Leishmania and human immunodeficiency virus coinfection: the first 10 years

Urine as a promising sample for Leishmania DNA extraction in the diagnosis of visceral leishmaniasis - a review

Visceral leishmaniasis is a serious and debilitating infection with high fatality rate in tropical and subtropical countries. As clinical symptoms of visceral leishmaniasis are not so specific, confirmatory diagnostic methods with high sensitivity and specificity are needed. Noninvasive methods have been developed using urine as a clinical sample for visceral leishmaniasis diagnosis. In fact, there is a clear correlation between kidney impairment and Leishmania DNA in urine. However, it has been proved that Leishmania nucleic acid may also be isolated from patients without any sign of renal involvement. Even though urine has become a promissing biological sample, it is still not widely used due to several issues, such as (i) incomprehension of the whole renal pathophysiology process in visceral leishmaniasis, (ii) presence of many amplification inhibitors in urine, and (iii) lack of an efficient urinary DNA extraction method. In this article, we performed a literature review to bring a new perspective for Leishmania DNA isolation in urine.

Particle velocity controls phase transitions in contagion dynamics

Interactions often require the proximity between particles. The movement of particles, thus, drives the change of the neighbors which are located in their proximity, leading to a sequence of interactions. In pathogenic contagion, infections occur through proximal interactions, but at the same time, the movement facilitates the co-location of different strains. We analyze how the particle velocity impacts on the phase transitions on the contagion process of both a single infection and two cooperative infections. First, we identify an optimal velocity (close to half of the interaction range normalized by the recovery time) associated with the largest epidemic threshold, such that decreasing the velocity below the optimal value leads to larger outbreaks. Second, in the cooperative case, the system displays a continuous transition for low velocities, which becomes discontinuous for velocities of the order of three times the optimal velocity. Finally, we describe these characteristic regimes and explain the mechanisms driving the dynamics.

IL12 p35 and p40 subunit genes administered as pPAL plasmid constructs do not improve protection of pPAL-LACK vaccine against canine leishmaniasis

Leishmania infantum causes zoonotic visceral leishmaniasis (ZVL) in the Mediterranean basin and South America. The parasite has been shown to co-infect HIV patients and an outbreak in central Spain was reported in the last decade. Therfore, ZVL is a public health problem, dogs being the parasite's reservoir. We have developed a DNA vaccine based on the L. infantum activated protein kinase A receptor (LACK) using different plasmid vectors and vaccinia virus strains as vehicles. Recently, we have generated an antibiotic resistance marker-free plasmid vector called pPAL. Homologous pPAL-LACK prime-boost vaccination protects Beagle dogs as well as a heterologous plasmid-virus regime. For both reasons, pPAL improves safety. IL12 was described to trigger Th1 response through IFN-γ production in infected dogs, being a good candidate for cytokine therapy in conventional treatment-unresponsive dogs. Herein, we report a complete protection study in dogs through inoculation of genes encoding for the p35 and p40 subunits which compose canine IL12 in combination with the LACK gene. A homologous plasmid-plasmid regime using independent pPAL constructs for each gene was inoculated in a 15-day interval. The infectious challenge using L. infantum promastigotes was successful. The outcome was pPAL-LACK vaccine protection suppression by IL12 administration. The important implications of this finding are discussed in the manuscript.

Severe post-kala-azar dermal leishmaniasis successfully treated with miltefosine in an Ethiopian HIV patient

Post-kala-azar dermal leishmaniasis (PKDL) is a neglected tropical disease characterized by a dermatosis which often appears after successful treatment of visceral leishmaniasis caused by Leishmania donovani. PKDL treatment options are few and have severe limitations. In East-Africa, the standard treatment of PKDL is with daily painful potentially toxic sodium stibogluconate injections, administered for a prolonged duration of 30-60 days. In the Indian subcontinent, PKDL is mainly treated with miltefosine, a safer orally administered drug. However, in East-Africa, there is very limited experience in the use of miltefosine for treatment of severe PKDL, with only one published case report. Here we report a severe PKDL case in an Ethiopian HIV patient successfully treated with oral miltefosine (100mg/day for 28 days). Miltefosine was efficacious, safe and well tolerated, suggesting that it can play an important role in the treatment of severe PKDL also in East-African patients. Further research is warranted.

Impact of substituents on the crystal structures and anti-leishmanial activity of new homoleptic Bi(iii) dithiocarbamates

Anti-leishmanial activity of six structurally characterised new functionalised homoleptic Bi(iii) dithiocarbamate complexes having monomeric, dimeric and rare polymeric structures has been explored.

Exploiting genetic polymorphisms in metabolic enzymes for rapid screening of Leishmania infantum genotypes

Background

Leishmania infantum is the aetiological agent of visceral leishmaniasis (VL) and cutaneous leishmaniasis (CL). Numerous strains and/or zymodemes have been identified and characterized by multilocus enzyme electrophoresis (MLEE). MLEE is considered the reference method for L. infantum parasite typing and it is based upon enzyme electrophoretic mobility analysis from promastigote cultures. However, the MLEE technique is cumbersome, time-consuming and does not detect silent genetic mutations or nucleotide changes that give rise to amino acid changes that do not alter electrophoretic mobility. As a result of these difficulties, many DNA-based typing methods have been developed over the past few years. However, relative to the enzymes utilized in MLEE analysis, we observed a shortage of DNA sequences available in the GenBank database or an absolute lack of sequences belonging to specific zymodemes. The aims of the present study were to (i) implement the number of sequences coding for metabolic enzymes used in MLEE; (ii) identify polymorphisms that characterize L. infantum zymodemes most prevalent in the Mediterranean basin; and (iii) exploit these polymorphisms to develop a rapid screening test that would give results comparable with existing MLEE typing.

