Visceral leishmaniosis in HIV-positive patients: primary infection, reactivation and latent infection. Impact of the CD4+ T-lymphocyte counts

Accuracy improvement enzyme-linked immunosorbent assay using superparamagnetic/polyethylene glycol) nanoparticles for leishmaniasis diagnostic

Serodiagnosis methods have been used as platforms for diagnostic tests for many diseases. Due to magnetic nanoparticles' properties to quickly detach from an external magnetic field and particle size effects, these nanomaterials' functionalization allows the specific isolation of target analytes, enhancing accuracy parameters and reducing serodiagnosis time. Superparamagnetic iron oxide nanoparticles (MNPs) were synthesized and functionalized with polyethylene glycol (PEG) and then associated with the synthetic Leishmaniosis epitope. This nano-peptide antigen showed promising results. Regarding Tegumentary leishmaniasis diagnostic accuracy, the AUC was 0.8398 with sensibility 75% (95CI% 50.50 - 89.82) and specificity 87.50% (95CI% 71.93 - 95.03), and Visceral leishmaniasis accuracy study also present high performance, the AUC was 0.9258 with sensibility 87.50% (95CI% 63.98 - 97.78) and specificity 87.50% (95CI% 71.93 - 95.03). Our results demonstrate that the association of the antigen with MNPs accelerates and improves the diagnosis process. MNPs could be an important tool for enhancing serodiagnosis.

Prevalence of visceral leishmaniasis among people with HIV: a systematic review and meta-analysis

Leishmaniasis is a parasitic infection expressing different clinical phenotypes. Visceral leishmaniasis (VL) is considered an opportunistic infection among people with human immunodeficiency virus (HIV). The objective of this review was to identify published data on the prevalence of Leishmania spp. infection among PWH and to define particular determinants that affect critically the epidemiological characteristics of VL-HIV coinfection and, potentially, its burden on public health. Two independent reviewers conducted a systematic literature search until June 30, 2022. Meta-analyses were conducted using random-effects models to calculate the summary prevalence and respective 95% confidence intervals (CI) of leishmaniasis among PWH. Meta-regression analysis was performed to investigate the impact of putative effect modifiers, such as the mean CD4 cell count, on the major findings. Thirty-four studies were eligible, yielding a summary prevalence of 6% (95%CI, 4-11%) for leishmaniasis (n = 1583) among PWH (n = 85,076). Higher prevalence rates were noted in Asia (17%, 95%CI, 9-30%) and America (9%, 95%CI, 5-17%) than in Europe (4%, 95%CI, 2-8%). Prevalence rates were significantly mediated by the age, sex, and CD4 cell count of participants. Heterogeneity remained significant in all meta-analyses (p < 0.0001). In the majority of included studies, people were coinfected with HIV and Leishmania species associated with VL, as opposed to those associated with cutaneous leishmaniasis. No sign of publication bias was shown (p = 0.06). Our summary of published studies on leishmaniasis among PWH is important to provide prevalence estimates and define potential underlying factors that could guide researchers to generate and further explore specific etiologic hypotheses.

Asymptomatic Visceral Leishmania infantum Infection in US Soldiers Deployed to Iraq

BACKGROUND

Visceral leishmaniasis (VL), due to Leishmania infantum, is a persistent intracellular parasitic infection transmitted by the bite of infected sand flies. Symptomatic VL has been reported in U.S. soldiers with Iraq deployment. Untreated symptomatic VL can be fatal; asymptomatic VL (AVL) may establish a lifelong risk of reactivation. We report prevalence and AVL risk factors in Operation Iraqi Freedom (OIF) deployers during 2002-11.

METHODS

Healthy soldiers exposed to VL endemic areas in Iraq and 50 controls who never traveled to endemic regions were recruited through military healthcare facilities (2015-17). Responses to a risk factor survey and blood samples were obtained. Leishmania research diagnostics utilized included enzyme-linked immunosorbent assay (ELISA), rk39 test strips, quantitative polymerase chain reaction (PCR), and interferon gamma release (IGRA) assays. Statistical analyses included Fisher exact test, Pearson χ2 test, Mann-Whitney U test, and logistic regression.

RESULTS

200 deployed subjects were enrolled, mostly males (84.0%), of white ethnicity (79.0%), and median age 41 (range 24-61) years. 64% were seropositive for Phlebotomus alexandri saliva antibodies. Prevalence of AVL (any positive test result) was 39/200 (19.5%, 95% confidence interval 14.4%-25.8%). Two (1.0%) PCR, 10 (5%) ELISA, and 28 (14%) IGRA samples were positive. Travel to Ninewa governorate increased risk for AVL (P = .01).

CONCLUSION

AVL was identified in 19.5% of OIF deployers; travel to northwest Iraq correlated with infection. Further studies are needed to inform risk for reactivation VL in US veterans and to target additional blood safety and surveillance measures.

Is Visceral Leishmaniasis the same in HIV-coinfected adults?

Introduction

Visceral Leishmaniasis is the most severe form of disease caused by the Leishmania donovani complex, with significant morbidity and mortality in developing countries. Worse outcomes occur among HIV-positive individuals coinfected with Leishmania. It is unclear, however, if there are significant differences on presentation between Visceral Leishmaniasis patients with or without HIV coinfection.

Methods

We reviewed medical records from adult patients with Visceral Leishmaniasis treated at a reference healthcare center in Fortaleza – Ceará, Brazil, from July 2010 to December 2013. Data from HIV-coinfected patients have been abstracted and compared to non-HIV controls diagnosed with Visceral Leishmaniasis in the same period.

Results

Eighty one HIV-infected patients and 365 controls were enrolled. The diagnosis in HIV patients took significantly longer, with higher recurrence and death rates. Kala-azar's classical triad (fever, constitutional symptoms and splenomegaly) was less frequently observed in Visceral Leishmaniasis-HIV patients, as well as jaundice and edema, while diarrhea was more frequent. Laboratory features included lower levels of hemoglobin, lymphocyte counts and liver enzymes, as well as higher counts of blood platelets and eosinophils. HIV-infected patients were diagnosed mainly through amastigote detection on bone marrow aspirates and treated more often with amphotericin B formulations, whereas in controls, rK39 was the main diagnostic tool and pentavalent antimony was primarily used for treatment.

Conclusions

Clinical and laboratory presentation of Visceral Leishmaniasis in HIV-coinfected patients may differ from classic kala-azar, and these differences may be, in part, responsible for the delay in diagnosing and treating leishmaniasis, which might lead to worse outcomes.

Asymptomatic carriers of Leishmania infantum in patients infected with human immunodeficiency virus (HIV) in Morocco

In Morocco, visceral leishmaniasis (VL) is a parasitic disease caused by the flagellated protozoan parasite Leishmania infantum. L. infantum is transmitted by the bite of female phlebotomine sandflies, and its main reservoir hosts are domestic dogs. Asymptomatic infection with L. infantum is more frequent than clinically apparent disease. In HIV-infected patients, the risk of clinical VL is increased due to immunosuppression that may reactivate latent infections. However, coinfected subjects do not necessarily develop VL and may remain as asymptomatic carriers depending on their immune status. The present study investigates the asymptomatic carriers of L. infantum in HIV-infected patients in central Morocco, where human cases of visceral leishmaniasis by L. infantum have been reported. A total of 200 HIV-infected patients attending the Infectious Diseases Unit of the Ibn Zohar Hospital of Marrakech participated in the study. Parasitological and serological blood analyses included a direct microscopic examination (DME), culture in Novy-McNeal-Nicolle (NNN) medium, and serology by indirect immunofluorescence (IFI). We found prevalence rates of 5% (10/200) by IFI, 3% (6/200) by DME, and 2.5% (5/200) by culture. The parasite was identified as L. infantum by PCR from positive cultures.

Lymphoproliferative response after stimulation with soluble leishmania antigen (SLA) as a predictor of visceral leishmaniasis (VL) relapse in HIV+ patients

The introduction of HAART resulted in the decrease of Leishmania/HIV co-infection cases; nevertheless, the number of relapses remains high and secondary prophylaxis is recommended. However, secondary prophylaxis is not necessary in all patients, and presents a high risk of toxicity and an elevated cost. Our aim was to study whether specific cellular response to Leishmania infantum (measured by cell proliferation response after stimulation with soluble Leishmania antigen (SLA)), could be a useful tool to attempt a secondary prophylaxis withdrawal. In June 2009 an outbreak of leishmaniasis by Leishmania infantum was declared in the southeast of Madrid, and since January 2013, we recruited 10 HIV+ patients that had been treated for visceral leishmaniasis. 6 patients had positive SLA-cell proliferation test. The mean CD4 cell counts of those patients with positive SLA were 140 cel/mm3 and 40 cel/mm3 in those with negative SLA test. 3 patients with positive SLA-cell proliferation test (CD4 count: 336, 307, 625) were not on prophylaxis, and the other 3 patients (CD4 count: 152, 189, 359) were on secondary prophylaxis that was withdrawn after the positive SLA-cell proliferation test with no posterior relapses (mean follow up 60 weeks). From the 4 patients, which had negative SLA-cell proliferation test and continued on prophylaxis, 3 had positive PCR for Leishmania at the end of the follow-up and 2 presented clinical relapses. The performance of SLA-cell proliferation test can be a useful tool that can permit us to try withdrawal of the prophylaxis in Leishmania/HIV co-infected patients with low CD4⁺ counts under clinical supervision, diminishing risk of toxicity and cost.

Magnitude of visceral leishmaniasis and poor treatment outcome among HIV patients: meta-analysis and systematic review

Background

Visceral leishmaniasis (VL) coinfection with HIV/AIDS most often results in unfavorable responses to treatment, frequent relapses, and premature deaths. Scarce data are available, regarding the magnitude and poor treatment outcomes of VL-HIV coinfection.

Objective

The main objective of this systematic review was to describe the pooled prevalence of VL and poor treatment outcome among HIV patients.

Review methods

Electronic databases mainly PubMed were searched. Databases, such as Google and Google scholar, were searched for gray literature. Articles were selected based on their inclusion criterion, whether they included HIV-positive individuals with VL diagnosis. STATA 11 software was used to conduct a meta-analysis of pooled prevalence of VL-HIV coinfection.

Results

Fifteen of the 150 articles fulfilled the inclusion criteria. A majority of the study participants were males between 25 years and 41 years of age. The pooled prevalence of VL-HIV coinfection is 5.2% with 95% confidence interval of (2.45–10.99). Two studies demonstrated the impact of antiretroviral treatment on reduction in relapse rate compared with patients who did not start antiretroviral treatment. One study showed that the higher the baseline CD4+ cell count (>100 cells/mL) the lower the relapse rate. Former VL episodes were identified as risk factors for relapse in two articles. In one of the articles, an earlier bout of VL remains significant in the model adjusted to other variables.

Conclusion

The pooled prevalence of VL in HIV-infected patients is low and an earlier bout of VL and CD4+ count <100 cells/mL at the time of primary VL diagnosis are factors that predict poor treatment outcome.

Visceral leishmaniasis due to Leishmania infantum with renal involvement in HIV-infected patients

Background

We describe histological, clinical findings and outcomes of renal involvement during Leishmania infantum infection in four HIV-infected patients in South France and North Italy hospital settings.

Cases presentation

Four HIV-infected Caucasian patients (age 24-49) performed renal biopsy during episodes of visceral leishmaniasis. They presented severe immunosuppression, frequent relapses of visceral leishmaniasis during a follow-up period of several years and partial or complete recovery of renal function after anti-parasitic treatment. Main clinical presentations were nephrotic or nephritic syndrome and/or acute renal failure secondary to membranoproliferative type III glomerulonephritis or acute interstitial nephritis. Clinical outcome was poor, probably as a consequence of insufficient immuno-virological control of the HIV infection.

Conclusions

Our findings suggest that the main histological findings in case of renal involvement due to Leishmania infantum infection in HIV-infected patients are type III MPGN and acute interstitial nephritis, with a histological specificity similar to that observed in canine leishmaniasis. Poor immune status in HIV-infected patients, altering the capacity for parasite clearance, and prolonged course of chronic active VL in this population may lead to the development of specific renal lesions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0561-9) contains supplementary material, which is available to authorized users.

Visceral leishmaniasis and HIV coinfection in the Mediterranean region

Visceral leishmaniasis is hypoendemic in Mediterranean countries, where it is caused by the flagellate protozoan Leishmania infantum. VL cases in this area account for 5%–6% of the global burden. Cases of Leishmania/HIV coinfection have been reported in the Mediterranean region, mainly in France, Italy, Portugal, and Spain. Since highly active antiretroviral therapy was introduced in 1997, a marked decrease in the number of coinfected cases in this region has been reported. The development of new diagnostic methods to accurately identify level of parasitemia and the risk of relapse is one of the main challenges in improving the treatment of coinfected patients. Clinical trials in the Mediterranean region are needed to determine the most adequate therapeutic options for Leishmania/HIV patients as well as the indications and regimes for secondary prophylaxis. This article reviews the epidemiological, diagnostic, clinical, and therapeutic aspects of Leishmania/HIV coinfection in the Mediterranean region.

A screen-and-treat strategy targeting visceral leishmaniasis in HIV-infected individuals in endemic East African countries: the way forward?

In the wake of the HIV epidemic, visceral leishmaniasis (VL), a disseminated protozoan infection caused by the Leishmania donovani complex, has been re-emerging, particularly in North Ethiopia where up to 40% of patients with VL are co-infected with HIV. Management of VL in HIV co-infection is complicated by increased drug toxicity, and high treatment failure and relapse rates with all currently available drugs, despite initiation of antiretroviral treatment. Tackling L. donovani infection before disease onset would thus be a logical approach. A screen-and-treat approach targeting latent or the early stage of infection has successfully been implemented in other HIV-associated opportunistic infections. While conceptually attractive in the context of VL-HIV, the basic understanding and evidence underpinning such an approach is currently lacking. Prospective cohort studies will have to be conducted to quantify the risk of VL in different risk groups and across CD4 cell count levels. This will allow developing clinical prognostic tools, integrating clinical, HIV and Leishmania infection markers. Interventional studies will be needed to evaluate prophylactic or pre-emptive treatment strategies for those at risk, ideally relying on an oral (combination) regimen. Issues like tolerability, emergence of resistance and drug interactions will require due attention. The need for maintenance therapy will have to be assessed. Based on the risk-benefit data, VL risk cut-offs will have to be identified to target treatment to those most likely to benefit. Such a strategy should be complemented with early initiation of antiretroviral treatment and other strategies to prevent HIV and Leishmania infection.

Case study of a patient with HIV-AIDS and visceral leishmaniasis co-infection in multiple episodes

Report of a 45-year-old male farmer, a resident in the forest zone of Pernambuco, who was diagnosed with human immunodeficiency virus (HIV) in 1999 and treated using antiretroviral (ARV) drugs. In 2005, the first episode of visceral leishmaniasis (VL), as assessed by parasitological diagnosis of bone marrow aspirate, was recorded. When admitted to the hospital, the patient presented fever, hepatosplenomegaly, weight loss, and diarrhea. Since then, six additional episodes of VL occurred, with a frequency rate of one per year (2005-2012, except in 2008). In 2011, the patient presented a disseminated skin lesion caused by the amastigotes of Leishmania, as identified by histopathological assessment of skin biopsy samples. In 2005, he was treated with N-methyl-glucamine-antimony and amphotericin B deoxycholate. However, since 2006 because of a reported toxicity, the drug of choice was liposomal amphotericin B. As recommended by the Ministry of Health, this report emphasizes the need for HIV patients living in VL endemic areas to include this parasitosis in their follow-up protocol, particularly after the first infection of VL.

Diagnosis of visceral leishmaniasis: the sensitivities and specificities of traditional methods and a nested PCR assay

In the present study, 67 patients suspected to be cases of visceral leishmaniasis (VL) were each checked for leishmanial infection by the microscopical evaluation of various biological specimens, in-vitro culture, serology and an assay based on nested PCR. Most (35) of the subjects were immunocompetent (IC) but 32 were immunodeficient (ID) as the result of HIV infection (18 cases), treatment to prevent transplanted organs being rejected (six) or haematological malignancies (eight). Forty-one (61.2%) of the subjects (19 IC subjects, 12 HIV-positive patients, four transplant patients and six patients with malignancies) were considered true cases of VL. For the IC subjects, only the production and microscopical examination of leucocytoconcentrates and cultures of Buffy coats gave sensitivities of <80%, the results of the other methods showing higher sensitivities and almost perfect agreement with the 'gold-standard' diagnoses. For the ID subjects, however, only the serological tests and the PCR gave reasonable sensitivities (of >80%). For the initial diagnosis of leishmaniasis in ID patients, IFAT and western blots may be useful, as, among the present ID patients, they gave sensitivities (of 80.9% and 88.2%, respectively) that were almost as high as that for the PCR, and specificities of 100%. In the diagnosis of VL in either IC or ID patients, the assay based on a nested PCR appeared to be particularly reliable, with sensitivities of 88.9% and 95.2%, respectively, and a specificity of 100% in both groups of patients. The testing of bone-marrow aspirates by PCR revealed very few VL cases who were not found positive when samples of their peripheral blood were checked in the same assay. For both IC and ID subjects therefore, the use of the PCR-based method to test samples of peripheral blood (which can be collected much more easily than bone-marrow aspirates and with much less pain for the subject) is recommended.

A century of leishmaniasis in Alpes-Maritimes, France

A century of publications on leishmaniasis in Alpes-Maritimes, in southern France, is here reviewed. Autochtonous human and canine leishmaniasis were first recognised in this département, which lies by the Mediterranean Sea and near the Italian border, in 1918 and 1925, respectively. The parasite responsible for the leishmaniasis, Leishmania infantum, is transmitted by Phlebotomus perniciosus and P. ariasi. The human leishmaniasis is zoonotic, with domestic dogs acting as the main 'reservoir' hosts. In prospective surveys over the last two decades, a mean of 12% of the domestic dogs checked in Alpes-Maritimes have been found seropositive for L. infantum but only about 50% of the seropositive animals showed any clinical signs of infection at the time of the surveys. During the last 30 years, 178 cases of human visceral leishmaniasis have been recorded in the area. Such cases are sporadic and often opportunistic, occurring predominantly in children (29% of the 178 cases) or HIV-positive subjects (31%). Recently, it has been demonstrated that, in Alpes-Maritimes, approximately 20% of those found seropositive in leishmanin skin tests are asymptomatic carriers, with amastigotes in their peripheral blood.

HIV and the transmission ofLeishmania

In many countries, Leishmania/HIV co-infection is now changing the epidemiology of visceral leishmaniasis. The levels of transmission of the parasites causing such leishmaniasis were previously dependent on the conventional zoonotic cycle, in which sandflies transmitted the parasites from infected canids to other canids or humans. The co-infection, however, has led not only to marked increases in the sandfly transmission of the parasites from immunodepressed individuals directly to other humans but also, probably, to artificial transmission between immunodepressed intravenous-drug users, as the result of needle sharing.

The diagnostic accuracy of serologic and molecular methods for detecting visceral leishmaniasis in HIV infected patients: meta-analysis

Background

Human visceral leishmaniasis (VL), a potentially fatal disease, has emerged as an important opportunistic condition in HIV infected patients. In immunocompromised patients, serological investigation is considered not an accurate diagnostic method for VL diagnosis and molecular techniques seem especially promising.

