LEISHMANIASIS

Diagnosis, Diagnostics, Immunodiagnosis & Immunodiagnostics:

January 2003

6086. Arya SC. Enzyme-linked immunosorbent assays for diagnosis of leishmaniasis in patients coinfected with human immunodeficiency virus. J Clin Microbiol. 2002 Aug;40(8):3110. No abstract.

6087. Dey T, Afrin F, Anam K, Ali N. Infectivity and virulence of Leishmania donovani promastigotes: a role for media, source, and strain of parasite. J Eukaryot Microbiol. 2002 Jul-Aug;49(4):270-4.

Transformation of promastigotes of Leishmania donovani strain AG83 from amastigotes derived from an infected animal was studied in three media, Schneider's Drosophila medium (SDM), Medium 199 (M199), and biphasic M199 (B-M199) with 10% fetal bovine serum. The media, SDM and B-M199, both supported a more efficient transformation of promastigotes in comparison with M199. Infectivity studies in hamsters and BALB/c mice showed that promastigotes isolated in B-M199 were several folds more infective than those obtained from M199. Comparison of the infectivity and virulence of promastigotes of AG83, with a recent isolate of kala-azar, SL94, harvested under similar conditions, revealed greater infectivity of SL94 for both macrophages and animal models. The present study demonstrates that the medium used for the conversion of amastigotes to promastigotes plays a major role in determining the infectivity of the freshly transformed L. donovani promastigotes in hamsters and BALB/c mice. The source and the strain of the parasite also influence the outcome of L. donovani infection.

6088. Gonzalez AC, Martinez E, Carmelo E, Pinero JE, Alonso V, Del Castillo A, Valladares B. Analysis of NLS and rRNA binding motifs in the L25 ribosomal protein from Leishmania (viannia) braziliensis: investigation of its diagnostic capabilities. Parasitology. 2002 Jul;125(Pt 1):51-7.

A cDNA clone codifying ribosomal protein L25 was isolated from a Leishmania braziliensis cDNA gene library. The alignment of the amino acid sequence deduced from this gene with other proteins revealed that this protein is related to the L23/25 rihosomal protein family. This is so because this protein shows, in its C-terminal end, the rRNA binding domains characteristic of these proteins and at the N-terminal end the NLS sequence necessary for its entry into the nucleus. Southern blot analysis showed 2 copies of gene L25 per genome arranged in tandem position and pointing in the same direction. Northern blot analysis showed that this gene is transcribed in 2 mRNAs when parasite promastigotes are in the logarithmic phase. In order to analyse the antigenic properties of L. braziliensis RPL25, it was purified as a recombinant protein and ELISA-tested against cutaneous, mucocutaneous and Chagasic sera. The results indicate that the recombinant RPL25 from L. braziliensis presents a non-specific reaction that disqualifies it for the diagnosis of cutaneous leishmaniasis. In contrast, some of the synthetic peptides derived from its sequence may serve as promising tools for the diagnosis of this disease.

6089. Hailu A, Kroon CC, Schoone GJ, Berhe N, Schallig HD, Kager PA. Sero-epidemiological assessment and diagnosis of visceral leishmaniasis in an endemic locality using Fast Agglutination Screening Test (FAST). Acta Trop. 2002 Aug;83(2):93-101.

The Fast Agglutination Screening Test (FAST) was employed on sera obtained from an endemic area of visceral leishmaniasis in southwestern Ethiopia, in February 2000. The study involved (i) active case detection among 1575 residents of two villages; and (ii) passive case detection in an outpatient clinic. Sera of 1587 individuals, including 143 sera of previously treated VL patients, were tested. Based on the size of agglutination mat, the FAST results were read qualitatively as non-reactive (-), weakly reactive (1+), moderately reactive (2+) and highly reactive (3+). All FAST reactive sera were re-tested with the Direct Agglutination Test (DAT). After clinical screening of 1625 individuals, 61 individuals with signs and symptoms of early or late VL were found; 26 sera were FAST positive. Twenty-two of these suspected VL cases were subjected to parasitological examination using lymph node aspirates. Eighteen (81.8%) were confirmed either by demonstration of amastigotes in smears or promastigotes in NNN cultures. FAST reactive anti-leishmanial antibodies were detected in 4.5% of untreated and 70.6% of previously treated patients. Forty-five sera of 1390 previously untreated asymptomatic individuals (3.2%) were found to be FAST positive. This report demonstrates that FAST is a rapid and cost-effective screening test for the diagnosis and sero-epidemiological surveillance of visceral leishmaniasis.

6090. Qadoumi M, Becker I, Donhauser N, Rollinghoff M, Bogdan C. Expression of inducible nitric oxide synthase in skin lesions of patients with american cutaneous leishmaniasis. Infect Immun. 2002 Aug;70(8):4638-42.

Cytokine-inducible (or type 2) nitric oxide synthase (iNOS) is indispensable for the resolution of Leishmania major or Leishmania donovani infections in mice. In contrast, little is known about the expression and function of iNOS in human leishmaniasis. Here, we show by immunohistological analysis of skin biopsies from Mexican patients with local (LCL) or diffuse (DCL) cutaneous leishmaniasis that the expression of iNOS was most prominent in LCL lesions with small numbers of parasites whereas lesions with a high parasite burden (LCL or DCL) contained considerably fewer iNOS-positive cells. This is the first study to suggest an antileishmanial function of iNOS in human Leishmania infections in vivo.

6091. Sundar S, Sahu M, Mehta H, Gupta A, Kohli U, Rai M, Berman JD, Murray HW. Noninvasive management of Indian visceral leishmaniasis: clinical application of diagnosis by K39 antigen strip testing at a kala-azar referral unit. Clin Infect Dis. 2002 Sep 1;35(5):581-6.

Firm diagnosis of visceral leishmaniasis (kala-azar) requires organ aspiration and microscopic examination of tissue specimens. To determine the usefulness of noninvasive diagnosis by strip test detection of anti-K39 immunoglobulin (Ig) G antibody in blood specimens obtained by fingerstick, 143 Indian patients with suspected kala-azar (fever, splenomegaly, anemia) were studied. Of 120 strip test-positive subjects (subjects with presumed kala-azar [group A]), amphotericin B treatment induced clinical cure in 119. Of 23 strip test-negative subjects (subjects presumed to have other diseases [group B]), 16 had other disorders diagnosed at entry, 4 responded to empiric antimalarial therapy, 2 were proven to have kala-azar, and 1 died elsewhere after undergoing splenic aspiration. Six months after treatment ended, all 120 patients in group A and the 18 assessable patients in group B were healthy. In a region in India where visceral infection is prevalent, strip test detection of anti-K39 IgG is a clinically promising diagnostic guide in persons with suspected kala-azar.

