Visceral Leishmaniasis: Kala-azar

Diagnostic techniques for visceral leishmaniasis: An overview of methods used in East Africa

Leishmanias is a parasitic infection caused by a protozoan belonging to the genus Leishmania and transmitted by sand fly, Phlebotomus fly in the old world and Lutzomyia in the New world. The disease is prevalent in the tropics, subtropics, and Southern Europe, where it affects about 1.5 million to 2 million people annually. India, Bangladesh, Sudan, South Sudan, Brazil and Ethiopia account for up to 90% of all the VL cases. While Leishmania cases in Asia are declining, cases in East Africa especially in Somalia, Sudan, South Sudan, Ethiopia and Kenya have been increasing. The rise in East African cases is partially attributed to ongoing armed conflicts especially in Somalia, Sudan and Southern Sudan, which has displaced people and increased their exposure to sand fly bites. Migration from endemic to non-endemic regions, misdiagnosis, famine, malnutrition, climate change and an increase in HIV cases are other contributing factors. The clinical diagnosis of Leishmania in East Africa combines the patient's clinical signs with either serological or parasitological test, with rK39 strip and microscopy being the major methods used. Diagnosis of the condition remains challenging, as current techniques have limitations, including the inability to detect parasites in tissue, the need for specialized expertise, prohibitive costs of testing equipment, low antibody titers, and the risk of misdiagnosis due to co-infections with diseases such as HIV, tuberculosis, malaria and typhoid. Various techniques, including serological and molecular parasitological methods, have been employed in attempts to address these challenges, but with limited success. This article therefore, reviews some of the techniques that have been used in Leishmania diagnosis in East Africa and discusses other available new techniques with aim of overcoming the current challenges.

Nanotechnological Formulation Incorporating Pectis brevipedunculata (Asteraceae) Essential Oil: An Ecofriendly Approach for Leishmanicidal and Anti-Inflammatory Therapy

Cutaneous leishmaniasis caused by Leishmania amazonensis is a significant public health issue. This study aimed to evaluate an ecofriendly, thermosensitive nanogel, developed using a low-energy, solvent-free method, incorporating F127 and Carbopol 974P copolymers, and enriched with Pectis brevipedunculata essential oil (EOPb) for its leishmanicidal and anti-inflammatory properties. The nanogel was prepared and characterized through FTIR, DLS, SEM, and AFM to confirm the incorporation of EOPb as well as its stability and rheological properties. In vitro leishmanicidal activity was evaluated on Leishmania amazonensis promastigotes, and in vivo anti-inflammatory effects were assessed using a rat paw edema model. In vitro, nGF3 (EOPb-loaded nanogel) demonstrated significant leishmanicidal activity, with promastigote mortality rates exceeding 80% at 24 h and 90% at 48 h. In vivo, nGF1, nGF2, and nGF3 exhibited anti-inflammatory effects, with nGF2 and nGF3 reducing edema by 62.7% at 2 h post-treatment. The empty nanogel (nGF0) showed minimal anti-inflammatory activity. The ecofriendly EOPb-loaded nanogel (nGF3) demonstrated strong leishmanicidal and anti-inflammatory effects, presenting a promising candidate for cutaneous leishmaniasis treatment. Further studies are necessary to explore its clinical potential.

Bronchoalveolar Lavage Fluid Metagenomic Second-Generation Sequencing Assists in Guiding the Treatment of Visceral Leishmaniasis: A Case Report

Purpose

The incidence of visceral leishmaniasis (VL), a global infectious disease, has been on the rise in China's Hebei province. When patients achieve clinical cure, they often do not reach an etiological cure, which may lead to recurrence of the disease. Here, we report a case of visceral leishmaniasis with a negative blood smear and bone marrow cytology.

Patients and Methods

A 65-year-old man and bronchoalveolar lavage fluid mNGS.

Results

A 65-year-old man developed a chronic fever, anorexia, splenomegaly, and pancytopenia. The blood metagenomic second-generation sequencing (mNGS) revealed Leishmania sequence readings, which led to the diagnosis of VL. After sodium antimony gluconate treatment, the blood smear and bone marrow cytology revealed no Leishmania bodies. However, pancytopenia and respiratory failure did not fully subside, and cardiotoxic damage emerged. The bronchoalveolar lavage fluid (BALF) mNGS was performed to detect the pathogen. Through BALF mNGS, Leishmania sequence was still detectable. Therefore, after the ECG returned to normal, antimony sodium gluconate was administered as a next course of treatment.

Conclusion

BALF mNGS may assist in evaluating the therapeutic efficacy of VL with respiratory failure, especially in patients with negative blood and bone marrow cytology.

Visceral leishmaniasis as a rare cause of granulomatous hepatitis

Visceral leishmaniasis (VL) is a potentially fatal infection caused by species of Leishmania. It is characterized by fever, weight loss, anemia, and enlargement of the spleen and liver. Hepatitis due to VL is one of the causes of granulomatous hepatitis rarely described in the literature. It poses a problem of differential diagnosis with other causes, notably infectious and autoimmune. Hence the need for a global clinical, biological, and histological evaluation to orientate this entity, especially in endemic countries like ours. In the present case study, a 2-year 8-month-old boy was diagnosed with VL and treated with meglumine antimoniate; the evolution was marked after 2 months by the persistence of a large liver; laboratory results showed elevated liver functions and anemia. A liver biopsy was performed, and the histological findings confirmed the diagnosis of granulomatous hepatitis.

Antimicrobial Peptides (AMP) in the Cell-Free Culture Media of Xenorhabdus budapestensis and X. szentirmaii Exert Anti-Protist Activity against Eukaryotic Vertebrate Pathogens including Histomonas meleagridis and Leishmania donovani Species

Anti-microbial peptides provide a powerful toolkit for combating multidrug resistance. Combating eukaryotic pathogens is complicated because the intracellular drug targets in the eukaryotic pathogen are frequently homologs of cellular structures of vital importance in the host organism. The entomopathogenic bacteria (EPB), symbionts of entomopathogenic-nematode species, release a series of non-ribosomal templated anti-microbial peptides. Some may be potential drug candidates. The ability of an entomopathogenic-nematode/entomopathogenic bacterium symbiotic complex to survive in a given polyxenic milieu is a coevolutionary product. This explains that those gene complexes that are responsible for the biosynthesis of different non-ribosomal templated anti-microbial protective peptides (including those that are potently capable of inactivating the protist mammalian pathogen Leishmania donovanii and the gallinaceous bird pathogen Histomonas meleagridis) are co-regulated. Our approach is based on comparative anti-microbial bioassays of the culture media of the wild-type and regulatory mutant strains. We concluded that Xenorhabdus budapestensis and X. szentirmaii are excellent sources of non-ribosomal templated anti-microbial peptides that are efficient antagonists of the mentioned pathogens. