Evaluation of biological behavior of Toxoplasma gondii atypical isolates # 14 and # 163

Bernstein, Mariana; Pardini, Lais Luján; Campero, Lucía María; Helman, Elisa; Unzaga, Juan Manuel; Venturini, Marı́a Cecilia; Moré, Gastón

doi:10.1016/j.exppara.2020.107860

Cited by 8 publications

(7 citation statements)

References 31 publications

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“…The severity of clinical toxoplasmosis is strongly dependent on the gestational stage at which infection occurs; during the early stages, infection is usually fatal, but as gestation progresses, premature births, stillbirths and lambs born clinically healthy but congenitally infected are more frequent ( 60 , 61 ). In addition, it is likely that genetic variability among the different populations of the parasite influences the clinical presentation, since atypical strains (i.e., strains with particular genotypic profiles that differ from the clonal types I, II, and III, and that are widespread in South America) are usually more virulent than clonal type II, which is the predominant lineage in Europe ( 62 , 63 ). Further studies on the genetic diversity of T. gondii infecting sheep in Uruguay are warranted.…”

Section: Discussionmentioning

confidence: 99%

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

et al. 2022

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The aim of this work was to identify causes of abortion through laboratory investigations in sheep flocks in Uruguay. One hundred cases of abortion, comprising 58 fetuses, 36 fetuses with their placentas, and 6 placentas were investigated in 2015–2021. Cases were subjected to gross and microscopic pathologic examinations, and microbiological and serological testing for the identification of causes of abortion, including protozoal, bacterial, and viral pathogens. An etiologic diagnosis was determined in 46 (46%) cases, including 33 (33%) cases caused by infectious pathogens, as determined by the detection of a pathogen along with the identification of fetoplacental lesions attributable to the detected pathogen. Twenty-seven cases (27%) were caused by Toxoplasma gondii, 5 (5%) by Campylobacter fetus subspecies fetus, and 1 (1%) by an unidentified species of Campylobacter. Fourteen cases (14%) had inflammatory and/or necrotizing fetoplacental lesions compatible with an infectious etiology. Although the cause for these lesions was not clearly identified, T. gondii was detected in 4 of these cases, opportunistic bacteria (Bacillus licheniformis, Streptococcus sp.) were isolated in 2 cases, and bovine viral diarrhea virus 1 subtype i (BVDV-1i) was detected in another. Campylobacter jejuni was identified in 1 (1%) severely autolyzed, mummified fetus. BVDV-2b was identified incidentally in one fetus with an etiologic diagnosis of toxoplasmosis. Microscopic agglutination test revealed antibodies against ≥1 Leptospira serovars in 15/63 (23.8%) fetuses; however, Leptospira was not identified by a combination of qPCR, culture, fluorescent antibody testing nor immunohistochemistry. Neospora caninum, Chlamydia abortus, Chlamydia pecorum, Coxiella burnetii and border disease virus were not detected in any of the analyzed cases. Death was attributed to dystocia in 13 (13%) fetuses delivered by 8 sheep, mostly from one highly prolific flock. Congenital malformations including inferior prognathism, a focal hepatic cyst, and enterohepatic agenesis were identified in one fetus each, the latter being the only one considered incompatible with postnatal life. Toxoplasmosis, campylobacteriosis and dystocia were the main identified causes of fetal losses. Despite the relatively low overall success rate in establishing an etiologic diagnosis, a systematic laboratory workup in cases of abortion is of value to identify their causes and enables zoonotic pathogens surveillance.

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Section: Discussionmentioning

confidence: 99%

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

et al. 2022

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“…In vivo murine models have been traditionally used to evaluate the virulence degree of Toxoplasma isolates by calculating the cumulative mortality rate [ 16 ]. On the other hand, in vitro culture models have also been shown to be highly suitable and informative for phenotypic characterization of apicomplexan parasite strains [ 17 – 20 ]. Regarding T. gondii , studies employing host target-cell lines such as those derived from central nervous system or placental tissues [ 21 – 24 ] are of special interest.…”

Section: Introductionmentioning

confidence: 99%

In vivo and in vitro models show unexpected degrees of virulence among Toxoplasma gondii type II and III isolates from sheep

