Clinical use of polymerase chain reaction performed on peripheral blood and bone marrow samples for the diagnosis and monitoring of visceral leishmaniasis in HIV-infected and HIV-uninfected patients: a single-center, 8-year experience in Italy and review of the literature

Visceral Leishmaniasis in a Twin Pregnancy: A Case Report and Review of the Literature

Visceral leishmaniasis (VL), often referred to as kala-azar, is quite rare in developed countries during pregnancy. Only few studies have evaluated its impact on perinatal outcome. It is caused primarily by Leishmania donovani or Leishmania infantum and presents with a wide spectrum of clinical manifestations from cutaneous ulcers to multisystem disease. Differential diagnosis is challenging as symptoms and signs are insidious, mimicking other diseases. Misdiagnosis can result in severe adverse perinatal outcomes, even maternal/neonatal death. Early treatment with liposomal amphotericin-B (LAmB) is currently the first choice with adequate effectiveness. We report a rare case of VL in a twin pregnancy with onset at the second trimester, presenting with periodic fever with rigors, right flank pain, and gradual dysregulation of all three cell lines. The positive rK39 enzyme-linked immunosorbent assay test confirmed the diagnosis. Treatment with LAmB resulted in clinical improvement within 48 h and in the delivery of two late-preterm healthy neonates with no symptoms or signs of vertical transmission. The one-year follow-up, of the mother and the neonates, was negative for recurrence. To our knowledge, this is the first reported case of VL in a twin pregnancy, and consequently treatment and perinatal outcome are of great importance.

The immune response in canine and human leishmaniasis and how this influences the diagnosis- a review and assessment of recent research

Leishmaniasis is a widespread but still underdiagnosed parasitic disease that affects both humans and animals. There are at least 20 pathogenic species of Leishmania, most of them being zoonotic. The diagnosis of leishmaniasis remains a major challenge, with an important role being played by the species of parasites involved, the genetic background, the immunocompetence of the host. This paper brings to the fore the sensitivity of the balance in canine and human leishmaniasis and addresses the importance of the host's immune response in establishing a correct diagnosis, especially in certain cases of asymptomatic leishmaniasis, or in the situation the host is immunosuppressed or acquired leishmaniasis through vertical transmission. The methods considered as a reference in the diagnosis of leishmaniasis no longer present certainty, the diagnosis being influenced mostly by the immune response of the host, which differs according to the presence of other associated diseases or even according to the breed in dogs. Consequently, the diagnosis and surveillance of leishmaniasis cases remains an open topic, requiring new diagnostic methods adapted to the immunological state of the host.

Delayed diagnosis among patients with visceral leishmaniasis

We aimed to estimate the diagnostic latency of patients with visceral leishmaniasis (VL). A monocentric retrospective observational study was conducted including all confirmed cases of VL diagnosed from January 2005 to March 2022. Epidemiological and clinical characteristics of patients with VL were collected. The diagnostic latency was defined as the number of days between the first contact with a health-care provider for signs and/or symptoms referable to VL and the laboratory diagnosis of leishmaniasis. Twenty-four cases of VL were included in the study, mostly male (75%) and Italians (79.2%), with a median age of 40 years [Inter Quartile Range (IQR 30-48)]. Fourteen (58.3%) VL cases were people living with HIV (PLWH) and 4 (16.6%) subjects were on immunosuppressive therapy. For VL the median diagnostic latency was 54 days (IQR 28-162). The shorter diagnostic latency was observed in PLWH [31 days (IQR 20-47)] followed by immunocompetent patients [160 days (IQR 133-247)] and those on immunosuppressive therapy [329 days (IQR 200-678)]. Twelve patients (50%) reported at least one medical encounter before the diagnosis of VL and 6 patients received a wrong therapy. Diagnostic delay in VL was significant in patients under immune suppressive treatment.

An Atypical Course of Visceral Leishmaniasis After Kidney Transplantation: A Case Report From Iran

BACKGROUND

Organ transplantation can lead to human visceral leishmaniasis (VL) transmission in humans. This report aims to describe the possible complications related to an atypical course of VL after kidney transplantation.

CASE PRESENTATION

A 61-year-old man who suffered end-stage renal failure received a deceased donor kidney transplant after 2 years of hemodialysis. Tacrolimus, mycophenolate mofetil, and prednisolone were used for immunosuppressive therapy, and renal function remained stable for 2.5 years. He was referred to our hospital because of fever and malaise. Physical and radiological examinations showed mild splenomegaly and cervical and inguinal lymphadenopathy. Laboratory data showed bicytopenia, elevated C-reactive protein, serum creatinine, and non-nephrotic proteinuria. Bone marrow biopsy aspiration showed no abnormality. Polymerase chain reaction confirmed the diagnosis of Leishmania infantum. Anti-leishmanial therapy was initiated with liposomal amphotericin B for 2 weeks, and the patient became clinically stable. So far, there has been no evidence of clinical or biological relapse, and kidney function is stable.

CONCLUSIONS

Considering that VL has become increasingly widespread in immunocompromised patients in endemic regions, especially in patients with transplants, it is crucial to screen and rule out VL as a cause of infection in these patients. The probability of this problem should be considered in every patient with a transplant in endemic and nonendemic areas. Furthermore, our study showed that through timely diagnosis using noninvasive methods and standard treatments, mortality caused by this disease can be properly prevented.

Mucosal Relapse of Visceral Leishmaniasis in a Child with SARS-CoV-2 Infection

Leishmaniasis is a vector-borne disease caused by protozoan parasites of the genus Leishmania and is transmitted through the bite of infected female sandflies. In the Mediterranean region, visceral leishmaniasis is caused by Leishmania. infantum, and it is usually responsible for symptoms such as fever, pancytopenia and enlargement of the liver and spleen. Relapse is rare in immunocompetent patients as much as the mucous involvement. We present a rare case of mucosal relapse of visceral leishmaniasis in a child with SARS-CoV-2 infection and perform an extensive review of the literature about leishmaniasis relapses in children. Atypical mucosal involvement during Leishmaniasis relapse is an eventuality in pediatric patients. Clinical follow-up and periodic PCR tests must be considered essential for the early recognition and treatment of an eventual relapse.

Review of the Clinical Presentation, Pathology, Diagnosis, and Treatment of Leishmaniasis

Leishmaniasis is a vector-borne infection caused by kinetoplastid protozoans in the genera Leishmania and Endotrypanum. The disease occurs worldwide in the tropics and subtropics and can be particularly burdensome in resource-limited settings. Diseases caused by leishmaniasis range in severity from mild cutaneous lesions to life-threatening visceral and disfiguring mucocutaneous illnesses. Rapid and accurate diagnosis is needed to ensure proper clinical management of patients afflicted with this disease. Complicating matters of diagnosis and treatment are the diversity of species within these 2 genera and the variable specificity of diagnostic assays. This mini-review provides laboratory professionals with an overview of Leishmania epidemiology, biology, pathogenesis, clinical presentations, and treatments with additional emphasis placed on the nuances involved in diagnosis.

Autochthonous visceral leishmaniasis in the Russian Federation and the role of polymerase chain reaction as an alternative diagnostic method

The aim of the work is to summarize the available literature data on cases of visceral leishmaniasis in children registered in the Russian Federation, as well as to describe our own clinical observation of autochthonous visceral leishmaniasis in a 9-year-old child, in the diagnosis of which the polymerase chain reaction (PCR) method was used.

Materials and methods: a review of domestic and foreign literature over the past 20 years, including Internet resources, was carried out. We observed a 9-year-old child hospitalized in the Russian Children's Clinical Hospital. Leishmania DNA was determined in blood serum by PCR using the Amplisens – Leishmania-Fl reagent kit.