Results

Partial sequences of seven metabolic enzyme genes (malic enzyme, 6-phosphogluconate dehydrogenase, mitochondrial isocitrate dehydrogenase, glucose-6-phosphate isomerase, glucose-6-phosphate dehydrogenase, phosphoglucomutase and mannose phosphate isomerase) were obtained from 11 L. infantum strains. The comparison of these sequences with those obtained from GenBank allowed for the identification of a few polymorphisms that could distinguish several zymodemes. In particular, the polymorphism 390T>G in the malic enzyme gene has been exploited to develop a high-resolution melt (HRM)-based assay to rapidly differentiate the genotype 390T, associated with zymodemes MON-1, MON-72 and MON-201, evidencing a partial agreement between genotyping results and MLEE. The assay has been successfully applied to L. infantum clinical isolates and clinical samples.

Conclusions

A HRM-based assay for rapid identification of genotypes associated with the most common L. infantum zymodemes in the Mediterranean basin has been developed and its potential application in epidemiological research for L. infantum population screening, without parasite isolation and culturing, has been demonstrated.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3143-7) contains supplementary material, which is available to authorized users.

Leishmaniasis

Leishmaniasis is a poverty-related disease with two main clinical forms: visceral leishmaniasis and cutaneous leishmaniasis. An estimated 0·7-1 million new cases of leishmaniasis per year are reported from nearly 100 endemic countries. The number of reported visceral leishmaniasis cases has decreased substantially in the past decade as a result of better access to diagnosis and treatment and more intense vector control within an elimination initiative in Asia, although natural cycles in transmission intensity might play a role. In east Africa however, the case numbers of this fatal disease continue to be sustained. Increased conflict in endemic areas of cutaneous leishmaniasis and forced displacement has resulted in a surge in these endemic areas as well as clinics across the world. WHO lists leishmaniasis as one of the neglected tropical diseases for which the development of new treatments is a priority. Major evidence gaps remain, and new tools are needed before leishmaniasis can be definitively controlled.

Detection of Leishmania DNA in saliva among patients with HIV/AIDS in Trang Province, southern Thailand

Leishmaniasis is a neglected tropical disease causing opportunistic infection among patients with HIV/AIDS. The fatal form of this disease is visceral leishmaniasis (VL). DNA of Leishmania can be detected in saliva, for which the collection is noninvasive and requires little expertise. This study aimed to evaluate the sensitivity and specificity of a nested-PCR to amplify the Internal Transcribed Spacer 1 (ITS1) to detect Leishmania DNA in paired saliva and buffy coat samples of 305 Thai patients with HIV/AIDS in Trang Hospital, Trang Province, southern Thailand. For asymptomatic Leishmania infection among Thai patients with HIV/AIDS, the sensitivity and specificity of the nested-PCR-ITS1 in buffy coat were 73.9 and 100%, respectively. However, the sensitivity in saliva was 26.1% and specificity was 100%. Using the nested-PCR-ITS1, saliva and buffy coat samples showed positive agreement in only 52.0% of patients. Saliva tested results with the nested-PCR-ITS1 showed positive agreement with the Direct Agglutination Test (DAT) in 46.5% of patients. Only 12.1% of the samples showed positive agreement for Leishmania infection among all the three tests: saliva, buffy coat and DAT results. Using nucleotide sequencing, at least three species of Leishmania infection were identified in saliva, i.e., L. siamensis (n = 28), L. martiniquensis (n = 9), and L. donovani complex (n = 1). As a result, buffy coat still appears to be a better specimen to diagnose asymptomatic VL infection among individuals with HIV. However, the use of both buffy coat and saliva together as clinical specimens would increase the sensitivity of Leishmania detection.

LACK Gene's Immune Response Induced by Cocktail DNA Vaccine with IL-12 Gene Against Cutaneous Leishmaniasis in BALB/c Mice

BACKGROUND

Leishmaniasis is caused by parasitic protozoa of the genus Leishmania which is an obligate intracellular parasite in the infected host. Individuals who have been recovered from clinical leishmaniasis develop strong immunity against reinfection. DNA vaccines are the new type of vaccines that induce expression of protein eukaryotic cells. DNA vaccines can be stimulated by the cellular and humoral immune responses using one or several genes.

METHODS

A DNA vaccine containing plasmids encoding the pcLACK+pcTSA genes of Leishmania major (L. major) (MHRO/IR/75/ER) in the vicinity of IL-12 gene expression was made and then its protective efficacy in comparison with single-gene of LACK was evaluated. Also, BALB/c mice were immunized intramuscularly three times. The humoral and cellular immune responses were evaluated after immunization with pcLACK, pcLACK+pcTSA+pCAGGS-IL12, and then challenged with L. major.

RESULTS

Humoral response and IFN-γ values were significantly higher than control groups after immunization with pcLACK, pcLACK+pcTSA+pCAGGS-IL12 and challenge with L. major (p≤0.05). IL-4 values were increased in the control groups in such a way that they were remarkably higher than the pcLACK, pcLACK+pcTSA+ pCAGGS-IL12 groups (p≤0.05) after immunization and challenge with L. major.

CONCLUSION

The survival time of the immunized mice with pcLACK, pcLACK+pcTSA+ pCAGGS-IL12 groups was higher than the control groups. Then, DNA vaccine of pcLACK appeared to be likely able to induce more protection against infection with L. major in mice. Therefore, cocktail DNA is effective to enhance specific immunity.

