A Toxoplasma gondii strain isolated in Okinawa, Japan shows high virulence in Microminipigs

Taniguchi, Yuji; Yanagihara, Itaru; Nakura, Yukiko; Ichikawa, Chihiro; Saito, Taizo; Appiah-Kwarteng, Cornelia; Matsuzaki, Motomichi; Fukumoto, Junpei; Nagamune, Kisaburo; Kyan, Hisako; Takasu, Masaki; Kitoh, Katsuya; Takashima, Yasuhiro

doi:10.1016/j.parint.2019.101935

Cited by 10 publications

(10 citation statements)

References 26 publications

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“…When tachyzoites of the same isolate were IP inoculated into laboratory mice no clinical signs of infection were observed either but 100-80% lethality was found in mice orally inoculated with low doses (100, 50 and 10) of tissue cysts of this isolate. Furthermore, a recently obtained Japanese isolate (TgCatJpOk4) showed notable mortality (60%) and morbidity (80%) rates when micro minipigs were IP inoculated with 10 7 tachyzoites ( Taniguchi et al., 2019 ), which is in concordance with its previously demonstrated 100% mortality in mice ( Fukumoto et al., 2020 ). In an interesting comparative study ( Xia et al., 2020 ), the virulence of a type PRU (ToxoDB #3) Chinese isolate (TgPIG-WH1) obtained from an aborted piglet was assessed in mice and pigs.…”

Section: In Vivo Models For Virulence Assessment: State and ...supporting

confidence: 84%

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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Section: In Vivo Models For Virulence Assessment: State and ...supporting

confidence: 84%

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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“…In recent study, with advances in gene analysis methods, there has been an increase in the number of known genotypes and details of the genetic diversity of this parasite [6,7,13]. Some of the strains in this study have been analyzed in detail [4,14], However, in order to characterize Okinawa's T. gondii, it is necessary not only to sequence the GRA6 gene for more strains but also to analyze other genes.…”

mentioning

confidence: 99%

<i>Toxoplasma gondii</i> antibody prevalence and isolation in free-ranging cats in Okinawa, Japan

Kyan

Takara

Taira

et al. 2021

The Journal of Veterinary Medical Science

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Cats are an important host of Toxoplasma gondii from an epidemiological perspective because they are the only definitive hosts that excrete oocysts in their feces. In this study, 201 free-ranging cats in Okinawa were examined for T. gondii infection. Using the latex agglutination test, we detected antibodies against T. gondii in 26.9% (54/201) of the cats. Oocysts of T. gondii were not detected upon microscopic examination of the feces of 128 cats. T. gondii was isolated from the tissues of 9 out of 24 seropositive or pseudo-seropositive cats with a bioassay using laboratory mice. Genotyping for the GRA6 gene revealed that five and four of the isolates were type I and II, respectively.

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“…In fact, a recent study found higher foetal mortality in sheep than in mice after infection with oocysts from the type-II TgShSp1 strain ( 20 ). Similarly, another report found no or low virulence in swine upon infection with the type III TgCatJpGil/TaJ isolate, as opposed to the high virulence observed in mice ( 26 ). When studying the TgCatJp4Ok4 isolate, which is phylogenetically close related to type II, virulence was high in both mouse and swine ( 26 ).…”

Section: Discussionmentioning

confidence: 95%

“…Similarly, another report found no or low virulence in swine upon infection with the type III TgCatJpGil/TaJ isolate, as opposed to the high virulence observed in mice ( 26 ). When studying the TgCatJp4Ok4 isolate, which is phylogenetically close related to type II, virulence was high in both mouse and swine ( 26 ). This result again suggests that T. gondii differs in virulence depending on the host species.…”

Section: Discussionmentioning

confidence: 95%

Archetypal type II and III Toxoplasma gondii oocysts induce different immune responses and clinical outcomes in experimentally infected piglets

et al. 2022

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Livestock animals, such as swine, are an important source of Toxoplasma gondii in the human population. Currently, there is limited knowledge regarding the potential influence that the T. gondii genotype might exert on establishing infection in swine. Herein, we investigated the role of 2 T. gondii isolates, type II and III, representative of the genotypes circulating in Europe, in the immune responses and infection dynamics in piglets. Recently obtained oocysts (103) from the T. gondii field isolates TgShSp1 (type II, ToxoDB genotype #3) and TgShSp24 (type III, #2) were used for oral infection. Thirteen 50-day-old female piglets of the Landrace-Large White crossbreed were randomly allocated into three different groups: Group 1 (G1, n=5), inoculated with TgShSp1; Group 2 (G2, n=5), inoculated with TgShSp24; and Group 3 (G3, n=3), a non-infected control group. Clinical signs were monitored daily until 42 days post-infection (dpi) when piglets were euthanized. Blood samples were collected weekly to test the cellular immune response in parasite-stimulated peripheral blood and specific IgG, IgG1 and IgG2, responses in sera. Parasite distribution and burden were evaluated in target tissues using a mouse bioassay and quantitative RT−PCR (qPCR). Apathy and a moderate decrease in feed consumption were observed in G1 and G2 piglets between 5 and 8 dpi, coinciding with fever (>40°C). G2 piglets had higher temperatures for a longer duration. Using mouse bioassay and qPCR, the detection frequency was higher in G2 vs. G1, and the highest parasite burdens in target tissues were also found in G2. Seroconversion was detected at 14 dpi in both infected groups, but higher antibody levels were observed in G2 piglets. Cytokine analyses revealed the production of IL-8, IL-1β and IFN-ɤ from 7 dpi in both infected groups. Moreover, IL-12 was produced from 7 dpi in G1 and from 14 dpi in G2. Levels of IL-8 were higher in G2, but IL-1β, IL-12 and IFN-ɤ were higher in G1 at 14 dpi. This cytokine profile reveals a predominant proinflammatory response that could be involved in limiting T. gondii infection in piglets, although it is more efficient against TgShSp1 type II-driven infection.

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A Toxoplasma gondii strain isolated in Okinawa, Japan shows high virulence in Microminipigs

Cited by 10 publications

References 26 publications

Unifying Virulence Evaluation in Toxoplasma gondii: A Timely Task

Unifying Virulence Evaluation in Toxoplasma gondii: A Timely Task

<i>Toxoplasma gondii</i> antibody prevalence and isolation in free-ranging cats in Okinawa, Japan

Archetypal type II and III Toxoplasma gondii oocysts induce different immune responses and clinical outcomes in experimentally infected piglets

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