Pathogenesis:

6093. Descoteaux A, Turco SJ. Functional aspects of the Leishmania donovani lipophosphoglycan during macrophage infection. Microbes Infect. 2002 Jul;4(9):975-81. Review.

The most abundant surface glycoconjugate of the Leishmania promastigotes is lipophosphoglycan, a glycosylphosphatidyl-inositol-anchored polymer of the repeating disaccharide-phosphate Gal(beta1,4)Manalpha1-PO4 unit. This complex molecule possesses properties that contribute to the ability of Leishmania to modulate macrophage signaling pathways during the initiation of infection.

6094. Jappe U. Unusual skin infections in military personnel.Clin Dermatol. 2002 Jul-Aug;20(4):425-34. Review. No abstract.

6095. Junghae M, Raynes JG. Activation of p38 mitogen-activated protein kinase attenuates Leishmania donovani infection in macrophages. Infect Immun. 2002 Sep;70(9):5026-35.

Leishmania-induced macrophage dysfunctions have been correlated with altered signaling events. In this work, we report that SB203580, a specific inhibitor of p38 mitogen-activated protein kinases (MAPK), increases Leishmania donovani survival in human peripheral blood mononuclear macrophages. Consistent with this finding, activation of p38 and c-jun N-terminal kinase (JNK) MAPK signaling pathways by anisomycin significantly reduced parasite survival within these cells. However, the majority of the effect was seen in a 50% reduction in the percentage of macrophages infected, with little effect on the highly infected macrophages. The observed effect was likely to be due to the p38 MAPK pathway since SB203580 was able to completely reverse the effect of anisomycin. These findings suggest that the previously reported p38 MAPK inhibition by Leishmania infection may be partially overcome by anisomycin. Similar effects were observed in pretreated macrophages or in treatment of infected macrophages. These results suggests that p38 MAPK activation may have a potential therapeutic value in the treatment of visceral leishmaniasis.

6096. Pineda JA, Martin-Sanchez J, Macias J, Morillas F. Leishmania spp infection in injecting drug users. Lancet. 2002 Sep 21;360(9337):950-1. No abstract.

Vaccines:

6097. Schallig HD, Oskam L. Molecular biological applications in the diagnosis and control of leishmaniasis and parasite identification. Trop Med Int Health 2002 Aug;7(8):641-51

Molecular biology is increasingly relevant to the diagnosis and control of infectious diseases. Information on DNA sequences has been extensively exploited for the development of polymerase chain reaction-based assays for the diagnosis of leishmaniasis and the identification of parasite species. It has also led to the use of cloned antigen for serodiagnosis. It is expected that the sequencing of the Leishmania major genome and the genomes of other Leishmania species will enable important progress in further improving diagnosis and control. The ability to use genome data to clone and sequence genes, which, when expressed, provide antigens for vaccine development, will increase the possibilities for rational vaccine development. Moreover, DNA on its own will provide the basis for the development of DNA vaccines that may overcome some of the problems encountered with protein-based vaccines. One of the greatest threats to parasite control is the development of drug resistance in parasites. Knowing the molecular basis of drug resistance and the ability to monitor its development with sensitive and specific DNA-based assays for 'resistance alleles' may aid maintaining the effectiveness of available anti-Leishmania drugs. Finally, techniques such as microarrays and nucleic acid sequence-based amplification will eventually allow rapid screening for specific parasite genotypes and assist in diagnostic and epidemiological studies.

Therapy:

6098. Esfandiarpour I, Alavi A. Evaluating the efficacy of allopurinol and meglumine antimoniate (Glucantime) in the treatment of cutaneous leishmaniasis. Int J Dermatol. 2002 Aug;41(8):521-4.

BACKGROUND: Cutaneous leishmaniasis is a common disease in Iran, particularly in Kerman province. It usually occurs via the bite of an infected sandfly. METHODS: One hundred and fifty patients suffering from cutaneous leishmaniasis were included in this study in Kerman. The patients were randomly divided into three groups. They were matched with regard to age, sex, duration of the disease, and type, number, and site of the lesions. For each group, one of the following therapeutic methods was applied: (i) oral allopurinol (15 mg/kg/day) for 3 weeks; (ii) intramuscular injection of Glucantime (30 mg/kg/day), corresponding to 8 mg/kg/day of pentavalent antimony, for 2 weeks; (iii) combined therapy. The lesions were re-examined at the end of treatment and 2 and 4 weeks later. The response to treatment was graded as excellent (reduction in the size of the lesion by at least 80% or complete clearance), good (reduction in the size of the lesion by 50%), and poor (minimal or no change in the lesion). RESULTS: The overall results indicated that 18% of patients showed excellent response, 6% good response, and 76% poor response in the first group. In the second group, 24% of patients showed excellent response, 6% good response, and 70% poor response. In the third group, 46% of patients showed excellent response, 8% good response, and 46% poor response. CONCLUSIONS: The results obtained by the three therapeutic methods indicated that combined therapy with allopurinol plus Glucantime was much more effective than that obtained by each of the two drugs when used alone (P < 0.05).

6099. Gilbert IH. Inhibitors of dihydrofolate reductase in Leishmania and trypanosomes. Biochim Biophys Acta. 2002 Jul 18;1587(2-3):249-57. Review.

The protozoan diseases leishmaniasis, Chagas' disease and African trypanosomiasis are major health problems in many countries, particularly developing countries, and there are few drugs available to treat these diseases. Dihydrofolate reductase (DHFR) inhibitors have been used successfully in the treatment of a number of other diseases such as cancer, malaria and bacterial infections; however they have not been used for the treatment of these diseases. This article summarises studies on leishmanial and trypanosomal DHFR inhibitor development and evaluation. Possible mechanisms of resistance to DHFR inhibitors are also discussed.

6100. Paterson R. Miltefosine presents new hope for leishmaniasis patients. Lancet Infect Dis. 2002 Aug;2(8):452. No abstract.

6101. Zvulunov A, Klaus S, Vardy D. Fluconazole for the treatment of cutaneous leishmaniasis. N Engl J Med. 2002 Aug 1;347(5):370-1; discussion 370-1. No abstract.