Transcriptional Profiling of Immune-Related Genes in Leishmania infantum-Infected Mice: Identification of Potential Biomarkers of Infection and Progression of Disease

Leishmania spp. is a protozoan parasite that affects millions of people around the world. At present, there is no effective vaccine to prevent leishmaniases in humans. A major limitation in vaccine development is the lack of precise understanding of the particular immunological mechanisms that allow parasite survival in the host. The parasite-host cell interaction induces dramatic changes in transcriptome patterns in both organisms, therefore, a detailed analysis of gene expression in infected tissues will contribute to the evaluation of drug and vaccine candidates, the identification of potential biomarkers, and the understanding of the immunological pathways that lead to protection or progression of disease. In this large-scale analysis, differential expression of 112 immune-related genes has been analyzed using high-throughput qPCR in spleens of infected and naïve Balb/c mice at four different time points. This analysis revealed that early response against Leishmania infection is characterized by the upregulation of Th1 markers and M1-macrophage activation molecules such as Ifng, Stat1, Cxcl9, Cxcl10, Ccr5, Cxcr3, Xcl1, and Ccl3. This activation doesn't protect spleen from infection, since parasitic burden rises along time. This marked difference in gene expression between infected and control mice disappears during intermediate stages of infection, probably related to the strong anti-inflammatory and immunosuppresory signals that are activated early upon infection (Ctla4) or remain activated throughout the experiment (Il18bp). The overexpression of these Th1/M1 markers is restored later in the chronic phase (8 wpi), suggesting the generation of a classical "protective response" against leishmaniasis. Nonetheless, the parasitic burden rockets at this timepoint. This apparent contradiction can be explained by the generation of a regulatory immune response characterized by overexpression of Ifng, Tnfa, Il10, and downregulation Il4 that counteracts the Th1/M1 response. This large pool of data was also used to identify potential biomarkers of infection and parasitic burden in spleen, on the bases of two different regression models. Given the results, gene expression signature analysis appears as a useful tool to identify mechanisms involved in disease outcome and to establish a rational approach for the identification of potential biomarkers useful for monitoring disease progression, new therapies or vaccine development.

The Risk and Predictors of Visceral Leishmaniasis Relapse in Human Immunodeficiency Virus-Coinfected Patients in Ethiopia: A Retrospective Cohort Study

Background

East Africa, where Leishmania donovani is prevalent, faces the highest burden world-wide of visceral leishmaniasis (VL) and human immunodeficiency virus (HIV) coinfection. However, data on the risk and predictors of VL relapse are scarce. Such information is vital to target medical follow-up and interventions to those at highest risk.

Methods

We conducted a retrospective cohort study at a Médecins Sans Frontières−supported health center in northwest Ethiopia. We included adult VL-HIV coinfected patients treated for VL and discharged cured between February 2008 and February 2013. The risk of relapse was calculated using Kaplan-Meier methods, and predictors were determined using Cox regression models.

Results

Of the 146 patients included, 140 (96%) were male and the median age was 31 years. At the index VL diagnosis, 110 (75%) had primary VL, 57 (40%) were on antiretroviral therapy (ART), and the median CD4 count was 149 cells/µL. The median follow-up time after cure was 11 months, during which 44 (30%) patients relapsed. The risk of relapse was 15% at 6 months, 26% at 12 months, and 35% at 24 months. Predictors of relapse were: not being on ART at VL diagnosis, ART not initiated during VL treatment, and high tissue parasite load (parasite grade 6+) at VL diagnosis.

Conclusions

The risk of VL relapse in coinfected patients was high, particularly in those not on ART or presenting with a high tissue parasite load. These patients should be preferentially targeted for secondary prophylaxis and/or regular medical follow-up. Timely ART initiation in all coinfected patients is crucial.

Does timing of antiretroviral treatment influence treatment outcomes of visceral leishmaniasis in Northwest Ethiopia?

Background

Visceral leishmaniasis (VL) patients with HIV co-infection should receive antiretroviral treatment (ART). However, the best timing for initiation of ART is not known. Among such individuals, we assessed the influence of ART timing on VL outcomes.

Methods

A retrospective cohort study was conducted in Northwest Ethiopia among VL patients starting ART between 2008 and 2015. VL outcomes were assessed by the twelfth month of starting ART, within 4 weeks of VL diagnosis or thereafter.

Results

Of 213 VL-HIV co-infected patients with ART initiation, 96 (45.1%) had moderate to severe malnutrition, 53 (24.9%) had active TB and 128 (60.1%) had hemoglobin levels under 9 g/dL. Eighty-nine (41.8%) were already on ART before VL diagnosis, 46 (21.6%) started ART within 4 weeks, and 78 (36.6%) thereafter. Definitive cure in those starting ART within 4 weeks 59% (95% CI 43–75%) and those starting thereafter 56% (95% CI 44–68%) was not significantly different. Those starting ART before primary VL had higher 12-months mortality compared to those starting later (RR 0.6; 95% CI 0.4–0.9; p=0.012).

Conclusions

VL-HIV patients are severely ill and with serious additional comorbidities. Outcomes of HIV-VL management are unsatisfactory and early ART initiation was associated with higher mortality. Further research on the optimal timing of ART initiation, and ensuring earlier diagnosis of VL patients, with improved management of comorbidities are needed.

