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

Re-emergence of human leishmaniasis in northern Italy, 2004 to 2022: a retrospective analysis

BackgroundHuman leishmaniasis is a protozoan disease transmitted by sand flies and endemic in the Mediterranean region. In Italy, leishmaniasis is present in the south and the western coastal regions, with an epidemic peak detected in northern Italy in the early 1970s.AimTo examine temporal trends, and demographic, clinical, geographical and environmental features of human leishmaniasis cases recorded by the local health unit (LHU) of Bologna, northern Italy.MethodsIn this retrospective observational study, we analysed human leishmaniasis cases recorded from 2004 to 2022 within the Bologna LHU. We also conducted serological investigations for canine leishmaniasis in owned dogs living near the place of infection of human cases.ResultsIn total, 173 cases of human leishmaniasis were detected, and 154 cases were considered autochthonous. An increase of human cases was observed since 2004, with incidence peaks above 2 cases/100,000 inhabitants in 2013, 2018 and 2022; epidemic peaks were preceded by dry summers. Most cases lived in the plain and hilly areas less than 400 m above sea level and many resided in isolated housing, in city outskirts, and/or near uncultivated areas, watercourses and railway sections. The incidence of canine leishmaniasis did not increase in the study period.ConclusionAn epidemic of human leishmaniasis with fluctuating annual numbers of cases, probably related to environmental and climatic factors, was identified in the Bologna LHU. Understanding the risk factors and the environmental characteristics related to places of infection is crucial to evaluate the public health implications of leishmaniasis.

A 10-Year Retrospective Study on Pediatric Visceral Leishmaniasis in a European Endemic Area: Diagnostic and Short-Course Therapeutic Strategies

BACKGROUND

Visceral leishmaniasis (VL) is a potentially fatal disease, with an increasing occurrence in northern Italy, affecting children and both immunocompetent and immunocompromised adults.

METHODS

This retrospective study conducted at the St. Orsola University Hospital of Bologna, Italy, evaluates the characteristics of 16 children (with a median age of 14.3 months) who were hospitalized between 2013 and 2022 for VL.

RESULTS

Seventy-five percent of patients presented with a triad of fever, cytopenia, and splenomegaly. An abdominal ultrasound examination revealed splenomegaly and hypoechoic spleen abnormalities in 93.8% and 73.3% of cases, respectively. Five VL cases were complicated by secondary hemophagocytic lymphohistiocytosis. Eleven patients were treated with a single 10 mg/kg dose of Liposomal Amphotericin B (L-AmB), while five received two doses (total of 20 mg/kg); one of the former groups experienced a recurrence. The fever generally decreased 48 h after the first L-AmB dose, and hemoglobin levels normalized within a month. The splenomegaly resolved in approximately 4.5 months.

CONCLUSIONS

Pediatricians should consider VL in children with fever of an unknown origin, anemia, cytopenia, and splenomegaly. In our experience, abdominal ultrasounds and molecular tests on peripheral blood contributed to diagnosis without the need for bone marrow aspiration. The short-course therapy with two 10 mg/kg doses of L-AmB is safe and effective.

The estimated distribution of autochthonous leishmaniasis by Leishmania infantum in Europe in 2005-2020

BACKGROUND

This study describes the spatial and temporal distribution between 2005 and 2020 of human and animal leishmaniasis by Leishmania infantum in European countries reporting autochthonous cases, and highlights potential activities to improve disease control.

