Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis.
OBJECTIVE
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.
Silveira
Cláudio
C
Hospital Israelita Albert Einstein, Av Albert Einstein 627/701, Chinuch Level, Josef Feher Building, São Paulo, SP - Brazil, CEP 05652-000.
Vallochi
Adriana Lima
AL
Rodrigues da Silva
Ulisses
U
Muccioli
Cristina
C
Holland
Gary N
GN
Nussenblatt
Robert B
RB
Belfort
Rubens
R
Rizzo
Luiz Vicente
LV
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001938:Brazil; D002648:Child; D002825:Chorioretinitis / Q000276:immunology / Q000469:parasitology*; D016054:DNA, Protozoan / Q000097:blood; D005260:Female; D006801:Humans; D007121:Immunocompetence; D008297:Male; D051379:Mice; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D014122:Toxoplasma / Q000276:immunology / Q000302:isolation & purification*; D014126:Toxoplasmosis, Ocular / Q000276:immunology / Q000469:parasitology*; D055815:Young Adult
D000913:Antibodies, Protozoan; D016054:DNA, Protozoan