AIDS Clinical Research in Spain-Large HIV Population, Geniality of Doctors, and Missing Opportunities

The first cases of AIDS in Spain were reported in 1982. Since then over 85,000 persons with AIDS have been cumulated, with 60,000 deaths. Current estimates for people living with HIV are of 145,000, of whom 20% are unaware of it. This explains the still high rate of late HIV presenters. Although the HIV epidemic in Spain was originally driven mostly by injection drug users, since the year 2000 men having sex with men (MSM) account for most new incident HIV cases. Currently, MSM represent over 80% of new yearly HIV diagnoses. In the 80s, a subset of young doctors and nurses working at Internal Medicine hospital wards became deeply engaged in attending HIV-infected persons. Before the introduction of antiretrovirals in the earlier 1990s, diagnosis and treatment of opportunistic infections was their major task. A new wave of infectious diseases specialists was born. Following the wide introduction of triple combination therapy in the late 1990s, drug side effects and antiretroviral resistance led to built a core of highly devoted HIV specialists across the country. Since then, HIV medicine has improved and currently is largely conducted by multidisciplinary teams of health care providers working at hospital-based outclinics, where HIV-positive persons are generally seen every six months. Antiretroviral therapy is currently prescribed to roughly 75,000 persons, almost all attended at clinics belonging to the government health public system. Overall, the impact of HIV/AIDS publications by Spanish teams is the third most important in Europe. HIV research in Spain has classically been funded mostly by national and European public agencies along with pharma companies. Chronologically, some of the major contributions of Spanish HIV research are being in the field of tuberculosis, toxoplasmosis, leishmaniasis, HIV variants including HIV-2, drug resistance, pharmacology, antiretroviral drug-related toxicities, coinfection with viral hepatitis, design and participation in clinical trials with antiretrovirals, immunopathogenesis, ageing, and vaccine development.

Chemotherapeutics of visceral leishmaniasis: present and future developments

Treatment of Visceral Leishmaniasis (VL), a neglected tropical disease, is very challenging with few treatment options. Long duration of treatment and drug toxicity further limit the target of achieving VL elimination. Chemotherapy remains the treatment of choice. Single dose of liposomal amphotericin B (LAmB) and multidrug therapy (LAmB + miltefosine, LAmB + paromomycin (PM), or miltefosine + PM) are recommended treatment regimen for treatment of VL in Indian sub-continent. Combination therapy of pentavalent antimonials (Sbv) and PM in East Africa and LAmB in the Mediterranean region/South America remains the treatment of choice. Various drugs having anti-leishmania properties are in preclinical phase and need further development. An effective treatment and secondary prophylaxis of HIV-VL co-infection should be developed to decrease treatment failure and drug resistance.

Case Report: Diffuse Cutaneous Leishmaniasis by Leishmania infantum in a Patient Undergoing Immunosuppressive Therapy: Risk Status in an Endemic Mediterranean Area

This case report highlights the risk of severe cutaneous leishmaniasis (CL) by Leishmania infantum in patients undergoing immunosuppressant therapy who either live in an endemic area or are visiting in the transmission season. The case patient, resident in Majorca (Balearic Islands), presented 12 disseminated erythematous skin lesions, 1-6 cm in diameter, located on the scalp, cheek, umbilical region, and lower extremities 8 years after undergoing anti-tumor necrosis factor (TNF) therapy. Parasite presence in peripheral blood and high levels of specific antibodies were also observed, indicating a possible risk of CL shifting toward a visceral infection. However, once CL was diagnosed, anti-TNF therapy was discontinued and liposomal amphotericin B was administered, resulting in a complete healing of lesions, no Leishmania DNA detection in blood, and an important serological decrease in antibodies. The lack of data on the supposed epidemiological association between leishmaniasis and immunosuppressive therapy highlights the importance of implementing surveillance systems in endemic areas. No obvious relationship was found based on the data provided by the Balearic Islands Epidemiological System, in contrast with data reported in nearby endemic areas. This indicates that if the suspected association is to be clarified, greater efforts are needed to report information about concomitant diseases and therapies in leishmaniasis patients.

Clinical management of canine leishmaniosis versus human leishmaniasis due to Leishmania infantum: Putting "One Health" principles into practice

The initiative One World, "One Health" tries to rapidly detect emerging or reemerging human and animal infectious diseases and prevent epidemiological situations such as deforestation, some agricultural practices or the appearance of new foci of leishmaniosis due to Leishmania infantum with alternative reservoirs. With this objective in mind, we here consider leishmaniosis in the Mediterranean basin and compare its current clinical management from two perspectives: that of a veterinarian specialized in infectious and parasitic diseases, and that of a physician specialized in infectious tropical diseases. We thus prepared a list of 10 key questions from epidemiology to control of the disease in both species: dogs and humans. This issue requires a concise and clear response to help animal and human health clinicians to improve their clinical management and understanding of this important zoonosis. Our ultimate aim is to update and bring together the information available backed by sound scientific evidence.

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.

Liposomal Amphotericin B for Visceral Leishmaniasis in a Kidney Allograft Patient

Objective

To report a case of visceral leishmaniasis treated with liposomal amphotericin B (LAB) after probable failure with amphotericin B lipid complex (ABLC).

Case Summary

A 62-year-old white renal transplant recipient was admitted for pyrexia, hepato-splenomegaly, and pancytopenia. Leishmania amastigotes were detected from bone marrow aspirate and in circulating blood monocytes and neutrophils. The patient, who weighed 56 kg, received ABLC at a starting dose of 200 mg/d (3.6 mg/kg of body weight per day) for 13 days, achieving a total dose of 2,600 mg (46 mg/kg) without clinical improvement. The patient was switched to 100 mg/d (1.8 mg/kg) of LAB for 10 days, after which a dose of 250 mg (4.5 mg/kg) was repeated on days 17,24,31, and 38. Twenty-four hours after the first dose of LAB, the patient showed an excellent clinical response. On the following days, there was a progressive increase in hemoglobin concentration and leukocyte and platelet counts. Three months later, the patient was asymptomatic.

Discussion

Although treatment with ABLC appears to be effective for the treatment of Indian patients with visceral leishmaniasis, experience with immunocompromised patients is limited. This is the first case of a renal transplant recipient in which ABLC was used to treat visceral leishmaniasis without remarkable efficacy, but with infusion-related adverse effects perhaps due to the use of higher doses.

Conclusions

A randomized comparative trial is needed to compare LAB with ABLC in the treatment of visceral leishmaniasis in patients who have received kidney allografts.

