Leishmaniasis among organ transplant recipients

Parasitic infections in solid organ transplant recipients

Parasitic diseases are rare infections after a solid organ transplant (SOT). Toxoplasmosis, Trypanosoma cruzi, and visceral leishmanias are the 3 main opportunistic protozoal infections that have the potential to be lethal if not diagnosed early and treated appropriately after SOT. Strongyloides stercoralis is the one helminthic disease that is life-threatening after transplant. This review addresses modes of transmission, methods of diagnosis, and treatment of the most serious parasitic infections in SOT. The role of targeted pretransplant screening of the donor and recipient for parasitic diseases is also discussed.

Atypical presentation of cutaneous leishmaniasis in a renal transplant recipient successfully treated with allopurinol and fluconazole

Leishmaniasis is a zoonotic infection acquired through the bite of a female sandfly, which introduces the amastigotes of Leishmania into the bloodstream. Cutaneous leishmaniasis is rare after solid organ transplantation. Its diagnosis is difficult in immunosuppressed patients. We report a case of isolated cutaneous leishmaniasis in a renal transplant patient resident in an endemic area. The patient was successfully treated with allopurinol and fluconazole and has remained relapse-free for 44 months. The diagnosis of cutaneous leishmaniasis must be considered in immunosuppressed patients living in endemic areas. Our report shows that cutaneous leishmaniasis may complicate the clinical course of kidney transplant recipients and its presentation can be atypical. Conventional treatment with pen.tavalent antimonial agents can cause many side effects; of particular concern in renal transplant pa.tients are pancreatitis and nephrotoxicity. These latter may be avoided by using a combination of allopurinol and fluconazole.

Visceral leishmaniasis: host-parasite interactions and clinical presentation in the immunocompetent and in the immunocompromised host

Visceral leishmaniases are vector-borne parasitic diseases caused by protozoa belonging to the genus Leishmania. The heterogeneity of clinical manifestations and epidemiological characteristics of the disease reflect the complex interplay between the infecting Leishmania species and the genetic and immunologic characteristics of the infected host. The clinical presentation of visceral leishmaniasis depends strictly on the immunocompetency of the host and ranges from asymptomatic to severe forms. Conditions of depression of the immune system, such as HIV infection or immunosuppressive treatments, impair the capability of the immune response to resolve the infection and allow reactivation and relapses of the disease.

Postrenal transplant laryngeal and visceral leishmaniasis - A case report and review of the literature

Visceral leishmaniasis (kala-azar) is a disease caused by protozoa of genus Leishmania. It is currently regarded as the second most dreaded parasitic disease, next to malaria. There have been very few case reports of visceral leishmaniasis among the renal transplant recipients. We present a renal allograft recipient with symptoms of fever, sore throat, hoarseness of voice, lymphadenopathy, splenomegaly, and pancytopenia after 7 years post-transplant period. On investigating, he was diagnosed to have extensive visceral leishmaniasis with laryngeal involvement. Despite extensive PubMed literature search, we could not find any case report of postrenal transplant visceral and laryngeal leishmaniasis and to the best of our knowledge this is the first case report of this kind.

The role of the clinical microbiology laboratory in solid organ transplantation programs

Infections remain a major complication of solid organ transplantation. For this reason, the clinical microbiology laboratory plays a key role in the success of transplant programs, which must have the support of a qualified laboratory, both technically and professionally. Transplant programs strongly condition the structure and functionality of microbiology laboratories, but at the same time, benefit greatly from the knowledge generated from these programs. The laboratory must make a special effort to implement rapid methods that can respond to the broad spectrum of potential pathogens in solid organ transplant patients. The integration of microbiologists in multidisciplinary teams is highly recommended, as only then can they obtain the highest quality and efficiency in the diagnostic process. This article provides an updated review of the techniques to be used once transplantation has occurred. The role of the microbiologist is also crucial in the pretransplant period, as good microbiological candidate evaluation at this time strongly conditions the success of the transplantation program.

Involvement of CD4⁺ Foxp3⁺ regulatory T cells in persistence of Leishmania donovani in the liver of alymphoplastic aly/aly mice