Objective

This work is a comprehensive systematic review and meta-analysis to evaluate the accuracy of serologic and molecular tests for VL diagnosis specifically in HIV-infected patients.

Methods

Two independent reviewers searched PubMed and LILACS databases. The quality of studies was assessed by QUADAS score. Sensitivity and specificity were pooled separately and compared with overall accuracy measures: diagnostic odds ratio (DOR) and symmetric summary receiver operating characteristic (sROC).

Results

Thirty three studies recruiting 1,489 patients were included. The following tests were evaluated: Immunofluorescence Antibody Test (IFAT), Enzyme linked immunosorbent assay (ELISA), immunoblotting (Blot), direct agglutination test (DAT) and polimerase chain reaction (PCR) in whole blood and bone marrow. Most studies were carried out in Europe. Serological tests varied widely in performance, but with overall limited sensitivity. IFAT had poor sensitivity ranging from 11% to 82%. DOR (95% confidence interval) was higher for DAT 36.01 (9.95–130.29) and Blot 27.51 (9.27–81.66) than for IFAT 7.43 (3.08–1791) and ELISA 3.06 (0.71–13.10). PCR in whole blood had the highest DOR: 400.35 (58.47–2741.42). The accuracy of PCR based on Q-point was 0.95; 95%CI 0.92–0.97, which means good overall performance.

Conclusion

Based mainly on evidence gained by infection with Leishmania infantum chagasi, serological tests should not be used to rule out a diagnosis of VL among the HIV-infected, but a positive test at even low titers has diagnostic value when combined with the clinical case definition. Considering the available evidence, tests based on DNA detection are highly sensitive and may contribute to a diagnostic workup.

Human visceral leishmaniasis (VL), a potentially fatal disease, has emerged as an important opportunistic condition in HIV infected patients. In immunocompromised patients, serological investigation is considered not an accurate diagnostic method for VL diagnosis and molecular techniques seem especially promising. Demonstration of Leishmania parasites in bone marrow aspirate or in other biologic specimen, either by visualization or culture, remains the most reliable diagnostic technique in the setting of HIV co-infection. However, these tests are difficult to perform in rural areas and some of them are invasive and carry a risk of complication. This work is a systematic review to evaluate the accuracy of serologic and molecular tests for VL diagnosis in HIV-infected patients. Two reviewers searched the literature, evaluating quality of studies and comparing performance of diagnostic tests. Thirty three studies were included. Most studies were carried out in Europe. Serological tests varied in performance, but with overall limited sensitivity. Based on the evidence, serological tests should not be used to rule out a diagnosis of VL among HIV-patients, but a positive test at even low titers has diagnostic value when combined with the clinical case definition. Tests based on DNA detection are highly sensitive and may contribute to a diagnostic workup.

Epidemiology of leishmaniasis in Spain based on hospitalization records (1997-2008)

All the records from the Spanish information system for hospital data of patients diagnosed with leishmaniasis during a 12-year period (1997-2008) were studied. The 2,028 individuals were hospitalized because of leishmaniasis, as indicated by the principal diagnostic code. The average hospitalization rate was 0.41/100,000 inhabitants. One-third of them were co-infected with human immunodeficiency virus (HIV). The incidence of hospitalization in the adult population with leishmaniasis co-infected with HIV increased with age, peaked at 35-39 years of age and subsequently declined. In the pediatric population, all leishmaniasis cases occurred in HIV-negative children. Incidence of hospitalizations was highest in Madrid and in the Mediterranean coast. The cost per inpatient hospital care was $9,601 corresponding to an annual direct cost of more than $1.5 million for inpatient care alone. The economical burden of leishmaniasis is not neglectable and in the 12-year study period it represented more than $19 million.

New challenges in the epidemiology and treatment of visceral leishmaniasis in periurban areas

Visceral leishmaniasis [VL] represents a major public health problem in many areas of the world. This review focuses on the impact of periurbanization on the epidemiology and treatment of VL, using Brazil as an example. VL continues to be mostly a disease of poverty with impact on families. However, the disease has expanded in Latin America, with foci reported as far south as Argentina. There is an increasing overlap of Leishmania infantum chagasi and HIV infections and other immunosuppressive conditions, resulting in VL emerging as an opportunistic infection. This new setting poses new challenges for VL disease control and patient management.

Importance of worldwide asymptomatic carriers of Leishmania infantum (L. chagasi) in human

Leishmaniasis due to Leishmania infantum (syn. L. chagasi) infection is a zoonotic disease present mainly in Mediterranean basin, central Asia and Brazil. Besides a limited number of human cases of clinical visceral leishmaniasis, a great number of infections remains asymptomatic. In this review, the prevalence of asymptomatic carriers of L. infantum was evaluated worldwide using parasitological methods or indirect testing such as a skin test or serology. The consequences of the presence of asymptomatic carriers on parasite transmission by blood donation or the development of clinical visceral leishmaniasis in immunocompromised individuals and its possible role as reservoir are discussed.

Leishmaniasis: new insights from an old and neglected disease

Leishmaniases are a clinically heterogeneous group of diseases caused by protozoa of the genus Leishmania. There is growing evidence that the true incidence of the disease is underestimated, especially in hyperendemic regions. Moreover, climate changes together with the increasing movement of humans and animals raise concerns about the possible introduction of Leishmania infection in previously spared areas. The disease is emerging in immunocompromised patients undergoing bone marrow or solid organ transplantation or treatment with biologic drugs. Furthermore, the deployment of military troops and travel to endemic areas are associated with the observation of a growing number of patients with cutaneous disease. Improvement in diagnostic methods, both in the field and in specialized laboratories, has been obtained through the implementation of molecular amplification methods and using the rK39 antigen as the substrate. Finally, new therapeutic approaches are gaining attention, such as the use of miltefosine for cutaneous leishmaniasis and paromomycin for visceral leishmaniasis, as well as the use of various antileishmanial drugs in combination.