Tropical Parasitic Infections in Individuals Infected with HIV

PURPOSE OF REVIEW

Neglected tropical diseases share both geographic and socio-behavioral epidemiological risk factors with HIV infection. In this literature review, we describe interactions between parasitic diseases and HIV infection, with a focus on the impact of parasitic infections on HIV infection risk and disease progression, and the impact of HIV infection on clinical characteristics of tropical parasitic infections. We limit our review to tropical parasitic infections of the greatest public health burden, and exclude discussion of classic HIV-associated opportunistic infections that have been well reviewed elsewhere.

RECENT FINDINGS

Tropical parasitic infections, HIV-infection, and treatment with antiretroviral therapy alter host immunity, which can impact susceptibility, transmissibility, diagnosis, and severity of both HIV and parasitic infections. These relationships have a broad range of consequences, from putatively increasing susceptibility to HIV acquisition, as in the case of schistosomiasis, to decreasing risk of protozoal infections through pharmacokinetic interactions between antiretroviral therapy and antiparasitic agents, as in the case of malaria. However, despite this intimate interplay in pathophysiology and a broad overlap in epidemiology, there is a general paucity of data on the interactions between HIV and tropical parasitic infections, particularly in the era of widespread antiretroviral therapy availability.

SUMMARY

Additional data are needed to motivate clinical recommendations for detection and management of parasitic infections in HIV-infected individuals, and to consider the implications of and potential opportunity granted by HIV treatment programs on parasitic disease control.

Colonic leishmaniasis in a patient with HIV: a case report

BACKGROUND

To describe an unusual clinical presentation of visceral leishmaniasis affecting the colon.

CASE REPORT

We report the case of an HIV-positive patient with visceral leishmaniasis. We describe the clinical case, the procedures performed, the treatment provided and the patient's evolution. A comparative table of previously reported similar cases is shown.

DISCUSSION

Visceral leishmaniasis with intestinal involvement is an uncommon process. Nevertheless, this possibility should be taken into consideration in the differential diagnosis of immunosuppressed patients with symptoms of diarrhea, as a favorable prognosis depends on early diagnosis and appropriate treatment.

Visceral leishmaniasis and HIV/AIDS in Brazil: Are we aware enough?

Background

The urbanization of visceral leishmaniasis (VL) and the concurrent movement of the HIV infection to rural areas in Brazil are possible mechanisms associated with an increased number of Leishmania/HIV coinfected people. This study aimed to describe the clinical and epidemiological profile of VL/HIV coinfected patients and compare this profile to non-coinfected VL patients.

Methods

Cases of VL/HIV coinfection were obtained through a probabilistic record linkage of databases of VL and AIDS cases from the Brazilian Ministry of Health.

Results

We retrieved 760 cases of VL/HIV coinfection, most prevalent in adult males, with incidence ranging from 0.01 to 0.07 cases, per 100.000 population, in 2001 and 2010, respectively. Case-fatality rates were 27.3% in 2001 and 23.2% in 2010. Weakness, weight loss, cough, other associated infections and haemorrhagic phenomena were more commonly found among coinfected patients, which had a fatality rate three times higher as compared to the non-coinfected group. The relapse proportion was two times greater among coinfected (6.3%) than non-coinfected (3.1%).

Conclusions

The results found herein contribute to the increase of knowledge of the epidemiological situation of VL/HIV coinfection in Brazil and reinforce the necessity of implementing specific strategies to improve early case detection and efficacious and less toxic treatment in order to achieve lower case-fatality rates.

Visceral leishmaniasis (VL) is an infectious disease present in 75 countries. Brazil is among the six countries that represent over 90% of the cases worldwide. AIDS is an emerging disease present in approximately 190 countries and a major public health problem worldwide due to its magnitude and damage extension. In Brazil, the recent alterations of the AIDS and VL distribution patterns, such as movement of the HIV infection to rural areas and the urbanization of VL associated to the rise of VL cases among the 20–49 years old age group, are possible factors associated with an increased risk of the population to present both infections. The coexistence of these diseases enhances the severity, seeing that VL accelerates the development of AIDS in HIV patients, and AIDS increases the risk of VL up to 100 to 1,000 times in endemic areas. Considering that the association of both infections is recent, however rising in several countries, our study contributes to the knowledge of the profile, magnitude and severity of VL/HIV coinfection, which can subsidize actions to overcome challenges related to both VL and AIDS and assist in guiding actions and decision-making processes.

A ready-to-use duplex qPCR to detect Leishmania infantum DNA in naturally infected dogs

Canine visceral leishmaniasis (CVL) is a systemic disease caused by Leishmania infantum. A precise CVL diagnosis would allow for a faster and more specific treatment. Quantitative PCR (qPCR) is a sensitive and specific technique that can diagnose CVL and also monitor parasite load in the animal during the course of the infection or treatment. The aim of this study was to develop a ready-to-use (gelified and freezer-free) duplex qPCR for the identification of infected animals. We combined a new qPCR protocol that detects the canine 18S rRNA gene with an existing protocol for L. infantum kDNA detection, creating a duplex qPCR. This duplex method was then developed into a ready-to-use format. The performance of the duplex and singleplex reactions were compared in the traditional format (liquid and freezer-stored). Furthermore, the duplex qPCR performance was compared between the ready-to-use and traditional formats. The singleplex and new duplex qPCR exhibited the same detection limit in the traditional format (0.1 parasites/reaction). The ready-to-use format showed a detection limit of 1 parasite/reaction without affecting the reaction efficiency. The performance of the new qPCR protocol in the two formats was assessed using canine tissue samples from 82 dogs in an endemic CVL area that were previously characterized by standard serological and parasitological protocols. Splenic aspirates provided a higher rate of positivity (92.9%) followed by skin (50%) and blood (35.7%). The reported detection limits were observed for all tissues studied. Our results show that the amplification of L. infantum kDNA and canine DNA in a single tube, using either the traditional or ready-to-use format, exhibited the same diagnostic performance as amplification of the parasite kDNA alone. The detection of the host gene strengthens the qPCR results by confirming the presence and quality of DNA in the samples and the absence of polymerase inhibitors. The ready-to-use duplex qPCR format has many advantages. By joining two qPCR protocols into one, more results can be obtained in the same amount of time with reduced costs and embedded quality control. Reagents are preloaded and stored on the plate, reducing the operator's hands-on time to set up a reaction, as well as decreasing manipulation steps, which reduces the risk of mistakes or contamination. Thus, the ready-to-use duplex format turns qPCR into a robust, easy-to-use tool, which could help increase the availability of qPCR for CVL diagnosis.

