Detection of Toxoplasma gondii by PCR and mouse bioassay in commercial cuts of pork from experimentally infected pigs

Tsutsui, Vinícius Suehiro; Freire, Roberta Lemos; Garcia, João Luís; Gennari, Solange Maria; Vieira, Daniel Perez; Marana, Elizabete Regina Marangoni; Prudêncio, Leonardo B.; Navarro, Italmar Teodorico

doi:10.1590/s0102-09352007000100006

Cited by 19 publications

(15 citation statements)

References 17 publications

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“…These results are similar to those found by da Silva and Langoni (2001), Garcia et al (2006), and Tsutsui et al (2007). On the other hand, Yai et al (2003) state that the bioassay has a lower sensitivity than PCR.…”

Section: Discussionsupporting

confidence: 90%

“…This is corroborated by Frazão-Teixeira et al (2006) who isolated T. gondii in 50.0% of pigs in the state of Rio de Janeiro. However, higher values were found by Yai et al (2003) and Tsutsui et al (2007), who found 87.5% and 67.5% of positive pigs, respectively. The latter two studies were performed on experimentally infected pigs, whereas naturally exposed pigs were examined in the present study.…”

Section: Discussionmentioning

confidence: 70%

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Comparison of methods for detection of Toxoplasma gondii in tissues of naturally exposed pigs

et al. 2011

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This study aimed to compare the sensitivity of five diagnostic methods commonly used for the detection of Toxoplasma gondii in tissues of naturally infected pigs. We purchased 20 heads of pigs in butcher shops in the city of Ilhéus, Bahia. Brain and tongue fragments were taken from each animal for the performance of PCR against T. gondii. The rest of these two tissues were processed and inoculated into three mice. These rodents were observed for 42 days and euthanized. We prepared slides with brain and lungs of each mouse for the visualization of T. gondii. From the tissues of mice, we carried out polymerase chain reaction (PCR), histopathology, and immunohistochemistry in an attempt to identify the parasite. The PCR direct from the tissue of pigs showed 10% (2/20) of positive samples, all from the brain. PCR in tissue from mice found that 55% (11/20) of pigs were positive: 55% (11/20) and 45% (9/20) for brains and tongues, respectively. Mice were inoculated with material obtained from the samples and examined by various methods for resulting Toxoplasma infection (bioassay). Cyst detection in bioassay mice identified 25% (5/20) and immunohistochemistry 30% (6/20) of the samples pigs as positive for T. gondii. Histopathology of mice tissue could not detect parasite; only suggestive pathological changes such as inflammation with foci of necrosis were seen. The results indicated PCR of mice tissue as the most sensitive among those tested.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 70%

Comparison of methods for detection of Toxoplasma gondii in tissues of naturally exposed pigs

et al. 2011

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“…We used RH tachyzoites as antigen, as well as anti-IgG conjugates (Sigma Chemical, St. Louis, MO, USA), together with positive and negative controls for horse and mouse sera. Positivity was defined as a titre ≥ 1:16 for mice (TSUTSUI et al, 2007) and ≥ 1:64 for horses (GARCIA et al, 1999).…”

Section: Indirect Fluorescent Antibody Testmentioning

confidence: 99%

Diagnosis and isolation of Toxoplasma gondii in horses from Brazilian slaughterhouses

Evers

Garcia

Navarro

et al. 2013

Rev. Bras. Parasitol. Vet.