Signs of an in situ inflammatory reaction in scars of human American tegumentary leishmaniasis

Skin inflammation plays an important role during the healing of American tegumentary leishmaniasis (ATL), the distribution of cells in active lesions may vary according to disease outcome and parasite antigens in ATL scars have already been shown. We evaluated by immunohistochemistry, 18 patients with 1- or 3-year-old scars and the corresponding active lesions and compared them with healthy skin. Small cell clusters in scars organized as in the active lesions spreaded over the fibrotic tissue were detected, as well as close to vessels and cutaneous glands, despite a reduction in the inflammatory process. Analysis of 1-year-old scar tissue showed reduction of NOS2, E-selectin, Ki67, Bcl-2 and Fas expression. However, similar percentages of lymphocytes and macrophages were detected when compared to active lesions. Only 3-year-old scars showed reduction of CD3(+), CD4(+) and CD8(+)T cells, in addition to reduced expression of NOS2, E-selectin, Ki67 and BCl-2. These results suggest that the pattern of cellularity of the inflammatory reaction observed in active lesions changes slowly even after clinical healing. Analysis of 3-year-old scars showed reduction of the inflammatory reaction as demonstrated by decrease in inflammatory cells and in the expression of cell-activity markers, suggesting that the host-parasite balance was only established after that period.

[Leishmaniases in France: an update]

Leishmaniases are parasitic diseases due to a flagellate protozoan of the genus Leishmania. They are transmitted from mammal to mammal by the bite of an arthropod vector: a female sandfly. Among the different clinical presentations, the zoonotic visceral leishmaniasis (ZVL) is due to Leishmania infantum. Dogs are the reservoir and can develop a deadly disease. ZVL is described in China, Pakistan, Latin America and in the Mediterranean region, particularly in the South of France. In recent years, many asymptomatic carriers have been described. Despite the fact that cases in immunocompromised adults are the majority, the classic Mediterranean ZVL in young children is still observed. The classic triad of symptoms is: fever, pallor, splenomegaly and hepatomegaly in half of the cases. The biological orientation is a low blood count (anemia, leuconeutropenia, and thrombocytopenia) and an inflammatory syndrome. Serological tests are useful, but the diagnosis is made by the identification of the parasite in a bone marrow sample. Today, the treatment is done by the liposomal amphotericin B (AmBisome) and the total dose must to be 20 mg/kg.

Virulence attenuation of a UDP-galactose/N-acetylglucosamine beta1,4 galactosyltransferase expressing Leishmania donovani promastigote

Protozoan parasites of the genus Leishmania are the causative agent of leishmaniasis, a disease whose manifestations in humans range from mild cutaneous lesions to fatal visceral infections. Human visceral leishmaniasis is caused by Leishmania donovani. Long-term culture in vitro leads to the attenuation of the parasite. This loss of parasite virulence is associated with the expression of a developmentally regulated UDP-Galactose/N-acetylglucosamine beta 1-4 galactosyltransferase and galactose terminal glycoconjugates as determined by their agglutination with the pea nut agglutinin (PNA). Thus, all promastigotes passaged for more than 11 times were 100% agglutinated with PNA, and represent a homogeneous population of avirulent parasites. Identical concentrations of PNA failed to agglutinate promastigotes passaged for < or =5 times. These PNA(-) promastigotes were virulent. Promastigotes passaged from 5 to 10 times showed a mixed population. The identity of populations defined by virulence and PNA agglutination was confirmed by isolating PNA(+) avirulent and PNA(-) virulent clones from the 7th passage promastigotes. Only the PNA(+) clones triggered macrophage microbicidal activity. The PNA(+) clones lacked lipophosphoglycan. Intravenous administration of [(14)C] galactose-labeled parasite in BALB/c mice resulted in rapid clearance of the parasite from blood with a concomitant accumulation in the liver. By enzymatic assay and RT-PCR we have shown the association of a UDP-Galactose/N-acetylglucosamine beta1,4 galactosyltransferase with only the attenuated clones. By immunofluorescence we demonstrated that the enzyme is located in the Golgi apparatus. By western blot analysis and SDS-PAGE of the affinity-purified protein, we have been able to identify a 29 KDa galactose terminal protein from the avirulent clones.

Leishmania major infection in a patient with visceral leishmaniasis: treatment with Amphotericin B

We have reported an acute form of visceral leishmaniasis, which was caused by Leishmania major, in Southern Iran. The parasite was isolated from a 30-year-old man living in Bushehr Province, Southern Iran, and an endemic region of kala-azar in south of Iran. The patient had typical clinical signs of Mediterranean kala-azar, and besides parasitological, biochemical, and immunological findings confirming diagnosis of visceral leishmaniasis, the agent was identified as L. major using Nested polymerase chain reaction. The patient was treated successfully with Amphotericin B during a 1-month period.

Consequences of the natural propensity of Leishmania and HIV-1 to target dendritic cells

Recent studies have shown that both Leishmania and HIV type-1 (HIV-1) hijack dendritic cell (DC) functions to escape immune surveillance using an array of elaborate strategies. Leishmania has developed a variety of adaptations to disrupt cellular defense mechanisms, whereas HIV-1 targets DCs to achieve a more efficient dissemination. The capacity of Leishmania and HIV-1 to target DCs through a common cell-surface molecule, namely DC-SIGN (dendritic cell specific ICAM-3-grabbing non-integrin), points to a possible dangerous liaison between these two pathogens. This review explores our knowledge of how Leishmania and HIV-1 interact dynamically with DCs, and how they exploit this cell type for their reciprocal benefit.

Parasitic central nervous system infections in immunocompromised hosts: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis

Immunosuppression associated with HIV infection or following transplantation increases susceptibility to central nervous system (CNS) infections. Because of increasing international travel, parasites that were previously limited to tropical regions pose an increasing infectious threat to populations at risk for acquiring opportunistic infection, especially people with HIV infection or individuals who have received a solid organ or bone marrow transplant. Although long-term immunosuppression caused by medications such as prednisone likely also increases the risk for acquiring infection and for developing CNS manifestations, little published information is available to support this hypothesis. In an earlier article published in Clinical Infectious Diseases, we described the neurologic manifestations of some of the more common parasitic CNS infections. This review will discuss the presentation, diagnosis, and treatment of the following additional parasitic CNS infections: malaria, microsporidiosis, leishmaniasis, and African trypanosomiasis.

A2 gene of Old World cutaneous Leishmania is a single highly conserved functional gene

BACKGROUND

Leishmaniases are among the most proteiform parasitic infections in humans ranging from unapparent to cutaneous, mucocutaneous or visceral diseases. The various clinical issues depend on complex and still poorly understood mechanisms where both host and parasite factors are interacting. Among the candidate factors of parasite virulence are the A2 genes, a family of multiple genes that are developmentally expressed in species of the Leishmania donovani group responsible for visceral diseases (VL). By contrast, in L. major determining cutaneous infections (CL) we showed that A2 genes are present in a truncated form only. Furthermore, the A2 genomic sequences of L. major were considered subsequently to represent non-expressed pseudogenes 1. Consequently, it was suggested that the structural and functional properties of A2 genes could play a role in the differential tropism of CL and VL leishmanias. On this basis, it was of importance to determine whether the observed structural/functional particularities of the L. major A2 genes were shared by other CL Leishmania, therefore representing a proper characteristic of CL A2 genes as opposed to those of VL isolates.