Leishmania (V.) braziliensis infecting bats from Pantanal wetland, Brazil: First records for Platyrrhinus lineatus and Artibeus planirostris

In the New World genus Leishmania parasites are etiological agents of neglected zoonoses known as leishmaniasis. Its epidemiology is very complex due to the participation of several species of sand fly vectors and mammalian hosts, and man is an accidental host. Control is very difficult because of the different epidemiological patterns of transmission observed. Studies about Leishmania spp. infection in bats are so scarce, which represents a large gap in knowledge about the role of these animals in the transmission cycle of these pathogens, especially when considering that Chiroptera is one of the most abundant and diverse orders among mammals. Leishmaniasis in Mato Grosso do Sul, Brazil are remarkably frequent, probably due to the abundance of its regional mastofauna. The recent record of L. braziliensis in bats from this state indicates the need to clarify the role of these mammals in the transmission cycle. In this study we evaluated the presence of Leishmania parasites in the skin of different species of bats, using PCR directed to Leishmania spp. kDNA for screening followed by PCR/RFLP analysis of the hsp70 gene for the identification of parasite species. Leishmania species identification was confirmed by PCR directed to the G6PD gene of L. braziliensis, followed by sequencing of the PCR product. Samples from 47 bats were processed, of which in three specimens (6.38%) was detected the presence of Leishmania sp. kDNA. PCR/RFLP and sequencing identified the species involved in the infection as L. braziliensis in all of them. This is the first report of Leishmania braziliensis in bats from Pantanal ecosystem and the first record of this species in Platyrrhinus lineatus and Artibeus planirostris, bats with a wide distribution in South America. These results reinforce the need to deepen the knowledge about the possibility of bats act as reservoirs of Leishmania spp. especially considering their ability of dispersion and occupation of anthropic environments.

Leishmania infections: Molecular targets and diagnosis

Progress in the diagnosis of leishmaniases depends on the development of effective methods and the discovery of suitable biomarkers. We propose firstly an update classification of Leishmania species and their synonymies. We demonstrate a global map highlighting the geography of known endemic Leishmania species pathogenic to humans. We summarize a complete list of techniques currently in use and discuss their advantages and limitations. The available data highlights the benefits of molecular markers in terms of their sensitivity and specificity to quantify variation from the subgeneric level to species complexes, (sub) species within complexes, and individual populations and infection foci. Each DNA-based detection method is supplied with a comprehensive description of markers and primers and proposal for a classification based on the role of each target and primer in the detection, identification and quantification of leishmaniasis infection. We outline a genome-wide map of genes informative for diagnosis that have been used for Leishmania genotyping. Furthermore, we propose a classification method based on the suitability of well-studied molecular markers for typing the 21 known Leishmania species pathogenic to humans. This can be applied to newly discovered species and to hybrid strains originating from inter-species crosses. Developing more effective and sensitive diagnostic methods and biomarkers is vital for enhancing Leishmania infection control programs.

Hematologic Changes Associated with Specific Infections in the Tropics

Anemia frequently accompanies and plays a minor role in the presentation and course of infection, whether parasitic, bacterial, or viral. However, a variety of infections, many of which are common in Africa and Asia, cause specific hematologic syndromes. The pathophysiology of these syndromes is complex, and to some extent, reduced red cell production may form part of an innate protective host response to infection. Across the world and in endemic areas, malaria is the most important among this group of infections and forms a major part of everyday practice.

Health and epidemiological approaches of Trypanosoma evansi and equine infectious anemia virus in naturally infected horses at southern Pantanal

Equine infectious anemia virus (EIAV) and Trypanossoma evansi are endemic in Brazilian Pantanal Biome, an important area for livestock production. In this sense, we evaluated the epidemiological single and co-infection effects of T. evansi and EIAV in naturally infected horses in the southern Pantanal wetland by serological tests and hematological assays. Both higher seroprevalence and heath poor condition of the sampled animals were associated with differences in horse management between farms. We found that the negative animals for both infectious agents (NN) represented the major group in F1 (37%), and the smallest group in F2 (19%). Furthermore, we recorded higher EIAV seroprevalence (56%) in F2, compared to F1 (38%). We observed that T. evansi infection was mostly related to young horses, as seen by their higher seroprevalence, ranging from 70.7% in the beginning of the rainy season to 81% in the end of flood period, in comparison with the values of 42% and 68%, respectively, in working animals. on the other hand, working animals showed a higher seroprevalence for EIAV (48%) in both seasons than young horses. We observed that the management of working horses could be a risk factor of EIAV infection. On the other hand, as T. evansi is maintained in the study region by many species of wild mammals, the mechanical transmission through blood-sucking vectors ensures the infection to horses since early. Our results showed that single or co-infection by EIAV and T. evansi caused different degree of anemia in the infected animals. Moreover, the health of horses in Brazilian Pantanal is also influenced by differences in horse management and environmental circumstances.