Results. It was established that the infection of the patient observed by us occurred on the territory of the Russian Federation in the Crimea. The diagnosis of leishmaniasis was confirmed by morphological examination of the bone marrow and the detection of pathogen DNA in the blood serum by PCR.

Conclusion. On the territory of the Russian Federation there are foci of autochthonous visceral leishmaniasis in the Crimea and the North Caucasus. Polymerase chain reaction is an alternative to bone marrow aspirate microscopy for the diagnosis of visceral leishmaniasis.

Laboratory diagnostics for human Leishmania infections: a polymerase chain reaction-focussed review of detection and identification methods

Leishmania infections span a range of clinical syndromes and impact humans from many geographic foci, but primarily the world's poorest regions. Transmitted by the bite of a female sand fly, Leishmania infections are increasing with human movement (due to international travel and war) as well as with shifts in vector habitat (due to climate change). Accurate diagnosis of the 20 or so species of Leishmania that infect humans can lead to the successful treatment of infections and, importantly, their prevention through modelling and intervention programs. A multitude of laboratory techniques for the detection of Leishmania have been developed over the past few decades, and although many have drawbacks, several of them show promise, particularly molecular methods like polymerase chain reaction. This review provides an overview of the methods available to diagnostic laboratories, from traditional techniques to the now-preferred molecular techniques, with an emphasis on polymerase chain reaction-based detection and typing methods.

Third Case of Visceral Leishmaniasis in COVID-19: Mini Review Article

Background: In the currently ongoing coronavirus pandemic, coinfections with unrelated life-threatening febrile conditions may pose a particular challenge to clinicians. Leishmaniasis is a zoonosis that may present general symptoms, including fever, malaise, and arthralgia, rendering it indistinguishable from COVID-19. Methods: In this paper, we aim to draw attention to this issue and analyze the clinical characteristics of the coinfection SARS-CoV-2/Leishmania through a systematic review of the literature. We were motivated by the observation of the first case of visceral leishmaniasis and COVID-19 in a paediatric patient. Conclusion: Our case is a reminder for healthcare providers to consider the diagnosis of visceral leishmaniasis in patients presenting with febrile syndrome in endemic regions during the COVID-19 pandemic.

Visceral Leishmaniasis Associated with B-Cell Chronic Lymphocytic Leukemia: Report of a Case and Review of the Literature

Infections often complicate the course of hematological diseases and may represent a diagnostic challenge. In particular, visceral leishmaniasis diagnosis may be missed in lymphoma patients, as lymphoma-related immunosuppression can lead to a misleadingly negative Leishmania serology and to atypical clinical manifestations, including the lack of fever, considered a common symptom in leishmaniasis. Herein, we report a case of visceral leishmaniasis in a patient with a long history of B-cell chronic lymphocytic leukemia presenting with increasing fatigue and diarrhea, in the absence of fever. Leishmania serology was negative. Bone marrow biopsy performed with the clinical suspicion of transformation to high-grade lymphoma disclosed intracytoplasmic inclusion bodies resembling Leishmania amastigotes within the cytoplasm of macrophages, and CD1a immunohistochemical expression helped to confirm the diagnosis of leishmaniasis. Liposomal amphotericin B was administered with complete symptom resolution. The correct identification of Leishmania is critical as visceral leishmaniasis represents a severe disease with an often fatal outcome, particularly in frail patients, unless promptly recognized and adequately treated. A review of the literature of visceral leishmaniasis cases occurring in B-cell chronic lymphocytic leukemia patients is performed.

Precision Medicine in Control of Visceral Leishmaniasis Caused by L. donovani

Precision medicine and precision global health in visceral leishmaniasis (VL) have not yet been described and could take into account how all known determinants improve diagnostics and treatment for the individual patient. Precision public health would lead to the right intervention in each VL endemic population for control, based on relevant population-based data, vector exposures, reservoirs, socio-economic factors and other determinants. In anthroponotic VL caused by L. donovani, precision may currently be targeted to the regional level in nosogeographic entities that are defined by the interplay of the circulating parasite, the reservoir and the sand fly vector. From this 5 major priorities arise: diagnosis, treatment, PKDL, asymptomatic infection and transmission. These 5 priorities share the immune responses of infection with L. donovani as an important final common pathway, for which innovative new genomic and non-genomic tools in various disciplines have become available that provide new insights in clinical management and in control. From this, further precision may be defined for groups (e.g. children, women, pregnancy, HIV-VL co-infection), and eventually targeted to the individual level.

Feline Leishmaniosis in Northwestern Italy: Current Status and Zoonotic Implications

Leishmaniasis remains one of the major neglected tropical diseases. The epidemiological profile of the disease comprises a wide range of hosts, including dogs and cats. Despite several studies about feline Leishmaniosis, the role of cats in disease epidemiology and its clinical impact is still debated. The present study raises awareness about the impact of leishmaniasis in cats from an endemic region in of Northwestern Italy (Liguria). A total number of 250 serum and 282 blood samples were collected from cats, then assessed for Leishmania infantum (L. infantum) serologically using western blot (WB) and molecularly using polymerase chain reaction (PCR). We also tested the association of Leishmania infection with some infectious agents like haemotropic Mycoplasma, Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV) together with the hematobiochemical status of the examined animals. Interestingly, all tested animals were asymptomatic and out of 250 examined serum samples, 33 (13.20%) samples (confidence interval (CI) 95% 9.56-17.96%) were positive at WB for L. infantum, whereas of the 282 blood samples, 80 (28.36%) returned a positive PCR (CI 95% 23.43-33.89%). Furthermore, there was a statistical association between PCR positivity for L. infantum and some hematological parameters besides FIV infection as well as a direct significant correlation between Mycoplasma infection and WB positivity. Taken together, the present findings report high prevalence of L. infantum among cats, which reinforces the significance of such positive asymptomatic animals and confirms the very low humoral response in this species. In addition, the laboratory values provide evidence that infection by the parasite is linked to alteration of some hematological parameters and is correlated to some infectious agents. These data are of interest and suggest future research for accurate diagnosis of such zoonosis.

Distinct Laboratory and Clinical Features of Secondary Hemophagocytic Lymphohistiocytosis in Pediatric Visceral Leishmaniasis: A Retrospective Analysis of 127 Children in Andalusia, Spain (2004-2019)

BACKGROUND

Visceral leishmaniasis (VL) is an endemic in Southern Europe. However, details regarding disease burden, clinical presentations, laboratory markers, management and outcome in children are scarce.

METHODS

Medical records of children (<14 years) admitted with VL to 10 pediatric units in Andalusia (2004-2019) were retrospectively reviewed. VL diagnosis was based on clinical presentation, serology, microscopy and molecular methods. Diagnosis of secondary hemophagocytic lymphohistiocytosis (sHLH) was established using the hemophagocytic lymphohistiocytosis-2004 criteria.

RESULTS

A total of 127 patients were identified. Median age was 14.5 months; the main clinical presentations were fever and splenomegaly (95.3% each). Cytopenias were the most common laboratory abnormalities. Diagnostics as well as treatment regimens varied over time and the participating centers. Liposomal amphotericin B was prescribed in 97.6%; relapses as well as adverse events were rarely observed (3.1% each). Thirty-seven patients, diagnosed with sHLH required longer hospital admission (P = 0.001), an increased number of platelet (P < 0.006) and red blood cell (P = 0.0001) transfusions and pediatric intensive care unit admission (P = 0.007). Monocytopenia (P = 0.011) and high C-reactive protein levels (P = 0.031), variables not included in the hemophagocytic lymphohistiocytosis-2004 criteria, were associated with sHLH. One patient deceased in the context of the Leishmania infection.

