Summary
The host parasite relationship in the brains of asymptomatic mice chronically infected withToxoplasma gondii was examined at 3, 6 and 12 months post-infection (PI) using electron microscopy. The parasites were located in large numbers within tissue cysts which ranged in size from 10–50 µm in diameter. The cysts were predominantly found in the grey matter. The toxoplasms were enclosed by a cyst wall consisting of a membrane, with irregular invaginations, and an underlying layer of homogeneous osmiophilic material. A detailed examination of 50 cysts revealed that all the cysts were present within intact host cells irrespective of their size or the period PI. The majority of host cells could be positively identified as neurons by the presence of synapses. No extracellular cysts were observed. It is probable that the intracellular location of the cysts protects them from recognition and attack by the host immune system.
Similar content being viewed by others
References
Adams JH, Corselli JJ, Duchen LW (eds). Greenfields Neuropathology. 4th Ed. Arnold, London 1984
Frenkel JK (1974) Advances in the biology of sporozoa. Z Parasitenk 45:125–162
Frenkel JK, Nelson BM, Arias-Stella J (1975) Immunosuppression and toxoplasmic encephalitis. Clinical and experimental aspects. Hum Pathol 6:97–111
Ghatak NR, Zimmerman HM (1973) Fine structure ofToxoplasma in the human brain. Arch Pathol 95:276–283
Hutchison WM (1986) Strain of mouse andToxoplasma used in the mouse model of congenital toxoplasmosis at Strathclyde University. Ann Trop Med Parasitol 80:253–255
Jacobs L (1967)Toxoplasma and toxoplasmosis. Adv Parasitol 5:1–44
Jacobs L (1973) New knowledge ofToxoplasma and toxoplasmosis. Adv Parasitol 11:631–669
Luft BJ, Naot Y, Araujo FG, Stinson EB, Remington JS (1983) Primary and reactivatedToxoplasma infection in patients with cardiac transplants: Clinical spectrum and problems of diagnosis in a defined population. Ann Intern Med 99:27–31
Mehlhorn H, Frenkel JK (1980) Ultrastructural comparison of cysts and zoites ofToxoplasma gondii, Sarcocystis muris andHammondia hammondi in skeletal muscle of mice. J Parasitol 66:59–67
Navia BA, Petito CK, Gold JW, Cho E-S, Jordan BD, Price RW (1986) Cerebral toxoplasmosis complicating the acquired immune deficiency syndrome: clinical and neuropathological findings in 27 patients. Ann Neurology 19:224–238
Peters A, Palay SL, Webster H de F (1976) The fine structure of the nervous system: the neurons and supporting cells. W.B. Saunders Company, Philadelphia
Ruskin J, Remington J (1976) Toxoplasmosis in the compromised host. Ann Intern Med 84:193–199
Scholtyseck E, Mehlhorn H, Muller BEG (1974) Feinstruktur der cyste und cystenwand vonSarcocystis tenella, Besnoitia jellisoni, Frenkelia sp. undToxoplasma gondii. J Protozool 21:284–294
Wanko T, Jacobs L, Gavin MA. (1962) Electron microscope study ofToxoplasma cysts in mouse brain. J Protozool 9:235–242
Zypen E van der (1966) Licht- und elktronmikroskopishe studien zur frage der entwicklung vonToxoplasma-Cysten in gehern der weissen maus. Z Parasitenk 28:31–44
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ferguson, D.J.P., Hutchison, W.M. The host-parasite relationship ofToxoplasma gondii in the brains of chronically infected mice. Vichows Archiv A Pathol Anat 411, 39–43 (1987). https://doi.org/10.1007/BF00734512
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00734512