METHODOLOGY/PRINCIPAL FINDINGS

It was based on a review of the scientific literature and data reported by the World Health Organization (WHO), the World Organization for Animal Health (WOAH) and the Ministries of Health, including hospital discharges in some countries. Autochthonous infections were reported in the scientific literature from 22 countries, including 13 and 21 countries reporting human and animal infections, respectively. In contrast, only 17 countries reported autochthonous human leishmaniasis cases to the WHO and 8 countries animal infections to the WOAH. The number of WOAH reported cases were 4,203, comprising 4,183 canine cases and 20 cases in wildlife. Of 8,367 WHO reported human cases, 69% were visceral leishmaniasis cases-of which 94% were autochthonous-and 31% cutaneous leishmaniasis cases-of which 53% were imported and mostly in France. The resulting cumulative incidence per 100,000 population of visceral leishmaniasis between 2005-2020, was highest in Albania (2.15 cases), followed by Montenegro, Malta, Greece, Spain and North Macedonia (0.53-0.42), Italy (0.16), Portugal (0.09) and lower in other endemic countries (0.07-0.002). However, according to hospital discharges, the estimated human leishmaniasis incidence was 0.70 in Italy and visceral leishmaniasis incidences were 0.67 in Spain and 0.41 in Portugal.

CONCLUSIONS/SIGNIFICANCE

Overall, there was no evidence of widespread increased incidence of autochthonous human leishmaniasis by L. infantum in European countries. Visceral leishmaniasis incidence followed a decreasing trend in Albania, Italy and Portugal, and peaked in Greece in 2013, 2014 and 2017, and in Spain in 2006-2007 and 2011-2013. Animal and human cutaneous leishmaniasis remain highly underreported. In humans, hospital discharge databases provide the most accurate information on visceral leishmaniasis and may be a valuable indirect source of information to identify hotspots of animal leishmaniasis. Integrated leishmaniasis surveillance and reporting following the One Health approach, needs to be enhanced in order to improve disease control.

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.

Updated diagnosis and graft involvement for visceral leishmaniasis in kidney transplant recipients: a case report and literature review

Purpose

Visceral leishmaniasis (VL) has become a rising concern to transplantation teams, being associated with graft dysfunction and reduced survival of renal transplant recipients. Here, we describe a case of VL occurring in a kidney transplant (KT) recipient in Italy, a country in which Leishmania infantum is endemic and we reviewed the literature on the clinical course and diagnosis of VL in KT recipients residing or travelling to southern Europe.

Results

The VL case was diagnosed 18 months after transplant and 28 days after the onset of symptoms by quantitative PCR (qPCR) on peripheral blood. A graft biopsy showed renal involvement, and PCR performed on graft tissue displayed the presence of Leishmania DNA. The retrospective confirmation of Leishmania-positive serology in a serum sample collected before transplantation, as well as the absence of anti-Leishmania IgG in the graft donor strongly suggest that reactivation of a latent parasitic infection caused VL in the current case.

Conclusion

VL is often underdiagnosed in transplant recipients, despite the presence of latent Leishmania infection being reported in endemic countries. This case report, as well as the literature review on leishmaniasis in KT recipients, underline the importance of rapid VL diagnosis to promptly undergo treatment. Serology is scarcely sensitive in immunocompromised patients, thus molecular tests in peripheral blood should be implemented and standardized for both VL identification and follow-up.

Visceral Leishmaniasis: Epidemiology, Diagnosis, and Treatment Regimens in Different Geographical Areas with a Focus on Pediatrics

Visceral Leishmaniasis (VL) is a vector-borne disease caused by an intracellular protozoa of the genus Leishmania that can be lethal if not treated. VL is caused by Leishmania donovani in Asia and in Eastern Africa, where the pathogens’ reservoir is represented by humans, and by Leishmania infantum in Latin America and in the Mediterranean area, where VL is a zoonotic disease and dog is the main reservoir. A part of the infected individuals become symptomatic, with irregular fever, splenomegaly, anemia or pancytopenia, and weakness, whereas others are asymptomatic. VL treatment has made progress in the last decades with the use of new drugs such as liposomal amphotericin B, and with new therapeutic regimens including monotherapy or a combination of drugs, aiming at shorter treatment duration and avoiding the development of resistance. However, the same treatment protocol may not be effective all over the world, due to differences in the infecting Leishmania species, so depending on the geographical area. This narrative review presents a comprehensive description of the clinical picture of VL, especially in children, the diagnostic approach, and some insight into the most used pharmacological therapies available worldwide.