CONCLUSIONS

We report data on the largest pediatric VL cohort from Europe, commonly associated with sHLH. Raised C-reactive protein levels and monocytopenia appear to be associated with sHLH. The latter may help to identify these patients and to guide decisions regarding need of additional supportive clinical care and immunomodulatory therapies. The observed high rate of heterogeneity in terms of diagnosis and management warrants the establishment of appropriate guidelines.

Molecular Tracking of the Leishmania Parasite

With the Visceral Leishmaniasis/Kala-azar Elimination Program in South Asia in its consolidation phase, the focus is mainly on case detection, vector control, and identifying potential sources of infection. Accordingly, emphasis is presently on curbing transmission, which is potentially achievable by identification and elimination of potential reservoirs. The strongest contenders for being the disease reservoir are cases of Post Kala-azar Dermal Leishmaniasis (PKDL) which occurs in a minor proportion of individuals apparently cured of Visceral Leishmaniasis (VL). The demonstration of parasites in tissue aspirates despite being a risky and invasive process is the gold standard for diagnosis of VL, but is now being replaced by serological tests e.g., rK39 strip test and direct agglutination test. However, these antibody based tests are limited in their ability to diagnose relapses, detect cases of PKDL, and monitor effectiveness of treatment. Accordingly, detection of antigen or nucleic acids by polymerase chain reaction has been successfully applied for monitoring of parasite kinetics. This review article provides updated information on recent developments regarding the available antibody or antigen/nucleic acid based biomarkers for longitudinal monitoring of patients with VL or PKDL and emphasizes the need for availability of studies pertaining to quantification of treatment response or relapse.

[Visceral leishmaniasis: a challenging diagnosis in internal medicine]

Leishmaniasis is a vector-born parasitic disease characterized by predominant cutaneous or visceral involvement with fever, hepatosplenomegaly and anemia. Leishmaniasis has relatively high prevalence in tropical and subtropical areas. Several sporadic and mostly imported cases are detected in Russian Federation. Nevertheless, some local incidents are noted in southern areas (Crimea, Dagestan). Lack of epidemiological alertness hampers confirmation of diagnosis and may lead to incorrect treatment. The article summarizes current state of knowledge in epidemiology, diagnostic approach and treatment of leishmaniasis. Particular clinical case is discussed.

Urine-Based Antigen (Protein) Detection Test for the Diagnosis of Visceral Leishmaniasis

This review describes and appraises a novel protein-based antigen detection test for visceral leishmaniasis (VL). The test detects in patient’s urine six proteins from Leishmania infantum (chagasi) and Leishmania donovani, the etiological agents of VL. The gold standard test for VL is microscopic observation of the parasites in aspirates from spleen, liver, or bone marrow (and lymph node for dogs). Culture of the parasites or detection of their DNA in these aspirates are also commonly used. Serological tests are available but they cannot distinguish patients with active VL from either healthy subjects exposed to the parasites or from subjects who had a successful VL treatment. An antigen detection test based on the agglutination of anti-leishmania carbohydrates antibody coated latex beads has been described. However, the results obtained with this carbohydrate-based test have been conflicting. Using mass spectrometry, we discovered six L. infantum/L. donovani proteins excreted in the urine of VL patients and used them as markers for the development of a robust mAb-based antigen (protein) detection test. The test is assembled in a multiplexed format to simultaneously detect all six markers. Its initial clinical validation showed a sensitivity of 93% and specificity of 100% for VL diagnosis.

Fungal and Parasitic Infections of the Liver

Hepatosplenic candidiasis and other fungal infections of the liver are uncommon in healthy individuals; however, high index of suspicion is essential in immunocompromised patients with prolonged fever. Parasitic infections are protozoan or helminthic; their distribution and epidemiology are variable among different world regions. Clonorchiasis, opisthorchiasis, fascioliasis, and ascariasis are helminthic infections that commonly involve the biliary systems. Signs and symptoms of cholangitis require prompt management to relieve biliary obstruction; addition of antihelminthic agents is essential. Parasitic infections are mostly transmitted to humans by fecally contaminated food and water. Proper hand and food sanitation measures are essential in preventing disease transmission.

Leishmaniasis diagnosis: an update on the use of parasitological, immunological and molecular methods

Diagnosis of leishmaniasis has always been a major challenge as its clinical features resemble some other commonly occurring diseases such as tuberculosis, typhoid, and malaria. Reliable laboratory methods become important for differential diagnosis. Demonstration of the parasites in stained preparations of bone marrow and splenic aspirates being risky and invasive is still the gold standard for diagnosis. Serological tests utilizing rapid immunochromatographic formats or rK39 in enzyme linked immune sorbent assay, immunoblotting, direct agglutination test have complications related to high proportions of positive asymptomatic individuals and the inability to diagnose a relapse. Among the molecular techniques, polymerase chain reaction is the most commonly used technique that is successfully implied for diagnosis. This review provides updated information on the recent developments in the field of diagnosis in leishmaniasis, various methods utilized with their advantages and limitations.

A spotlight on the diagnostic methods of a fatal disease Visceral Leishmaniasis

Leishmania donovani (a causative agent of visceral leishmaniasis) poses a serious health threat to the human population which is fatal if left untreated. The life cycle of Leishmania alternates between vertebrate host and Phlebotomine fly as intermediate ones. Due to the difficulties linked to vector (sandfly) control and the lack of an effective vaccine, the control of leishmaniasis relies mostly on chemotherapy. Unfortunately, the prevalence of parasites becoming resistant to the first-line drug pentavalent antimonial (Sb^V )/sodium antimony gluconate (SAG) and some other anti-leishmanial drug is increasing in several parts of the world. With the alarming rise of drug resistance and other issues related to VL, there is an urgent need to focus on early detection and quick diagnosis of VL case. Therefore, we have reviewed most of the methods used in the diagnostic process of VL. Along with existing diagnostic methods, developing more effective and sensitive diagnostic methods and biomarkers is also vital for enhancing VL identification and control programs. This review gathers the comprehensive information on diagnostics methods of VL under a single umbrella that could be the prominent tools for the development of rapid, accurate and cost-effective diagnostic kits for VL which can be used in field conditions.

Impact of sequelae of visceral leishmaniasis and their contribution to ongoing transmission of Leishmania donovani

Visceral leishmaniasis (VL) in the Old World is caused by infection with Leishmania donovani. Although the numbers of new reported cases of VL in Africa have been relatively stable for several years, the low numbers currently reported on the Indian subcontinent suggest a positive impact of new treatments and intervention strategies. In both regions, however, VL relapse and post-kala-azar dermal leishmaniasis (PKDL) maintain infectious reservoirs and therefore present a threat to control programs. In this review, we outline the evolving appreciation of PKDL as an impactful disease in its own right and discuss the various diagnostic methods that can be applied for the detection and characterization of PKDL cases. We also highlight the data that indicate the potential, and likely contribution, of PKDL cases to ongoing transmission of L. donovani.

Urine-based antigen detection assay for diagnosis of visceral leishmaniasis using monoclonal antibodies specific for six protein biomarkers of Leishmania infantum / Leishmania donovani

The development of an accurate protein-based antigen detection assay for diagnosis of active visceral leishmaniasis (VL) would represent a major clinical advance. VL is a serious and fatal disease caused by the parasites Leishmania infantum and Leishmania donovani. The gold standard confirmatory diagnostic test for VL is the demonstration of parasites or their DNA from aspirates from spleen, lymph node, and bone marrow or from blood buffy coats. Here we describe the production and use of monoclonal antibodies (mAbs) for the development of a sensitive and specific antigen detection capture ELISA for VL diagnosis. This test simultaneously detects six leishmania protein biomarkers that we have previously described (Li-isd1, Li-txn1, Li-ntf2, Ld-mao1, Ld-ppi1 and Ld-mad1). The initial clinical validation of this new mAb-based multiplexed capture ELISA showed a sensitivity of ≥93%. The test was negative with 35 urine samples from healthy control subjects as well as with 30 patients with confirmed non-VL tropical diseases (cutaneous leishmaniasis, n = 6; Chagas disease, n = 6; schistosomiasis, n = 6; and tuberculosis, n = 12). These results strongly support the possible utility of this mAb-based multiplexed capture ELISA as a promising diagnostic test for active VL as well as for monitoring the treatment efficacy of this disease. The test is ready for upscaling and validation for clinical use.

