Jaume Carrió

Serological and parasitological follow-up in dogs experimentally infected with Leishmania infantum and treated with meglumine antimoniate.

Six healthy beagle dogs were infected with Leishmania infantum (MCAN/ES/92/BCN-83/MON-1) by intravenous inoculation of 5 x 10(7) promastigotes and two others were used as controls. When animals showed clinical signs of disease at 29, 37, 41 and 45 weeks post-infection (p.i.), they were treated with meglumine antimoniate (20.4 mg Sb/kg/12 h) subcutaneously for two periods of 10 days each. Sera were tested periodically for Leishmania antibodies by Dot-ELISA, ELISA and Western blot (WB). Aspirates of popliteal lymph node (PLN), peripheral blood sample (PB) and healthy skin were cultured in NNN and Schneiders medium. PLNs were positive between 8 and 20 weeks p.i. and in one animal PB was positive 6 weeks p.i. Samples of healthy skin, obtained before treatment, were also positive. Dot-ELISA and ELISA detected specific antibodies at an early stage between 4 and 12 weeks p.i and surpassed the cut-off between 16-24 weeks p.i., while the WB was positive between 10-19 weeks p.i. The pattern of bands revealed during the first stages of infection was variable and only in two cases did the positivity start with bands of low molecular weight (12-14 kD); the number of bands increased until 15-24 weeks p.i., after which sera revealed a complete pattern of bands, from 12 to 85 kD, in the antigen of Leishmania. After treatment the clinical improvement of the animals was accompanied by a decrease in antibody titers (Dot-ELISA and ELISA) although the parasites remained in the PLN. This was reflected in the WB by a decrease in the intensity of bands, especially those in the region of 12-30 kD. A new increase in the antibody levels between 3 and 5 months after terminating the therapy was detected in the WB by a restoration of the initial complete pattern of bands.

Epidemiology of canine leishmaniosis in Catalonia (Spain): The example of the Priorat focus

An epidemiological survey of canine leishmaniosis was conducted in the Priorat, a rural region in the Northeast of Spain, for 10 years (1985-1994). Seroprevalence throughout the region, determined by dot-ELISA and IFI, was 10.2% (8-12%). Forty percent of the dogs studied had a low level of anti-Leishmania antibodies, whereas only 50% were seronegative. Only one-third of the seropositive dogs had evident symptoms of the disease. Annual incidence of the disease was 5.7% and the level of endemicity was stable during the study. Four Leishmania zymodemes (MON-1, MON-29, MON-77, MON-105) were present in the focus, and their distribution in the different hosts is discussed. Apart from dogs and foxes, no other reservoir host has been found in the region.

Asymptomatic infection by Leishmania infantum in blood donors from the Balearic Islands (Spain)

BACKGROUND: Visceral leishmaniasis (VL) caused by Leishmania infantum is a zoonotic disease endemic throughout the Mediterranean basin. The existence of asymptomatic human infection entails the risk of transmission by blood transfusion.

Evaluation of a latex agglutination test (KAtex) for detection of Leishmania antigen in urine of patients with HIV-Leishmania coinfection: value in diagnosis and post-treatment follow-up

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.

In vitro susceptibility to pentavalent antimony in Leishmania infantum strains is not modified during in vitro or in vivo passages but is modified after host treatment with meglumine antimoniate

BackgroundLeishmaniasis is a common parasitic disease in Southern Europe, caused by Leishmania infantum. The failures of current treatment with pentavalent antimonials are partially attributable to the emergence of antimony-resistant Leishmania strains. This study analyses the in vitro susceptibility to pentavalent antimony of intracellular amastigotes from a range of L. infantum strains, derived from the same infected animal, during in vitro and in vivo passages and after host treatment with meglumine antimoniate.ResultsSbV-IC50 values for strains from two distinct isolates from the same host and one stock after two years of culture in NNN medium and posterior passage to hamster were similar (5.0 ± 0.2; 4.9 ± 0.2 and 4.4 ± 0.1 mgSbV/L, respectively). In contrast, a significant difference (P < 0.01, t test) was observed between the mean SbV-IC50 values in the stocks obtained before and after treatment of hosts with meglumine antimoniate (4.7 ± 0.4 mgSbV/L vs. 7.7 ± 1.5 mgSbV/L). Drug-resistance after drug pressure in experimentally infected dogs increased over repeated drug administration (6.4 ± 0.5 mgSbV/L after first treatment vs. 8.6 ± 1.4 mgSbV/L after the second) (P < 0.01, t test).ConclusionsThese results confirm previous observations on strains from Leishmania/HIV co-infected patients and indicate the effect of the increasing use of antimony derivatives for treatment of canine leishmaniasis in endemic areas on the emergence of Leishmania antimony-resistant strains.