April 2003

6766. Bacellar O, Lessa H, Schriefer A, Machado P, Ribeiro de Jesus A, Dutra WO,Gollob KJ, Carvalho EM. Up-regulation of Th1-type responses in mucosal leishmaniasis patients.Infect Immun 2002 Dec;70(12):6734-40

The cytokine profile produced by peripheral blood mononuclear cells (PBMC) in response to leishmania antigens and the ability of interleukin-10 (IL-10) and transforming growth factor beta (TGF-beta) to modulate the immune response were evaluated in 21 mucosal leishmaniasis patients. Patients with mucosal disease exhibited increased gamma interferon (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) secretion and decreased IL-10 secretion compared to patients with classical cutaneous leishmaniasis. CD4(+) Th1 cells were the main source of IFN-gamma and TNF-alpha production in mucosal leishmaniasis patients. Evaluation of cytokine gene expression in PBMC of these patients showed that there was strong up-regulation of IFN-gamma transcripts upon stimulation with leishmania antigen, in contrast to the baseline levels of IL-10 mRNA. IL-10 suppressed IFN-gamma production by 48% in cell cultures from cutaneous leishmaniasis patients and by 86% in cell cultures from healthy subjects stimulated with purified protein derivative, whereas in similar conditions IL-10 suppressed IFN-gamma production by 19% in cell cultures from mucosal leishmaniasis patients stimulated with leishmania antigen. TGF-beta suppressed IFN-gamma levels to a greater extent in healthy subjects than in mucosal leishmaniasis and cutaneous leishmaniasis patients. These data indicate that a poorly modulated T-cell response in mucosal leishmaniasis patients leads to production of high levels of proinflammatory cytokines, such as IFN-gamma and TNF-alpha, as well as a decreased ability of IL-10 and TGF-beta to modulate this response. These abnormalities may be the basis for the pathological findings observed in this disease.

6767. Bosch RJ, Rodrigo AB, Sanchez P, de Galvez MV, Herrera E. Presence of Leishmania organisms in specific and non-specific skin lesions in HIV-infected individuals with visceral leishmaniasis. Int J Dermatol 2002 Oct;41(10):670-5

BACKGROUND: Leishmania coinfection is frequently seen in human immunodeficiency virus (HIV)-infected patients in endemic areas, and from time to time the protozoan is detected in cutaneous biopsies. OBJECTIVE: To establish the characteristics and possible ethiologic role of the presence of Leishmania in these lesions. METHODS: We studied 12 cutaneous biopsies with Leishmania organisms from nine HIV-infected patients (seven men and two women) with visceral leishmaniasis, diagnosed by bone marrow examination, seen over a period of 9 years. RESULTS: Based on clinical characteristics, evolution and response to anti-leishmanial treatment, cutaneous alterations were found to be related to the presence of the protozoan in six cases, whereas in the other six cases it was not considered responsible for the dermatological lesions (dermatofibroma, and lesions of psoriasis, Reiter's syndrome, bacillary angiomatosis, cryptococcosis and oral aphthae). Of note was the high prevalence of specific mucocutaneous manifestations, usually accompanied by intense pruritus, great variability, and a tendency to relapse after treatment stopped. On two occasions, detection of the protozoa in skin biopsies led to the diagnosis of a previously unsuspected visceral leishmaniasis. CONCLUSIONS: Cutaneous detection of Leishmania is frequent in HIV-infected individuals with visceral leishmaniasis. Sometimes Leishmania is associated with changes attributable to other dermatological processes, and its presence does not imply a causative role. A clear relationship between the systemic process and the therapeutic response is necessary to demonstrate an ethiologic role.

Pathogenesis:

6768. Rodrigues EH, Felinto de Brito ME, Mendonca MG, Werkhauser RP, Coutinho EM, Souza WV, Militao de Albuquerque Mde F, Jardim ML, Abath FG. Evaluation of PCR for diagnosis of American cutaneous leishmaniasis in an area of endemicity in northeastern Brazil. J Clin Microbiol 2002 Oct;40(10):3572-6. PCR-based approaches targeting kinetoplast DNA were evaluated for the diagnosis of American cutaneous leishmaniasis (ACL) in regions of endemicity in northeastern Brazil. A total of 119 cutaneous biopsy specimens from patients with ACL and nonleishmaniasis cutaneous lesions were studied. Two PCR-based systems were used; one was specific for the subgenus Viannia, and the other was specific for the genus Leishmania. The PCR specific for the subgenus Viannia had a sensitivity of 95.4%, whereas the genus-specific PCR detected the target DNA in 88.2% of the samples tested. The specificities of the assays, determined with samples from a group with nonleishmaniasis cutaneous lesions, was 100%. The results of the conventional tests indicate that the sensitivities of the PCR-based methods were significantly higher than those of smear examination, histological staining, and isolation by culture (P < 0.05). Antibodies specific for Leishmania braziliensis were detected by indirect immunofluorescence in 82.9% of the patients tested. Parasites were isolated from 40 of 86 patients (46.5%). Sixty-seven percent of dermal scrapings and 66.2% of stained tissue sections were positive by microscopy. Amplified products from the subgenus-specific PCR hybridized with the Leishmania panamensis minicircle, confirming infection consistent with L. braziliensis. The evidence available at present incriminates L. braziliensis as the only causative agent of ACL in the state of Pernambuco in Brazil.

6769. Vilela RB, Bordin JO, Chiba AK, Castelo A, Barbosa MC. RBC-associated IgG in patients with visceral leishmaniasis (kala-azar): a prospective analysis. Transfusion 2002 Nov;42(11):1442-7

BACKGROUND: Despite the fact that anemia is one of the most striking clinical features of visceral leishmaniasis (kala-azar), the factors involved in its pathogenesis are not fully understood. Although the cause of the anemia seen in these patients is often multifactorial, sequestration and destruction of the RBCs in the enlarged spleen, immune mechanisms, and alterations in RBC membrane permeability have been implicated. STUDY DESIGN AND METHODS: To investigate whether RBCs of patients with kala-azar were coated with IgG, blood samples of 67 patients were tested, prospectively, before (Day 1), during (Day 30), and after (Day 90) antimonial therapy, to examine the presence of RBC-associated IgG, circulating immune complexes (CICs), and rheumatoid factor (RF). RESULTS: The prevalence of a positive DAT on Day 1 was significantly greater than the prevalence of a positive DAT performed on Day 30 and on Day 90 (32.8 vs. 4 vs. 0%, p < 0.001). With an enzyme-linked antiglobulin test (ELAT) to measure the number of IgG molecules per RBC more accurately, it was found that the amount of IgG molecules per RBC was increased (mean, 298 molecules of IgG per RBC) in the group of patients with kala-azar tested before antimonial therapy, but was considered normal (<50 molecules of IgG per RBC) in all patients tested 90 days after treatment. The prevalence of a positive eluate test was low (15.0%) in DAT (anti-IgG)-positive patients and the positivity of DATs and ELATs correlated with the presence of either RF or CICs, respectively. CONCLUSIONS: These data suggest that a nonspecific adsorption of CICs on the RBC surface is probably the most important factor involved in the increased amount of RBC-associated IgG in patients with untreated visceral leishmaniasis; however, further prospective studies are required to establish the exact role of the RBC-associated antibodies, CICs, and RF as contributing factors of the anemia seen in these patients.

