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Rosa RB, da Costa MS, Teixeira SC, de Castro EF, Dantas WM, Ferro EAV, da Silva MV. Calomys callosus: An Experimental Animal Model Applied to Parasitic Diseases Investigations of Public Health Concern. Pathogens 2022; 11:pathogens11030369. [PMID: 35335694 PMCID: PMC8948650 DOI: 10.3390/pathogens11030369] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 03/07/2022] [Accepted: 03/14/2022] [Indexed: 01/27/2023] Open
Abstract
The appearance and spread of parasitic diseases around the world aroused the interest of the scientific community to discover new animal models for improving the quality and specificity of surveys. Calomys callosus is a rodent native to South America, an easy handling model, with satisfactory longevity and reproducibility. C. callosus is susceptible to toxoplasmosis and can be used as experimental model for the study the pathogenesis, treatment, vertical transmission, and ocular toxoplasmosis. C. callosus can also be used to study cutaneous and visceral leishmaniasis, as the animals present cutaneous lesions, as well as parasites in the organs. C. callosus has epidemiological importance in Chagas disease, and since it is a Trypanosoma cruzi natural host in which rodents show high parasitemia and lethality, they are also effective as a model of congenital transmission. In the study of schistosomiasis, Schistosoma mansoni was proven to be a C. callosus natural host; thus, this rodent is a great model for fibrosis, hepatic granulomatous reaction, and celloma associated with lymphomyeloid tissue (CALT) during S. mansoni infection. In this review, we summarize the leading studies of parasitic diseases that used C. callosus as a rodent experimental model, describing the main uses and characteristics that led them to be considered an effective model.
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Affiliation(s)
- Rafael Borges Rosa
- Rodents Animal Facilities Complex, Federal University of Uberlandia, Uberlandia 38400-902, Brazil; (R.B.R.); (M.S.d.C.); (E.F.d.C.)
| | - Mylla Spirandelli da Costa
- Rodents Animal Facilities Complex, Federal University of Uberlandia, Uberlandia 38400-902, Brazil; (R.B.R.); (M.S.d.C.); (E.F.d.C.)
| | - Samuel Cota Teixeira
- Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia 38405-318, Brazil; (S.C.T.); (E.A.V.F.)
| | - Emilene Ferreira de Castro
- Rodents Animal Facilities Complex, Federal University of Uberlandia, Uberlandia 38400-902, Brazil; (R.B.R.); (M.S.d.C.); (E.F.d.C.)
| | | | - Eloisa Amália Vieira Ferro
- Institute of Biomedical Sciences, Federal University of Uberlandia, Uberlandia 38405-318, Brazil; (S.C.T.); (E.A.V.F.)
| | - Murilo Vieira da Silva
- Rodents Animal Facilities Complex, Federal University of Uberlandia, Uberlandia 38400-902, Brazil; (R.B.R.); (M.S.d.C.); (E.F.d.C.)
- Correspondence:
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Barros M, Teixeira D, Vilanova M, Correia A, Teixeira N, Borges M. Vaccines in Congenital Toxoplasmosis: Advances and Perspectives. Front Immunol 2021; 11:621997. [PMID: 33658997 PMCID: PMC7917294 DOI: 10.3389/fimmu.2020.621997] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/29/2020] [Indexed: 12/03/2022] Open
Abstract
Congenital toxoplasmosis has a high impact on human disease worldwide, inducing serious consequences from fetus to adulthood. Despite this, there are currently no human vaccines available to prevent this infection. Most vaccination studies against Toxoplasma gondii infection used animal models in which the infection was established by exogenous inoculation. Here, we review recent research on potential T. gondii vaccines using animal models in which infection was congenitally established. Endeavors in this field have so far revealed that live or subunit vaccines previously found to confer protection against extrinsically established infections can also protect, at least partially, from vertically transmitted infection. Nevertheless, there is no consensus on the more adequate immune response to protect the host and the fetus in congenital infection. Most of the vaccination studies rely on the assessment of maternal systemic immune responses, quantification of parasitic loads in the fetuses, and survival indexes and/or brain parasitic burden in the neonates. More research must be carried out not only to explore new vaccines but also to further study the nature of the elicited immune protection at the maternal-fetal interface. Particularly, the cellular and molecular effector mechanisms at the maternal-fetal interface induced by immunization remain poorly characterized. Deeper knowledge on the immune response at this specific location will certainly help to refine the vaccine-induced immunity and, consequently, to provide the most effective and safest protection against T. gondii vertical infection.