Visceral leishmaniasis (VL) is a chronic and fatal disease in humans and dogs caused by the intracellular protozoan parasites, Leishmania donovani and L. infantum (L. chagasi). Relapse of disease is frequent in immunocompromised patients, in which the number of VL cases has been increasing recently. The present study is aimed to improve the understanding of mechanisms of L. donovani persistence in immunocompromised conditions using alymphoplastic aly/aly mice. Hepatic parasite burden, granuloma formation and induction of regulatory T cells were determined for up to 7 months after the intravenous inoculation with L. donovani promastigotes. While control aly/+ mice showed a peak of hepatic parasite growth at 4 weeks post infection (WPI) and resolved the infection by 8 WPI, aly/aly mice showed a similar peak in hepatic parasite burden but maintained persistent in the chronic phase of infection, which was associated with delayed and impaired granuloma maturation. Although hepatic CD4⁺Foxp3⁺ but not CD8⁺Foxp3⁺ T cells were first detected at 4 WPI in both strains of mice, the number of CD4⁺Foxp3⁺ T cells was significantly increased in aly/aly mice from 8 WPI. Immunohistochemical analysis demonstrated the presence of Foxp3⁺ T cells in L. donovani–induced hepatic granulomas and perivascular neo-lymphoid aggregates. Quantitative real-time PCR analysis of mature granulomas collected by laser microdissection revealed the correlation of Foxp3 and IL-10 mRNA level. Furthermore, treatment of infected aly/aly mice with anti-CD25 or anti-FR4 mAb resulted in significant reductions in both hepatic Foxp3⁺ cells and parasite burden. Thus, we provide the first evidence that CD4⁺Foxp3⁺ Tregs mediate L. donovani persistence in the liver during VL in immunodeficient murine model, a result that will help to establish new strategies of immunotherapy against this intracellular protozoan pathogen.

The protozoan parasite Leishmania donovani is the causative agent of visceral leishmaniasis (VL) with a variety of outcomes ranging from asymptomatic to fatal infection. In the last decade, an increasing number of VL cases in immunocompromised conditions have been reported. Loss of the control of parasite persistence causes relapse of the disease in these patients. To clarify why parasite persistence and disease are caused in an immunocompromised condition, we examined L. donovani infection in alymphoplastic aly/aly mice that completely lack lymph nodes and have disturbed spleen architecture. Although parasites grew in the liver of aly/+ mice for the first 4 weeks post infection (WPI) and parasites were eliminated by 8 WPI, we found that parasites persisted in the liver of aly/aly mice with the ineffective of granuloma formation to kill the parasites. These aly/aly mice showed significant increases in CD4⁺Foxp3⁺ regulatory T cells in the liver. Consequently, we treated infected mice with anti-CD25 or anti-FR4 mAb to inhibit the function of Tregs, and found significant reductions in both hepatic Foxp3⁺ cells and parasite burden. These results clearly demonstrated for the first time that the expansion of CD4⁺Foxp3⁺ Tregs is involved in hepatic L. donovani persistence in immunodeficient murine model.

Visceral leishmaniasis in immunosuppressed Caucasian patient

A 64-year-old man was admitted with fever, weight loss, fatigue and night sweats. He was known to have rheumatoid arthritis and had been taking methotrexate for 1 year. He had worked in Saudi Arabia until 1994 and had been living in Spain for 6 months every year. Clinical examination showed an enlarged spleen. Routine investigations showed pancytopaenia. Serial blood cultures were negative. CT scan confirmed splenomegaly and was otherwise unremarkable. Bone marrow biopsy revealed Leishmania amastigote consistent with a diagnosis of visceral leishmaniasis. After discussing with the hospital for tropical diseases (HTD), he was started on liposomal amphotericin B. Following two infusions of amphotericin B, he started improving as his fever, night sweats and weakness had settled. He was then discharged and followed up in HTD clinic 4 weeks later where he was found to be consistently improving.

Signet ring cell primary cutaneous CD30+ lymphoproliferative disorder presenting as a monomorphic T-cell posttransplant lymphoproliferative disease

T-cell posttransplant lymphoproliferative disorders are rare, with peripheral T-cell lymphoma not otherwise specified being the most common type. Although cases of the signet ring cell variant of primary cutaneous CD30+ lymphoproliferative disorder have been reported, such cases have not been described in the posttransplant setting. We describe a case with emphasis on the special contextual differential diagnostic considerations.

Leishmaniasis in the United States: treatment in 2012

Although civilian physicians in the United States seldom encounter patients with leishmaniasis, therapeutic advances in endemic regions have opened the door to approaches that can be applied in this country. Advances revolve around the use of oral miltefosine in all forms of leishmaniasis and the use of short-course intravenous liposomal amphotericin B in visceral and possibly cutaneous infection. Lengthy, traditional intravenous treatment with pentavalent antimony (sodium stibogluconate) still has a role in the United States; however, although expensive, miltefosine and liposomal amphotericin B are considerably more appealing selections for initial therapy.

Transplant-associated and blood transfusion-associated tropical and parasitic infections

Blood transfusion and transplantation may represent efficient mechanisms of spreading infectious agents to naive populations. In the developed countries, as a consequence of globalization, several factors such as international commerce, tourism, and immigration have acted as important features for the emergence or reemergence of infectious diseases previously referred to as tropical. This article reviews the relevant bacterial, protozoan and viral infections that are more frequently associated with blood transfusion and/or solid organ or marrow transplantation and may affect susceptible populations worldwide.

