Toxoplasma gondii tissue cyst formation and density of tissue cysts in shoulders of pigs 7 and 14 days after feeding infected mice tissues

Rani, Surabhi; Cerqueira‐Cézar, Camila K.; Murata, Fernando Henrique Antunes; Sadler, Meghan; Kwok, O. C. H.; Pradhan, Abani K.; Hill, Dolores E.; Urban, Joseph F.; Dubey, J. P.

doi:10.1016/j.vetpar.2019.04.004

Cited by 10 publications

(11 citation statements)

References 8 publications

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“…For the "Pru-like" parasite infections the very low parasite burden indicates that most of these parasites are eliminated before they can reach suitable tissues to form cysts, although these parasites might have the greatest cyst-forming potential. These results indicate the complete ME49EW recrudescence pathway that unfolds over one week following bradyzoite infections is required for expansion, dissemination, and establishing tissue cysts in brain tissue and this is consistent with a recent study showing maximum tissue cyst formation in pig muscle is reached seven days after oral infection with tissue cysts from mice tissues (32). Laboratory-adapted strains are unable to reproduce many of the key features of this bradyzoite recrudescence pathway.…”

Section: Discussionsupporting

confidence: 89%

An ex vivo model ofToxoplasmarecrudescence

Goerner

Vizcarra

Hong

et al. 2020

Preprint

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Efforts to develop therapies against Toxoplasma reactivation have been hampered by the lack of an in vitro model of bradyzoite recrudescence. To overcome this issue, we established a new ex vivo model of bradyzoite recrudescence using bradyzoites from an unadapted Type II ME49 strain isolated from murine brain tissue to infect human foreskin fibroblasts and neonatal murine astrocytes. Bradyzoite infection of both host cell types produced two sequential tachyzoite growth stages that appeared similar to previous sporozoite in vitro infections; a fast-growing stage was followed by spontaneous formation of a slowergrowing stage. In astrocytes, but not in fibroblasts, there was evidence of second bradyzoite to bradyzoite recrudescent pathway that occurred simultaneously with the bradyzoite to tachyzoite pathway.Thus, the host cell environment strongly influenced the pathway of bradyzoite recrudescence. Infections of mice with either the fast-growing or slow-growing recrudescent tachyzoites showed progressive decreases in brain cyst formation that could be fully recovered using serial tissue cyst passage demonstrating the loss of developmental capacity was reversible. By contrast, poor tissue cyst formation of laboratory-adapted tachyzoites was not reversible by these approaches indicating developmental incompetence was permanent in these strains. In order to develop methods to distinguish strain developmental competency, we identified Toxoplasma genes highly expressed in ME49EW in vivo tissue cysts and developed a qPCR approach that differentiates immature from mature bradyzoites. In summary, the results presented describe a new ex vivo bradyzoite recrudescence model that fully captures the reported growth and developmental processes observed during toxoplasmosis reactivation in vivo opening the door to the further study of these important features of the Toxoplasma intermediate life cycle.

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Section: Discussionsupporting

confidence: 89%

An ex vivo model ofToxoplasmarecrudescence

Goerner

Vizcarra

Hong

et al. 2020

Preprint

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“…Despite this infection is asymptomatic in the majority of the cases, when acute infection occurs during pregnancy causes severe neonatal malformations and ocular complications in the foetus 9,10 . Economically, toxoplasmosis can cause significant financial loss if infection occurs during pregnancy, especially in sheep, which often results in abortion 11,12 …”

Section: Introductionmentioning

confidence: 99%

Characterization of murine extracellular vesicles and Toxoplasma gondii infection

Maia

Cruz

Pereira

et al. 2021

Parasite Immunology

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This study characterized extracellular vesicles (EVs) of sera from mice infected with Toxoplasma gondii or immunized with EVs derived T gondii. EVs were purified of sera from four groups (5 A/Sn mice/group). EV‐IM: Mice immunized with T gondii‐released EVs; ACT: mice in acute infection; CHR: mice in chronic infection; and NI: normal mice. EVs were purified by ultracentrifugation. Concentration of serum‐derived EVs from NI group was smaller than EV‐IM, ACT and CHR groups. Most of the EVs from ACT and CHR groups were microvesicles, and they were bigger than the NI group. The same results were shown by Transmission Electron Microscopy. The presence of exosomes was shown in immunoblotting by tetraspanin (CD63 and CD9) evidence. Splenocytes of EV‐IM, CHR and NI groups were stimulated with T. gondii derived EVs. EV‐IM and CHR groups up‐expressed IFN‐γ; TNF‐α and IL‐17, when compared with the NI group. IL‐10 was up‐expressed only in the EV‐IM group. EV‐IM, ACT and CHR groups expressed more miR‐155‐5p, miR‐29c‐3p and miR‐125b‐5p than the NI group. Host‐T gondii interaction can occur, also, via EVs. miRNAs participate in the modulation of cellular immune response against T gondii. These data give subsidies to propose the differentiation between infect or noninfect hosts by concentration of EVs.

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“…The cyst burden in muscles has continuously been shown to be low, which is why sensitive methods such as cat and mouse bioassays have to be used to efficiently detect T. gondii (Rani et al, 2019;Dubey, 2010;Dubey, 2001). However, in the past decade, a more sensitive PCR method has been devised, which utilizes magnetic capture (MC) technology for DNA extraction to discriminately bind small amounts of T. gondii DNA present in large volumes of meat lysate.…”

Section: Raw Pork -Risky Cutsmentioning

confidence: 99%

“…Importantly, it was shown by mouse bioassay of shoulder muscle samples as small as 5 grams that tissue cysts are unevenly distributed in the muscle and that they are formed very early post infection (day 7). Thus, even recently infected pigs can be a source of infection for humans (Rani et al, 2019).…”

Section: Raw Pork -Risky Cutsmentioning

confidence: 99%

Toxoplasma gondii in pork & pork products - too much on our plate?

Klun

Djurković–Djaković

2021

VET GLASNIK

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Background. The constant growth of the global population has led to increasing food production, which has been particularly evident in the production of pork in recent years. In 2015, the number of pigs surpassed one billion, and in 2018 a record high of 120 million tonnes of pork was produced worldwide. In spite of the expansion and dominance of specialized industrial farming in developed countries, Toxoplasma gondii infection in pigs as a source of human infection remains an issue in traditional smallscale farming. The disease burden of toxoplasmosis is estimated to be the highest of all parasitic infections and even higher than that of salmonellosis and campylobacteriosis. Scope and Approach. This paper reviews the latest research on T. gondii-contaminated pork and pork products, published in the past decade. As current methods do not allow for practical and cost-effective detection of T. gondii at slaughter, efforts towards safe meat have focused on the detection of the parasite in pork and ready-to-eat pork products and on post-harvest mitigation measures. Key Findings and Conclusions. In contrast to recommendations for preventing Trichinella infection, there are no globally applicable standardised and validated inactivation procedures for rendering T. gondii infected pork/pork products safe for consumers. Moreover, there are no EU regulations in place for the prevention of T. gondii infection by consumption of pork and pork products. Recommended actions, both at the producer and consumer levels, include post-harvest processing such as cooking, freezing, and proper salting/curing.

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Toxoplasma gondii tissue cyst formation and density of tissue cysts in shoulders of pigs 7 and 14 days after feeding infected mice tissues

Cited by 10 publications

References 8 publications

An ex vivo model ofToxoplasmarecrudescence

An ex vivo model ofToxoplasmarecrudescence

Characterization of murine extracellular vesicles and Toxoplasma gondii infection

Toxoplasma gondii in pork & pork products - too much on our plate?

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