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Affiliation(s)
- Mariana Barros
- Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Daniela Teixeira
- Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Manuel Vilanova
- Immunobiology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal.,Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Alexandra Correia
- Immunobiology Group, Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Porto, Portugal.,Departamento de Imuno-Fisiologia e Farmacologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, Portugal
| | - Natercia Teixeira
- Applied Molecular Biosciences Unit/Rede de Química e Tecnologia (UCIBIO/REQUIMTE), Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
| | - Margarida Borges
- Applied Molecular Biosciences Unit/Rede de Química e Tecnologia (UCIBIO/REQUIMTE), Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
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3
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Franco PS, da Silva NM, de Freitas Barbosa B, de Oliveira Gomes A, Ietta F, Shwab EK, Su C, Mineo JR, Ferro EAV. Calomys callosus chronically infected by Toxoplasma gondii clonal type II strain and reinfected by Brazilian strains is not able to prevent vertical transmission. Front Microbiol 2015; 6:181. [PMID: 25806028 PMCID: PMC4354403 DOI: 10.3389/fmicb.2015.00181] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 02/19/2015] [Indexed: 11/13/2022] Open
Abstract
Considering that Toxoplasma gondii has shown high genetic diversity in Brazil, the aim of this study was to determine whether Calomys callosus chronically infected by the ME-49 strain might be susceptible to reinfection by these Brazilian strains, including vertical transmission of the parasite. Survival curves were analyzed in non-pregnant females chronically infected with ME-49 and reinfected with the TgChBrUD1 or TgChBrUD2 strain, and vertical transmission was analyzed after reinfection of pregnant females with these same strains. On the 19th day of pregnancy (dop), placentas, uteri, fetuses, liver, spleen, and lung were processed for detection of the parasite. Blood samples were collected for humoral and cellular immune response analyses. All non-pregnant females survived after reinfection and no changes were observed in body weight and morbidity scores. In pregnant females, parasites were detected in the placentas of ME-49 chronically infected females and reinfected females, but were only detected in the fetuses of reinfected females. TgChBrUD2 reinfected females showed more impaired pregnancy outcomes, presenting higher numbers of animals with fetal loss and a higher resorption rate, in parallel with higher levels of pro-inflammatory cytokines and IgG2a subclass antibodies. Vertical transmission resulting from chronic infection of immunocompetent C. callosus is considered a rare event, being attributed instead to either reactivation or reinfection. That is, the pregnancy may be responsible for reactivation of the latent infection or the reinfection may promote T. gondii vertical transmission. Our results clearly demonstrate that, during pregnancy, protection against T. gondii can be breached after reinfection with parasites belonging to different genotypes, particularly when non-clonal strains are involved in this process and in this case the reinfection promoted vertical transmission of both type II and Brazilian T. gondii strains.