Therapy:

6770. Del Giudice P, Mary-Krause M, Pradier C, Grabar S, Dellamonica P, Marty P, Gastaut JA, Costagliola D, Rosenthal E; French Hospital Database on HIV Clinical Epidemiologic Group. Impact of highly active antiretroviral therapy on the incidence of visceral leishmaniasis in a French cohort of patients infected with human immunodeficiency virus. J Infect Dis 2002 Nov 1;186(9):1366-70

The incidence of human immunodeficiency virus (HIV)-Leishmania coinfections in France was estimated on the basis of the French Hospital Database on HIV, and risk factors for the occurrence of visceral leishmaniasis (VL) were analyzed by a multivariate Cox model. VL was diagnosed in 165 of 55,626 HIV-infected patients followed since 1992. The incidence of VL decreased from 11.6+/-1.2 per 10,000 persons-years before 1996 to 6.3+/-0.7 per 10,000 persons-years after 1996, the year when highly active antiretroviral therapy (HAART) was initiated in France. The relative hazard (RH) for development of VL was higher in (1) intravenous drug users versus other transmission groups (RH=1.56; 95% CI, 1.13-2.15), (2) patients living in southern France versus those living in northern France (RH=3.36; 95% CI, 2.44-4.61), and (3) patients who had a CD4 cell count of </=50/mm(3) during their follow-up versus those who did not (RH=6.45; 95% CI, 4.27-9.75) but was lower in (4) patients who received antiretroviral therapy including >/=3 drugs versus those who did not (RH=0.41; 95% CI, 0.26-0.65). We found a significant decrease in the incidence of HIV-Leishmania coinfections after 1996, associated with the introduction of HAART in France.

6771. Jacobs S. An oral drug for leishmaniasis. N Engl J Med 2002 Nov 28;347(22):1737-8 No abstract.

July 2003

7285. Amato VS, de Andrade HF, Duarte MI. Mucosal leishmaniasis: in situ characterization of the host inflammatory response, before and after treatment. Acta Trop. 2003 Jan;85(1):39-49.

Mucosal leishmaniasis (ML) generally shows progressive tissue destruction, not yet fully elucidated, associated with an intense inflammatory response. To contribute to the understanding of this process and of how treatment interferes with it, we studied several anatomopathological parameters, including those analyzed by immunohistochemistry, such as Leishmania antigens, cells participating in the immune response and cytokine expression. Biopsies were taken from 20 patients with ML before and after treatment. A mixed Th1 and Th2 pattern response occurred inside ML before treatment, persist after treatment. Nevertheless, this mixed response was smaller than in active lesions, with reduced but present numbers of cells expressing TNF-alpha, IFN-gamma and IL-4 and sustained numbers of cells expressing IL-10. We may conclude that specific treatment causes a reduction of inflammatory lesions and disappearance of amastigote forms of Leishmania although the factors related to the pathogenesis of the lesion, such as T CD4+ and T CD8+ lymphocytes and Leishmania antigens, persist in treated lesions. The maintenance of these inflammatory patterns may be due to a specific host-parasite relationship response, strongly indicating the need for continuous surveillance of LM patients at risk of reactivation, despite effective cicatrization after therapy. Copyright 2002 Elsevier Science B.V.

7286. Haider S, Boutross-Tadross O, Radhi J, Momar N. Cutaneous ulcer in a man returning from Central America. CMAJ. 2003 Mar 4;168(5):590-1. No abstract available.

7287. Lagler H, Willheim M, Traunmuller F, Wahl K, Winkler H, Ramharter M, Graninger W, Winkler S. Cellular profile of cytokine production in a patient with visceral leishmaniasis: gammadelta+ T cells express both type 1 cytokines and interleukin-10. Scand J Immunol. 2003 Mar;57(3):291-5.

The cytokine profile of CD4+, CD8+ T cells, gammadelta+ T cells and natural killer (NK) cells (CD94+CD3-) was studied in a patient with visceral leishmaniasis (VL). The otherwise healthy, human immunodeficiency virus-negative patient acquired the disease in Tuscany, Italy. Diagnosis was made by demonstration of high concentrations of antibodies against Leishmania antigens in serum. Flow cytometry for the detection of intracellular interferon-gamma (IFN-gamma), interleukin (IL)-2, IL-4, IL-6, IL-10, IL-13 and tumour necrosis factor (TNF)-alpha expression in peripheral blood mononuclear cells stimulated with phorbol 12-myristate 13-acetate and ionomycin was performed, followed by treatment with liposomal amphotericin B. CD4+ cells were identified as major cytokine-expressing cells, capable of producing both type 1 and type 2 cytokines. A high frequency of IL-4- and IL-13-expressing CD8+ cells was noted. NK cells and gammadelta+ T cells, thought to be involved in innate host defences against Leishmania, expressed IFN-gamma and TNF-alpha. Ten per cent of gammadelta+ T cells expressed IL-10, predominantly together with IFN-gamma, suggesting additional immune-regulatory roles for this T-cell subset in VL.

7288. Veeken H, Ritmeijer K, Seaman J, Davidson R. Comparison of an rK39 dipstick rapid test with direct agglutination test and splenic aspiration for the diagnosis of kala-azar in Sudan. Trop Med Int Health. 2003 Feb;8(2):164-7.

We compared an rK39 dipstick rapid test (Amrad ICT, Australia) with a direct agglutination test (DAT) and splenic aspirate for the diagnosis of kala-azar in 77 patients. The study was carried out under field conditions in an endemic area of north-east Sudan. The sensitivity of the rK39 test compared with splenic aspiration was 92% (46/50), the specificity 59% (16/27), and the positive predictive value 81% (46/57). Compared with the diagnostic protocol used by Medecins sans Frontieres, the sensitivity of the rK39 test was 93% (50/54), the specificity 70% (16/23), and the positive predictive value 88% (50/57). Compared with splenic aspirates, the sensitivity of a DAT with a titre > or =1:400 was 100% (50/50), but its specificity only 55% (15/27) and the positive predictive value was 80% (50/62). Using a DAT titre > or =1:6400, the sensitivity was 84% (42/50), the specificity 85% (23/27) and the positive predictive value 91% (42/46). All four patients with DAT titre > or =1:6400 but negative splenic aspirate were also rK39 positive; we consider these are probably 'true' cases of kala-azar, i.e. false negative aspirates, rather than false DAT and rK39 seropositives. There were no false negative DATs (DAT titre < or =1:400 and aspirate positive), but there were four false negative rK39 tests (rK39 negative and aspirate positive). The rK39 dipstick is a good screening test for kala-azar; but further development is required before it can replace the DAT as a diagnostic test in endemic areas of the Sudan.

Pathogenesis:

7289. Belhadj S, Pratlong F, Hammami M, Kallel K, Dedet JP, Chaker E. Human cutaneous leishmaniasis due to Leishmania infantum in the Sidi Bourouis focus (Northern Tunisia): epidemiological study and isoenzymatic characterization of the parasites.Acta Trop. 2003 Jan;85(1):83-6.