ELISA-based evaluation of antibody response to Leishmania in a region endemic for cutaneous leishmaniasis

Leishmaniasis includes several clinical forms. While routine diagnosis of cutaneous leishmaniasis (CL) is by microscopy, an antibody response to CL has been reported in several recent studies. This study evaluated anti-leishmanial immunoglobulin G (IgG) antibody responses as a biomarker of active leishmaniasis and a measure of exposure to Leishmania. Sera from 50 untreated CL patients, 140 patients under treatment and 280 healthy individuals residing in endemic regions collected as part of an epidemiological survey, was analysed with an enzyme-linked immunosorbent assay established in-house using receiver operator characteristic curve at optimized cut-off value. The assay showed high performance as a diagnostic tool in identifying exposure in endemic individuals (sensitivity: 98%, specificity: 90.3%). All patients showed lower antibody levels over time since onset of lesion/s. Antibody levels were higher (p ˂ .01) and persisted for a longer period in untreated patients. In patients under treatment, the level of anti-IgG antibodies was negatively correlated with the total duration the patient had been on treatment. The anti-leishmanial IgG response in Leishmania donovani-induced CL is transient and is unlikely to confer protective immunity. Optimized serological assays may be useful in endemic settings for diagnosis and monitoring the treatment response in CL.

Test combination to detect latent Leishmania infection: A prevalence study in a newly endemic area for L. infantum, northeastern Italy

Background

Most people infected with Leishmania remain asymptomatic, which is a common element that may promote the resurgence of clinically evident leishmaniasis in individuals with impaired cell-mediated immune responses. Unfortunately, there is no universally accepted assay to identify asymptomatic infection. This cross-sectional study focuses on the employment of three methods targeting different features of the parasitic infection to be used in combination for the screening of latent leishmaniasis in a newly endemic area of northeastern Italy.

Methodology/principal findings

The selected methods included highly sensitive Real-Time PCR for detection of parasitic kinetoplast (k)DNA in peripheral blood, Western Blot (WB) for detection of specific IgG, and Whole Blood stimulation Assay (WBA) to evaluate the anti-leishmanial T-cell response by quantifying the production of IL-2 after stimulation of patients’ blood with Leishmania specific antigens. Among 145 individuals living in a municipality of the Bologna province, northeastern Italy, recruited and screened for Leishmania infection, 23 subjects tested positive (15.9%) to one or more tests. Positive serology was the most common marker of latent leishmaniasis (15/145, 10%), followed by the detection of specific cell-mediated response (12/145, 8%), while only few individuals (6/145, 4%) harbored parasitic DNA in the blood.

Conclusions/significance

Combining different tests substantially increased the yield of positivity in detecting latent Leishmania infection. The test combination that we employed in this study appears to be effective to accurately identify latent leishmaniasis in an endemic area.

After infection with Leishmania infantum cutaneous or visceral leishmaniasis can develop, but in most cases the host becomes an asymptomatic carrier of the parasite. This key population of individuals with latent leishmaniasis can undergo reactivation of the infection with severe outcome in case of immunosuppression and can contribute to disease transmission.

The public health impact of leishmaniasis is currently underestimated in Europe, despite Leishmania infection is endemic in the Mediterranean countries and outbreaks of human leishmaniasis have been reported in the last decades, including northeastern Italy. One of the causes contributing to this neglect is that the available diagnostic tests exhibit scarce sensitivity in identification of latent leishmaniasis.

In this study, we identified latent Leishmania infection in a newly endemic area of northeastern Italy by using three different diagnostic methods; serological, molecular and immunological tests. Sixteen percent of individuals residing in the selected area were shown to be positive to at least one of the three tests, which indicates a previous contact with the parasite. This study highlights the importance of test combination to enhance the ability to identify latent Leishmania infection.