Leishmaniasis-HIV coinfection: current challenges

Leishmaniasis – human immunodeficiency virus (HIV) coinfection can manifest itself as tegumentary or visceral leishmaniasis. Almost 35 countries have reported autochthonous coinfections. Visceral leishmaniasis is more frequently described. However, usual and unusual manifestations of tegumentary leishmaniasis have been reported mainly in the Americas, but the real prevalence of Leishmania infection in HIV-infected patients is not clear. Regarding the clinical manifestations, there are some reports showing unusual manifestations in visceral leishmaniasis and tegumentary leishmaniasis in HIV-infected patients; yet, the usual manifestations are more frequent. Leishmaniasis diagnosis relies on clinical methods, but serological tests are used to diagnose visceral leishmaniasis despite them having a low sensitivity to tegumentary leishmaniasis. The search for the parasite is used to diagnose both visceral leishmaniasis and tegumentary leishmaniasis. Nevertheless, in HIV-infected patients, the sensitivity of serology is very low. Drugs available to treat leishmaniasis are more restricted and cause severe side effects. Furthermore, in HIV-infected patients, these side effects are more prominent and relapses and lethality are more recurrent. In this article, we discuss the current challenges of tegumentary leishmaniasis and visceral leishmaniasis–HIV infection, focusing mainly on the clinical manifestations, diagnosis, and treatment of leishmaniasis.

Evaluation of urine for Leishmania infantum DNA detection by real-time quantitative PCR

The availability of some sorts of biological samples which require noninvasive collection methods has led to an even greater interest in applying molecular biology on visceral leishmaniasis (VL) diagnosis, since these samples increase the safety and comfort of both patients and health professionals. In this context, this work aimed to evaluate the suitability of the urine as a specimen for Leishmania infantum kinetoplast DNA detection by real-time quantitative PCR (qPCR). Subsequent to the reproducibility analysis, the detection limit of the qPCR assay was set at 5fg (~0.025 parasites) per μL of urine. From the comparative analysis performed with a set of diagnostic criteria (serological and molecular reference tests), concordance value of 96.08% was obtained (VL-suspected and HIV/AIDS patients, n=51) (P>0.05). Kappa coefficient (95% CI) indicated a good agreement between the test and the set of diagnostic criteria (k=0.778±0.151). The detection of Leishmania DNA in urine by qPCR was possible in untreated individuals, and in those with or without suggestive renal impairment. Fast depletion of the parasite's DNA in urine after treatment (from one dose of meglumine antimoniate) was suggested by negative qPCR results, thus indicating it as a potential alternative specimen to follow up the efficacy of therapeutic approaches. Even when evaluated in a clinically heterogeneous set of patients, the urine showed good prospect as sample for VL diagnosis by qPCR, also indicating a good negative predictive value for untreated suspected patients.

Worldwide risk factors in leishmaniasis

Recently, vector-borne parasitic diseases such as leishmaniasis have been emerged or re-emerged in many geographical areas and resulted in global health and economic concerns that involve humans, domestic animals and wild life. The ecology and epidemiology of leishmaniasis are affected by the between host, reservoir and vector (human, animal and sandfly) and the environment. Important drivers for the emergence and spread of leishmaniasis include environmental factors such as alterations in temperature and water storage, irrigation habits, deforestation, climate changes, immunosuppression by HIV or organ transplant, development of drug resistance, increase traveling to endemic regions and dog importation. War, poor socio-economic status and low level household are also major contributors to the spread of this disease. Health education via the public media and training should be implemented by international organizations and governmental agencies in collaboration with research institutions. Fully protection during transmission season, using bednets and insecticides and reservoirs' control should be also mentioned in the planning. Based on the findings of the recent studies and high prevalence of leishmaniasis, it is concluded that serious public health monitoring should be considered.

Recent developments and future prospects in the treatment of visceral leishmaniasis

Limited therapeutic options in visceral leishmaniasis (VL) make the treatment of this neglected disease very challenging. In addition to this, long treatment duration and toxic adverse effects make it even more difficult. With no effective vaccine available to date, treatment of VL is based only on chemotherapy. In the Indian subcontinent, a single dose of liposomal amphotericin B (L-AmB) and multidrug therapy (L-AmB + miltefosine, L-AmB + paromomycin [PM], or miltefosine + PM) are the treatments of choice for VL. In East Africa, however, combination therapy of pentavalent antimonials (Sb(v)) and PM remains the treatment of choice, and in the Mediterranean region and South America, L-AmB is the recommended drug. Fexinidazole and PA-824 are new promising drugs which have shown encouraging results in preclinical studies.

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.

Antileishmanial, DNA Interaction, and Docking Studies of Some Ferrocene-Based Heteroleptic Pentavalent Antimonials

A series of ferrocenyl pentavalent antimonials (1-8) were synthesized and characterized by elemental analysis, FT-IR, and multinuclear ((1) H and (13) C) NMR spectroscopy. These antimonials were evaluated for their antileishmanial potential against Leishmania tropica KWH23, and by biocompatibility and membrane permeability assays. Moreover, mechanistic studies were carried out, mediated by DNA targeting followed by computational docking of ferrocenyl antimonials against the leishmanial trypanothione reductase enzyme. It was observed that the antimonials 1-8 were 390-fold more efficacious (IC50 ) as compared with the standard antimonial drug used. Cytotoxicity results showed that these antimonials are highly active even at low concentrations and are biocompatible with human macrophages. Antimonials 1-8 exhibited extensive intercalation with DNA and, furthermore, docking interactions highlighted the potential interactive binding of the anitimonials within the trypanothione reductase active site, with van der Waals interactions contributing significantly to the process. Hence, it is suggested that the reported antimonials demonstrate high efficacy, less toxicity, and target multiple sites of the Leishmania parasite.

