ABSTRACT
The distribution of T. gondii in commercial cuts of pork (ham, tenderloin, spareribs and arm picnic) by PCR and bioassay from experimentally infected pigs, was evaluated. Eighteen mixed breed pigs were divided into two groups (G). The G1 animals (n=10) were infected with 4 x10(4) oocysts of the T. gondii VEG strain and the G2 animals (n=8) were used as control. Pigs of both groups were slaughtered at 59th day after infection, and meat samples were collected for bioassay and PCR. All animals from G1 were positive by at least one or both tests, and all control animals were negative. T. gondii was identified in pork by mouse bioassay and PCR in 27/40 (67.5 percent) and in 9/40 (22.5 percent) of the evaluated samples, respectively. There were no statistical differences in the distribution of tissue cysts from commercial cuts of pork by bioassay (P>0.05). However, statistical differences were observed when mouse bioassay and PCR were compared (P<0.01).
Avaliou-se a presença de T. gondii em cortes comerciais de carne suína (pernil, lombo, costela e paleta), por meio do bioensaio e PCR, em animais experimentalmente inoculados. Dois grupos (G) foram formados. Os animais do G1 (n=10) foram inoculados com 4 x10(4) oocistos da cepa VEG e os do G2 (n=8) permaneceram como grupo-controle, não inoculado. Todos os animais foram abatidos no dia 59 após a infecção, quando foram colhidas as amostras de carne para a realização das provas de bioensaio e da PCR. Todos os suínos do G1 apresentaram-se positivos a pelo menos um dos testes de diagnóstico ou a ambos, e os do grupo-controle permaneceram negativos. Não houve diferenças significativas em relação aos tipos de cortes comerciais e à presença do parasita no bioensaio (P>0,05). O bioensaio foi capaz de detectar T. gondii em 27/40 (67,5 por cento) amostras e a PCR em 9/40 (22,5 por cento). O estudo mostrou diferença entre o bioensaio e a PCR (P<0,01).
Subject(s)
Biological Assay/methods , Meat/analysis , Mice , Polymerase Chain Reaction/methods , Toxoplasma/isolation & purificationABSTRACT
The prevalence of Toxoplasma gondii in free range chickens is a good indicator of the prevalence of T. gondii oocysts in the environment because chickens feed from the ground. In the present study, prevalence of T. gondii in 40 free range chickens (Gallus domesticus) from a rural area surrounding Paraná, Brazil was assessed. Blood, heart, and brain from each chicken were examined for T. gondii infection. Antibodies to T. gondii, assayed with the modified agglutination test (MAT> or =1:5) were found in 16 chickens. Hearts and brains of seropositive (MAT> or =1:5) chickens were bioassayed in mice. Additionally, hearts and brains of seronegative (MAT<1:5) chickens were bioassayed in two T. gondii-free cats (12 chickens per cat). T. gondii was isolated from 13 of 16 (81%) seropositive chickens. Of the two cats fed tissues pooled form seronegative chickens, one shed T. gondii oocysts. Nine of the 13 T. gondii isolates killed 100% of infected mice. The T. gondii isolate from the cat was also virulent for mice. Genotyping of 13 chicken isolates of T. gondii using the SAG2 locus indicated that seven isolates were type I and six were type III; three of these type III isolates killed all infected mice suggesting that all strains virulent for mice are not type I. The isolate from the feces of the cat fed chicken tissues was type I.