An exploratory analysis of C-X-C motif chemokine ligand 10 as a new biomarker of asymptomatic Leishmania infantum infection in Solid-Organ Transplant Recipients

OBJECTIVE

Sensitive and less laborious assays are needed to detect asymptomatic Leishmania among solid organ transplant (SOT) recipients. Using SLA-stimulated plasma from SOT recipients living where an outbreak of Leishmania infantum occurred, we examined potential biomarkers to identify asymptomatic Leishmania infections.

METHODS

Concentrations of cytokines/chemokines in plasma from whole blood stimulated with specific Leishmania antigen (SLA) were compared against infection status as determined by a currently used cell proliferation assay.

RESULTS

Twenty-six percent (13/50) of the SOT recipients had a cell proliferation assay (CPA) indicating asymptomatic infection, and showed higher processed plasma C-X-C motif chemokine ligand 10 (CXCL10 or IP-10) concentrations than did non-infected subjects (median 2272.0 pg/ml [IQR-1570-2772] vs. 18.2 pg/ml [IQR 1-150.1]; p<0.0001). CXCL10 showed a sensitivity of 93% and a specificity of 95% compared to CPA. In addition, we demonstrated that the number of asymptomatic infections detected using CXCL10, decreased with distance from a park at the centre of the mentioned outbreak.

CONCLUSION

CXCL10 in plasma from SLA-stimulated blood could be a robust biomarker of asymptomatic L. infantum infection in solid organ transplant recipients.

Advancement in leishmaniasis diagnosis and therapeutics: An update

Leishmaniasis is regarded as a neglected tropical disease by World Health Organization (WHO) and is ranked next to malaria as the deadliest protozoan disease. The primary causative agents of the disease comprise of diverse leishmanial species sharing clinical features ranging from skin abrasions to lethal infection in the visceral organs. As several Leishmania species are involved in infection, the role of accurate diagnosis becomes pivotal in adding new dimensions to anti-leishmanial therapy. Diagnostic methods must be fast, reliable, easy to perform, highly sensitive, and specific to differentiate among similar parasitic diseases. Herein, we present the conventional and recent approaches impended for the disease diagnosis and their sensitivity, specificity, and clinical application in parasite detection. Furthermore, we have also elaborated various new methods to cure leishmaniasis, which include host-directed therapies, drug repurposing, nanotechnology, and combinational therapy. This review addresses novel techniques and innovations in leishmaniasis, which can aid in unraveling new strategies to fight against the deadly infection.

Leishmaniases in the European Union and Neighboring Countries

A questionnaire survey of animal and human health authorities in Europe revealed that leishmaniases are not notifiable in all countries with autochthonous cases. Few countries implement surveillance and control targeting both animal and human infections. Leishmaniases are considered emergent diseases in most countries, and lack of resources is a challenge for control.

Identification of Leishmania infantum in blood donors from endemic regions for visceral leishmaniasis

Visceral leishmaniasis is an endemic protozoonosis observed in over 60 countries, with over 500 000 new cases recorded annually. Although the diagnostic procedure of its symptomatic forms is well established, for asymptomatic patients, who represent about 85% of those infected, there is no consensus on the best method for its identification. Recent studies have presented molecular techniques as viable identification methods, with good sensitivity and specificity indices in asymptomatic individuals. Therefore, we aimed to use molecular methods to assess their effectiveness in identifying the presence of asymptomatic infection by Leishmania infantum (L. infantum) individuals from endemic regions of Brazil. Screening was performed by real-time polymerase chain reaction (qPCR) and confirmed by sequencing the cytochrome B gene. Of the 127 samples [from 608 blood donors who had participated in a previous study, of which 34 were positive by the enzyme-linked immunosorbent assay (ELISA) rK39] tested by qPCR, 31 (24.4%) were positive. In the sequencing of 10 qPCR-positive samples, five were identified as L. infantum. Complimentary samples of the ELISA rK39 and conventional PCR showed only reasonable and low agreement with qPCR, respectively. The qPCR confirmed the presence of infection in five of the 10 sequenced samples, ELISA confirmed three, and the conventional PCR confirmed none.

