Tissue and blood protozoa including toxoplasmosis, Chagas disease, leishmaniasis, Babesia, Acanthamoeba, Balamuthia, and Naegleria in solid organ transplant recipients- Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice.

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of tissue and blood protozoal infections in the pre- and post-transplant period. Significant new developments in the field have made it necessary to divide the previous single guideline published in 2013 into two sections, with the intestinal parasites separated from this guideline devoted to tissue and blood protozoa. The current update reflects the increased focus on donor screening and risk-based recipient monitoring for parasitic infections. Increased donor testing has led to new recommendations for recipient management of Toxoplasma gondii and Trypanosoma cruzi. Molecular diagnostics have impacted the field, with access to rapid diagnostic testing for malaria and polymerase chain reaction testing for Leishmania. Changes in Babesia treatment regimens in the immunocompromised host are outlined. The risk of donor transmission of free-living amebae infection is reviewed. Changing immigration patterns and the expansion of transplant medicine in developing countries has contributed to the recognition of parasitic infections as an important threat to transplant outcomes. Medications such as benznidazole and miltefosine are now available to US prescribers as access to treatment of tissue and blood protozoa is increasingly prioritized.

Leishmaniasis in solid organ and hematopoietic stem cell transplant recipients.

Leishmaniasis occurs in <1% of solid organ and hematopoietic stem cell transplant recipients in endemic countries in which transplants are performed. Visceral leishmaniasis (VL) makes up the bulk of reported cases. The onset generally occurs months after transplantation and the mode of acquisition is often impossible to determine, but de novo vector-borne infection and reactivation of inapparent infection are thought to be the principal means. The potential role of clinically inapparent donor infection is uncertain and screening is not currently recommended, nor is it recommended for recipients from endemic areas, some of whom may have detectable circulating protozoan nucleic acid. While transplant recipients with VL often present with the non-specific findings of fever and cytopenia, the additional presence of hepatosplenomegaly in patients from endemic areas should lead to a directed diagnostic evaluation with bone marrow examination and PCR testing of marrow and peripheral blood having a high yield. Management may often be complicated by the presence of concomitant infections. A lipid formulation of amphotericin B is the preferred treatment, especially for VL, but the relapse rate in transplant recipients is approximately 25%. PCR monitoring of blood for either secondary prophylaxis or preemptive therapy requires further study.

Is leishmaniasis an "unusual suspect" of infection in allogeneic transplantation?

Leishmaniasis is a disease of the immunocompetent population, more often affecting infants and young children. However, the number of leishmaniasis cases associated with immunosuppression has increased over the last 20 years. The visceral form of the disease, visceral leishmaniasis (VL), is identified as an opportunistic infection in immunosuppressed individuals, occurring mainly after solid organ transplantation, especially in renal transplant recipients. Limited data are available about VL after hematopoietic stem cell transplantation (HSCT). We report the cases of 3 patients with late VL after allogeneic HSCT, and review the literature.

Disseminated leishmaniasis in a four-year-old child in Yaoundé, Cameroon.

Leishmaniasis is a disease caused by a protozoan parasite of the genus leishmania with worldwide distribution and is transmitted to man by phlebotomine sand flies. The clinical presentation could range from a single cutaneous ulcer to disseminated leishmaniasis. We report the case of a four-year-old boy admitted to our hospital with ulcers, wasting, progressively distending abdomen, and fatigue evolving for about two months. On admission, he was febrile and pale, with diffuse oozing wet ulcers on the limbs and face, hepatosplenomegaly, and enlarged inguinal lymph nodes. The complete blood count revealed pancytopenia with low reticulocyte count, and serum protein electrophoresis showed hypoalbuminemia and hypergammaglobulinemia. Skin biopsy revealed amastigotes in phagocytic cells. The above findings suggested cutaneous and visceral localization of the leishmania; however, the parents absconded with the boy just when treatment was instituted, believing that the child was bewitched. The outcome is expected to be fatal visceral involvement.

Development of loop-mediated isothermal amplification (LAMP) assay using SYBR safe and gold-nanoparticle probe for detection of Leishmania in HIV patients.

