Toxoplasmosis of rats: a review, with considerations of their value as an animal model and their possible role in epidemiology

Dubey, J. P.; Frenkel, J. K.

doi:10.1016/s0304-4017(97)00227-6

Cited by 130 publications

(100 citation statements)

References 90 publications

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“…However, Thiermann (1957) with the C.M strain, Remington et al (1958) with RH strain, Remington et al (1961) with the Beverley strain and Dubey et al (1997) observed a low rate of conge nital transmission in pups born from chronically infected mothers (for review, see Dubey & Frenkel, 1998 …”

Section: Discussionmentioning

confidence: 99%

Experimental congenital toxoplasmosis in Wistar and Holtzman rats

Paulino

Vítor

1999

Parasite

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Summary :Congenital toxoplasmosis was evaluated in Wistar and Holtzman rats using two strains of Toxoplasma gondii isolated in Brazil. Pregnant rats were inoculated by subcutaneous or intraperitoneal routes with 10 6 or 8 x 10 6 tachyzoites of N strain (virulent for mice) and by subcutaneous or oral routes with 10 2 or 1.2 x 10 3 cysts of P strain (avirulent for mice). The tissues of rat pups born from these rats were bioassayed for T. gondii infection. T. gondii was not observed in the pups born from rats inoculated with N strain. In the animals inoculated with P strain, congenital toxoplasmosis occurred in 22.8 % (Wistar rats inoculated with 10 2 cysts by the subcutaneous route), 11.4 % (Wistar rats inoculated with 10 2 cysts by the oral route), 21.2% (Wistar rats inoculated with 1.2 x 10 3 cysts by the oral route) and 2.9 % of fetal infection (Holtzman rats inoculated with 10 2 cysts by the oral route). None of the pups born from chronically infected mother were infected with T. gondii.

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Section: Discussionmentioning

confidence: 99%

Experimental congenital toxoplasmosis in Wistar and Holtzman rats

Paulino

Vítor

1999

Parasite

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“…Results from genetic studies in animal models can be applied to human pathology through comparative genomics (5,6). Rats, like humans, usually develop subclinical toxoplasmosis (7); this contrasts with the severity of the disease developed in most strains of mice. Surprisingly, the LEW rat strain exhibits a complete resistance to Toxoplasma infection (8).…”

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The ratToxo1locus directs toxoplasmosis outcome and controls parasite proliferation and spreading by macrophage-dependent mechanisms

Cavaillès

Sergent

Bisanz

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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Toxoplasmosis is a healthcare problem in pregnant women and immunocompromised patients. Like humans, rats usually develop a subclinical chronic infection. LEW rats exhibit total resistance to Toxoplasma gondii infection, which is expressed in a dominant mode. A genome-wide search carried out in a cohort of F 2 progeny of susceptible BN and resistant LEW rats led to identify on chromosome 10 a major locus of control, which we called Toxo1. Using reciprocal BN and LEW lines congenic for chromosome 10 genomic regions from the other strain, Toxo1 was found to govern the issue of T. gondii infection whatever the remaining genome. Analyzes of rats characterized by genomic recombination within Toxo1, reduced the interval down to a 1.7-cM region syntenic to human 17p13. In vitro studies showed that the Toxo1-mediated refractoriness to T. gondii infection is associated with the ability of the macrophage to impede the proliferation of the parasite within the parasitophorous vacuole. In contrast, proliferation was observed in fibroblasts whatever the genomic origin of Toxo1. Furthermore, ex vivo studies indicate that macrophage controls parasitic infection spreading by a Toxo1-mediated mechanism. This forward genetics approach should ultimately unravel a major pathway of innate resistance to toxoplasmosis and possibly to other apicomplexan parasitic diseases.T he protozoan Toxoplasma gondii is an obligate intracellular parasite that infects humans and a broad spectrum of vertebrate hosts. It is found worldwide, and the infection is common as indicated by a high prevalence of specific Ab among almost all human populations. T. gondii infection occurs by oral ingestion of either cysts from infected animal tissues, or oocysts excreted by cats. In healthy individuals, T. gondii establishes a chronic asymptomatic infection characterized by a specific immune response and the encystment of dormant bradyzoites into host tissues. A serious threat to human health can occur under congenital infection or reactivation of a latent infection in immunodeficient patients (1).Epidemiological studies have indicated that the genetic make-up of the host and of the parasite are involved in the phenotypic expression of toxoplasmosis (2-4). Genetic studies in humans are hampered by both population heterogeneity and environment variability. In experimental conditions, genetic and environmental factors are under control. Results from genetic studies in animal models can be applied to human pathology through comparative genomics (5, 6). Rats, like humans, usually develop subclinical toxoplasmosis (7); this contrasts with the severity of the disease developed in most strains of mice. Surprisingly, the LEW rat strain exhibits a complete resistance to Toxoplasma infection (8). Indeed, unlike susceptible BN and F344 rats, LEW rats do not show trace of parasitic infection as shown by negative serology and lack of brain cysts. F 1 hybrid (LEW ϫ BN) and (LEW ϫ F344) rats are resistant to T. gondii, indicating a dominant effect of the involved gene(s) (9). W...

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“…Cats acquire the infection by hunting rats and birds 5 . However, a previous study with domiciled cats in Curitiba showed a seroprevalence of 16.3% for T. gondii, despite no association with hunting and/or outdoor access 17 .…”

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“…Toxoplasmosis is caused by Toxoplasma gondii, a ubiquitous protozoan with a worldwide distribution 5 . Rodents are intermediate hosts for T. gondii, as they are preyed upon by infected felids, which are the defi nitive hosts 5 .…”

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Serosurvey of Leptospira spp. and Toxoplasma gondii in rats captured from two zoos in Southern Brazil

Pellizzaro

Conrado

Martins

et al. 2017

Rev. Soc. Bras. Med. Trop.

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Introduction: Norway rats (Rattus norvegicus) are zoonotic reservoirs for Leptospira spp. and Toxoplasma gondii, and infl uence diseases in urban areas. Methods: Free-ranging and laboratory-raised rats from two zoos in southern Brazil were tested for Leptospira spp. and T. gondii using microscopic agglutination and modifi ed agglutination tests, respectively. Results: Overall, 25.6% and 4.6% free-ranging rats tested positive for Leptospira spp. and T. gondii, respectively, with co-seropositivity occurring in two animals. For laboratory-raised rats, 20% tested positive for Leptospira spp. Also, Leptospira bifl exa serovar Patoc and Leptospira noguchii serovar Panama were found. Conclusions: Serosurveys can show the environmental prevalence of zoonotic pathogens.

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Toxoplasmosis of rats: a review, with considerations of their value as an animal model and their possible role in epidemiology

Cited by 130 publications

References 90 publications

Experimental congenital toxoplasmosis in Wistar and Holtzman rats

Experimental congenital toxoplasmosis in Wistar and Holtzman rats

The ratToxo1locus directs toxoplasmosis outcome and controls parasite proliferation and spreading by macrophage-dependent mechanisms

Serosurvey of Leptospira spp. and Toxoplasma gondii in rats captured from two zoos in Southern Brazil

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