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Affiliation(s)
- Priscila S Franco
- Laboratory of Immunophysiology of Reproduction, Department of Histology and Embryology, Federal University of Uberlândia , Uberlândia, Brazil
| | - Neide M da Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia , Uberlândia, Brazil
| | - Bellisa de Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Department of Histology and Embryology, Federal University of Uberlândia , Uberlândia, Brazil
| | - Angelica de Oliveira Gomes
- Laboratory of Immunophysiology of Reproduction, Department of Histology and Embryology, Federal University of Uberlândia , Uberlândia, Brazil
| | - Francesca Ietta
- Department of Life Sciences, University of Siena , Siena, Italy
| | - E K Shwab
- Department of Microbiology, The University of Tennessee , Knoxville, TN, USA
| | - Chunlei Su
- Department of Microbiology, The University of Tennessee , Knoxville, TN, USA
| | - José R Mineo
- Laboratory of Immunoparasitology, Department of Immunology, Microbiology and Parasitology, Federal University of Uberlândia , Uberlândia, Brazil
| | - Eloisa A V Ferro
- Laboratory of Immunophysiology of Reproduction, Department of Histology and Embryology, Federal University of Uberlândia , Uberlândia, Brazil
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Toxoplasma gondii superinfection and virulence during secondary infection correlate with the exact ROP5/ROP18 allelic combination. mBio 2015; 6:e02280. [PMID: 25714710 PMCID: PMC4358003 DOI: 10.1128/mbio.02280-14] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The intracellular parasite Toxoplasma gondii infects a wide variety of vertebrate species globally. Infection in most hosts causes a lifelong chronic infection and generates immunological memory responses that protect the host against new infections. In regions where the organism is endemic, multiple exposures to T. gondii likely occur with great frequency, yet little is known about the interaction between a chronically infected host and the parasite strains from these areas. A widely used model to explore secondary infection entails challenge of chronically infected or vaccinated mice with the highly virulent type I RH strain. Here, we show that although vaccinated or chronically infected C57BL/6 mice are protected against the type I RH strain, they are not protected against challenge with most strains prevalent in South America or another type I strain, GT1. Genetic and genomic analyses implicated the parasite-secreted rhoptry effectors ROP5 and ROP18, which antagonize the host’s gamma interferon-induced immunity-regulated GTPases (IRGs), as primary requirements for virulence during secondary infection. ROP5 and ROP18 promoted parasite superinfection in the brains of challenged survivors. We hypothesize that superinfection may be an important mechanism to generate T. gondii strain diversity, simply because two parasite strains would be present in a single meal consumed by the feline definitive host. Superinfection may drive the genetic diversity of Toxoplasma strains in South America, where most isolates are IRG resistant, compared to North America, where most strains are IRG susceptible and are derived from a few clonal lineages. In summary, ROP5 and ROP18 promote Toxoplasma virulence during reinfection. Toxoplasma gondii is a widespread parasite of warm-blooded animals and currently infects one-third of the human population. A long-standing assumption in the field is that prior exposure to this parasite protects the host from subsequent reexposure, due to the generation of protective immunological memory. However, this assumption is based on clinical data and mouse models that analyze infections with strains common to Europe and North America. In contrast, we found that the majority of strains sampled from around the world, in particular those from South America, were able to kill or reinfect the brains of hosts previously exposed to T. gondii. The T. gondii virulence factors ROP5 and ROP18, which inhibit key host effectors that mediate parasite killing, were required for these phenotypes. We speculate that these results underpin clinical observations that pregnant women previously exposed to Toxoplasma can develop congenital infection upon reexposure to South American strains.
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Camossi LG, Fornazari F, Richini-Pereira VB, da Silva RC, Cardia DFF, Langoni H. Immunization of Wistar female rats with 255-Gy-irradiated Toxoplasma gondii: preventing parasite load and maternofoetal transmission. Exp Parasitol 2014; 145:157-63. [PMID: 25169764 DOI: 10.1016/j.exppara.2014.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 08/12/2014] [Accepted: 08/14/2014] [Indexed: 11/27/2022]
Abstract
Toxoplasmosis, caused by an obligate intracellular protozoan parasite, Toxoplasma gondii, is an worldwide parasitic disease, with significant importance for animal production and considerable impact to the public health. This study was aimed to evaluate the dynamic of the distribution of T.gondii in tissues of female Wistar rats and their puppies tissues, after the immunization by oral rote with irradiated tachyzoites. One week after pregnancy confirmation, rats was challenged by gavage with T. gondii bradyzoites, oocysts or tachyzoites of T. gondii. Forty-eight pregnant rats were grouped as follow: immunized and challenged with bradyzoites (BZ*); non-immunized and challenged with bradyzoites (BZ); immunized and challenged with oocysts (OC*); non-immunized and challenged with oocysts (OC); immunized and challenged with tachyzoites (TZ*); non-immunized and challenged with tachyzoites (TZ); only immunized (I); control group (C). After parturition the rats were sacrificed and the tissues were researched for the DNA of T. gondii by polymerase chain reaction (PCR) and the parasite load determined by the quantitative PCR (qPCR). It was verified that the immunization with irradiated tachyzoites of T. gondii induced the reduction of parasitic load in most organs analyzed, although not prevent the establishment of infection with the parasite. And also, the immunization showed a favorable effect on the birth rate and litter size.
