Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis

Br J Ophthalmol. 2010 Jul 3. [Epub ahead of print]

Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis

Silveira C, Vallochi AL, Rodrigues da Silva U, Muccioli C, Holland GN, Nussenblatt RB, Belfort R, Rizzo LV.

Escola Paulista de Medicina-Federal University of São Paulo, São Paulo, Brazil.

Abstract
Background and aims Toxoplasmic retinochoroiditis may recur months or years after the primary infection. Rupture of dormant cysts in the retina is the accepted hypothesis to explain recurrence. Here, the authors present evidence supporting the presence of Toxoplasma gondii in the peripheral blood of immunocompetent patients. Methods Direct observation by light microscopy and by immunofluorescence assay was performed, and results were confirmed by PCR amplification of parasite DNA. Results The authors studied 20 patients from Erechim, Brazil, including acute infected patients, patients with recurrent active toxoplasmic retinochoroiditis, patients with old toxoplasmic retinal scars, and patients with circulating IgG antibodies against T gondii and absence of ocular lesions. Blood samples were analysed, and T gondii was found in the blood of acutely and chronically infected patients regardless of toxoplasmic retinochoroiditis. Conclusions The results indicate that the parasite may circulate in the blood of immunocompetent individuals and that parasitaemia could be associated with the reactivation of the ocular disease.

PMID: 20601663 [PubMed - as supplied by publisher]