Fernández‐Escobar

Calero‐Bernal

Regidor‐Cerrillo

et al. 2021

Vet Res

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Toxoplasma gondii is an important zoonotic agent with high genetic diversity, complex epidemiology, and variable clinical outcomes in animals and humans. In veterinary medicine, this apicomplexan parasite is considered one of the main infectious agents responsible for reproductive failure in small ruminants worldwide. The aim of this study was to phenotypically characterize 10 Spanish T. gondii isolates recently obtained from sheep in a normalized mouse model and in an ovine trophoblast cell line (AH-1) as infection target cells. The panel of isolates met selection criteria regarding such parameters as genetic diversity [types II (ToxoDB #1 and #3) and III (#2)], geographical location, and sample of origin (aborted foetal brain tissues or adult sheep myocardium). Evaluations of in vivo mortality, morbidity, parasite burden and histopathology were performed. Important variations between isolates were observed, although all isolates were classified as “nonvirulent” (< 30% cumulative mortality). The isolates TgShSp16 (#3) and TgShSp24 (#2) presented higher degrees of virulence. Significant differences were found in terms of in vitro invasion rates and tachyzoite yield at 72 h post-inoculation (hpi) between TgShSp1 and TgShSp24 isolates, which exhibited the lowest and highest rates, respectively. The study of the CS3, ROP18 and ROP5 loci allelic profiles revealed only type III alleles in ToxoDB #2 isolates and type II alleles in the #1 and #3 isolates included. We concluded that there are relevant intra- and inter-genotype virulence differences in Spanish T. gondii isolates, which could not be inferred by genetic characterization using currently described molecular markers.

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“…In vitro models are considered also suitable first approaches to phenotypically characterize apicomplexan parasite strains ( Regidor-Cerrillo et al., 2011 ; Dellarupe et al., 2014 ; Frey et al., 2016 ; Jiménez-Pelayo et al., 2017 ; García-Sánchez et al., 2019 ). However, only a small proportion of the publications addresses the virulence characterization of non-laboratory T. gondii isolates in vitro ( Loeuillet et al., 2019 ; Sánchez-Sánchez et al., 2019 ; Bernstein et al., 2020 ; Uzelac et al., 2020 ; Fernández-Escobar et al., 2021 ; Salman et al., 2021 ).…”

Section: Complementary Approaches On the Determination Of Virulence I...mentioning

confidence: 99%

“…Overall, it is generally claimed that type I strains present enhanced proliferation capacity and lower host immune system stimulation than type II isolates ( Mammari et al., 2014 ). Regarding the in vitro virulence assessment of non-laboratory (field) isolates, the number of studies is relatively low; however, its use as a complement to the evaluation of virulence in mice has increased in recent years ( Loeuillet et al., 2019 ; Sánchez-Sánchez et al., 2019 ; Bernstein et al., 2020 ; Fukumoto et al., 2020 ; Uzelac et al., 2020 ; Fernández-Escobar et al., 2021 ; Salman et al., 2021 ).…”

Section: Complementary Approaches On the Determination Of Virulence I...mentioning

confidence: 99%

Unifying Virulence Evaluation in Toxoplasma gondii: A Timely Task

Calero‐Bernal

Fernández‐Escobar

Katzer

et al. 2022

Front. Cell. Infect. Microbiol.

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Toxoplasma gondii, a major zoonotic pathogen, possess a significant genetic and phenotypic diversity that have been proposed to be responsible for the variation in clinical outcomes, mainly related to reproductive failure and ocular and neurological signs. Different T. gondii haplogroups showed strong phenotypic differences in laboratory mouse infections, which provide a suitable model for mimicking acute and chronic infections. In addition, it has been observed that degrees of virulence might be related to the physiological status of the host and its genetic background. Currently, mortality rate (lethality) in outbred laboratory mice is the most significant phenotypic marker, which has been well defined for the three archetypal clonal types (I, II and III) of T. gondii; nevertheless, such a trait seems to be insufficient to discriminate between different degrees of virulence of field isolates. Many other non-lethal parameters, observed both in in vivo and in vitro experimental models, have been suggested as highly informative, yielding promising discriminatory power. Although intra-genotype variations have been observed in phenotypic characteristics, there is no clear picture of the phenotypes circulating worldwide; therefore, a global overview of T. gondii strain mortality in mice is presented here. Molecular characterization has been normalized to some extent, but this is not the case for the phenotypic characterization and definition of virulence. The present paper proposes a baseline (minimum required information) for the phenotypic characterization of T. gondii virulence and intends to highlight the needs for consistent methods when a panel of T. gondii isolates is evaluated for virulence.

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Evaluation of biological behavior of Toxoplasma gondii atypical isolates # 14 and # 163

Cited by 8 publications

References 31 publications

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

Diagnostic Investigation of 100 Cases of Abortion in Sheep in Uruguay: 2015–2021

In vivo and in vitro models show unexpected degrees of virulence among Toxoplasma gondii type II and III isolates from sheep

Unifying Virulence Evaluation in Toxoplasma gondii: A Timely Task

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