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Affiliation(s)
- Lucilene Granuzzio Camossi
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil.
| | - Felipe Fornazari
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil
| | - Virgínia Bodelão Richini-Pereira
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil
| | - Rodrigo Costa da Silva
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil
| | - Daniel Fontana Ferreira Cardia
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil
| | - Helio Langoni
- Faculdade de Medicina Veterinária e Zootecnia, UNESP Univ Estadual Paulista, Campus de Botucatu, Departamento de Higiene Veterinária e Saúde Pública, Botucatu, SP, Brazil.
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Franco PS, Silva DAO, Costa IN, Gomes AO, Silva ALN, Pena JDO, Mineo JR, Ferro EAV. Evaluation of vertical transmission of Toxoplasma gondii in Calomys callosus model after reinfection with heterologous and virulent strain. Placenta 2010; 32:116-20. [PMID: 21146211 DOI: 10.1016/j.placenta.2010.11.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Revised: 11/12/2010] [Accepted: 11/17/2010] [Indexed: 11/25/2022]
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite that causes a variety of clinical syndromes, but the infection is severe in immunocompromised individuals and during pregnancy due to the possibility of transplacental transmission of the parasite causing congenital toxoplasmosis. Vertical transmission of the parasite usually occurs when females are primarily infected during pregnancy. Calomys callosus is resistant to T. gondii ME49 strain, which presents a moderate virulence and congenital disease occurs only during the acute phase of infection. The aim of this study was to determine whether vertical transmission occurs when females of C. callosus chronically infected with ME49 strain of T. gondii are reinfected with a highly virulent strain (RH, type I). Females were infected with cysts of the ME49 strain. On the 1st day of pregnancy, animals were reinfected with tachyzoites of the RH strain. In the 19th day of pregnancy, placentas and embryos were processed for morphological analysis, immunohistochemistry and for detection of the parasite by PCR and mouse bioassay. Morphological and immunohistochemical analyses revealed the presence of parasites only in placental tissues. Mouse bioassay results showed seroconversion only in mice that were inoculated with placental tissues. Also, T. gondii DNA was detected only in placental samples. Congenital toxoplasmosis does not occur in C. callosus females chronically infected with the moderately virulent ME49 strain of T. gondii and reinfected with the highly virulent RH strain, thus indicating that primary T. gondii infection before pregnancy leads to an effective long-term immunity preventing transplacental transmission to the fetus.
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Affiliation(s)
- P S Franco
- Laboratory of Histology and Embriology, Institute of Biomedical Sciences, Federal University of Uberlândia, 38405-320 Uberlândia, MG, Brazil.
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Wang T, Liu M, Gao XJ, Zhao ZJ, Chen XG, Lun ZR. Toxoplasma gondii: the effects of infection at different stages of pregnancy on the offspring of mice. Exp Parasitol 2010; 127:107-12. [PMID: 20619261 DOI: 10.1016/j.exppara.2010.07.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/25/2010] [Accepted: 07/01/2010] [Indexed: 11/28/2022]
Abstract
Congenital toxoplasmosis can cause fetal damage in humans and domestic animals. This study was focused on the effects of Toxoplasma gondii (Prugniaud strain) infection at different stages of pregnancy on the offspring of mice. Results showed that newborn mice from all infected groups were significantly lower in weight than those from the control group but significant difference was not found among these groups at day 60 after birth. The survival rate of the offspring from the group of mice infected at the earlier stage of pregnancy was significantly lower than those of infected and control groups. The positive offspring (with cysts found in their brain tissues) born from the mice infected at the earlier and intermediate stages of pregnancy showed a shorter latency and greater number of errors in the step-through passive avoidance test than those born from the mice infected at the late stage of pregnancy, the control group and the negative offspring from the infected groups. The number of cysts in the brain tissue was significantly higher in the offspring born from the groups of mice infected at the earlier and intermediate stages of pregnancy than those from the group of mice infected at the late stage of pregnancy. In addition, our results indicated that a high congenital transmission rate (90%) occurred in this NIH mouse model. In conclusion, the earlier and intermediate maternal infection of T. gondii can result in severe congenital toxoplasmosis, exhibiting conditions such as stillbirth or non-viability, and learning or memory capability damage in this mouse model. These results not only provide useful data for better understanding the effects of T. gondii infection on the offspring of mice infected at different stages of pregnancy but also for better consideration of the effect of this infection on other mammalian hosts including humans.
