Environmental Factors as Key Determinants for Visceral Leishmaniasis in Solid Organ Transplant Recipients, Madrid, Spain

Epidemiology and pathogen characteristics of infections following solid organ transplantation

Solid organ transplantation (SOT) recipients have a heightened risk for infection due to prolonged immunosuppressive drug use following transplant procedures. The occurrence of post-transplant infections is influenced not only by the transplanted organ type but also by varied factors. The kidney is the most common organ in SOT, followed by the liver, heart, and lung. This review aims to provide a comprehensive overview of the current epidemiological characteristics of infections after kidney, liver, heart, and lung transplantation, focusing on bacterial, fungal, and viral infections. The incidence and infection types demonstrated significant variability across different SOTs. Furthermore, this review attempts to elucidate the clinical characteristics of infections across patients following different SOTs and contribute to the development of individualized prevention strategies according to infection incidence, ultimately enhancing the quality of life of transplant recipients.

Spatial Relationship between a Regional Outbreak and a Higher-than-Expected Incidence of Leishmaniasis in Urban Southern Madrid, Spain

The largest outbreak of human leishmaniasis in Europe took place in Fuenlabrada, Spain, between 2009 and 2017. The University Hospital "12 de Octubre" in Madrid serves the population residing in three districts of Madrid located just north of the outbreak area (Villaverde, Usera, and Carabanchel). Villaverde and Usera are connected by rail to the outbreak area, unlike Carabanchel. We performed a retrospective study including all cases of leishmaniasis diagnosed between 2011 and 2020. Fifty-one cases were documented. In the districts connected by rail to the outbreak area, a higher-than-expected incidence was observed (13.45-15.55 versus 5.2 per 100,000 inhabitants). Apart from the linear distance from the place of residence to the railway tracks, no differences in terms of demographics or risk factors were detected between the populations of the districts. We hypothesize that the direct connection with the outbreak area by rail could explain the higher incidence observed in Villaverde and Usera.

Leishmaniasis in transplant patients: what do we know so far?

PURPOSE OF REVIEW

The number of cases of visceral leishmaniasis associated with transplant-associated immunosuppression has increased in recent years. Reviewing and updating the latest developments in its diagnostic management, treatment, and follow-up is necessary and relevant.

RECENT FINDINGS

Visceral leishmaniasis cases associated with non-HIV immunosuppression are a growing cause of the parasitic infections, and the transplant patients are included in this context. These have been described especially in kidney transplantation. Liposomal amphotericin B is the first-line treatment. Due to immunosuppression, these patients often suffer from recurrent infections. The use of markers that indicate whether the patient has developed an adequate cellular response against Leishmania after treatment seems to be good biomarkers of cure and useful for monitoring and guiding secondary prophylaxis.

SUMMARY

There is a lack of consensus regarding the need for leishmaniasis screening in donors and recipients and the indications for secondary prophylaxis. The study of new biomarkers of cure may be useful in all three contexts.

A prospective longitudinal study on the elimination trend of rural cutaneous leishmaniasis in southeastern Iran: Climate change, population displacement, and agricultural transition from 1991 to 2021

Leishmaniasis is a complex disease. Any change in weather conditions affects the humans' social and agricultural expansion and, consequently, the parasite's life cycle in terms of ecology, biodiversity, social stigma, and exclusion. This population-based prospective longitudinal investigation was conducted between 1991 and 2021 in a well-defined CL (cutaneous leishmaniasis) focus in Bam County, southeastern Iran. A robust health clinic and health surveillance system were responsible for the ongoing systematic documentation, detection, identification, and management of CL cases. The exponential smoothing method via the state space model was used in the univariate time series. The TTR, smooth, and forecast packages were used in R software. Landsat satellite images from 1991, 2001, 2011, and 2021 were employed in the physical development. During this period, the temperature increased while the rainfall and humidity decreased. The findings showed a downward trend in the standardized drought index. Also, the results showed that climate warming and ecological changes profoundly affected the area's agricultural patterns and topographical features. Furthermore, the last three decades witnessed an elimination trend for zoonotic CL (ZCL) and the predominance of anthroponotic CL (ACL). The present findings showed that the critical factors in the predominance of ACL and elimination of ZCL were rising temperature, drought, migration, unplanned urbanization, earthquake, and agrarian reform. The wall-enclosed palm tree gardens excluded the primary ZCL reservoir host. They controlled the disease while providing suitable conditions for the emergence/re-emergence of ACL in the newly established settlements and the unplanned ecozone. Therefore, robust health infrastructures, sustained financial support, and evidence-based research studies are crucial to facilitating the necessary surveillance, monitoring, and evaluation to control and eliminate the disease.