Serodiagnosis of Visceral Leishmaniasis in Northeastern Italy: Evaluation of Seven Serological Tests

This study compares the performance of seven assays, including two ELISA (Leishmania ELISA IgG + IgM, Vircell Microbiologists; Leishmania infantum IgG ELISA, NovaTec), three rK39-based immunochromatographic tests (rK39-ICTs) (Leishmania Dipstick Rapydtest, Apacor; On Site Leishmania IgG/IgM Combo Rapid Test, CTK Biotech; LEISHMANIA Strip quick Test, Cypress Diagnostic), one indirect immunofluorescent antibody test (IFAT) (Leishmania-Spot IF, BioMérieux), and one western blot (WB) (Leishmania WESTERN BLOT IgG, LDBio Diagnostics) for serodiagnosis of visceral leishmaniasis (VL). Serum samples from 27 VL patients living in northeastern Italy were analyzed, as well as the serum samples from 50 individuals in whom VL diagnosis was excluded. The WB and the IFAT had 96% sensitivity, followed by the ELISA (63% and 74%, respectively). The rK39-ICT exhibited the worst performance among the serological tests, with sensitivities ranging from 52% to 70%. By combining selected ELISA/ICT, the sensitivity of VL detection reached 89%. IFAT and WB outperformed ELISA and rK39-ICT by possessing optimal sensitivity, but their high cost and complexity of execution would not allow their employment as screening tests. In conclusion, the combination of easy-to-perform tests, such as ICT and ELISA, could improve sensitivity in the serodiagnosis of Mediterranean VL.

Risk-free point-of-care visceral leishmaniasis diagnostics: combining buffy coat microscopy and immunoassay in tertiary rural hospitals in Sudan

Visceral Leishmaniasis (VL), a life-threating disease in Sudan and Eastern Africa, is usually diagnosed by a painful and invasive tissue aspirate microscopy. This study assessed the diagnostic effectiveness of buffy coat (BC) microscopy and the rK39 immunoassay test separately and combined as an easy non-invasive method applied to peripheral blood sample for field diagnosis of VL. 151 VL suspected patients were recruited from tertiary rural hospitals in Bazura, Gedaref state, from 2014-2015. All patients were tested for VL using rK39 ICT and microscopy smears from LN aspirate and BC in addition to PCR from BC as a reference standard test. Both BC and LN aspirate microscopy showed perfect specificity (100%) with false negative results, while the majority of true positives (81%) had a low-parasite burden. ICT showed almost perfect agreement but limited by its poor specificity. Each of these three tests is inadequate as a consistent single diagnostic tool and should be replaced by PCR in routine practice. Combining the results of risk-free BC microscopy and rk39 ICT, using peripheral blood sample, improved VL diagnosis with almost perfect agreement and 93.4% accuracy. Our findings indicate that combined BC microscopy and ICT are accurate, simple and easy point-of-care VL diagnostic tools in community and rural hospitals that can replace or reduce the use of invasive tissue aspirates microscopy, when PCR is unavailable. This is particularly of value in endemic rural areas, decreasing the delay in final diagnosis and preventing deaths caused by VL.

Laboratorial algorithm for serological diagnosis of visceral leishmaniasis using rK39-ICT, DAT-LPC and FC-Simplex IgG1

The performance of distinct serological tests (rK39-ICT, IFAT, DAT-LPC, FC-Simplex IgG1) was assessed and a laboratorial algorithm was proposed for accurate diagnosis of VL. DAT-LPC and FC-Simplex IgG1 showed outstanding accuracy (AUC = 0.93) to identify VL patients. The use of a sequential serological algorithm (rK39-ICT screening followed by DAT-LPC or FC-Simplex IgG1) improved the global accuracy for VL (97.2%) diagnosis. An alternative approach for diagnosis of VL has been also assessed for interchangeable use of serum/whole blood lysate samples in DAT-LPC and FC-Simplex IgG1. Our data showed an outstanding agreement for the results obtained with whole blood lysate samples as compared to serum samples (DAT-LPC =100%; FC-Simplex IgG1 = 99%). Together, these findings provide insights to improve the current overall accuracy of VL diagnosis and present innovative laboratorial tests and alternative samples from use in public health services.