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Affiliation(s)
- Tao Wang
- Center for Parasitic Organisms, State Key Laboratory of Biocontrol, School of Life Sciences, and Key Laboratory of Tropical Diseases Control, The Ministry of Education, Zhongshan Medical College, Sun Yat-Sen Zhongshan University, Guangzhou 510275, PR China
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Costa I, Angeloni M, Santana L, Barbosa B, Silva M, Rodrigues A, Rostkowsa C, Magalhães P, Pena J, Silva D, Mineo J, Ferro E. Azithromycin Inhibits Vertical Transmission of Toxoplasma gondii in Calomys callosus (Rodentia: Cricetidae). Placenta 2009; 30:884-90. [DOI: 10.1016/j.placenta.2009.08.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 08/03/2009] [Accepted: 08/04/2009] [Indexed: 10/20/2022]
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Evaluation of Toxoplasma gondii placental transmission in BALB/c mice model. Exp Parasitol 2009; 123:168-72. [PMID: 19563804 DOI: 10.1016/j.exppara.2009.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 06/18/2009] [Accepted: 06/23/2009] [Indexed: 11/22/2022]
Abstract
Toxoplasma gondii infection is common worldwide and highly important to pregnant women as it can be transmitted to the fetus via the placenta. This study aimed at evaluating the prevention of placental transmission in two different strains after chronic infection with each one of the strains. A BALB/c mice model was inoculated 30days before breeding (immunization) and re-infected 12 and 15days after pregnancy (challenge). Seven experimental groups were assayed: G1: ME49-immunization (type II), M7741-challenge (type III); G2: M7741-immunization, ME49-challenge; G3, ME49-immunization; G4: M7741-immunization; G5: ME49-challenge; G6: M7741-challenge; G7: saline solution inoculation. Serology, mouse bioassay, PCR and RLFP of the uterus, placenta and fetus were performed to determine the congenital transmission of the strains challenged after chronic infection. IgG T. gondii antibodies were detected in G1, G2, G3 and G4, but not in G5, G6 and G7. All animals of G5 and G6 were IgM-positive. Congenital infection was not detected by bioassay and PCR. Nonetheless, placentas from G3 and G4 resulted positive but no corresponding fetal infection was detected. G1 and G2 did not show the genotype of the strain challenged during pregnancy, only those of chronic infection. Thus, the chronically infected BALB/c mice showed no re-infection after inoculation with another strain during pregnancy. Further studies with different parasite loads and different mice lineages are needed.
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de Oliveira TC, Silva DAO, Rostkowska C, Béla SR, Ferro EAV, Magalhães PM, Mineo JR. Toxoplasma gondii: effects of Artemisia annua L. on susceptibility to infection in experimental models in vitro and in vivo. Exp Parasitol 2009; 122:233-41. [PMID: 19389400 DOI: 10.1016/j.exppara.2009.04.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 04/08/2009] [Accepted: 04/12/2009] [Indexed: 10/20/2022]
Abstract
Considering that the treatment for toxoplasmosis is based on drugs that show limited efficacy due to their substantial side effects, the purpose of the present study was to evaluate the effects of Artemisia annua on in vitro and in vivo Toxoplasma gondii infection. A. annua infusion was prepared from dried herb and tested in human foreskin fibroblasts (HFF) or mice that were infected with the parasite and compared with sulfadiazine treatment. For in vitro experiments, treatment was done on parasite before HFF infection or on cells previously infected with T. gondii and the inhibitory concentration (IC(50)) values for each treatment condition were determined. Viability of HFF cells in the presence of different concentrations of A. annua infusion and sulfadiazine was above 72%, even when the highest concentrations from both treatments were tested. Also, the treatment of T. gondii tachyzoites with A. annua infusion before infection in HFF cells showed a dose-response inhibitory curve that reached up to 75% of inhibition, similarly to the results observed when parasites were treated with sulfadiazine. In vivo experiments with a cystogenic T. gondii strain demonstrated an effective control of infection using A. annua infusion. In conclusion, our results indicate that A. annua infusion is useful to control T. gondii infection, due to its low toxicity and its inhibitory action directly against the parasite, resulting in a well tolerated therapeutic tool.