METHODS

In the present study we amplified by PCR and sequenced the A2 genes from genomic DNA and from clonal libraries of the four Old World CL species comparatively to a clonal population of L. infantum VL parasites. Using RT-PCR we also amplified and sequenced A2 mRNA transcripts from L. major.

RESULTS

A unique A2 sequence was identified in Old World cutaneous Leishmania by sequencing. The shared sequence was highly conserved among the various CL strains and species analysed, showing a single polymorphism C/G at position 58. The CL A2 gene was found to be functionally transcribed at both parasite stages.

CONCLUSION

The present study shows that cutaneous strains of leishmania share a conserved functional A2 gene. As opposed to the multiple A2 genes described in VL isolates, the CL A2 gene is unique, lacking most of the nucleotide repeats that constitute the variable region at the 5'end of the VL A2 sequences. As the variable region of the VL A2 gene has been shown to correspond to a portion of the protein which is highly immunogenic, the present results support the hypothesis of a possible role of the A2 gene in the differential tropism of CL and VL leishmania parasites.

Disseminated cutaneous leishmaniasis after visceral disease in a patient with AIDS

Leishmaniasis is emerging as a common and serious opportunistic disease for patients with HIV infection. Almost all cases of HIV-Leishmania coinfection have been described in Mediterranean countries and they occur with various clinical presentations, ranging from typical visceral forms to asymptomatic or atypical cases, including cutaneous and mucocutaneous leishmaniasis. Pentavalent antimony compounds have been the mainstays of antileishmanial therapy for half a century and new lipid formulations of amphotericin B seem reliable, but the most effective treatment remains unknown. We describe a patient who was HIV infected and an intravenous drug user, with an unusual disseminated cutaneous leishmaniasis, after an initial visceral disease and after a 13-month maintenance treatment with liposomal amphotericin. The severe concurrent immunosuppression probably played an essential role in leading to this atypical cutaneous form, characterized by diffuse, nonulcerated, nonscabby maculopapular lesions.

Aging and infectious diseases in the developing world

Although demographic aging does not remain restricted to industrialized countries, the medical challenge arising from the aging population will be distinct in the developing world. This is particularly true with respect to infectious diseases, which have a distinct spectrum in the elderly population, as well as a greater overall relevance in the developing world. Tropical diseases have a specific presentation and epidemiology in elderly patients. Infectious diseases with a worldwide distribution impact elderly patients in the developing world in a specific manner, which is most obvious with respect to human immunodeficiency virus and tuberculosis but is also true with respect to "trivial" manifestations of infection, such as diarrhea and pneumonia. Malnutrition contributes in a major way to the immunodeficiency of elderly patients in the developing world. Poorly controlled use of antimicrobial drugs leads to multidrug-resistant microorganisms, which, together with the limited resources available for drug treatment, makes appropriate treatment of infections in elderly patients in developing countries very difficult. Infections in elderly patients will have an increasing impact on the public health and economy of developing countries.

[Liposomal amphotericin B in secondary prophylaxis of visceral leishmaniasis in HIV-infected patients: report of five clinical cases]

Treatment of visceral leishmaniasis in HIV patients encounters inefficacy and relapse due to drug resistance, toxicity and immunodepression. Our goal was to evaluate treatment of these patients by liposomal amphotericin B (L-AmB). Since 1998, five clinical files were exploitable out of 13 patients. Protocols used bolus doses ranging between 2.9 and 4.1 mg/kg dispatched on 5-24 days, followed by maintenance dose ranging from 2.7 to 3.8 mg/kg every 15 days. Attack treatment involved high bolus dose (cumulated doses ranging from 60 to 86 mg/kg at day 30) and allowed favorable clinical and biological results with healing in four patients. Secondary prophylaxis with L-AmB has been efficacious and well tolerated in three patients. Although literature and study results cannot indicate a standard therapeutic care in these patients, an initial treatment by L-AmB at doses higher than marketing-approved doses with a secondary prophylaxis by L-AmB associated with an antiretroviral treatment seem to be major asset in order to obtain healing. Expanding this study to a multicenter trial should allow to better define the frequency and duration of the secondary prophylaxis and to evaluate the risk of therapeutic escape as well as the life-span increase.

The biological diagnosis of leishmaniasis in HIV-infected patients

This review emphasises the particular difficulties encountered in confirming a suspected case of cutaneous or visceral leishmaniasis when that case is co-infected with HIV. HIV infection appears to have a more profound impact on the development of visceral leishmaniasis than on the evolution of the purely cutaneous disease. The various techniques available for immunological, parasitological and molecular diagnosis are presented and evaluated. The value of serodiagnosis for the detection of antileishmanial antibodies is in part dependent on the antigens used. Western blots may have a use not only in diagnosis but also in predicting the cases of HIV infection that are at most risk of developing symptomatic leishmaniasis. The presence of leishmanial parasites may still only be demonstrated incontrovertibly by the microscopical examination of smears or the culture of blood or biopsy samples. The use of cultures not only permits diagnosis but also detailed study of the parasites. The potential use of PCR in diagnosis is explored and related to other possible tests. A recommended, standardized procedure for the diagnosis of leishmaniasis in HIV-infected patients is presented.

Visceral leishmaniasis in those infected with HIV: clinical aspects and other opportunistic infections

Cases of visceral leishmaniasis (VL) in HIV-positive individuals have been reported from most areas of the world where the geographical distributions of the two infections overlap. The majority of the co-infected cases that have been recorded, however, live around the Mediterranean basin. In these subjects, the length of the incubation period of VL is presumably very short, particularly in those who have severe immunodepression. At diagnosis, almost all cases of VL/HIV co-infection have been found to have fewer than 200 CD4+ cells/microl blood, and about 50% meet the AIDS-defining criteria during their first episode of VL. The clinical manifestations of VL in HIV-infected individuals may be similar to those seen in HIV-negative cases; fever, pancytopenia and hepato-splenomegaly, for example, are found in 75% of all the HIV-positive cases. Following the dissemination of the parasites, however, the HIV-positive cases may develop unusual, multi-organ pathology. Almost all the cases of co-infection are very prone to VL relapses, even after carefully managed antileishmanial treatment. The opportunistic infections that are often seen in HIV-positives frequently develop during VL episodes, the signs and symptoms of the leishmaniasis then confusingly overlapping with those of the other infections.