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

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

Nonneoplastic mucocutaneous lesions in organ transplant recipients

Nonneoplastic mucocutaneous lesions are frequent in organ transplant recipients. Many of them are caused by a direct toxicity of immunosuppressive drugs, in particular glucocorticoids and cyclosporine. The effects of these agents are dose- and time-dependent. Glucocorticoids can cause acne, Cushingoid appearance, irregular purpuric areas, friable skin, and wide and violaceous stripes. Cyclosporine can cause hypertrichosis, pilosebaceous lesions, and gum hypertrophy. Patients with esthetic changes may show poor adherence to treatment with these immunosuppressive agents that may lead to progressive graft dysfunction. Apart from this direct toxicity, vigorous immunosuppression may render the transplant recipients more susceptible to mucocutaneous infections. Fungal infection, viral warts, and bacterial folliculitis are the most frequent types of mucocutaneous infection. Some fungal infections, such as oral candidiasis and pityriasis versicolor, are relatively trivial, but other mycotic infections can cause severe or disfigurating lesions. Among viral infections, warts and condylomata caused by human papilloma virus are frequent and may favor the development of nonmelanoma skin cancer. Bacterial infections are usually trivial in the early period after transplantation, being represented almost exclusively by folliculitis. However, subcutaneous infections may cause a necrotizing fasciculitis which is a life-threatening disorder, usually sustained by polymicrobial pathogens.

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

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

Urban parasitology: visceral leishmaniasis in Brazil

Since the early 1980s, visceral leishmaniasis (VL) which is, in general, a rural zoonotic disease, has spread to the urban centers of the north, and now the south and west of Brazil. The principal drivers differ between cities, though human migration, large urban canid populations (animal reservoir), and a decidedly peripatetic and adaptable sand fly vector are the primary forces. The exact number of urban cases remains unclear as a result of challenges with surveillance. However, the number of urban cases registered continues to increase annually. Most control initiatives (e.g. culling infected dogs and household spraying to kill the sand fly) could be effective, but have proven hard to maintain at large scales due to logistical, financial and other reasons. In this article, the urbanization of VL in Brazil is reviewed, touching on these and other topics related to controlling VL within and outside Brazil.

Leishmaniasis: new insights from an old and neglected disease

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

Cryptic Leishmaniosis by Leishmania infantum, a feature of canines only? A study of natural infection in wild rabbits, humans and dogs in southeastern Spain

An epidemiological study was carried out to investigate asymptomatic Leishmania infantum infection by PCR and ELISA in wild rabbits, humans and domestic dogs in southeastern Spain. Seroprevalence was 0% (0/36) in rabbits, 2% (13/657) in humans and 7% (14/208) in dogs. The prevalence of PCR-positives was 0.6% (1/162) in rabbits tested in a wide range of tissue samples, 2% (8/392) in humans analysed in blood samples and 10% (20/193) and 67% (29/43) in dogs analysed in blood and lymphoid tissue samples, respectively. Results suggest that wild rabbits have a very low risk of becoming chronically infected with L. infantum, and provide further evidence that cryptic L. infantum infection is widespread in the domestic dog population and is also present in a comparatively smaller proportion of healthy humans. The epidemiological and clinical implications of these findings are discussed.

Visceral leishmaniasis with endobronchial involvement in an immunocompetent adult

Visceral leishmaniasis is characterized by fever, cachexia, hepatosplenomegaly, pancytopenia, and hypergammaglobulinemia. Cough may be a presenting symptom as well. However, pulmonary involvement is considered rare and mainly described in immunocompromised patients. We describe a case of an immunocompetent adult whose clinical presentation was dominated by cough and hemoptysis. Bronchoscopy revealed a discreet polypoid mucosal endobronchial lesion whose biopsy yielded Leishmania amastigotes within histiocytes. Transbronchial needle biopsy of a right paratracheal lymph node was also positive. Leishmania amastigotes were also found on bone marrow and liver biopsies. Treatment with IV Amphotericin B was successful. In conclusion, cough should not be overlooked as a presenting symptom of visceral leishmaniasis and may be a sign of pulmonary involvement.

Emerging and established parasitic lung infestations

Many lung infestations from established and newly emerging parasites have been reported as a result of the emergence of HIV/AIDS, the increasing use of immunosuppressive drugs, increasing organ transplantations, the increase in global travel, and climate change. A renewed interest in parasitic lung infections has been observed recently because many protozoal and helminthic parasites cause clinically significant lung diseases. The diseases caused by these parasites may mimic common and complicated lung diseases ranging from asymptomatic disease to acute respiratory distress syndrome requiring critical care management. The availability of new molecular diagnostic methods and antiparasitic drugs enables early diagnosis and prompt treatment to avoid the morbidity and mortality associated with these infestations. Good hygiene practices, improvement in socioeconomic conditions, vector control measures, and consumption of hygienically prepared and properly cooked food are essential to reduce the occurrence of parasitic infestations.