The authors report an increase of the number of case of cutaneous leishmaniasis in the Sidi Bourouis region community of Siliana Governorate (Tunisia), with 38 cases diagnosed in 6 months (1st November 2000-30th April 2001), contrary to its usual sporadic character. The isoenzymatic identification of 15 isolated strains emphasizes the role of the Leishmania infantum zymodeme MON-1 as an important factor in the genesis of the sporadic cutaneous leishmaniasis of Northern Tunisia. In fact it was isolated in 6 cases while L. infantum MON-24, the usual agent was isolated in 9 cases. Copyright 2002 Elsevier Science B.V.

Vaccines:

7290. Ahmed S, Colmenares M, Soong L, Goldsmith-Pestana K, Munstermann L, Molina R, McMahon-Pratt D. Intradermal infection model for pathogenesis and vaccine studies of murine visceral leishmaniasis. Infect Immun 2003 Jan;71(1):401-10

The levels of protection found in vaccine studies of murine visceral leishmaniasis are significantly lower than for cutaneous leishmaniasis; whether this is due to the high-challenge murine model employed and/or is a consequence of differences required in tissue-specific local immune responses is not understood. Consequently, an intradermal murine model of visceral leishmaniasis has been explored. Intradermal inoculation established a chronic infection in susceptible mice which was associated with a pattern of parasite clearance with time postinfection in the liver and skin; in contrast, parasite persistence and expansion was observed in lymphoid tissue (spleen and draining lymph node). The course of disease found appears to be similar to those reported for subclinical canine and human visceral leishmaniasis. Clearance of parasites from the skin was correlated with an inflammatory response and the infiltration and activation of CD4(+) and CD8(+) T cells. In contrast, in lymphoid tissue (lymph node or spleen), the production of Th1/Th2 cytokines (interleukin-4 [IL-4], IL-10, and gamma interferon) appeared to correlate with parasite burden and pathogenesis. In vaccination experiments employing the Leishmania infantum D-13 (p80) antigen, significantly higher levels of protection were found with the intradermal murine model (29 to 7,500-fold more than naive controls) than were found with a low-dose intravenous infection model (9 to 173-fold). Thus, this model should prove useful for further investigation of disease pathogenesis as well as vaccine studies of visceral leishmaniasis.

Therapy:

7291. Belhadj S, Pratlong F, Hammami M, Kallel K, Dedet JP, Chaker E. Human cutaneous leishmaniasis due to Leishmania infantum in the Sidi Bourouis focus (Northern Tunisia): epidemiological study and isoenzymatic characterization of the parasites. Acta Trop 2003 Jan;85(1):83-6

7292. Mehmet T, Hokelek M. Pneumonia associated with visceral leishmaniasis in childhood. J Trop Pediatr 2003 Feb;49(1):61. No abstract available.

7293. Zijlstra EE, Musa AM, Khalil EA, el-Hassan IM, el-Hassan AM. Post-kala-azar dermal leishmaniasis.Lancet Infect Dis 2003 Feb;3(2):87-98

Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL); it is characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well. The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity. It is mainly seen in Sudan and India where it follows treated VL in 50% and 5-10% of cases, respectively. Thus, it is largely restricted to areas where Leishmania donovani is the causative parasite. The interval at which PKDL follows VL is 0-6 months in Sudan and 2-3 years in India. PKDL probably has an important role in interepidemic periods of VL, acting as a reservoir for parasites. There is increasing evidence that the pathogenesis is largely immunologically mediated; high concentrations of interleukin 10 in the peripheral blood of VL patients predict the development of PKDL. During VL, interferon gamma is not produced by peripheral blood mononuclear cells (PBMC). After treatment of VL, PBMC start producing interferon gamma, which coincides with the appearance of PKDL lesions due to interferon-gamma-producing cells causing skin inflammation as a reaction to persisting parasites in the skin. Diagnosis is mainly clinical, but parasites can be seen by microscopy in smears with limited sensitivity. PCR and monoclonal antibodies may detect parasites in more than 80% of cases. Serological tests and the leishmanin skin test are of limited value. Treatment is always needed in Indian PKDL; in Sudan most cases will self cure but severe and chronic cases are treated. Sodium stibogluconate is given at 20 mg/kg for 2 months in Sudan and for 4 months in India. Liposomal amphotericine B seems effective; newer compounds such as miltefosine that can be administered orally or topically are of major potential interest. Although research has brought many new insights in pathogenesis and management of PKDL, several issues in particular in relation to control remain unsolved and deserve urgent attention.

October 2003

8016. Gangneux JP, Menotti J, Lorenzo F, Sarfati C, Blanche H, Bui H, Pratlong F, Garin YJ, Derouin F. Prospective value of PCR amplification and sequencing for diagnosis and typing of old world Leishmania infections in an area of nonendemicity. J Clin Microbiol. 2003 Apr;41(4):1419-22.

We assessed the prospective value of PCR amplification of a repetitive sequence from Leishmania nuclear DNA and sequencing for the diagnosis and typing of Old World Leishmania infection in an area of nonendemicity. During this 42-month study, 29 of 168 consecutive samples were examined and classified as positive for Leishmania by direct examination and/or in vitro culture. This molecular approach showed excellent sensitivity (97%) and specificity (100%) compared to direct examination (86 and 100%, respectively) and in vitro culture (72 and 100%, respectively). Isoenzymatic and molecular typing allowed similar identification for 12 samples. Besides, PCR and subsequent sequencing of DNA products permitted the species identification of 14 samples for which parasite culture remained negative or did not allow isoenzymatic characterization, indicating the complementarity of parasitological and molecular tools.

8017. Goswami BK, Datta S, Chakrabarti S, Chakrabarti S, Giri A, Debnath NB, Datta K, Bandopadhayay G, Das S. Experience of visceral leishmaniasis in the northern districts of West Bengal – the emerging sodium stibogluconate unrespensiveness. Indian med J 2002, 96 (7), 173-6. ISA 004575, Vol 39, No 5, 1 Mar 2003.

8018. Haseeb AN, el-Shazly AM, Arafa MA, Morsy AT. Evaluation of excretory/secretory Fasciola (Fhes) antigen in diagnosis of human fascioliasis. J Egypt Soc Parasitol. 2003 Apr;33(1):123-38.