Visceral leishmaniasis (VL) or kala-azar is a systemic parasitic disease that is endemic in 75 countries with more than 500 million people at risk of infection. VL is caused primarily by the parasites known as Leishmania infantum and Leishmania donovani. It is estimated that VL affects 50,000–90,000 people each year, with 90% of the cases occurring in India, Kenya, Somalia, Sudan, South Sudan and Brazil. VL is a fatal disease if not treated. Laboratory diagnosis of this disease can be performed using several different approaches. However, there is still a need for a simple, non-expensive, sensitive and specific test that can be used not only for the accurate diagnosis of this serious disease but also to monitor the efficacy of its treatment. Here we describe a new test that can circumvent most of the drawbacks of existing approaches. This new test detects six leishmanial proteins or biomarkers that are eliminated in the urine of patients with VL. The test is a conventional ELISA assembled with monoclonal antibodies (mAbs) specific for each of the six different biomarkers and it is performed in urine samples of suspected patients. An initial clinical validation demonstrated that the test has a sensitivity of ≥93% and specificity of 100%. This new and accurate mAb-based multiplexed assay could be a useful resource to diagnose most clinical forms and/or the severity of the disease e.g., active VL, asymptomatic VL, post kala-azar dermal leishmaniasis, VL/HIV co-infection, etc.

Evaluation of six commercial kits for the serological diagnosis of Mediterranean visceral leishmaniasis

Background

Zoonotic visceral leishmaniasis (VL) is endemic in the Mediterranean basin. However, large-scale comparative analyses of the commercial kits for the serological diagnosis of this neglected disease are lacking. This study compared the performances of four enzyme-linked immunosorbent assays (ELISA) and two immunochromatographic tests (ICT) as screening tests for the serodiagnosis of human VL in the Mediterranean region.

Methodology/Principal findings

Serum samples from 319 patients living in France, Tunisia or Morocco were tested using two ICT (IT LEISH and TruQuick LEISH IgG/IgM Meridian) and four ELISA reagents (NovaLisa Leishmania infantum IgG, Bordier Leishmania infantum, Ridascreen Leishmania IgG, and Vircell Leishmania). The population with proven VL (n = 181) included 65 immunocompromised patients. Significantly higher percentages of false-negative results were obtained with all assays in immunocompromised patients, compared with the immunocompetent population. In the whole population, sensitivity and specificity ranged from 80.7% to 93.9% and from 95.7% to 100%, respectively. The maximum accuracy was observed with the Bordier and Vircell ELISA kits (96.2%), and the lowest accuracy with Ridascreen reagent (88.7%). New thresholds of positivity are proposed for the Bordier, Vircell and NovaLisa ELISA kits to achieve 95% sensitivity with the highest possible specificity. Western blot (WB), used as a confirmation method, showed 100% sensitivity and identified 10.1% of asymptomatic carriers among the control population from the South of France.

Conclusions/Significance

This is the first study that compared commercially available kits for VL serodiagnosis in the endemic region of the Mediterranean basin. It provides specific information about the tests’ performance to help clinicians and biologists to select the right assay for VL screening.

Human visceral leishmaniasis (VL) is a neglected disease endemic in the Mediterranean region, caused by Leishmania infantum. Accurate VL diagnosis is critical for rapid and correct patient management. Various serological tests are used, including commercial kits that require qualifications with specific information about their performance. In this study, we compared the performance of six commercial kits, two immunochromatographic tests (ICT; IT LEISH and TruQuick LEISH IgG/IgM Meridian) and four enzyme-linked immunosorbent assays (ELISA; NovaLisa Leishmania infantum IgG, Bordier Leishmania infantum, Ridascreen Leishmania IgG, and Vircell Leishmania), available in France and used as screening tests. The Bordier and Vircell ELISA reagents displayed the highest analytic performance compared with all the other kits. However, no test displayed 95% sensitivity at the thresholds recommended by the manufacturers. To reach this sensitivity value with the highest possible specificity, new thresholds are proposed for the Bordier, Vircell and NovaLisa ELISA reagents. Positive and negative results obtained with the six screening tests were confirmed by Western blot (100% sensitivity). Overall, this study presents a comparative analysis of commercially available kits for the serodiagnosis of human VL and provides additional information on the prevalence of asymptomatic carriers in the Mediterranean basin.

A case of visceral leishmaniasis found by left oblique hernia: A case report

Visceral leishmaniasis (VL) is an infectious disease caused by Leishmania protozoa. Since sporadic cases of this disease are noted in non-endemic areas and are associated with a limited outbreak, the disease is easily overlooked. In addition, other illnesses exhibit similar symptoms. It is difficult for clinicians to establish an accurate diagnosis and develop effective treatments for this disease. The present study reported a case of a 25-year-old young man admitted to the hospital due to oblique hernia. The case was diagnosed as VL. The patient presented with persistent night sweats and fatigue as described in his admission history. However, the body temperature was normal. Routine examination revealed that the patient exhibited chronic hepatitis B infection, pancytopenia, hepatosplenomegaly, increased erythrocyte sedimentation rate, significant plasma cell infiltration in bone marrow aspirate and hypergammaglobulinemia. The retrospective analysis of the present case can improve the diagnostic accuracy and treatment rate of VL in non-epidemic areas.

Parasitic Infections of the Stem Cell Transplant Recipient and the Hematologic Malignancy Patient, Including Toxoplasmosis and Strongyloidiasis

Hematopoietic stem cell transplantation (HSCT) recipients may infrequently develop parasitic infections at the time of the procedure via contamination from allograft tissue or blood products, and in the post-transplantation period through the traditional route of infection or as a reactivation caused by immunosuppression related to the transplant. To reduce risk, efforts should be directed at performing a comprehensive history, maintaining a high index of suspicion, and adhering to preventive measures. Additional strategies for the prevention, screening and careful follow-up, identification, and pre-emptive treatment of parasitic infections are required to reduce morbidity and mortality in HSCT patients.

Development and Clinical Evaluation of Loop-Mediated Isothermal Amplification (LAMP) Assay for the Diagnosis of Human Visceral Leishmaniasis in Brazil

Visceral leishmaniasis (VL) is considered a major public health concern in Brazil and several regions of the world. A recent advance in the diagnosis of infectious diseases was the development of loop-mediated isothermal amplification (LAMP). The aim of this study was to develop and evaluate a new LAMP assay for detection of K26 antigen-coding gene of L. donovani complex. A total of 219 blood samples of immunocompetent patients, including 114 VL cases and 105 non-VL cases, were analyzed for the diagnosis of VL in the present study. Diagnostic accuracy was calculated against a combination of parasitological and/or serological tests as a reference standard. The results were compared to those of kDNA Leishmania-PCR. The detection limit for the K26-Lamp assay was 1fg L. infantum purified DNA and 100 parasites/mL within 60 min of amplification time with visual detection for turbidity. The assay was specific for L. donovani complex. Sensitivity, specificity, and accuracy were 98.2%, 98.1%, and 98.2%, respectively, for K26-LAMP and 100%, 100%, and 100%, respectively, for kDNA Leishmania-PCR. Excellent agreement was observed between K26-LAMP and kDNA Leishmania-PCR assays (K = 0.96). A highly sensitive and specific LAMP assay targeting K26 antigen-coding gene of L. donovani complex was developed for diagnosis in peripheral blood samples of VL patients.