The impact of highly active antiretroviral therapy (HAART) on visceral leishmaniasis in Spanish patients who are co-infected with HIV

Clinicians in Madrid have been observing and treating HIV-positive patients with visceral leishmaniasis (VL) for over a decade. As their records cover some of the co-infection cases that occurred before and after highly active antiretroviral therapy (HAART) was introduced into Spain, retrospective analysis of the records has allowed some of the effects of HAART on local VL to be determined. Encouragingly, HAART appears to have decreased the annual incidence of VL among local AIDS cases, from 4.81 cases/100 to just 0.8 case/100 (P <0.0005), a first episode of VL now appearing only when there is obvious HAART failure. Unfortunately, it does not seem to be very good at preventing VL relapses; within 24 months of antileishmanial treatment, 70% of patients who were receiving HAART had such relapses. The mean time between antileishmanial treatment and VL relapse was, however, longer when HAART was used than when it was not (20 v. 13 months). In those receiving HAART, relapses of the VL often occurred despite increasing CD4+ cell counts and undetectable HIV loads, indicating that successful treatment of the viral infection is insufficient to prevent the relapse of the leishmaniasis. These results are in general agreement with other observations made in Spain. VL relapses are possible and even frequent in HIV-positives who have no more than 200 CD4+ cells/microl, but secondary prophylaxis to prevent VL relapses may be safely suspended if a CD4+ count of >200 cells/microl can be maintained using HAART. VL also seems to hamper the immunological recovery of the HIV-positive, although HAART appears to have little effect on the clinical manifestations of VL.

The pathogenesis of Leishmania/HIV co-infection: cellular and immunological mechanisms

The intracellular protozoan parasites of the genus Leishmania have been recognized as opportunistic pathogens in immunosuppressed individuals, including those infected with human immunodeficiency virus type-1 (HIV-1). Leishmaniasis and AIDS overlap in several sub-tropical and tropical regions around the world, including the Mediterranean area. In 1994, 3%-7% of HIV-1-infected individuals in southern Europe developed visceral leishmaniasis. In humans, interestingly, both HIV-1 and Leishmania interact with, invade, and multiply within cells of myeloid or lymphoid origin. The combined modulation of Leishmania - and HIV-1-related pathogenesis in the co-infected cases is therefore probably a realistic goal. In the light of the recent demonstration that L. donovani can up-regulate HIV-1 replication, both in monocytoid and lymphoid cells in vitro and in co-infected individuals, it is clear from the epidemiological data available that Leishmania can probably act as a powerful co-factor in the pathogenesis of HIV-1 infection. In those who are co-infected, complex mechanisms involving cytokine secretion and cellular-signalling events play pivotal roles in the Leishmania-mediated activation and pathogenesis of HIV-1. An overview of the recent findings concerning this Leishmania/HIV-1 interaction is presented here.

Real-time PCR assay for clinical management of human immunodeficiency virus-infected patients with visceral leishmaniasis

To evaluate the usefulness of a real-time PCR for Leishmania DNA in the diagnosis and follow-up of patients with human immunodeficiency virus type 1 (HIV-1) and Leishmania coinfection, Leishmania DNA levels were measured in whole peripheral blood from 25 HIV-infected patients with clinical features suggestive of visceral leishmaniasis. Leishmania DNA was detected in 10 of 25 patients with microscopically confirmed visceral leishmaniasis and in none of those without this disease. Following treatment with liposomal amphotericin B, a clinical response was observed in 9 of 10 patients, in association with significantly decreased parasite loads. Seven patients relapsed clinically a median of 110 days after the end of treatment, in association with substantial increases in Leishmania DNA levels. Leishmania DNA levels correlated with the clinical course of visceral leishmaniasis, and their measurement at diagnosis and during and after treatment seems to be useful in the clinical management of HIV-infected patients with this disease.

Leishmania major and HIV co-infection in Burkina Faso

The incidence of cutaneous leishmaniasis (CL) has increased in Ouagadougou, Burkina Faso since 1996. A study was carried out from September to November 2000 to determine the impact of HIV on this outbreak. Of 74 CL patients, 10 were co-infected with HIV. The percentage of CL in patients positive for HIV was slightly higher than the percentage of HIV patients in Ouagadougou. However, the study showed that HIV infection did not increase the risk of CL infection.

Effect of highly active antiretroviral therapy on the incidence and clinical manifestations of visceral leishmaniasis in human immunodeficiency virus-infected patients

This study analyzes the effect of highly active antiretroviral therapy (HAART) on visceral leishmaniasis in human immunodeficiency virus-infected individuals. We describe 66 episodes diagnosed in our hospital from 1994 through 2000 (35 episodes in patients who were not receiving HAART and 31 episodes in patients who were receiving HAART). Since HAART became available, the incidence of visceral leishmaniasis has significantly decreased and the number of first episodes has decreased, although the number of relapses is increasing.

A novel Leishmania infantum nuclear phosphoprotein Lepp12 which stimulates IL1-beta synthesis in THP-1 transfectants

BACKGROUND

We report cloning and characterization of a novel Leishmania infantum protein which we termed Lepp12, and we examine its possible implication in the interference with intramacrophage signaling pathways.

RESULTS

The protein Lepp12 contains 87 amino acid sequence and exhibits 5 potential phosphorylation sites by protein kinase C (PKC). Recombinant GST-Lepp12 is phosphorylated in vitro by exogenous PKC and by PKC-like activities present in promastigote and in the myelomonocytic THP-1 cell line, indicating that at least one phosphorylation site is functional on the recombinant Lepp12. The natural Lepp12 protein is present in L. infantum promastigotes, as evidenced using specific anti-Lepp12 antibodies produced by immunopurification from acute phase VL patient sera. Interestingly, human patient sera are strongly reactive with GST-Lepp12, demonstrating immunogenic properties of Lepp12 in man, but no immune response to Lepp12 is detectable in experimentally infected animals. When isolated from promastigotes, Lepp12 migrates as two species of apparent MW of 18.3 kDa (major) and 14 kDa (minor), localizes in the nuclear fraction and appears constitutively phosphorylated. Natural Lepp12 is phosphorylable in vitro by both exogenous PKC and PKC-like activity present in THP-1 extracts. The intracellular Lepp12 transfected into THP-1 cells activates these cells to produce IL-1beta and induces an enhancing effect on PMA stimulated IL-1beta synthesis, as demonstrated using GST-Lepp12 transfectants.

CONCLUSIONS

Together these results indicate that Lepp12 represents a substrate for PKC or other PKC-like activities present in the promastigote form and the host cell and therefore may interfere with signal transduction pathways involving PKC.