Visceral leishmaniasis in a kidney transplant recipient: parasitic interstitial nephritis, a cause of renal dysfunction

Visceral leishmaniasis (VL) due to Leishmania infantum is an endemic parasitic infection in the Mediterranean area. It most commonly affects immunosuppressed individuals, especially HIV patients and less frequently organ transplant recipients. Renal involvement seems to be frequent and is mostly associated with tubulointerstitial nephritis, as described in autopsy reports. In the 61 cases of renal transplant recipients with VL reported in the literature, renal dysfunction was noted at clinical presentation and was more frequently observed as a complication of antiparasitic therapy. However, no pathological analysis of the allograft lesions was reported. We present the case of a Swiss renal transplant recipient who developed VL after vacations in Spain and Tunisia, complicated by acute parasitic nephritis in the renal allograft 3 months after a well-conducted treatment of liposomal amphotericin B.

Epidemiology of neglected tropical diseases in transplant recipients: review of the literature and experience of a Brazilian HSCT center

The rising success rate of solid organ (SOT) and haematopoietic stem cell transplantation (HSCT) and modern immunosuppression make transplants the first therapeutic option for many diseases affecting a considerable number of people worldwide. Consequently, developing countries have also grown their transplant programs and have started to face the impact of neglected tropical diseases (NTDs) in transplant recipients. We reviewed the literature data on the epidemiology of NTDs with greatest disease burden, which have affected transplant recipients in developing countries or may represent a threat to transplant recipients living in other regions. Tuberculosis, Leprosy, Chagas disease, Malaria, Leishmaniasis, Dengue, Yellow fever and Measles are the topics included in this review. In addition, we retrospectively revised the experience concerning the management of NTDs at the HSCT program of Amaral Carvalho Foundation, a public transplant program of the state of São Paulo, Brazil.

Asymptomatic Leishmania infantum infection in an area of northwestern Italy (Piedmont region) where such infections are traditionally nonendemic

The prevalence of Leishmania infantum-specific antibodies and asymptomatic infection was assessed in a randomized sample of 526 healthy adults from a continental area of northwestern Italy where L. infantum is not endemic and where autochthonous cases of visceral leishmaniasis (VL) were recently reported. L. infantum-specific antibodies were detected by Western blotting (WB) in 39 subjects (7.41%), while L. infantum kinetoplast DNA was amplified from buffy coat in 21 out of 39 WB-positive subjects, confirming asymptomatic infection in 53.8% of seropositives. Risk factors significantly associated with WB positivity were uninterrupted residence since childhood in a local rural environment (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.7 to 7.3), daily contact with animals though not exclusively with dogs (OR, 3.7; 95% CI, 1.3 to 10.7), older age (OR, 2.31; 95% CI, 1.2 to 4.5), and agricultural/other outdoor activities (OR, 3.8; 95% CI, 0.99 to 3.7.) Logistic regression analysis showed that uninterrupted residence in a local rural environment and an age of >65 years were the only independent predictors of seropositivity assessed by WB. Follow-up at 24 months did not show evidence of VL in either seropositive or PCR-positive subjects. The detection of a high seroprevalence rate, confirmed as asymptomatic infection by PCR in more than half of the cases, among healthy residents in a continental area of northwestern Italy makes local L. infantum transmission very likely. In a region where VL is considered nonendemic, these findings warrant further epidemiological investigations as well as interventions with respect to both the canine reservoir and vectors, given the possible risks for immunosuppressed patients.

Transmission, reservoir hosts and control of zoonotic visceral leishmaniasis

Zoonotic visceral leishmaniasis (ZVL) caused by Leishmania infantum is an important disease of humans and dogs. Here we review aspects of the transmission and control of ZVL. Whilst there is clear evidence that ZVL is maintained by sandfly transmission, transmission may also occur by non-sandfly routes, such as congenital and sexual transmission. Dogs are the only confirmed primary reservoir of infection. Meta-analysis of dog studies confirms that infectiousness is higher in symptomatic infection; infectiousness is also higher in European than South American studies. A high prevalence of infection has been reported from an increasing number of domestic and wild mammals; updated host ranges are provided. The crab-eating fox Cerdocyon thous, opossums Didelphis spp., domestic cat Felis cattus, black rat Rattus rattus and humans can infect sandflies, but confirmation of these hosts as primary or secondary reservoirs requires further xenodiagnosis studies at the population level. Thus the putative sylvatic reservoir(s) of ZVL remains unknown. Review of intervention studies examining the effectiveness of current control methods highlights the lack of randomized controlled trials of both dog culling and residual insecticide spraying. Topical insecticides (deltamethrin-impregnated collars and pour-ons) have been shown to provide a high level of individual protection to treated dogs, but further community-level studies are needed.