First molecular characterization of Leishmania infantum species in patients infected with visceral leishmaniasis in Misiones province, Argentina

Introduction: Cutaneous leishmaniasis caused by L. braziliensis has been historically endemic in Argentina and several cases of visceral leishmaniasis following initial cutaneous leishmaniasis have been reported. Visceral leishmaniasis started to appear in Argentina in 2006 in the city of Posadas, Misiones province, affecting both humans and dogs. Objective: To identify the etiologic agent to species level in patients with visceral leishmaniasis diagnosis in Misiones province and describe its clinical and epidemiological characteristics. Materials and methods: A cohort of 24 patients from Misiones province was studied from 2009 to 2016, all with a confirmed diagnosis of visceral leishmaniasis. To identify the Leishmania species involved, patient samples were analyzed by microscopy, serologic studies, DNA detection, and sequencing. Variables such as age, sex, place of residence, clinical signs and symptoms consistent with visceral leishmaniasis were also recorded. Results: 75% (18/24) of the patients studied were males and 25% (6/24) were younger than 4 years. The most frequent symptom was a prolonged fever in 87.5% of the patients (21/24), followed by splenomegaly in 70.8% (17/24). Leishmania infantum was the only parasite species identified in all patients. Conclusion: This finding constitutes the first molecular identification of the Leishmania infantum species in autochthonous patients of Misiones province, Argentina. This study highlights the importance of PCR for species identification in epidemiological studies of visceral leishmaniosis in Argentina.

Development of a Multiplexed Assay for Detection of Leishmania donovani and Leishmania infantum Protein Biomarkers in Urine Samples of Patients with Visceral Leishmaniasis

Visceral leishmaniasis (VL) is a serious and fatal disease caused by the parasites Leishmania infantum and Leishmania donovani The gold standard diagnostic test for VL is the demonstration of parasites or their DNA in spleen, lymph node, or bone marrow aspirates. Serological tests exist but cannot distinguish active VL from either prior exposure to the parasites or previously treated VL disease. Using mass spectroscopy, we have previously identified three L. infantum protein biomarkers (Li-isd1, Li-txn1, and Li-ntf2) in the urine of VL patients and developed a sensitive and specific urine-based antigen detection assay for the diagnosis of VL that occurs in Brazil (where VL is caused by L. infantum). However, unpublished observations from our laboratory at DetectoGen showed that these biomarkers were detected in only 55% to 60% of VL patients from India and Kenya, where the disease is caused by L. donovani Here, we report the discovery and characterization of two new biomarkers of L. donovani (Ld-mao1 and Ld-ppi1) present in the urine of VL patients from these two countries. Capture enzyme-linked immunosorbent assays using specific rabbit IgG and chicken IgY were developed, and the assays had sensitivities of 44.4% and 28.8% for the detection of Ld-mao1 and Ld-ppi1, respectively. In contrast, a multiplexed assay designed to simultaneously detect all five leishmanial biomarkers markedly increased the assay sensitivity to 82.2%. These results validate the utility of leishmanial protein biomarkers found in the urine of VL patients as powerful tools for the development of an accurate diagnostic test for this disease.

Fever of Unknown Origin: Don't Forget Kala-Azar Even in Europe

We present the case of a 70-year-old male patient with fever of unknown origin after a long period of convalescence from a previous admission to a chronic care hospital. During the admission, multiple combinations of antibiotic and antifungal treatments were prescribed, but with persistent fever and, eventually, neutropenia (200 lymphocytes, 0 neutrophils). Given the suspicion of infection at bone marrow level, a biopsy was performed as was serology of Leishmania, both diagnostic determinations. Treatment with amphotericin B liposomal resulted in a good outcome.

Validation of SYBR green I based closed tube loop mediated isothermal amplification (LAMP) assay and simplified direct-blood-lysis (DBL)-LAMP assay for diagnosis of visceral leishmaniasis (VL)

Background

The World Health Organization has targeted elimination of visceral leishmaniasis (VL) in the Indian subcontinent (ISC) by 2020. Despite distinctive decline seen in the number of VL cases in ISC, there is still a quest for development of a diagnostic test which has the utility for detection of active infection and relapse cases and as a test of cure. The present study validated the sensitivity and specificity of SYBR Green I based closed tube LAMP assay reported by us for diagnosis of VL.

Methodology

The validation study was carried out at two endemic sites in India, located at Rajendra Memorial Research Institute of Medical Sciences (RMRIMS), Patna and Institute of Medical Sciences (IMS), Banaras Hindu University (BHU), Varanasi. Standard operating protocols were provided at the two sites for applying LAMP assay on confirmed VL cases. The diagnostic accuracy of LAMP assay was evaluated by Receiver operator curve (ROC) analysis. Furthermore, a simplified LAMP assay based on direct blood lysis, DBL-LAMP, was developed and verified for its diagnostic accuracy.

Principal findings

A total of 267 eligible participants were included in the study which comprised of 179 VL cases and 88 controls. Sensitivity and specificity of the LAMP assay were 98.32% (95% C.I– 95.2–99.7%) and 96.59% (95% C.I.-90.4–99.3%), respectively. ROC curve analysis depicted no significant difference between area under curve (AUC_ROC) for LAMP assay and rK39 RDT, indicative of LAMP as an excellent diagnostic test. DBL-LAMP assay, performed on 67 VL and 100 control samples, yielded a sensitivity of 93.05% (95% C.I- 84.75–97%) and specificity of 100% (95% C.I.- 96.30–100%).

Conclusions/Significance

The validated closed tube LAMP for diagnosis of VL will provide impetus to the ongoing VL elimination programme in ISC. The assay based on direct blood lysis promotes its scope for application in field settings by further reducing time and cost.

Definitive diagnosis of visceral leishmaniasis(VL) by demonstration of amastigotes by microscopy is invasive and risky. Serology based diagnosis using rK39 rapid diagnostic test(RDT) has excellent sensitivity of~97% when combined with clinical symptoms but is inconclusive for detection of active infection and relapses due to persistence of anti-leishmanial antibodies. The developed SYBR Green I based closed tube LAMP assay overcomes these constraints and further, direct blood lysis (DBL)-LAMP, makes it more suitable for field application. The study involved validation of LAMP assay at two endemic sites in India, on a total of 179 VL patients confirmed by rK39 RDT and/ or microscopy and 88 controls. The assay was highly sensitive (98.32%) and specific (96.59%). Further, DBL-LAMP assay yielded a sensitivity and specificity of 93.05% and 100%, respectively. In conclusion, the study has validated the field potential of LAMP assay for diagnosis of VL which will provide momentum to ongoing VL elimination in the Indian subcontinent (ISC).

Evaluation of Real-time PCR for Diagnosis of Post-Kala-azar Dermal Leishmaniasis in Endemic Foci of Bangladesh

Background

Post-kala-azar dermal leishmaniasis (PKDL) is a sequel to visceral leishmaniasis (VL), which is found in VL-endemic countries including Bangladesh. Because of these enigmatic cases, the success of the National Kala-azar Elimination Program is under threat. To date, diagnostic methods for PKDL cases in endemic regions have been limited to clinical examination and rK39 test or microscopy, and a suitable and accurate alternative method is needed. In this study, we investigated the application of real-time polymerase chain reaction (PCR) as a potential method for diagnosis of PKDL in comparison with microscopy.

Methods

Ninety-one suspected macular PKDL cases from Mymensingh district, Bangladesh, were enrolled in the study after diagnosis by clinical examination and an rK39 strip test. All of them responded after completion of the treatment with miltefosine. During enrollment, a skin biopsy was done for each patient, and both microscopy and real-time PCR were performed for detection and quantification of Leishmania donovan body (LDB) and LD DNA, respectively.