No doubt, human fascioliasis is an increasing worldwide zoonotic liver fluke. Clinically, human fascioliasis has to be differentially diagnosed from many hepatic diseases as acute & chronic hepatitis, schistosomiasis mansoni, visceral toxocariasis, visceral leishmaniasis, hepatic amoebiasis, biliary tract diseases and others. The parasitological diagnosis based on the demonstration of the eggs in stool, duodenal contents or bile is usually unsatisfactory due to false passage of eggs, ectopic fascioliasis, and failure of immature worm to maturation. So, ELISA-Fhes antigen (Fasciola hepatica excretory/secretory) and IHAT were evaluated in the immunodiagnosis of parasitologically proven cases of human fascioliasis compared with proven cases of human schistosomiasis mansoni and parasite-free individuals. ELISA-Fhes gave 100% sensitivity and 100% specificity. On the other hand, IHAT was less sensitive and less specific.

8019. Ikonomopoulos J, Kokotas S, Gazouli M, Zavras A, Stoitsiou M, Gorgoulis VG. Molecular diagnosis of leishmaniosis in dogs. Comparative application of traditional diagnostic methods and the proposed assay on clinical samples. Vet Parasitol. 2003 Apr 18;113(2):99-113.

Leishmaniosis is a zoonotic, parasitic disease caused by members of the genus Leishmania. The disadvantages of the traditional methods have currently rendered the polymerase chain reaction (PCR), the most reliable alternative for the laboratory diagnosis of this disease. Several relevant protocols have been described in the past but their application is in most cases limited to research use. The latter combined with the diagnostic problems that can be caused by the genetic variability of the different Leishmania strains or the presence of PCR inhibitors, indicate that an alternative approach should be followed for the development of a standard diagnostic tool for leishmaniosis.In the present study, we have evaluated several PCR-based protocols, in order to identify a primer combination that would allow the reliable detection of Leishmania DNA from clinical material and the verification of its results, in a manner that could be applicable even for routine use.The evaluation consisted of a BLAST verification of the specificity of the previously described primers, PCR testing, and optimisation of the reaction conditions. Our assessment was completed with the comparative evaluation of the results produced by the proposed PCR assay, light microscopy, and indirect fluorescent antibody technique (IFAT), on clinical samples collected from dogs suspected of leishmaniosis.The proposed assay which consists of a combination of two pairs of primers, targeted to different areas of the kinetoplast DNA of Leishmania spp., specific for Leishmania infantum, Leishmania donovani and Leishmania chagasi, showed optimum performance on our test samples, and detected 41.9% Leishmania-positive dogs from our 160 clinical cases. From the same number of cases, 46.25% were positive by IFAT (titre > or =200), and 19% by microscopic examination of lymph node aspirates.

8020. Rahman SB, Bari AU. Laboratory profile in patients of cutaneous leishmaniasis from various regions of Pakistan. J Coll Physicians Surg Pak. 2003 Jun;13(6):313-6.

OBJECTIVE: To delineate the different laboratory findings in patients of

-cutaneous leishmaniasis and to see the efficacy of some recent immunodiagnostic tools in the diagnosis of disease. DESIGN: Descriptive case-control study. PLACE AND DURATION OF STUDY: The study was conducted over a period of two years in Military Hospital (MH) and Armed Forces Institute of Pathology (AFIP), Rawalpindi, Pakistan. PATIENTS AND METHODS: Fifty patients with clinical diagnosis of cutaneous leishmaniasis(CL), were included in the study from western, south-western and northern regions of the country (Quetta, Multan, Chakwal, Kohat, Northern areas and Islamabad). Complete blood picture, blood groups, skin slit smears, impression smears and skin biopsies and serological tests including Enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test (IFAT), and indirect hemagglutination assay (IHA) were done in all cases. Immunohistochemistry with IFAT was performed in 20 patients and kDNA (kinetoplast DNA) probes in 16 patients. These tests were then evaluated to see their efficacy in diagnosis of CL. RESULTS: Blood CP was normal except for low hemoglobin levels. Most prevalent blood group was B-positive. Skin slit smear and impression smears were positive in 30% and 36% cases respectively. On histopathology four distinct histological patterns emerged. Results with H&E, Giemsa and Leishman stains were similar (36%) and PAS failed to stain parasite. On tissue section IFAT yielded 36%, peroxidase-antiperoxidase (PAP) 45% and kDNA probes 25% positive results. Serology was positive in 56% with ELISA, in 50% each with IFAT and IHA tests. CONSLUSION: Routine blood tests have no role in diagnosis of CL. Skin slit smear and touch impression smears are rapid means of diagnosis. Modern immunodiagnostic methods can produce better results but these are costly and availability is limited. In our setup slit skin smear/impression smear and light microscopy with routine H and E staining are probably the most co-effective accurate diagnostic methods.

8021. Reithinger R, Espinoza JC, Courtenay O, Davies CR. Evaluation of PCR as a diagnostic mass-screening tool to detect Leishmania (Viannia) spp. in domestic dogs (Canis familiaris). J Clin Microbiol. 2003 Apr;41(4):1486-93.

Several studies have suggested that the PCR could be used in epidemiological mass-screening surveys to detect Leishmania (Viannia) spp. infection in human and animal hosts. Dogs from an area of Leishmania braziliensis and Leishmania peruviana endemicity were screened for American cutaneous leishmaniasis (ACL) infection by established PCR-based and enzyme-linked immunosorbent antibody test (ELISA) protocols. PCR detected Leishmania (Viannia) infection in a total of 90 of 1,066 (8.4%) dogs: 32 of 368 (8.7%), 65 of 769 (8.5%), and 7 of 42 (16.7%) dogs were PCR positive by testing of whole blood, buffy coat, and bone marrow aspirates, respectively. ELISA detected infection in 221 of 1,059 (20.9%) tested dogs. The high prevalence of Leishmania (Viannia) detected by PCR and ELISA in both asymptomatic (7.5 and 19.2%, respectively) and symptomatic (32 and 62.5%, respectively) dogs is further circumstantial evidence for their suspected role as reservoir hosts of ACL. However, the low sensitivity of PCR (31%) compared to ELISA (81%) indicates that PCR cannot be used for mass screening of samples in ACL epidemiological studies. Unless more-sensitive PCR protocols were to be developed, its use should be restricted to the diagnosis of active (canine and human) cases and to the parasitological monitoring of patients after chemotherapy.

8022. Whittemore JC, Salman MD. Think screening unnecessary, unrealistic for all blood donors. J Am Vet Med Assoc. 2003 Jun 1;222(11):1502; author reply 1502. No abstract

Pathogenesis:

8023. Bertholet S, Dickensheets HL, Sheikh F, Gam AA, Donnelly RP, Kenney RT. Leishmania donovani-induced expression of suppressor of cytokine signaling 3 in human macrophages: a novel mechanism for intracellular parasite suppression of activation. Infect Immun. 2003 Apr;71(4):2095-101.

