Toxoplasma gondii: Determination of the onset of chronic infection in mice and the in vitro reactivation of brain cysts

Exp Parasitol. 2011 Oct 18. [Epub ahead of print]

Toxoplasma gondii: Determination of the onset of chronic infection in mice and the in vitro reactivation of brain cysts.

Kit CW, Wah MJ, Ambu S, Segarra I.

SourceDepartment of Human Biology, School of Medicine, International Medical University, No. 126 Jalan 19/155B, Bukit Jalil, 57000 Kuala Lumpur, Malaysia.

Abstract
Toxoplasma gondii is an intra-cellular parasite that infects humans through vertical and horizontal transmission. The cysts remain dormant in the brain of infected humans and can reactivate in immunocompromised hosts resulting in acute toxoplasmic encephalitis which may be fatal. We determined the onset and progression of brain cysts generation in a mouse model following acute toxoplasmosis as well as the ability of brain cysts to reactivate in vitro. Male Balb/c mice, (uninfected control group, n=10) were infected orally (study group, n=50) with 1000 tachyzoites of T. gondii (ME49 strain) and euthanized at 1, 2, 4, 8 and 16weeks post infection. Brain tissue was harvested, homogenized, stained and the number of brain cysts counted. Aliquots of brain homogenate with cysts were cultured in vitro with confluent Vero cells and the number of cysts and tachyzoites counted after 1week. Brain cysts but not tachyzoites were detected at week 2 post infection and reached a plateau by week 4. In vitro Vero cells culture showed similar pattern for cysts and tachyzoites and reactivation of cyst in vitro was not influenced by the age of the brain cysts.

Copyright © 2011 Elsevier Inc. All rights reserved.

PMID:22027550[PubMed - as supplied by publisher]