techniques. These results demonstrate that the multilocus PCR-RFLP assay underestimated the true diversity of the T. gondii population in this study. Thus, DNA sequencing is the preferred technique to infer the genetic diversity and population structure of T. gondii strains from Brazil. Moreover, it is necessary to develop new molecular markers to group and characterize atypical T. gondii isolates from South America.

Isolation and Genotyping of Toxoplasma gondii in Brazilian Dogs

“…There was also no resemblance to the genotypes identified in the reports [11,13], which genotyped isolates from swine and sheep, respectively, in the same Bahia microregion as surveyed in this study (Table 2). This reinforces the fact that T. gondii in Brazil is far more genetically diverse than T. gondii in other countries.…”

“…Sequences of T. gondii isolates from the same geographical origin, with sequences of 8 isolates from pigs [11], 3 isolates from sheep [13], and 3 isolates from porcupines ( Chaetomys subspinosus ) [20], all from the southern region of Bahia State, Brazil. The RH strain of T. gondii was used as a positive control.…”

“…Studies on the genetic variability of T. gondii isolates by PCR with restriction fragment length polymorphism (PCR-RFLP) using various multilocus markers have shown the variety of parasite genotypes in Brazil and worldwide [4,9,10]. In Brazil, new genotypes of T. gondii are frequently identified in various animal species, including dogs, suggesting extremely high genetic diversity of the parasite in human and animal populations in the country [11–14]. This genetic diversity indicates an unusual population structure or recombination of the protozoan.…”

Detection of Toxoplasma gondii DNA in naturally infected sheep’s milk

“…The definitive hosts for the parasite consist of members of the Felidae family (Dubey, 1998), and the intermediate hosts are homeothermic animals including farm animals such as birds (de Oliveira et al, 2009), goats (Ragozo et al, 2009), cattle (Fajardo et al, 2013), pigs (Bezerra et al, 2012), and sheep (Edwards and Dubey, 2013). When humans consume raw or undercooked animal tissue, this protozoan can enter into their systems and cause infection.…”

First report of genotype #65 of Toxoplasma gondii in pigs

“…In Brazil, type I, type II, and atypical strains have been described in pigs, and the importance of these isolates has been confirmed (Santos et al 2005;Pena et al 2008;Frazão-Teixeira et al 2011;Ferreira et al 2011;Dubey 2009;Dubey et al 2012). It is important to highlight that some atypical strains described, have never been recorded in Brazil (Frazão-Teixeira et al 2011;Bezerra et al 2012;Clementino-Andrade et al 2013). Thus, the purpose of the present study was to isolate and genotype T. gondii from pigs raised on pig farms and destined for human consumption in the Pernambuco State, Northeastern Brazil.…”