Leishmania donovani protozoan parasites, the causative agent of visceral

-leishmaniasis, establish an infection partly by interfering with cytokine signaling in the host macrophages. Therefore, we investigated the expression of the suppressor of cytokine signaling (SOCS) genes in human macrophages infected with L. donovani. The expression of SOCS3 mRNA was induced transiently after exposure to live or heat-killed parasites, but not purified lipophosphoglycan, while that of other SOCS genes remained unchanged. SOCS3 gene expression was not dependent on phagocytosis or on cytokines released by L. donovani-infected macrophages, such as interleukin-1beta or tumor necrosis factor alpha. In addition, Leishmania used a different signaling pathway(s) than bacterial lipopolysaccharide to induce SOCS3 mRNA, as indicated by the kinetics of induction and sensitivity to polymyxin B inhibition. Finally, phosphorylation of the STAT1 transcription factor was significantly reduced in L. donovani-infected macrophages and required de novo transcription. The induction of SOCS3 provides a potent inhibitory mechanism by which intracellular microorganisms may suppress macrophage activation and interfere with the host immune response.

8024. Cordeiro-da-Silva A, Cardoso L, Araujo N, Castro H, Tomas A, Rodrigues M, Cabral M, Vergnes B, Sereno D, Ouaissi A. Identification of antibodies to Leishmania silent information regulatory 2 (SIR2) protein homologue during canine natural infections: pathological implications. Immunol Lett. 2003 Apr 3;86(2):155-62.

Dogs are the domestic reservoir of zoonotic visceral Leishmaniasis caused by Leishmania infantum in the Mediterranean basin and thus constitute an important health problem in both human and veterinary medicine. Until vaccines become available, conventional measures such as epidemiological surveillance including reservoir control will be among the practical options for prevention and containment of the disease. We have recently characterised novel Leishmania sp. genes encoding parasite proteins named (LmS3a: homologous to mammalian ribosomal protein S3a; LmSIR2: homologous to the silent information regulatory 2 protein family; LimTXNPx: homologous to the peroxiredoxin family with N-terminal mitochondrial leader sequence) that may contribute to the host immune dysfunction in murine experimental Leishmaniasis. In the present study we have investigated the humoral responses against the parasite antigens in groups of L. infantum-infected dogs with different clinical status: symptomatic and asymptomatic with DTH positive or negative test. The determination of immunoglobulin (Ig) isotypes revealed high levels of total IgG in both symptomatic and asymptomatic animals when compared to IgM. Furthermore, the IgG2 appeared to be the predominant subclass of Ig present in the sera of infected animals particularly in the case of symptomatic dogs. The IgG subclass reactivity analysis revealed a broad specific recognition range of parasite recombinant antigens. Interestingly, differential profiles of IgG1 and IgG2 antibody reactivity were observed in asymptomatic and symptomatic dogs. The LmSIR2 protein was found to be a highly reactive molecule with IgG2 from most of the asymptomatic and symptomatic animals. Considering the fact that LmSIR2 secreted by the parasites can be bound and taken up by neighbouring cells, the latter could be a target for anti-LmSIR2 antibodies and this may contribute to the immunopathological alterations and host tissue damage. The implications of these observations in the pathogenesis of Leishmaniasis are discussed.

8025. Lang T, Courret N, Colle JH, Milon G, Antoine JC. The levels and patterns of cytokines produced by CD4 T lymphocytes of BALB/c mice infected with Leishmania major by inoculation into the ear dermis depend on the infectiousness and size of the inoculum. Infect Immun. 2003 May;71(5):2674-83.

The production of cytokines by CD4 lymph node T lymphocytes derived from BALB/c mice recently infected in the ear dermis with high (10(6) parasites) or low (10(3) parasites) doses of Leishmania major metacyclic promastigotes (MP) was examined over a 3-week period following inoculation. Results were compared with those obtained when mice were injected with less infectious parasite populations, namely, stationary-phase or log-phase promastigotes (LP). Cells were purified 16 h and 3, 8, and 19 days after inoculation, and the amounts of gamma interferon (IFN-gamma) and interleukin-4 (IL-4) released in response to LACK (Leishmania homolog of receptors for activated C kinase) or total L. major antigens were assessed. We found that LACK-reactive T cells from mice inoculated with a high dose of parasites first produced IFN-gamma and later on IL-4; the level of IFN-gamma produced early by these cells was dependent upon the stage of the promastigotes inoculated, the highest level being reached with cells recovered from mice inoculated with the least infectious parasites, LP; sequential production of IFN-gamma and then of IL-4 also characterized L. major antigen-reactive CD4 T cells, suggesting that the early production of IFN-gamma does not impede the subsequent rise of IL-4 and finally the expansion of the parasites; after low-dose inoculation of MP, cutaneous lesions developed with kinetics similar to that of lesions induced after inoculation of 10(6) LP, but in this case CD4 T lymphocytes did not release IFN-gamma or IL-4 in the presence of LACK and neither cytokine was produced in response to L. major antigens before the onset of lesion signs. These results suggest the existence of a discreet phase in terms of CD4 T-cell reactivity for at least the first 8 days following inoculation, a time period during which parasites are able to grow moderately. In conclusion, the levels and profiles of cytokines produced by Leishmania-specific CD4 T lymphocytes clearly depend on both the stage of differentiation and number of parasites used for inoculation.

8026. Lima VM, Goncalves ME, Ikeda FA, Luvizotto MC, Feitosa MM. Anti-leishmania antibodies in cerebrospinal fluid from dogs with visceral leishmaniasis. Braz J Med Biol Res. 2003 Apr;36(4):485-9. Epub 2003 Apr 08.

Visceral leishmaniasis in Brazil is caused by Leishmania (Leishmania) chagasi and the dog is its most important reservoir. The clinical features in dogs include loss of weight, lymphadenopathy, renal failure, skin lesions, fever, hypergammaglobulinemia, hepatosplenomegaly, anemia, and, rarely, neurological symptoms. Most infected animals develop active disease, characterized by high anti-leishmania antibody titers and depressed lymphoproliferative ability. Antibody production is not primarily important for protection but might be involved in the pathogenesis of tissue lesions. An ELISA test was used to determine if there is an association between neurological symptoms and the presence of anti-L. chagasi antibodies in cerebrospinal fluid (CSF). Thirty serum and CSF samples from symptomatic mixed breed dogs (three with neurological symptoms) from a region of high incidence of visceral leishmaniasis in Brazil were examined for antibody using total parasite antigen and anti-dog IgG peroxidase conjugate. A high level of L. chagasi antibodies was observed in sera (mean absorbance SD, 1.939 0.405; negative control, N = 20, 0.154 0.074) and CSF (1.571 0.532; negative control, N = 10, 0.0195 0.040) from all animals studied. This observation suggests that L. chagasi can cause breakdown of filtration barriers and the transfer of antibodies and antigens from the blood to the CSF compartment. No correlation was observed between antibody titer in CSF and neurological symptoms.