Asymptomatic leishmaniasis cases have continuously increased, especially among patients with HIV who are at risk to develop further symptoms of cutaneous and visceral leishmaniasis. Thus, early diagnosis using a simple, sensitive and reliable diagnostic assay is important because populations at risk mostly reside in rural communities where laboratory equipment is limited. In this study, the highly sensitive and selective determination of Leishmania infection in asymptomatic HIV patients was achieved using dual indicators (SYBR safe and gold-nanoparticle probe; AuNP-probe) in one-step LAMP method based on basic instruments. The assay can be simply evaluated under the naked eye due to clear interpretation of fluorescent emission of LAMP-SYBR safe dye-complex and colorimetric precipitate of specific AuNP-probes. The sensitivities and specificities of fluorescent SYBR safe dye and AuNP-probe indicators were equal, which were as high as 94.1 and 97.1%, respectively. Additionally, detection limits were 102 parasites/mL (0.0147 ng/µL), ten times more sensitivity than other related studies. To empower leishmaniasis surveillance, this inexpensive one-step SYBR safe and AuNP-LAMP assay is reliably fast and simple for field diagnostics to point-of-care settings, which can be set up in all levels of health care facilities including resource limited areas, especially in low to middle income countries.

Unraveling the Role of Immune Checkpoints in Leishmaniasis.

Leishmaniasis are Neglected Tropical Diseases affecting millions of people every year in at least 98 countries and is one of the major unsolved world health issues. Leishmania is a parasitic protozoa which are transmitted by infected sandflies and in the host they mainly infect macrophages. Immunity elicited against those parasites is complex and immune checkpoints play a key role regulating its function. T cell receptors and their respective ligands, such as PD-1, CTLA-4, CD200, CD40, OX40, HVEM, LIGHT, 2B4 and TIM-3 have been characterized for their role in regulating adaptive immunity against different pathogens. However, the exact role those receptors perform during Leishmania infections remains to be better determined. This article addresses the key role immune checkpoints play during Leishmania infections, the limiting factors and translational implications.

Leishmaniasis emergence in Europe.

Leishmaniasis emergence in Europe is reviewed, based on a search of literature up to and including 2009. Topics covered are the disease, its relevance, transmission and epidemiology, diagnostic methods, treatment, prevention, current geographical distribution, potential factors triggering changes in distribution, and risk prediction. Potential factors triggering distribution changes include vectorial competence, importation or dispersal of vectors and reservoir hosts, travel, and climatic/environmental change. The risk of introducing leishmaniasis into the European Union (EU) and its spread among Member States was assessed for the short (2-3 years) and long term (15-20 years). There is only a low risk of introducing exotic Leishmania species because of the absence of proven vectors and/or reservoir hosts. The main threat comes from the spread of the two parasites endemic in the EU, namely Leishmania infantum, which causes zoonotic visceral and cutaneous leishmaniasis in humans and the domestic dog (the reservoir host), and L. tropica, which causes anthroponotic cutaneous leishmaniasis. The natural vector of L. tropica occurs in southern Europe, but periodic disease outbreaks in Greece (and potentially elsewhere) should be easily contained by surveillance and prompt treatment, unless dogs or other synanthropic mammals prove to be reservoir hosts. The northward spread of L. infantum from the Mediterranean region will depend on whether climate and land cover permit the vectors to establish seasonal biting rates that match those of southern Europe. Increasing dog travel poses a significant risk of introducing L. infantum into northern Europe, and the threat posed by non-vectorial dog-to-dog transmission should be investigated.

Interleukin-27 Functional Duality Balances Leishmania Infectivity and Pathogenesis.

IL-27 is a cytokine that exerts diverse effects on the cells of innate and adaptive immune systems. Chiefly expressed in macrophages and dendritic cells during the early phase of Leishmania infection, IL-27 contributes to the protection against L. major infection but suppresses the protective Th1 response against L. donovani, L. infantum, L. amazonensis and L. braziliensis infections, suggesting its functional duality. During the late stage of Leishmania infection, IL-27 limits the immunopathogenic reactions and tissue damages. Herein, we analyze the mechanism of the functional duality of IL-27 in the resistance or susceptibility to Leishmania infection, prompting IL-27 for anti-Leishmanial therapy.

Case Report: Hyper IgM Syndrome Identified by Whole Genome Sequencing in a Young Syrian Man Presenting With Atypical, Severe and Recurrent Mucosal Leishmaniasis.