Leishmaniasis in HIV infection

Herein we review the particular aspects of leishmaniasis associated with HIV infection. The data in this review are mainly from papers identified from PubMed searches and from papers in reference lists of reviewed articles and from the authors' personal archives. Epidemiological data of HIV/Leishmania co-infection is discussed, with special focus on the influence of Highly Active Antiretroviral Therapy (HAART) on incidence of leishmaniasis and transmission modalities. Microbiological characteristics, pathogenesis, clinical presentation and specific treatment of the co-infection are also presented.

Recent understanding in the treatment of visceral leishmaniasis

Visceral leishmaniasis (VL) is a severe disease associated with infection of the reticuloendothelial system by Leishmania species. The infection is acquired through sandfly bites. Recent large scale epidemics of VL in east Africa and India and the emergence of a HIV epidemic make VL a priority for the World Health Organization. Pentavalent antimonials have been cornerstone of treatment for the last six decades. The appearance of antimonial-resistance and the development of lipid formulations of amphotericin B have changed the pattern of VL treatment. Within the past five years, miltefosine has been demonstrated as the first effective and safe oral treatment against VL. The price of miltefosine is yet to be determined. However, miltefosine will certainly be cheaper than lipid formulations of amphotericin B, which are beyond the financial capacity of the poor countries. Because it can be administered orally, miltefosine is suited for the treatment of large number of patients who get affected during epidemics, particularly in regions where the parasites are resistant to the currently used agents. Here, we recommend different treatment schedules according to the resistance pattern and the region-specific socio-economical and cultural factors.

Presence of Leishmania organisms in specific and non-specific skin lesions in HIV-infected individuals with visceral leishmaniasis

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.

Opsonization modulates Rac-1 activation during cell entry by Leishmania amazonensis

Lesions caused by Leishmania amazonensis normally heal, but relapses occur due to parasite persistence in host tissues. It has been proposed that infection of fibroblasts plays an important role in this process by providing the parasites with a safe haven in which to replicate. However, most previous studies have focused on the entry of Leishmania into macrophages, a process mediated by serum opsonins. To gain insight into a possible role of nonopsonic entry in the intracellular persistence of amastigotes, we examined the invasion of Chinese hamster ovary (CHO) cells. Amastigotes entered CHO cells by a cytochalasin D, genistein, wortmannin, and 2,3-butanedione monoxime-sensitive pathway and replicated within phagolysosomes. However, unlike most phagocytic processes described to date, amastigote internalization in CHO cells involved activation of the GTPases Rho and Cdc42 but not Rac-1. When uptake was mediated by fibronectin or when amastigotes were opsonized with immunoglobulin G and internalized by Fc receptor-expressing CHO cells, Rac-1 activation was restored and found to be required for parasite internalization. Given the essential role of Rac in assembly of the respiratory burst oxidase, invasion through this nonopsonic, Rac-1-independent pathway may play a central role in the intracellular survival of Leishmania in immune hosts.

Leishmaniasis: recognition and management with a focus on the immunocompromised patient

Leishmaniasis is a protozoan disease whose clinical manifestations depend both on the infecting species of Leishmania and the immune response of the host. Transmission of the disease occurs by the bite of a sandfly infected with Leishmania parasites. Infection may be restricted to the skin in cutaneous leishmaniasis (CL), to the mucous membranes in mucosal leishmaniasis or spread internally in visceral leishmaniasis (VL). In the last 2 decades, leishmaniasis, especially VL, has been recognized as an opportunistic disease in immunocompromised patients, particularly those infected with HIV. Leishmaniasis is characterized by a spectrum of disease phenotypes that correspond to the strength of the host's cell-mediated immune response. Both susceptible and resistant phenotypes exist within human populations. Clinical cutaneous disease ranges from a few spontaneously-healing lesions, to diffuse external or internal disease, to severe mucous membrane involvement. Spontaneously-healing lesions are associated with positive antigen-specific T cell responsiveness, diffuse cutaneous and visceral disease with T cell non-responsiveness, and mucocutaneous disease with T cell hyperresponsiveness. Current research is focused on determining the extent to which this spectrum of host response is genetically determined. In endemic areas, diagnosis is often made on clinical grounds alone including: small number of lesions; on exposed areas; present for a number of months; resistant to all types of attempted treatments; and usually no pain or itching. Multiple diagnostic techniques are available. When evaluating treatment, the natural history of leishmaniasis must be considered. Lesions of CL heal spontaneously over 1 month to 3 years, while lesions of mucocutaneous and VL rarely, if ever, heal without treatment. Consequently, all the latter patients require treatment. Therapy is not always essential in localized CL, although the majority of such patients are treated. Patients with lesions on the face or other cosmetically important areas are treated to reduce the size of the resultant scar. In addition, the species of parasite should be identified so that infection with Leishmania braziliensis and Leishmania panamensis can be treated to reduce the risk of development of mucocutaneous disease. Treating patients with Leishmania and HIV co-infection requires close monitoring for effectiveness of treatment, especially because of the high relapse rates. Proven treatments include: antimonials, pentamidine, amphotericin B, interferon with antimony. Treatments where current clinical experience is too limited include: allopurinol, ketoconazole, itraconazole, immunotherapy, rifampin, dapsone, localized heat, paromomycin ointment and cryotherapy. Investigational treatments include: WR6026, liposomal amphotericin and miltefosine. In addition, vaccines for leishmaniasis are being investigated in clinical trials.

A nested polymerase chain reaction for diagnosis and follow-up of human visceral leishmaniasis patients using blood samples

A nested polymerase chain reaction (PCR) assay for the diagnosis of human visceral leishmaniasis (VL) due to Leishmania infantum infection was developed using primers selected from the parasite's genomic deoxyribonucleic acid (DNA). The assay, which is based on the use of leucocytes separated from blood samples by Ficoll-Paque centrifugation, was compared with culture in vitro. Blood samples were collected from 17 patients in Spain with a history of clinical VL, 15 of whom were also infected with human immunodeficiency virus (HIV) (13 samples during the VL episode and 31 samples during post-treatment monitoring) and one sample was collected from each of 28 patients with HIV infection and fever but no history of VL. The nested PCR using blood detected all the cases of parasitologically confirmed, clinically active VL, while culture detected 92%. The nested PCR detected Leishmania DNA in 18% of the HIV-infected patients with fever and no history of VL, none of whom gave a positive culture. Follow-up examination of the VL patients by nested PCR and culture demonstrated the persistence of L. infantum in blood for a long time after treatment.