Place of Serology in the Diagnosis of Zoonotic Leishmaniases With a Focus on Visceral Leishmaniasis Due to Leishmania infantum

Leishmaniases are a group of parasitic diseases transmitted through the bite of female phlebotomine sandflies. Depending on the Leishmania species, the reservoirs can be humans (anthroponosis) or different animals (zoonosis). Zoonotic leishmaniasis present several clinical forms in function of the species involved: visceral leishmaniasis (VL), cutaneous leishmaniasis (CL), and muco-cutaneous leishmaniasis (MCL). The biological diagnosis is of utmost importance because the clinical features are not specific. In addition to parasitological and molecular biology (polymerase chain reaction, PCR) assays, serology is routinely used for the diagnosis of leishmaniasis. Indeed, although PCR is more sensitive than serological assays, its implementation is limited to referral laboratories and research centers. Therefore, serology is still a key element for their diagnosis. Here, we discuss the different serological assays available for the diagnosis of zoonotic leishmaniasis. We will review the enzyme-linked immunosorbent assay, immunofluorescence antibody test, immunochromatography test (ICT), direct agglutination test, and western blot as well as the different diagnostic strategies in function of the clinical form (VL, CL, and MCL). We will also discuss the place of serology for detecting asymptomatic carriers and for the follow-up of VL. Depending on the laboratory, different assays can be used, from ICT, which is appropriate for field testing, to a combination of serological tests to improve the sensitivity.

Clinical aspects of visceral leishmaniasis caused by L. infantum in adults. Ten years of experience of the largest outbreak in Europe: what have we learned?

BACKGROUND

An outbreak of leishmaniasis caused by Leishmania infantum was declared in the southwest of the Madrid region (Spain) in June 2009. This provided a unique opportunity to compare the management of visceral leishmaniasis (VL) in immunocompetent adults (IC-VL), patients with HIV (HIV-VL) and patients receiving immunosuppressants (IS-VL).

METHODS

A cohort of adults with VL, all admitted to the Hospital Universitario de Fuenlabrada between June 2009 and June 2018, were monitored in this observational study, recording their personal, epidemiological, analytical, diagnostic, treatment and outcome variables.

RESULTS

The study population was made up of 111 patients with VL (10% HIV-VL, 14% IS-VL, 76% IC-VL). Seventy-one percent of the patients were male; the mean age was 45 years (55 years for the IS-VL patients, P = 0.017). Fifty-four percent of the IC-VL patients were of sub-Saharan origin (P = 0.001). Fever was experienced by 98% of the IC-VL patients vs 73% of the LV-HIV patients (P = 0.003). Plasma ferritin was > 1000 ng/ml in 77% of the IC-VL patients vs 17% of the LV-HIV patients (P = 0.007). Forty-two percent of patients fulfilled the criteria for haemophagocytic lymphohistiocytosis. RDT (rK39-ICT) serological analysis returned sensitivity and specificity values of 45% and 99%, respectively, and ELISA/iIFAT returned 96% and 89%, respectively, with no differences in this respect between patient groups. Fourteen (13.0%) patients with VL experienced treatment failure, eight of whom were in the IC-VL group. Treatment with < 21 mg/kg (total) liposomal amphotericin B (LAB) was associated with treatment failure in the IC-VL patients [P = 0.002 (OR: 14.7; 95% CI: 2.6-83.3)].