A previously healthy 19-year-old Syrian man presented with atypical and severe mucosal leishmaniasis caused by Leishmania tropica. During a 2-year period, he had three severe relapses despite various treatment strategies, including liposomal amphotericin B and Miltefosine. Because of the unusual clinical presentation, potential underlying immunodeficiency was investigated. Normal T and NK cell counts were found. The B cell count was slightly elevated at 0.7 × 109 cells/L (0.09 × 109 to 0.57 × 109 cells/L), but the proportions of memory and isotype switched memory B cells were severely diminished IgG levels were low, at 309 mg/dL (610-1490 mg/dL). The initial IgM and IgA levels were within normal range, but the IgA levels decreased to 57 mg/dL (70-430 mg/dL) during follow up. Common variable immunodeficiency (CVID) was initially suspected, because the immunological results of low IgG and IgA, low switched memory B cells, no profound T cell deficiency found and absence of secondary cause of hypogammaglobulinemia were compatible with this diagnosis (ESID 2019). However, the highly unusual and severe clinical presentation of L. tropica is not suggestive of B-cell deficiency or CVID. Eventually a pathogenic nonsense variant in the CD40 ligand gene [p.(Arg11∗)] was identified by whole genome sequencing, thus enabling the diagnosis of X-linked hyper IgM syndrome. This case illustrates and supports the potential for the use of whole genome sequencing in accurate diagnosis of primary immunodeficiencies.

Leishmaniasis, autoimmune rheumatic disease, and anti-tumor necrosis factor therapy, Europe.

We report 2 cases of leishmaniasis in patients with autoimmune rheumatic diseases in Greece. To assess trends in leishmaniasis reporting in this patient population, we searched the literature for similar reports from Europe. Reports increased during 2004-2008, especially for patients treated with anti-tumor necrosis factor agents.

Implication of Phlebotomus sand flies as vectors of bartonellosis and leishmaniasis as early as 1764.

A written account implicating Phlebotomus sand flies as vectors of Carrion's disease and cutaneous leishmaniasis in Peru was published by Cosme Bueno in 1764. Bueno's report precedes other publications implicating sand flies in the transmission of human pathogens by nearly a century and a half.

[PCR-RFLP and RAPD for typing neotropical Leishmania]. / PCR-RFLP y RAPD para la tipificación de Leishmania neotropical.

INTRODUCTION: The analysis of the PCR-restriction fragment length polymorphism and random amplified polymorphic DNA have been useful tools for Leishmania identification. OBJECTIVES: Molecular procedures were demonstrated for identification and typing of reference strains of New World Leishmania and their applicability was validated for clinical samples. MATERIALS AND METHODS: DNA was extracted from 16 reference strains of Latin American Leishmania as well as from clinical samples of leishmaniasis patients. A sequence coding for cysteine proteinase B was amplified by PCR and subjected to restriction fragment length polymorphism analysis. The enzyme used was Taq1. For eight of the reference strains, the random amplified polymorphic desoxyribonucleic acid technique (RAPD) was applied. Band patterns for Leishmania species differentiation were established each each method. The sample size of the clinical sample was of 5. RESULTS: PCR products of the cysteine proteinase B gene were obtained for L. braziliensis, L. peruviana, L. panamensis and L. guyanensis. For the other species, L. mexicana, L. amazonensis, L. garnhami, L. lainsoni, L. chagasi, L. naiffi, no amplification occurred. The patterns of restriction fragments revealed band patterns in common for L. peruviana, L. guyanensis and L. panamensis, whereas L. braziliensis had a distinctive pattern. When human samples were examined, amplification occurred for all cases, and the profiles corresponded to the common profile of L. peruviana, L. guyanensis and L. panamensis. The RAPD technique demonstrated reproducible and distinctive patterns for each of the 8 reference strains, L. mexicana, L. amazonensis, L. garnhami, L. lainsoni, L. chagasi, L. naiffi, making possible to differentiate all them. The advantages and limitations of each procedure are discussed. CONCLUSIONS: The combination of RFP and RAPD methodologies provide useful tools to identify medical important species of Leishmania by recognizing DNA sequences characteristic of each species.

What's eating you? sand flies.

As thousands of Americans descended upon Brazil for the Olympic games in the summer of 2016, the mosquito-borne Zika virus became a source of great concern among the countless athletes and travelers in Rio. As is often the case, the media frenzy that ensued drew travelers' attention away from a lesser known flying vector that often carries with it grave consequences. The Phlebotominae, commonly known as sand flies, are biting insects known for their ability to transmit the protozoa Leishmania as well as a number of other viruses and bacteria. As the impact of sand flies continues to grow in the United States and worldwide, knowledge of the vector is important for proper treatment and prevention of the diseases they carry.

Cytokine patterns in the pathogenesis of human leishmaniasis.

The host response to infection appears to be regulated by specific patterns of local cytokine production. In the mouse, resistance to many pathogens including Leishmania is associated with a TH1 cytokine profile, IL-2 and IFN-gamma; whereas susceptibility to infection is associated with production of TH2 cytokines, IL-4, IL-5, and IL-10. To determine the cytokine patterns of the local immune response to Leishmania infection in humans, we used the polymerase chain reaction to compare cytokine mRNAs in biopsy specimens of American cutaneous leishmaniasis. In localized cutaneous leishmaniasis and the Montenegro delayed-type hypersensitivity reaction, type 1 cytokine mRNAs such as IL-2, IFN-gamma, and lymphotoxin were relatively predominant. In the chronic and destructive mucocutaneous form of leishmaniasis, there was a mixture of type 1 and type 2 cytokines, with a striking abundance of IL-4 mRNA in lesions. These results suggest that clinical course of infection with Leishmania braziliensis in man is associated with specific local patterns of cytokine production.