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Affiliation(s)
- Taísa Carrijo de Oliveira
- Laboratory of Immunoparasitology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, 38400-902 Uberlândia, MG, Brazil
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11
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Abstract
Toxoplasma gondii is a parasite that infects animals and humans worldwide. Despite the current knowledge of immunology, pathology and genetics related to the parasite, a safe vaccine for prevention of the infection in both humans and animals does not exist. Here, we review some aspects concerning vaccination against T. gondii.
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Affiliation(s)
- João Luis Garcia
- Department of Preventive Veterinary Medicine, Londrina State University, Campus Universitário, Rodovia Celso Garcia Cid, Pr 445 Km 380, Cx. Postal 6001, Londrina, PR 86051-990, Brazil.
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Toxoplasma gondii: an improved rat model of congenital infection. Exp Parasitol 2008; 120:142-6. [PMID: 18634785 DOI: 10.1016/j.exppara.2008.06.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 05/07/2008] [Accepted: 06/19/2008] [Indexed: 11/21/2022]
Abstract
The objective of this study was to refine the rat model of congenital toxoplasmosis. In Fischer rats we found that visualization of spermatozoa in vaginal exudates and the detection of at least 6g body weight increase between days 9 and 12 of pregnancy, allowed the diagnosis and timing of pregnancy with 60% specificity and 84% sensitivity. A dose of 10(4) Toxoplasma gondii bradyzoites or 10(2) T. gondii oocysts of the Prugniaud strain resulted in more than 50% of congenital infection of the rat litters. Transmission of T. gondii via lactation was not detected in rats inoculated with either bradyzoites or oocysts. Bioassays of 51 neonates born from mothers inoculated with bradyzoites (in tissue cysts) and 29 neonates from mothers inoculated with oocysts demonstrated that both liver and lungs can be used for the diagnosis of congenital transmission in this model.
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Barbosa BF, Silva DAO, Costa IN, Pena JDO, Mineo JR, Ferro EAV. Susceptibility to vertical transmission of Toxoplasma gondii is temporally dependent on the preconceptional infection in Calomys callosus. Placenta 2006; 28:624-30. [PMID: 17182099 DOI: 10.1016/j.placenta.2006.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 10/30/2006] [Accepted: 10/31/2006] [Indexed: 11/18/2022]
Abstract
Toxoplasma gondii is an obligate intracellular parasite that causes a variety of clinical syndromes, but the infection is more severe in immunocompromised individuals and in cases of congenital toxoplasmosis. This study aimed to verify if the susceptibility to vertical transmission of Toxoplasma gondii is temporally dependent on the preconceptional infection in Calomys callosus. Twelve C. callosus females were infected with 20 cysts of T. gondii ME49 strain and divided into three groups of four animals that were mated after approximately 10 days (group 1), 30 days (group 2), and 50 days (group 3) of infection. The animals were sacrificed from the 17th to 20th day of pregnancy, when placentas and embryos were collected for morphological and immunohistochemical studies, mouse bioassay for evaluating seroconversion and PCR for detecting parasite DNA. Serum samples from C. callosus females and mice used in bioassay were analysed for the detection of IgG antibodies to T. gondii by ELISA. Detection of T. gondii was observed by mouse bioassay and PCR in placentas and embryos from C. callosus females infected around 10 days pre-conception. However, only placentas, but not embryos, from females infected around 30 and 50 days pre-conception showed positivity for parasite DNA and seroconversion by mouse bioassay. In conclusion, this study model shows that vertical transmission of T. gondii may take place when maternal infection occurs within one month before conception, thus demonstrating the time of preconceptional seroconversion that rule out a risk of congenital toxoplasmosis.
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Affiliation(s)
- B F Barbosa
- Laboratory of Histology and Embriology, Universidade Federal de Uberlândia, Av. Pará 1720, Uberlândia 38405-320, MG, Brazil
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