CONCLUSIONS

IS-VL was more common than HIV-VL; the lack of experience in dealing with IS-VL is a challenge that needs to be met. The clinical features of the patients in all groups were similar, although the HIV-VL patients experienced less fever and had lower plasma ferritin concentrations. RDT (rK39-ICT) analysis returned a good specificity value but a much poorer sensitivity value than reported in other scenarios. The patients with HIV-VL, IS-VL and IC-VL returned similar serological results. Current guidelines for treatment seem appropriate, but the doses of LAB required to treat patients with HIV-VL and IS-VL are poorly defined.

18F-FDG PET/CT in visceral leishmaniasis: uptake patterns in the context of a multiannual outbreak in Northern Italy

OBJECTIVES

Visceral leishmaniasis (VL) is the most severe manifestation of the infection caused by the protozoan Leishmania, recently on increase in Italy and Spain. The aim of the study was to describe FDG uptake patterns in VL patients (pts) who underwent 18F-FDG PET/CT.

METHODS

A retrospective monocentric study of pts who underwent FDG PET/CT between 2008 and 2017 and later diagnosed with VL was performed. Semi-quantitative parameters were calculated in FDG-positive lesions: SUVmax, SUVmax spleen/SUVmax liver ratio (SLR), SUVmax focal/diffuse spleen ratio (FDR).

RESULTS

Overall, 23 pts were included. PET/CT was negative in 2 immunocompromised pts, positive in 21/23 (91%) [6 spleen only, 2 spleen + nodes, 7 spleen + bone marrow (BM), 4 spleen + BM + nodes, 1 spleen + BM + lung, 1 BM only + nodes, 2 nodes only]. Splenic involvement was demonstrated in 20/23 (87%) pts. Two different splenic patterns were observed: diffuse (13/20 pts, mean spleen SUVmax = 7.3 ± 4.2 [4.0-14.1], mean SLR = 2.2 ± 1.6 [1.3-6.7]) and focal over diffuse (7/20 pts, mean SUVmax = 12.6 ± 4.5 [9.5-20.5], mean SLR = 2.8 ± 0.8 [2.1-4.4], mean FDR = 2.1 ± 0.8 [1.2-3.6]). Extra-splenic FDG-avid findings were detected in 15/21 pts (65%): bone marrow in 13/15 (mean SUVmax = 4.0 ± 1.3 [2.8-6.0]), nodes in 67/15 and lung in 1/15.

CONCLUSIONS

PET/CT demonstrated splenic FDG uptake in all immunocompetent VL pts; two splenic patterns (diffuse/focal over diffuse) were observed and indistinguishable from splenic involvement by other disorders. The most frequent extra-splenic FDG-positive sites were BM and lymph nodes. Considering the potential disease aggressiveness and recent outbreaks in north-eastern Italy, VL should be considered in the differential diagnosis of FDG-positive splenic findings in pts from endemic areas or reporting travels to endemic countries.

Two cases of relapsed HIV-associated visceral leishmaniasis successfully treated with combination therapy

Background

The management of visceral leishmaniasis (VL) in HIV-infected patients is often complex with patients experiencing higher mortality rates, more toxic side effects and a higher possibility of treatment failure and relapse than HIV-negative individuals with VL.

Case presentation

We report on successful salvage therapy in two HIV-infected patients suffering with disseminated cutaneous and visceral leishmaniasis, recalcitrant to therapy with liposomal amphotericin B. After the employment of combination anti-leishmanial treatment, parasite genomes were not detectable up to the last follow up visit, 57 and 78 weeks after treatment onset, respectively. CD4+ lymphocyte counts fluctuated over time, but were generally higher than counts detected at treatment onset, which likely contributed to protection against VL relapse.

Conclusions

Results achieved with the anti-leishmanial combination treatment were promising, but are based on only two patients. Future investigation is necessary to confirm the efficacy of this salvage therapy in sustaining the immunological response and control of VL.

