Cryptic Leishmania infection is highly prevalent in blood donors from the Balearic Islands. DTH and L. infantum nested PCR appear to be more sensitive to detect asymptomatic infection than the serology. The use of leukodepletion filters appears to remove parasites from RBC units efficiently.

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The usefulness of antigen detection in urine as an alternative tool for diagnosis of leishmaniasis and post-treatment follow-up in patients with Leishmania-HIV coinfection was evaluated with a latex agglutination test (KAtex; Kalon Biological, UK). Forty-nine HIV-infected patients with visceral leishmaniasis were included in the study. Antigen detection in urine (ADU) was positive in 42 of 49 (sensitivity, 85.7%) samples obtained during a primary episode. After treatment, a follow-up study in 23 patients was performed by simultaneous ADU and culture of peripheral blood mononuclear cells in 148 determinations. The two methods gave concordant results in 94 cases, 38 of which were positive and 56 negative. In five cases, ADU was negative and culture of peripheral blood mononuclear cells was positive: two of these cases corresponded to clinical relapses. In 49 cases, culture of peripheral blood mononuclear cells was negative and ADU was positive. In the absence of clinical symptoms, the detection of parasite antigens in 71 of 130 (54.6%) urine samples was not associated with clinical disease. The Kaplan-Meier estimates of the probability of relapse at 6, 12, 18, and 24 months were 16% (95%CI, 15-17%), 20% (95%CI, 18-22%), 31% (95%CI, 27-35%), and 71% (95%CI, 52-89%), respectively, in patients with a positive ADU result. In contrast, when ADU was negative, the probability of relapse was 5% at 6 months (95%CI, 2-8%) (only 2 of 11 patients who relapsed had a negative test). ADU by KAtex is appropriate for primary diagnosis of visceral leishmaniasis, for monitoring the efficacy of treatment, and for detection of subclinical infection.

L-AMB is well tolerated and useful for secondary prophylaxis of VL.

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The use of culture and a nested polymerase chain reaction (PCR) of blood in predicting the probability of relapse was evaluated in 20 patients co-infected with Leishmania and human immunodeficiency virus (HIV). Fourteen of 20 patients relapsed, with 24 clinical relapses diagnosed. During clinical relapse, the parasite was detected by culture in 21 of 24 blood samples and by nested PCR in 23 of 24 blood samples. After treatment and during asymptomatic periods, the parasite was detected by culture in 18 (19.1%) of 94 blood samples and by nested PCR in 58 (61.7%) of 94 blood samples. For positive blood cultures, the Kaplan-Meier probability estimates for relapse at 6, 12, 18, and 24 months were 44%, 68%, 76%, and 76%, respectively, while for positive nested PCRs, the estimates were 20%, 33%, 45%, and 50%, respectively. For negative blood cultures, relapse probabilities for the same time points were 7%, 12%, 12%, and 12%, while for negative nested PCRs, these probabilities were 8%, 14%, 21%, and 26%. Nested PCR-positive results in asymptomatic periods indicated presence of the parasite, but not necessarily relapse. However, the presence of viable parasites during post-treatment follow-up increased the probability of relapse and showed that culture positivity could be a good relapse marker.

The aim of the present study was to evaluate the in vitro activity and cytotoxicity of meglumine antimoniate microspheres produced by spray drying on Leishmania infantum and the effect of the excipients used in them. The parasite strain shows sensitivity to the meglumine antimoniate microspheres prepared. All the antimony IC50 values from encapsulated meglumine antimoniate (3.80 +/- 0.34 to 9.53 +/- 0.70 microg SbV/ml for promastigotes assay) are considerably lower compared to the mean value of IC50 in Glucantime solution (112 +/- 12.74 microg SbV/ml). Interesting IC50 values for the excipient chitosan (112.64 +/- 0.53 mg/ml for promastigotes and 100.81 +/- 26.45 mg/ml for amastigotes) were obtained (without cytotoxic activity), whereas the rest of the excipients did not show any activity. This new delivery system could offer a new pharmacological tool for the treatment of leishmaniosis that reduces the doses required, lowering toxic side effects because of meglumine antimoniate.