Results

Real-time PCR detected 83 cases among all suspected PKDL patients, with an encouraging sensitivity of 91.2% (83.4%–96.1%), whereas microscopy showed 50.6% (39.9%–61.2%) sensitivity. Among all suspected PKDL cases, 42 cases were positive in both microscopy and qPCR, whereas 41 cases were detected as positive through qPCR only.

Conclusions

This study provides evidence that real-time PCR is a promising tool for diagnosis of PKDL in endemic regions. In addition to diagnosis, the quantitative ability of this method could be further exploited for after-treatment prognosis and cure assessment of PKDL cases.

Visceral leishmaniasis in hematopoietic cell transplantation: Case report and review of the literature

Visceral leishmaniasis has been recognized as an opportunistic infection affecting people with cellular-immunity impairment, including hematopoietic cell transplantation (HCT) recipients. We describe the case of a young Italian man with Hodgkin lymphoma, who developed visceral leishmaniasis after multiple lines of chemotherapy and allogenic HCT. Literature review of visceral leishmaniasis in HCT recipients was also performed. Eleven patients (median age 50 years, 9 male) developed visceral leishmaniasis after allogenic (n = 9) and autologous (n = 2) HCT. Most of them presented with fever and pancytopenia. Bone marrow examination was the main diagnostic technique; liposomal amphotericin B was the treatment of choice. Four out of eight patients (for whom data are available) experienced visceral leishmaniasis relapse. Visceral leishmaniasis in HCT recipients is a rare event that should be suspected in patients with persistent fever, pancytopenia and possible exposure to Leishmania spp., remembering that - as well as South-East Asia, East Africa and South America - it is endemic in several European regions.

Comparative analysis of real-time PCR assays in the detection of canine visceral leishmaniasis

Dogs are important hosts and reservoirs of leishmaniasis, a disease caused by protozoan parasites from the genus Leishmania, affecting ~12 million people worldwide. The detection of visceral leishmaniasis (VL) in dogs by real-time PCR (qPCR) may improve on diagnosis, but the different qPCR methods available for Leishmania DNA detection have not been established as routine in diagnostic tools and/or epidemiologic studies for canine VL. Here, we compared three qPCR assays (DNApol, Linj31, and LDON) in the detection of VL by Leishmania infantum in spleen (n = 48; 7), skin (n = 48; 7), and whole blood (n = 44; 7) samples from serologically positive and negative dogs, respectively. Overall, the DNApol performed better than the Linj31 and LDON assays in the detection of positive samples in all tissues tested, yielding from 66.7 to 100.0% of positivity for both skin and spleen samples. For spleen samples, we observed no statistically significant differences between positive detection by the LDON and DNApol assays. Whole blood samples yielded the lowest rates of positive detection, regardless of the qPCR assay used. In contrast, positive detection of Leishmania DNA was as efficient from skin samples using the DNApol assay as from spleen samples using either the DNApol or the LDON assay. Although qPCR assays from skin samples may not be practical for use in the field, our study suggests that the DNApol and LDON assays from skin samples could be used in future to evaluate canine VL treatment in veterinary clinics.

Epidemiological and clinical features of visceral leishmaniasis in children in Alicante Province, Spain

BACKGROUND

Visceral leishmaniasis (VL) is endemic to the Mediterranean basin. In children, VL often presents with non-specific symptoms and can be life-threatening without proper treatment.

AIM

To describe the epidemiological and clinical features of pediatric VL in children in Alicante, Spain.

METHODS

The study included all paediatric (<15 years) cases admitted to three hospitals in the province of Alicante from May 1992 to May 2015 with diagnosis of VL (detection was either by anti-Leishmania antibodies in serology or Leishmania in blood and/or bone marrow aspirates).

RESULTS

There were 38 cases of pediatric VL (18 aged <24 months, 15 aged 24-59 months and 5 aged ≥5 years). The main symptoms were fever (97.4%), followed by pallor (75.0%) and loss of appetite (46.4%). Eighty-seven per cent of patients were anaemic (haemoglobin < 9 g/dL), 73.7% had neutropenia and 68.4% had thrombocytopenia. Before 2004, 92.3% of patients were treated with meglumine antimoniate (MA) and 7.7% with liposomal amphotericin B (LAmB); after 2004, 84% were treated with LAmB and just one (16%) with MA (p < 0.001). LAmB performed better than MA in terms of mean treatment length (7.4 days vs 25.9 days, p < 0.001), time to becoming afebrile (1.7 vs 13.7 days, p < 0.001), and length of hospital stay (10.9 vs 19.4 days, p = 0.001).

CONCLUSION

Paediatric VL in Alicante mainly affects children under five. Children aged ≤24 months present with a lower haemoglobin and white blood cell count. Treatment with LAmB reduces treatment length, time to becoming afebrile and length of hospital stay.

Molecular diagnosis of protozoan parasites by Recombinase Polymerase Amplification

Infections caused by protozoan parasites affect millions of people around the world. Traditionally, diagnosis was made by microscopy, which is insensitive and in some cases not specific. Molecular methods are highly sensitive and specific, but equipment costs and personnel training limit its availability only to specialized centers, usually far from populations with the highest risk of infection. Inexpensive methods that can be applied at the point of care (POC), especially in places with limited health infrastructure, would be a major advantage. Isothermal amplification of nucleic acids does not require thermocyclers and is relatively inexpensive and easy to implement. Among isothermal methods, recombinase polymerase amplification (RPA) is sensitive and potentially applicable at POC. We and others have developed RPA diagnostic tests to detect protozoan parasites of medical importance. Overall, our results have shown high specificity with limits of detection similar to PCR. Currently, the optimization of RPA for use at the POC is under development, and in the near future the tests should become available to detect protozoan infections in the field. In this review we discuss the current status, challenges, and future of RPA in the field of molecular diagnosis of protozoan parasites.

Evaluation of fluorimetry and direct visualization to interpret results of a loop-mediated isothermal amplification kit to detect Leishmania DNA

Background

Nucleic acid amplification tests (NAATs) have proven to be advantageous in the diagnosis of leishmaniases, allowing sensitive diagnosis of: (i) cutaneous leishmaniasis in long duration lesions and (ii) visceral leishmaniasis using a less-invasive sample like peripheral blood, in opposition to tissue aspiration required for parasite demonstration by microscopy. Despite their benefits, the implementation of NAATs for leishmaniasis diagnosis at the point-of-care has not been achieved yet, mostly due to the complexity and logistical issues associated with PCR-based methods.

Methods

In this work, we have evaluated the performance of a ready-to-use loop-mediated isothermal amplification (LAMP) kit using two real time fluorimeters to amplify leishmanial DNA obtained by silica column-based and Boil & Spin protocols.

Results

The different approaches used to run and interpret the LAMP reactions showed a performance equivalent to PCR and real-time PCR, using spiked and clinical samples. The time to positivity obtained with real-time fluorimetry showed an excellent correlation with both Ct values and parasite load from real-time quantitative PCR.

Conclusions

The results obtained open the possibility of using a highly stable, ready-to-use LAMP kit for the accurate diagnosis of leishmaniasis at the point-of-care. Furthermore, the feasibility of relating time to positivity, determined with a portable real-time fluorimeter, with the parasite burden could have a wider application in the management of leishmaniasis, such as in treatment efficacy monitoring or as a pharmacodynamics tool in clinical trials.