Leishmania infantum infection after visiting southern Spain in patients on biological treatment; an observational, longitudinal, cohort study

BACKGROUND

Reports of leishmaniasis in immunosuppressed patients after visiting the Mediterranean Basin are becoming increasingly common. Still, awareness of the risk of infection and its clinical manifestations may be insufficient among healthcare professionals in the travellers' home countries.

METHODS

This observational, longitudinal study included 47 patients from Sweden with rheumatic disease and ongoing immunomodulatory treatment, who visited a rehabilitation centre in southern Spain where leishmaniasis is endemic. Patients were evaluated for clinical signs of leishmaniasis at baseline and after three years. Patients with leishmaniasis were followed for 4-5 years. The treatment outcome was assessed by clinical evaluation and determination of the cell-mediated immunological response to Leishmania by a whole blood cytokine release assay.

RESULTS

Seven patients (15%) were diagnosed with leishmaniasis. The median time from exposure to the onset of symptoms was 3 [1-17] months. The median delay between the onset of symptoms and treatment start was 9 [1-12] months. All patients with leishmaniasis responded well to treatment. Only one patient had a relapse, which occurred within the first year.

CONCLUSION

Healthcare professionals need to be aware of the increased risk of leishmaniasis for travellers who are immunosuppressed. Knowledge of the symptoms is crucial for a timely diagnosis and early treatment.

Epidemiology, Clinical Characteristics, Diagnostic Work Up, and Treatment Options of Leishmania Infection in Kidney Transplant Recipients: A Systematic Review

Current knowledge on Leishmania infection after kidney transplantation (KT) is limited. In order to offer a comprehensive guide for the management of post-transplant Leishmaniasis, we performed a systematic review following the latest PRISMA Checklist and using PubMed, Scopus, and Embase as databases. No time restrictions were applied, including all English-edited articles on Leishmaniasis in KT recipients. Selected items were assessed for methodological quality using a modified Newcastle-Ottawa Scale. Given the nature and quality of the studies (case reports and retrospective uncontrolled case series), data could not be meta-analyzed. A descriptive summary was therefore provided. Eventually, we selected 70 studies, describing a total of 159 cases of Leishmaniasis. Most of the patients were adult, male, and Caucasian. Furthermore, they were frequently living or travelling to endemic regions. The onset of the disease was variable, but more often in the late transplant course. The clinical features were basically similar to those reported in the general population. However, a generalized delay in diagnosis and treatment could be detected. Bone marrow aspiration was the preferred diagnostic modality. The main treatment options included pentavalent antimonial and liposomal amphotericin B, both showing mixed results. Overall, the outcomes appeared as concerning, with several patients dying or losing their transplant.

Oral and Intragastric: New Routes of Infection by Leishmania braziliensis and Leishmania infantum?

Although Leishmania transmission in nature is associated with the bite of an infected sandfly vector, other possible transmission routes are speculated to occur, such as the oral route. We evaluated the possibility of infection by this route in golden hamsters (Mesocricetus auratus) using Leishmania braziliensis (Lb) and Leishmania infantum (Li). Hamsters were exposed to experimental oral or intragastrical infection with axenic promastigotes, besides oral ingestion of a suspension of cultivated macrophages infected with amastigotes, lesion-fed Lutzomyia longipalpis, skin lesion or infective spleen fragment. The parasite's isolation, besides a positive PCR and IFAT, confirmed the intragastric infection by promastigote parasites. The oral ingestion of macrophages infected with L. braziliensis amastigotes was also infective. These results confirmed that Leishmania parasites could infect mammals by the intragastric route through the ingestion of promastigote forms (what can happen after a sandfly ingestion) and by the oral ingestion of infected macrophages (what can happen in nature in a predator-prey interaction). The better understanding of these alternative routes is essential to understand their transmission dynamics in nature. As far as we know, this is the first time that oral and intragastric Leishmania transmission has been experimentally demonstrated, constituting new infection routes, at least for L. infantum and L. braziliensis.