Diagnostic lipid changes in patients with visceral leishmaniasis

BACKGROUND

Visceral leishmaniasis (VL) has been associated with the increase in triglyceride (TG) levels and the decrease in high-density lipoprotein cholesterol (HDL-C) concentration. The aim of the study was to evaluate whether there is a diagnostic cut-off point in these lipid profile changes.

MATERIALS AND METHODS

We included 100 patients with febrile infections. Analytically, 22 patients with VL, 18 patients with leptospirosis, 20 patients with Brucella melitensis, and 40 age- and sex-matched patients with fever and proven bacteremia (endocarditis and pyelonephritis). The lipid parameters were assessed for their diagnostic accuracy using logistic regression and receiver operating characteristic statistics.

RESULTS

It was observed that coexistence of HDL-C < 15 mg/dL and ΤG > 180 mg/dL had 100% sensitivity and 67.5% specificity for the confirmation of VL. The corresponding positive and negative predictive values were 59.4% and 100%, respectively.

CONCLUSION

Coexistence of high TGs and low HDL-C values may suggest VL infection in a febrile patient.

Validation of rK39 immunochromatographic test and direct agglutination test for the diagnosis of Mediterranean visceral leishmaniasis in Spain

Background

Visceral leishmaniasis (VL), the most severe form of leishmaniasis, is endemic in Europe with Mediterranean countries reporting endemic status alongside a worrying northward spread. Serological diagnosis, including immunochromatographic test based on the recombinant antigen rK39 (rK39-ICT) and a direct agglutination test (DAT) based on the whole parasite antigen, have been validated in regions with high VL burden, such as eastern Africa and the Indian subcontinent. To date, no studies using a large set of patients have performed an assessment of both methods within Europe.

Methodology/Principal findings

We selected a range of clinical serum samples from patients with confirmed VL (including HIV co-infection), Chagas disease, malaria, other parasitic infections and negative samples (n = 743; years 2009–2015) to test the performance of rK39-ICT rapid test (Kalazar Detect Rapid Test; InBios International, Inc., USA) and DAT (ITM-DAT/VLG; Institute of Tropical Medicine Antwerp, Belgium). An in-house immunofluorescence antibody test (IFAT), was included for comparison. Estimated sensitivities for rK39-ICT and DAT in HIV-negative VL patients were 83.1% [75.1–91.2] and 84.2% [76.3–92.1], respectively. Sensitivity was reduced to 67.3% [52.7–82.0] for rK39 and increased to 91.3% [82.1–100.0] for DAT in HIV/VL co-infected patients. The in-house IFAT was more sensitive in HIV-negative VL patients, 84.2% [76.3–92.1] than in HIV/VL patients, 79.4% [73.3–96.2]. DAT gave 32 false positives in sera from HIV-negative VL suspects, compared to 0 and 2 for rK39 and IFAT, respectively, but correctly detected more HIV/VL patients (42/46) than rK39 (31/46) and IFAT (39/46).

Conclusions/Significance

Though rK39-ICT and DAT exhibited acceptable sensitivity and specificity a combination with other tests is required for highly sensitive diagnosis of VL cases in Spain. Important variation in the performance of the tests were seen in patients co-infected with HIV or with other parasitic infections. This study can help inform the choice of serological test to be used when screening or diagnosing VL in a European Mediterranean setting.

Visceral leishmaniasis is the most severe form of leishmaniasis, a disease transmitted through the bite of an infected sandfly. Although the biggest burden of leishmaniasis is in eastern Africa and the Indian subcontinent, the disease is also endemic in parts of Europe. Previous studies have looked at performance of diagnostic methods, but not in great detail on samples derived from a European setting. Using a large set of samples from a national reference laboratory in Madrid, Spain, we assessed a leishmaniasis rapid test and a direct agglutination test for serological diagnosis of visceral leishmaniasis in Europe. Both tests were effective at diagnosing VL, but important differences were seen when testing patients co-infected with HIV or with other parasitic infections. This study can help inform which diagnostic tests are suitable for use in a European Mediterranean setting.