Leishmania Antigenuria to Predict Initial Treatment Failure and Relapse in Visceral Leishmaniasis/HIV Coinfected Patients: An Exploratory Study Nested Within a Clinical Trial in Ethiopia

Background: Biomarkers predicting the risk of VL treatment failure and relapse in VL/HIV coinfected patients are needed. Nested within a two-site clinical trial in Ethiopia (2011–2015), we conducted an exploratory study to assess whether (1) levels of Leishmania antigenuria measured at VL diagnosis were associated with initial treatment failure and (2) levels of Leishmania antigenuria at the end of treatment (parasitologically-confirmed cure) were associated with subsequent relapse.

Methods:Leishmania antigenuria at VL diagnosis and cure was determined using KAtex urine antigen test and graded as negative (0), weak/moderate (grade 1+/2+) or strongly-positive (3+). Logistic regression and Kaplan-Meier methods were used to assess the association between antigenuria and (1) initial treatment failure, and (2) relapse over the 12 months after cure, respectively.

Results: The analysis to predict initial treatment failure included sixty-three coinfected adults [median age: 30 years interquartile range (IQR) 27–35], median CD4 count: 56 cells/μL (IQR 38–113). KAtex results at VL diagnosis were negative in 11 (17%), weak/moderate in 17 (27%) and strongly-positive in 35 (36%). Twenty (32%) patients had parasitologically-confirmed treatment failure, with a risk of failure of 9% (1/11) with KAtex-negative results, 0% (0/17) for KAtex 1+/2+ and 54% (19/35) for KAtex 3+ results. Compared to KAtex-negative patients, KAtex 3+ patients were at increased risk of treatment failure [odds ratio 11.9 (95% CI 1.4–103.0); P: 0.025].

Forty-four patients were included in the analysis to predict relapse [median age: 31 years (IQR 28–35), median CD4 count: 116 cells/μL (IQR 95–181)]. When achieving VL cure, KAtex results were negative in 19 (43%), weak/moderate (1+/2+) in 10 (23%), and strongly positive (3+) in 15 patients (34%). Over the subsequent 12 months, eight out of 44 patients (18%) relapsed. The predicted 1-year relapse risk was 6% for KAtex-negative results, 14% for KAtex 1+/2+ and 42% for KAtex 3+ results [hazard ratio of 2.2 (95% CI 0.1–34.9) for KAtex 1+/2+ and 9.8 (95% CI 1.8–82.1) for KAtex 3+, compared to KAtex negative patients; P: 0.03].

Conclusion: A simple field-deployable Leishmania urine antigen test can be used for risk stratification of initial treatment failure and VL relapse in HIV-patients. A dipstick-format would facilitate field implementation.

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.

Sensitive and less invasive confirmatory diagnosis of visceral leishmaniasis in Sudan using loop-mediated isothermal amplification (LAMP)

Background

Confirmatory diagnosis of visceral leishmaniasis (VL), as well as diagnosis of relapses and test of cure, usually requires examination by microscopy of samples collected by invasive means, such as splenic, bone marrow or lymph node aspirates. This causes discomfort to patients, with risks of bleeding and iatrogenic infections, and requires technical expertise. Molecular tests have great potential for diagnosis of VL using peripheral blood, but require well-equipped facilities and trained personnel. More user-friendly, and field-amenable options are therefore needed. One method that could meet these requirements is loop-mediated isothermal amplification (LAMP) using the Loopamp Leishmania Detection Kit, which comes as dried down reagents that can be stored at room temperature, and allows simple visualization of results.

Methodology/Principal findings

The Loopamp Leishmania Detection Kit (Eiken Chemical Co., Japan), was evaluated in the diagnosis of VL in Sudan. A total of 198 VL suspects were tested by microscopy of lymph node aspirates (the reference test), direct agglutination test-DAT (in house production) and rK28 antigen-based rapid diagnostic test (OnSite Leishmania rK39-Plus, CTK Biotech, USA). LAMP was performed on peripheral blood (whole blood and buffy coat) previously processed by: i) a direct boil and spin method, and ii) the QIAamp DNA Mini Kit (QIAgen). Ninety seven of the VL suspects were confirmed as cases by microscopy of lymph node aspirates. The sensitivity and specificity for each of the tests were: rK28 RDT 98.81% and 100%; DAT 88.10% and 78.22%; LAMP-boil and spin 97.65% and 99.01%; LAMP-QIAgen 100% and 99.01%.

Conclusions/Significance

Due to its simplicity and high sensitivity, rK28 RDT can be used first in the diagnostic algorithm for primary VL diagnosis, the excellent performance of LAMP using peripheral blood indicates that it can be also included in the algorithm for diagnosis of VL as a simple test when parasitological confirmatory diagnosis is required in settings that are lower than the reference laboratory, avoiding the need for invasive lymph node aspiration.

Tissue aspiration, either from spleen, bone marrow or lymph node, remains the Gold Standard for parasitological confirmation in patients suspected of visceral leishmaniasis (VL), and is often used for detection of relapses, and as a test of cure. The procedure is invasive, with risks of severe complications, requires skilled personnel to perform, and appropriate facilities to manage severe adverse events, if they occur. These drawbacks can be solved by using sensitive diagnostic test based on peripheral blood. Nucleic acid amplification tests (NAAT) are sensitive for the detection of Leishmania parasites in blood; however, in VL-endemic settings, most NAAT are restricted to well-equipped laboratories. A robust NAAT, Loopamp Leishmania Detection Kit has recently been developed in a collaboration between FIND, Eiken Chemical Co. Ltd., Japan and other partners. We have evaluated this kit in Sudan and obtained a sensitivity of 97.6% and specificity of 99.1%, using DNA obtained from peripheral blood through a simple boil and spin method. Its simplicity and excellent diagnostic performance make this kit ideal for parasitological confirmation of VL in less equipped laboratories.

Real-time PCR in detection and quantitation of Leishmania donovani for the diagnosis of Visceral Leishmaniasis patients and the monitoring of their response to treatment

Sustained elimination of Visceral Leishmaniasis (VL) requires the reduction and control of parasite reservoirs to minimize the transmission of Leishmania donovani infection. A simple, reproducible and definitive diagnostic procedure is therefore indispensable for the early and accurate detection of parasites in VL, Relapsed VL (RVL) and Post Kala-azar Dermal Leishmaniasis (PKDL) patients, all of whom are potential reservoirs of Leishmania parasites. To overcome the limitations of current diagnostic approaches, a novel quantitative real-time polymerase chain reaction (qPCR) method based on Taqman chemistry was devised for the detection and quantification of L. donovani in blood and skin. The diagnostic efficacy was evaluated using archived peripheral blood buffy coat DNA from 40 VL, 40 PKDL, 10 RVL, 20 cured VL, and 40 cured PKDL along with 10 tuberculosis (TB) cases and 80 healthy endemic controls. Results were compared to those obtained using a Leishmania-specific nested PCR (Ln-PCR). The real time PCR assay was 100% (95% CI, 91.19-100%) sensitive in detecting parasite genomes in VL and RVL samples and 85.0% (95% CI, 70.16-94.29%) sensitive for PKDL samples. In contrast, the sensitivity of Ln-PCR was 77.5% (95% CI, 61.55-89.16%) for VL samples, 100% (95%CI, 69.15-100%) for RVL samples, and 52.5% (95% CI, 36.13-68.49%) for PKDL samples. There was significant discordance between the two methods with the overall sensitivity of the qPCR assay being considerably higher than Ln-PCR. None of the assay detected L. donovani DNA in buffy coats from cured VL cases, and reduced infectious burdens were demonstrated in cured PKDL cases who remained positive in 7.5% (3/40) and 2.5% (1/40) cases by real-time PCR and Ln-PCR, respectively. Both assays were 100% (95% CI, 95.98-100) specific with no positive signals in either endemic healthy control or TB samples. The real time PCR assay we developed offers a molecular tool for accurate detection of circulating L. donovani parasites in VL, PKDL and RVL patients, as well as being capable of assessing response to treatment. As such, this real time PCR assay represents an important contribution in efforts to eliminate VL.