Liposomal systems as carriers for bioactive compounds

Since the revolutionary discovery that phospholipids can form closed bilayered structures in aqueous systems, the study of liposomes has become a very interesting area of research. The versatility and amazing biocompatibility of liposomes has resulted in their wide-spread use in many scientific fields, and many of their applications, especially in medicine, have yielded breakthroughs in recent decades. Specifically, their easy preparation and various structural aspects have given rise to broadly usable methodologies to internalize different compounds, with either lipophilic or hydrophilic properties. The study of compounds with potential biotechnological application(s) is generally related to evaluation and risk assessment of the possible cytotoxic or therapeutic effects of the compound under study. In most cases, undesirable side-effects are associated with an interaction of the liposome with the cell membrane and/or its absorption and subsequent interaction with a cellular biomolecule. Liposomal carrier systems have an unprecedented potential for delivering bioactive substances to specific molecular targets due to their biocompatibility, biodegradability and low toxicity. Liposomes are therefore considered to be an invaluable asset in applied biotechnology studies due to their potential for interaction with both hydrophilic and lipophilic compounds.

Rapid Tests and the Diagnosis of Visceral Leishmaniasis and Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome Coinfection

After the emergence of the human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), the number of visceral leishmaniasis (VL)-HIV/AIDS coinfections has increased worldwide. Herein, we assessed the usefulness of an rK39-based immunochromatographic test (rK39 ICT) (DiaMed-IT LEISH(®); DiaMed AG, Cressier-sur-Morat, Switzerland) and a latex agglutination test (KAtex; Kalon Biological, Guildford, United Kingdom) for urinary antigen detection to diagnose VL in 15 HIV/AIDS patients from northeastern Brazil. VL diagnosis was based on clinical findings, cytology, serology, parasite DNA, and/or urinary antigen detection. VL was confirmed in seven out of 15 HIV/AIDS patients. Only three patients were positive in bone marrow cytology, three patients were conventional polymerase chain reaction (PCR) positive, while six were real-time PCR positive. All patients were direct agglutination test (DAT) (Royal Tropical Institute, Amsterdam, The Netherlands) positive; of these, four were positive by rK39 ICT and five by KAtex. Large-scale studies are needed to validate the use of the KAtex in the national public health laboratory network in Brazil, aiming at improving the diagnosis of VL in HIV/AIDS patients in this country.

Visceral Leishmaniasis/HIV co-infection in northeast Brazil: evaluation of outcome

Since the beginning of the HIV burden, Visceral Leishmaniasis (VL)/HIV co-infection has been diagnosed not only in areas where VL is endemic (Latin America, India, Asia, Southern Europe), but also in North America, were it is considered an opportunistic disease. Clinical presentation, diagnostic tests sensitivity and treatment response in this population differs from VL alone.

OBJECTIVES

To evaluate factors related to an unfavorable outcome in patients with VL/HIV diagnosis in a reference center in northeast Brazil.

METHODS

Co-infected patients, diagnosed from 2010 to 2012, were included. Data from medical records were collected until one year after VL treatment completion.

RESULTS

Forty-two HIV-infected patients were included in the study. Anemia, leukopenia, and thrombocytopenia were present in 95%, 70.7%, and 63.4%, respectively. Mean T CD4+ (LTCD4) lymphocyte count was 183 cells/dL. Highly active antiretroviral therapy (HAART) was being used by 54.7% of cases. A favorable outcome was seen in 71.4% of cases. Recurrence of VL occurred in nine patients and deaths were secondary to infectious complications (3/42 patients). Very low LTCD4 count (<100 cells/dL) was the only independent variable associated with an unfavorable outcome in multivariate analysis (p=0.03).

CONCLUSION

Low LTCD4 count at presentation was associated with unfavorable outcome in VL/HIV patients.

Antileishmanial activity and evaluation of the mechanism of action of strychnobiflavone flavonoid isolated from Strychnos pseudoquina against Leishmania infantum

The present study aimed to investigate the in vitro antileishmanial activity of strychnobiflavone flavonoid against Leishmania infantum, as well as its mechanism of action, and evaluate the ex vivo biodistribution profile of the flavonoid in naive BALB/c mice. The antileishmanial activity (IC50 value) of strychnobiflavone against stationary promastigote and amastigote-like stages of the parasites was of 5.4 and 18.9 μM, respectively; with a 50% cytotoxic concentration (CC50) value of 125.0 μM on murine macrophages, resulting in selectivity index (SI) of 23.2 and 6.6, respectively. Amphotericin B, used as a positive control, presented SI values of 7.6 and 3.3 for promastigote and amastigote-like stages of L. infantum, respectively. The strychnobiflavone was also effective in reducing in significant levels the percentage of infected macrophages, as well as the number of amastigotes per macrophage, after the treatment of infected macrophages using the flavonoid. By using different fluorescent probes, we investigated the bioenergetics metabolism of L. infantum promastigotes and demonstrated that the flavonoid caused the depolarization of the mitochondrial membrane potential, without affecting the production of reactive oxygen species. In addition, using SYTOX(®) green as a fluorescent probe, the strychnobiflavone demonstrated no interference in plasma membrane permeability. For the ex vivo biodistribution assays, the flavonoid was labeled with technetium-(99m) and studied in a mouse model by intraperitoneal route. After a single dose administration, the scintigraphic images demonstrated a highest uptake by the liver and spleen of the animals within 60 min, resulting in low concentrations after 24 h. The present study therefore demonstrated, for the first time, the antileishmanial activity of the strychnobiflavone against L. infantum, and suggests that the mitochondria of the parasites may be the possible target organelle. The preferential distribution of this compound into the liver and spleen of the animals could warrant its employ in the treatment of visceral leishmaniasis.