Experimental model of congenital toxoplasmosis in guinea-pigs: use of quantitative and qualitative PCR for the study of maternofetal transmission.
Maternofetal transmission of Toxoplasma gondii was assessed in pregnant guinea-pigs, with a gestational period of 65 +/- 5 days. A total of 56 female guinea pigs was infected by the intraperitoneal route (RH strain), by the oral or the intraperitoneal route (Prugniaud strain; PRU) or by the oral route (76K strain). Inoculation was performed 90 +/- 18 days or 30 +/- 9 days before the onset of gestation or 20 +/- 6 days or 40 +/- 6 days after. Gestational age was determined by a progesterone assay. Parasite loads (fetal brain and liver) were assessed by nested PCR and real-time PCR quantification on Light Cycler was performed with a SYBR Green I technique. The 76K strain appeared to be the most virulent in the model: the neonatal survival rate was 31%, in contrast to 53% and 68% for the PRU and RH strains, respectively. The percentage of survival of neonates for all strains taken together was lower after inoculation at 40 days' gestation (25%) than at 20 days' gestation (77%). Whatever the strain, maternofetal transmission determination was greater with nested PCR (54% for RH, 84% for PRU and 86% for 76K strains) than with real-time quantitative PCR (31% for RH, 66% for PRU and 76% for 76K strains). However, real-time quantitative PCR showed that neonatal parasite load was greater with the cystogenic strains (76K, PRU) and that high hepatic load (> 10000 parasites/g) was often associated with disease severity (11 of 12 cases). Therefore, this technique may provide an important element in understanding this congenital disease.
Flori
P
P
Hafid
J
J
Groupe Immunité des Muqueuses et Agents Pathogènes (GIMAP), Faculté de Médecine Jacques Lisfranc, 15 rue Ambroise Paré, 42023 Saint Etienne, France and *Unité d'Immunologie et de Physiologie, Département de Biologie, Faculté des Sciences et Techniques, Avenue A. El Khattabi, BP 618, 40000 Marrakech, Morocco.
Bourlet
T
T
Raberin
H
H
Genin
C
C
Tran Manh Sung
R
R
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006168:Guinea Pigs; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D016133:Polymerase Chain Reaction / Q000379:methods / Q000706:statistics & numerical data; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000469:parasitology; D012680:Sensitivity and Specificity; D014122:Toxoplasma / Q000235:genetics / Q000302:isolation & purification; D014124:Toxoplasmosis, Animal / Q000150:complications / Q000151:congenital* / Q000469:parasitology / Q000635:transmission*; D016781:Toxoplasmosis, Cerebral / Q000150:complications / Q000469:parasitology / Q000635:transmission