In vitro parasite-monocyte interactions in human leishmaniasis. Evidence for an active role of the parasite in attachment.

Leishmania are obligate intracellular parasites of mononuclear phagocytes in the mammalian host. To more clearly define features of the early events in host-parasite interaction, human monocytes were so-cultured with Leishmania tropica amastigotes in vitro. Infection of monocytes was time dependent and inhibited at 4 degrees C and in the presence of cytochalasin B. Pretreatment of amastigotes with cytochalasins prevented their attachment to normal monocytes. Untreated amastigotes attached normally but could not enter cytochalasin-pretreated monocytes. This suggests that amastigotes actively participate in attachment but require host cell participation for interiorization.

Systemic hypertension in dogs with leishmaniasis: prevalence and clinical consequences.

A prospective study was performed (November 1998 to December 2003) to determine the prevalence of systemic hypertension (SH) in dogs with glomerular disease secondary to leishmaniasis. One hundred and five dogs with leishmaniasis were screened and staged for the presence of renal disease (RD) and SH. For the purpose of the study, RD was defined as serum creatinine concentration > or = 1.4 mg/dL, a urine protein/creatinine ratio > or = 0.5, or both. SH was defined as a systolic blood pressure (SBP) > or =180 mm Hg or an SBP between 150 and 179 mm Hg in the presence of clinical manifestations of SH. Fifty-two (49.5%) of the dogs had some degree of RD, and 32 (61.5%) of these dogs were diagnosed with SH. Moreover, SH also was diagnosed in 3 dogs without RD. Left ventricular hypertrophy (LVH), estimated by echocardiography, was the most frequently observed systemic consequence of hypertension, being present in 32 (91.4%) of the hypertensive dogs. Echocardiographic abnormalities were not detected in any of the 33 dogs with leishmaniasis without RD, which were used as controls. Ocular consequences of SH were observed in only 2 (5.7%) of the dogs with hypertension. We conclude that SH is prevalent in dogs with RD secondary to leishmaniasis, not only in the more severe stages but also in the early course of the illness before azotemia becomes apparent. Canine leishmaniasis may be a useful natural model to study SH secondary to glomerular disease.

[Immunopathogenesis of Leishmania infections]. / Leishmania enfeksiyonlarinin immünopatogenezi.

Leishmaniasis represents a complex of diseases with a clinical and epidemiological diversity. Leishmaniasis remains a severe public health problem and its burden is increasing. The disease is caused by a parasite belonging to the genus Leishmania. Approximately 350 billion people in 88 different countries are thought to be infected with Leishmania spp. Clinical forms of leishmaniasis are particularly diverse representing different diseases: visceral (VL), cutaneous (CL), diffuse cutaneous (DCL) and muco-cutaneous (MCL) leishmaniasis. Being the most important determinant not only cellular immunity plays the essential role in the control of leishmaniasis, but the virulence, tropism and pathogenicity that is modulated by environmental and genetic factors of their mammalian hosts and sandfly vectors, are the key interactions. These eukaryotic pathogens have evolved with the vertebrate immune system and typically produce long lasting chronic infections. A critical step in their host interaction is the evasion of innate immune defenses. The ability to avoid attack by humoral effector mechanisms, such as complement lysis, and to resist killing by lysosomal enzymes and toxic metabolytes is of particular importance. They do so by remodelling the phagosomal compartments in which they reside and by interfering with signalling pathways that lead to cellular activation. In addition they modify the antigen presenting and immunoregulatory functions of dendritic cells, a process that fascilitates their evasion of both innate and adaptive immunity. Experimental animal studies revealed that these modifications and interference mechanisms led to two different pathogenesis schemes. For CL, the polarization of Th2/Th1 cells is responsible for the progression of the disease which than leads to the chronic-persistant state. The Th2/Th1 paradigm does not apply for visceral leishmaniasis. Immunosupression rather than polarization is responsible for the systemic and progressive outcome of the disease in VL. Based on experience with animal models and humans, new vaccine and novel immunotherapy strategies especially for the locations where the disease is endemic, hold promise for the near future. In this review article the immunopathogenesis of leishmaniasis has been discussed under the light of recent literature.