title: Mouse model of congenital infection with a non-virulent Toxoplasma gondii strain: Vertical transmission, "sterile" fetal damage, or both?
abstract: Congenital transmission of Toxoplasma gondii may occur if the mother gets infected for the first time while pregnant. The risk of mother-to-child transmission depends on the gestation trimester at infection, being lowest in the first and highest in the last. Conversely, fetal damage is frequent and more severe at the beginning of pregnancy. The objective of this study was to evaluate congenital transmission and pathological aspects in the placenta and the fetus using a mouse model of congenital infection of the second gestation third. Forty-five female BALB/c mice were infected intravenously with 2.5-10.0 × 10(6) tachyzoites of the ME49 strain at middle gestation. Samples of maternal spleen and fetal/placental units were taken 72 h later. We determined parasite load and vertical transmission by qPCR, as well as damage macroscopically and by histopathology. With the lowest dose, 18% of the fetuses were infected. Also, 40% of fetuses/litter were altered, while this value was 10% in the control group (P < 0.05). These results are similar to those described in humans in terms of vertical transmission and fetal damage during the second third of gestation. The maternal spleen had 10-1000 times more tachyzoites than the placenta, and the later retained 90-99% of the parasites that could reach the fetus. Nevertheless, we found resorptions, abortions or fetal tissue damage in the presence but also in the absence of parasites. Our data indicate a strong protective effect of maternal organs and the placenta against fetal infection, but extensive damage of the later may led to resorption or abortion without vertical transmission.
authors.affiliation: Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico.
authors.forename: J A
authors.initials: JA
authors.lastname: Vargas-Villavicencio
authors.affiliation: Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico.
authors.forename: C
authors.initials: C
authors.lastname: Cedillo-Peláez
authors.affiliation: Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico.
authors.forename: C P
authors.initials: CP
authors.lastname: Rico-Torres
authors.affiliation: Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico; Doctorado en Ciencias de la Salud y Reproducción Animal, FMVZ, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Besné-Mérida
authors.affiliation: Departamento de Anatomía Patológica, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico.
authors.forename: F
authors.initials: F
authors.lastname: García-Vázquez
authors.affiliation: Investigador Cátedra CONACyT en el Instituto Nacional de pediatría, Laboratorio de Inmunología Experimental, Mexico City, Mexico.
authors.forename: J I
authors.initials: JI
authors.lastname: Saldaña
authors.affiliation: Laboratorio de Inmunología Experimental, Instituto Nacional de Pediatría, SSa. Torre de Investigación, Av. Insurgentes Sur 3700-C, Col. Insurgentes Cuicuilco, Mexico City 04530, Mexico. Electronic address: mariadol@yahoo.com.
authors.forename: D
authors.initials: D
authors.lastname: Correa
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D004195:Disease Models, Animal; D020964:Embryo Loss / Q000469:parasitology; D005260:Female; D005333:Fetus / Q000469:parasitology* / Q000473:pathology; D006470:Hemorrhage; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009336:Necrosis; D059208:Parasite Load; D010920:Placenta / Q000469:parasitology* / Q000473:pathology; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000469:parasitology* / Q000473:pathology; D013047:Specific Pathogen-Free Organisms; D013154:Spleen / Q000469:parasitology; D013927:Thrombosis; D014124:Toxoplasmosis, Animal / Q000151:congenital* / Q000473:pathology / Q000635:transmission
chemical_list: D004268:DNA-Binding Proteins; C499308:Rag2 protein, mouse
keywords: Congenital toxoplasmosis; Mouse model; Parasitic load; Pathology