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.

Reactivation of latent infections in solid organ transplant recipients from sub-Saharan Africa: What should be remembered?

International migration from Sub-Saharan African countries to the European Union and the United States has significantly increased over the past decades. Although the vast majority of these immigrants are young and healthy people, a minority can be affected by chronic conditions eventually leading to solid organ transplantation (SOT). Importantly, these candidates can bear geographically restricted fungal and parasitic latent infections that can reactivate after the procedure. An appropriate evaluation before transplantation followed by treatment, whenever necessary, is essential to minimize such risk, as covered in the present review. In short, infection due to helminths (Schistosoma spp. and Strongyloides stercoralis) and intestinal protozoa (Entamoeba histolytica, Giardia lamblia or Cyclospora cayetanensis) can be diagnosed by multiple direct stool examination, serological assays and stool antigen testing. Leishmaniasis can be assessed by means of serology, followed by nucleic acid amplification testing (NAAT) if the former test is positive. Submicroscopic malaria should be ruled out by NAAT. Screening for Histoplasma spp. or Cryptococcus spp. is not routinely indicated. Consultation with an Infectious Diseases specialist is recommended in order to adjust preemptive treatment among Sub-Saharan African SOT candidates and recipients.

Visceral leishmaniasis in northwest China from 2004 to 2018: a spatio-temporal analysis

BACKGROUND

Although visceral leishmaniasis (VL), a disease caused by parasites, is controlled in most provinces in China, it is still a serious public health problem and remains fundamentally uncontrolled in some northwest provinces and autonomous regions. The objective of this study is to explore the spatial and temporal characteristics of VL in Sichuan Province, Gansu Province and Xinjiang Uygur Autonomous Region in China from 2004 to 2018 and to identify the risk areas for VL transmission.

METHODS

Spatiotemporal models were applied to explore the spatio-temporal distribution characteristics of VL and the association between VL and meteorological factors in western China from 2004 to 2018. Geographic information of patients from the National Diseases Reporting Information System operated by the Chinese Center for Disease Control and Prevention was defined according to the address code from the surveillance data.

RESULTS

During our study period, nearly 90% of cases occurred in some counties in three western regions (Sichuan Province, Gansu Province and Xinjiang Uygur Autonomous Region), and a significant spatial clustering pattern was observed. With our spatiotemporal model, the transmission risk, autoregressive risk and epidemic risk of these counties during our study period were also well predicted. The number of VL cases in three regions of western China concentrated on a few of counties. VL in Kashi Prefecture, Xinjiang Uygur Autonomous Region is still serious prevalent, and integrated control measures must be taken in different endemic areas.

CONCLUSIONS

The number of VL cases in three regions of western China concentrated on a few of counties. VL in Kashi Prefecture, Xinjiang Uygur Autonomous Region is still serious prevalent, and integrated control measures must be taken in different endemic areas. Our findings will strengthen the VL control programme in China.

New insights into leishmaniasis in the immunosuppressed

Immunosuppression contributes significantly to the caseload of visceral leishmaniasis (VL). HIV coinfection, solid organ transplantation, malnutrition, and helminth infections are the most important immunosuppression-related factors. This review briefly describes the challenges of these associations. East Africa and the Indian subcontinent are the places where HIV imposes the highest burden in VL. In the highlands of Northern Ethiopia, migrant rural workers are at a greater risk of coinfection and malnutrition, while in India, HIV reduces the sustainability of a successful elimination programme. As shown from a longitudinal cohort in Madrid, VL is an additional threat to solid organ transplantation. The association with malnutrition is more complex since it can be both a cause and a consequence of VL. Different regimes for therapy and secondary prevention are discussed as well as the role of nutrients on the prophylaxis of VL in poverty-stricken endemic areas.