8027. Pelletier I, Hashidate T, Urashima T, Nishi N, Nakamura T, Futai M, Arata Y, Kasai K-, Hirashima M, Hirabayashi J, Sato S. Specific recognition of Leishmania major poly-beta-galactosyl epitopes by galectin-9: possible implication of galectin-9 in interaction between L. major and host cells. J Biol Chem. 2003 Jun 20;278(25):22223-30. Epub 2003 Apr 08.

Leishmania parasites are the causative agents of leishmaniasis, manifesting itself in a species-specific manner. The glycan epitopes on the parasite are suggested to be involved in the Leishmania pathogenesis. One of such established species-unique glycan structures is the poly-beta-galactosyl epitope (Galbeta1-3)n found on L. major, which can develop cutaneous infections with strong inflammatory responses. Interestingly, the polygalactosyl epitope is also suggested to be involved in the development of the parasites in its host vector, sand fly. Thus, the recognition of the galactosyl epitope by lectins expressed in host or sand fly should be implicated in the species-specific manifestations of leishmaniasis and in the parasite life cycle, respectively. We recently reported that one host beta-galactoside-binding protein, galectin-3, can distinguish L. major from the other species through its binding to the poly-beta-galactosyl epitope, proposing a role for galectin-3 as an immunomodulator that could influence the L. major-specific immune responses in leishmaniasis. Here we report that galectin-9 can also recognize L. major by binding to the L. major-specific polygalactosyl epitope. Frontal affinity analysis with different lengths of poly-beta-galactosyllactose revealed that the galectin-9 affinity for polygalactose was enhanced in proportion to the number of Galbeta1-3 units present. Even though both galectins have comparable affinities toward the polygalactosyl epitopes, only galectin-9 can promote the interaction between L. major and macrophages, suggesting distinctive roles for the galectins in the L. major-specific development of leishmaniasis in the host.

8028. Reithinger R, Espinoza JC, Courtenay O, Davies CR. Evaluation of PCR as a diagnostic mass-screening tool to detect Leishmania (Viannia) spp. in domestic dogs (Canis familiaris). J Clin Microbiol. 2003 Apr;41(4):1486-93.

Therapy:

8029. Carter KC, Sundar S, Spickett C, Pereira OC, Mullen AB. The in vivo susceptibility of Leishmania donovani to sodium stibogluconate is drug specific and can be reversed by inhibiting glutathione biosynthesis. Antimicrob Agents Chemother. 2003 May;47(5):1529-35.

Resistance to pentavalent antimonial (Sb(v)) agents such as sodium stibogluconate (SSG) is creating a major problem in the treatment of visceral leishmaniasis. In the present study the in vivo susceptibilities of Leishmania donovani strains, typed as SSG resistant (strain 200011) or SSG sensitive (strain 200016) on the basis of their responses to a single SSG dose of 300 mg of Sb(v)/kg of body weight, to other antileishmanial drugs were determined. In addition, the role of glutathione in SSG resistance was investigated by determining the influence on SSG treatment of concomitant treatment with a nonionic surfactant vesicle formulation of buthionine sulfoximine (BSO), a specific inhibitor of the enzyme gamma-glutamylcysteine synthetase which is involved in glutathione biosynthesis, and SSG, on the efficacy of SSG treatment. L. donovani strains that were SSG resistant (strain 200011) and SSG sensitive (strain 200016) were equally susceptible to in vivo treatment with miltefosine, paromomycin and amphotericin B (Fungizone and AmBisome) formulations. Combined treatment with SSG and vesicular BSO significantly increased the in vivo efficacy of SSG against both the 200011 and the 200016 L. donovani strains. However, joint treatment that included high SSG doses was unexpectedly associated with toxicity. Measurement of glutathione levels in the spleens and livers of treated mice showed that the ability of the combined therapy to inhibit glutathione levels was also dependent on the SSG dose used and that the combined treatment exhibited organ-dependent effects. The SSG resistance exhibited by the L. donovani strains was not associated with cross-resistance to other classes of compounds and could be reversed by treatment with an inhibitor of glutathione biosynthesis, indicating that clinical resistance to antimonial drugs should not affect the antileishmanial efficacies of alternative drugs. In addition, it should be possible to identify a treatment regimen that could reverse antimony resistance.

8030. Cauchetier E, Paul M, Rivollet D, Fessi H, Astier A, Deniau M. Therapeutic evaluation of free and nanocapsule-encapsulated atovaquone in the treatment of murine visceral leishmaniasis. Ann Trop Med Parasitol. 2003 Apr;97(3):259-68.

The activities of free atovaquone (ATV) and of poly(D,L-lactide) nanocapsules loaded with the drug, in the treatment of mice with visceral leishmaniasis caused by Leishmania infantum, were compared. Each mouse was infected intravenously with 2x10(7) promastigotes, on day 0. On days 15, 17 and 19, most of the infected mice were treated either with free ATV, in a dimethylsulphoxide/cremophor/water mixture, or with the ATV-loaded nanocapsules (at, respectively, 0.2-1.6 and 0.125-1.0 mg ATV/kg, on each treatment day). The rest of the mice were left untreated, as controls. All the mice were killed on day 21 and dissected so that their livers and spleens could be weighed. The liver parasite burdens, evaluated using the Stauber method, indicated that the ATV-loaded nanocapsules were significantly more effective than the free drug. In nanocapsules, for example, a total dose of 3.0 mg ATV/kg reduced liver burdens by 71.3%, whereas treatment with a higher total dose of the free drug (4.8 mg/kg) only cut the number of liver parasites by 34.4%. The dose-response data indicated that livers would have been cleared of parasites if the nanocapsule preparation had been given as three doses each equivalent to 3 mg ATV/kg, whereas the maximum suppression possible with the free drug would have been about 61%, whatever the dose.

8031. Montero JA, Ruiz-Moreno JM, Sanchis E. Intraretinal hemorrhage associated with leishmaniasis. Ophthalmic Surg Lasers Imaging. 2003 May-Jun;34(3):212-4.

A 39-year-old man presented with sudden loss of visual acuity caused by two retinal hemorrhages with no choroidal neovascularization (confirmed by fluorescein angiography). The patient was hospitalized for malaise, progressive pancytopenia, hepatosplenomegaly, progressive anemia, and perianal inflammation. Positive serologies were obtained for toxoplasmosis (IgG) and Leishmania (1/160). A diagnosis of visceral leishmaniasis was made, and the patient was treated with pentavalent antimonials. Two months later, best-corrected visual acuity was 20/25, with no residual scotoma. Indirect ophthalmoscopy showed complete resolution of the hemorrhages. This patient was an otherwise healthy immunocompetent adult who presented frank visceral leishmaniasis and retinal hemorrhages as the only ocular or systemic hemorrhagic findings, with spontaneous resolution after improvement of platelet levels. This rare cause of macular hemorrhage should be considered in areas where Leishmania is endemic.

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