Serological and molecular tools to diagnose visceral leishmaniasis: 2-years' experience of a single center in Northern Italy

The diagnosis of visceral leishmaniasis (VL) remains challenging, due to the limited sensitivity of microscopy, the poor performance of serological methods in immunocompromised patients and the lack of standardization of molecular tests. The aim of this study was to implement a combined diagnostic workflow by integrating serological and molecular tests with standardized clinical criteria. Between July 2013 and June 2015, the proposed workflow was applied to specimens obtained from 94 in-patients with clinical suspicion of VL in the Emilia-Romagna region, Northern Italy. Serological tests and molecular techniques were employed. Twenty-one adult patients (22%) had a confirmed diagnosis of VL by clinical criteria, serology and/or real-time polymerase chain reaction; 4 of these patients were HIV-positive. Molecular tests exhibited higher sensitivity than serological tests for the diagnosis of VL. In our experience, the rK39 immunochromatographic test was insufficiently sensitive for use as a screening test for the diagnosis of VL caused by L. infantum in Italy. However, as molecular tests are yet not standardized, further studies are required to identify an optimal screening test for Mediterranean VL.

Novel PCR primers to diagnose visceral leishmaniasis using peripheral blood, spleen or bone marrow aspirates

OBJECTIVE

To establish a suitable method of diagnosis of visceral leishmaniasis (VL) using peripheral blood, spleen or bone marrow aspirates.

METHODS

Peripheral blood, bone marrow and spleen aspirate samples were collected from clinically suspected VL patients (n = 26). A new PCR primer pair (MK1F/R) was designed targeting kinetoplast mini circle DNA sequences of Leishmania donovani, and Leishmania infantum, and was used to diagnose VL along with some other established primers for VL in polymerase chain reactions. Test was validated by comparing with several other diagnostic methods.

RESULTS

The designed primer set showed 100% specificity and 98% sensitivity in detecting VL using blood samples, when compared with more invasive samples: bone marrow or spleen aspirates.

CONCLUSIONS

The newly designed primer MK1F/R could be a better alternative for PCR based diagnosis of VL using less invasive sample, peripheral blood instead of bone marrow or spleen aspirates.

Cost-effectiveness of diagnostic-therapeutic strategies for paediatric visceral leishmaniasis in Morocco

Introduction

Visceral leishmaniasis (VL) is a neglected parasitic disease with a high fatality rate if left untreated. Endemic in Morocco, as well as in other countries in the Mediterranean basin, VL mainly affects children living in rural areas. In Morocco, the direct observation of Leishmania parasites in bone marrow (BM) aspirates is used to diagnose VL and meglumine antimoniate (SB) is the first line of treatment. Less invasive, more efficacious and safer alternatives exist. In this study we estimate the cost-effectiveness of alternative diagnostic-therapeutic algorithms for paediatric VL in Morocco.

Methods

A decision tree was used to estimate the cost-effectiveness of using BM or rapid diagnostic tests (RDTs) as diagnostic tools and/or SB or two liposomal amphotericin B (L-AmB) regimens: 6-day and 2-day courses to treat VL. Incremental cost-effectiveness ratios, expressed as cost per death averted, were estimated by comparing costs and effectiveness of the alternative algorithms. A threshold analysis evaluated at which price L-AmB became cost-effective compared with current practices.

Results

Implementing RDT and/or L-AmB treatments would be cost-effective in Morocco according to the WHO thresholds. Introducing the 6-day course L-AmB, current second-line treatment, would be highly cost-effective if L-AmB price was below US$100/phial. The 2-day L-AmB treatment, current standard treatment of paediatric VL in France, is highly cost-effective, with L-AmB at its market price (US$165/phial).

Conclusions

The results of this study should encourage the implementation of RDT and/or short-course L-AmB treatments for paediatric VL management in Morocco and other North African countries.

Exploring prognosis in chronic relapsing visceral leishmaniasis among HIV-infected patients: Circulating Leishmania DNA

BACKGROUND

Visceral leishmaniasis (VL) affecting HIV-infected patients is considered a challenging condition because of its high mortality and relapse rates. The approach of this condition is still surrounded by many uncertainties, especially regarding the criteria to institute and discontinue secondary prophylaxis for VL. The aim of this study was to evaluate the Leishmania parasitism kinetic assessed by polymerase chain reaction (PCR) as a possible tool in the prognostic assessment in a context in which patients are receiving highly active antiretroviral therapy and secondary prophylaxis.

METHODS

A prospective observation of Leishmania-HIV-co infected patients was performed and two groups with distinct clinical prognosis unpredicted by their CD4 count at the moment of VL diagnosis and not related to their HIV load control were confirmed.

RESULTS

Relapsing (R) and non-relapsing (NR) patients had similar antiviral therapy use rates, CD4 lymphocyte count medians and HIV load levels at VL-diagnosis. At the 12-month follow-up, R-patients presented a significantly lower CD4 lymphocyte count than NR-patients, without difference in HIV load control. The time between HIV and VL diagnoses was longer in the R than NR-group. Comparison between Kaplan-Meier relapse-free survival curves (time to relapse) using a log rank test showed that patients presenting circulating Leishmania DNA had a significantly higher risk of clinical VL relapse within 4 months after a positive test (p=0.001).

CONCLUSIONS

These results reinforce that a negative PCR could be a useful tool to support prophylaxis interruption among patients with CD4 counts above 200cells/mm³ and that a positive PCR suggests imminent VL relapse.

Development of a rapid loop-mediated isothermal amplification assay for diagnosis and assessment of cure of Leishmania infection

Background

Leishmaniasis is a spectrum of diseases with great relevance to public health. Conventional diagnostic methods are time consuming, needing trained personnel. A robust, rapid and cost effective diagnostic test is warranted for on-time diagnosis and field application.

Methods

We have developed a loop mediated isothermal amplification (LAMP) assay with primers (n = 6) based on Leishmania donovani kDNA for detection of Leishmania infection, using a closed tube to prevent cross-contamination. The assay was used to detect Leishmania infection in biological samples obtained from patients of visceral leishmaniasis (VL), post kala-azar dermal leishmaniasis (PKDL) and cutaneous leishmaniasis (CL).

Results

The assay was positive for L. donovani, L. tropica and L. major parasites, with the highest sensitivity towards L. donovani (1 fg DNA). The high sensitivity of the assay for detection of L. donovani was reflected in its ability to detect parasite DNA within 30 min of amplification time with a threshold detection limit of ≥25 copies per reaction. The assay detected parasite in 64 of 66 VL blood samples (sensitivity, 96.9%; 95% CI: 89.6-99.2%), 15 of 15 VL bone marrow aspirate samples (sensitivity, 100%; 95% CI:79.6-100%), 65 of 67 PKDL tissue biopsy samples (sensitivity, 97%; 95% CI:89.7-99.2%). The assay was evaluated in a few cases of CL wherein it was found positive in 8 of 10 tissue biopsies (sensitivity, 80%; 95% CI: 49-94.3%). The assay was negative in all control blood (n = 76) and tissue biopsy (n = 24) samples (specificity, 100%; 95% CI: 96.3-100%). Further, the assay was evaluated for its utility in assessment of cure in treated VL and PKDL patients. The assay detected parasite DNA in 2 of 20VL blood samples and 2 of 21 PKDL tissue samples. Out of 4 cases that were positive for parasite DNA at post treatment stage, 2 patients (1VL and 1 PKDL) returned with relapse.

Conclusions

The study demonstrated a Leishmania genus specific closed tube LAMP assay for reliable and rapid molecular diagnosis of VL and PKDL with potential for application in assessment of cure.