A NEW MURINE MODEL OF SEVERE ACUTE TOXOPLASMIA ENCEPHALITIS

We have developed a new murine model of toxoplasmic encephalitis based on the intracerebral inoculation of tachyzoites of the highly virulen t RH strain of Toxoplasma gondii. Intracerebral infection resulted in a mortality of 100% on day five. Large inflammatory abscessed infiltra tes developed by the second day after inoculation and expanded through out the remaining period of observation. Numerous tachyzoites were det ectable in brain parenchyma by the second day of infection. The marked and precocious histopathological brain lesions produced by the RH str ain are useful to detect therapeutic rather than prophylactic effects of drugs against toxoplasmic encephalitis. In this model pyrimethamine , sulphadiazine and its combination were useful in terms of mortality, histopathology and spread of infection whereas clindamycin showed no activity. This murine model of toxoplasmic encephalitis is useful to e valuate antitoxoplasma agents with high therapeutic activity.