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This study aimed to investigate anti-Toxoplasma gondii antibodies and to isolate the parasite from the brains of horses processed at slaughterhouses in Brazil. We collected brain and blood samples from 398 horses of various ages, from six Brazilian states. Serum samples were evaluated by indirect fluorescent antibody test (IFAT cut-off titre ≥ 1:64), and brains were submitted to mouse bioassay. Among the 398 horses, positivity for T. gondii was identified in 46 (11.6%) by IFAT and in 14 (3.5%) by mouse bioassay. In 12 of those 14 bioassays, mice were positive only by IFAT (cut-off titre ≥ 1:16), T. gondii being isolated in the remaining two. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of 18S rDNA to differentiate among T. gondii, Neospora caninum, and Sarcocystis neurona, we found that two of the 14 brains were positive for T. gondii only. For genotyping of the two isolates and the PCR-positive brain, we performed PCR-RFLP based on 13 markers, and SAG2 all samples were Toxoplasma gondii type I. Collectively, IFAT of horse sera and mouse bioassay identified positivity in 60 (15%) of the samples. Our results show that some horses sent to slaughter in Brazil have been exposed to T. gondii.Keywords: Slaughterhouse, horses, Toxoplasma gondii, bioassay, indirect fluorescent antibody test, nested PCR-RFLP. ResumoO objetivo do estudo foi investigar anticorpos anti-Toxoplasma gondii e isolar o parasita do cérebro de equídeos abatidos em matadouros-frigoríficos no Brasil. Colheram-se amostras de 398 cérebros e sangue de equídeos machos e fêmeas de idades variadas, provenientes de seis estados brasileiros. As amostras de soro foram avaliadas pelo teste de imunofluorescência indireta (IFI) para T. gondii (ponto de corte ≥ 64), e os fragmentos de cérebros foram submetidos ao bioensaio em camundongos. Por meio da IFI, 46 (11,6%) equídeos foram soropositivos. Pelo bioensaio em camundongos, 14 (3,5%) cérebros de equídeos testados foram positivos. Em doze dos bioensaios, os camundongos foram positivos somente pela IFI (ponto de corte ≥ 16) e T. gondii foi isolado nos outros dois bioensaios. A PCR-RFLP com base em 18S rDNA para diferenciar entre T. gondii, Neospora caninum, e Sarcocystis neurona foram feitas em todos os 14 cérebros e dois foram positivos apenas para T. gondii. De dois isolados positivos para T. gondii e do cérebro positivo à PCR em que realizou-se a PCR-RFLP, com base em 13 marcadores e SAG2, a genotipagem mostrou ser o T. gondii tipo I para todas as amostras. A IFI de soros de equídeos e do bioensaio em camundongos identificaram positividade em 60 (15%) amostras testadas. Os resultados mostram que alguns cavalos enviados para abate foram expostos ao T. gondii.

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“…The mouse bioassay's superiority compared to PCR has also been verified in pig tissues or semen by Garcia[39], Tsutsui [48] and Moura[31, 32], in dogs by Arantes[32], in sheep by Lopes et al . [33]and Lopes[35], in cats by Montoya [49] and in cattle by Scarpelli et al .…”

Section: Discussionmentioning

confidence: 98%

Congenital Toxoplasmosis in Chronically Infected and Subsequently Challenged Ewes

et al. 2016

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This experiment studied congenital transmission in sheep experimentally infected with oocysts of Toxoplasma gondii and reinfected at one of three stages of pregnancy. Twenty ewes were experimentally infected with T. gondii strain ME49 (day 0). After the T. gondii infection became chronic (IFAT≤512), the ewes were allocated with rams for coverage. After the diagnosis of pregnancy, these ewes were allocated into four experimental groups (n = 5): I-reinfected with T. gondii on the 40th day of gestation (DG); II-reinfected on DG 80; III-reinfected on DG 120; and IV-saline solution on DG 120 (not reinfected). Five ewes (IFAT<64) were kept as negative controls (uninfected, group V), therefore in groups I-III were infected prior to pregnancy and re-infected during pregnancy, group IV was only infected prior to pregnancy, and group V was not infected. Parasitism by T. gondii was investigated (histopathology, immunohistochemistry, mouse bioassay and PCR) in mothers and lambs tissue. All ewes produced lambs serologically positive for T. gondii. The results of the mouse bioassay, immunohistochemistry and PCR assays revealed the presence of T. gondii in all 20 sheep and their lambs. The congenital transmission of T. gondii was associated with fetal loss and abnormalities in persistently infected sheep and in ewes infected and subsequently reinfected by this protozoan. Therefore, congenital T. gondii infection was common when ewes were chronically infected prior to pregnancy, with or without reinfection during at various stages of gestation.

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Detection of Toxoplasma gondii by PCR and mouse bioassay in commercial cuts of pork from experimentally infected pigs

Cited by 19 publications

References 17 publications

Comparison of methods for detection of Toxoplasma gondii in tissues of naturally exposed pigs

Comparison of methods for detection of Toxoplasma gondii in tissues of naturally exposed pigs

Diagnosis and isolation of Toxoplasma gondii in horses from Brazilian slaughterhouses

Congenital Toxoplasmosis in Chronically Infected and Subsequently Challenged Ewes

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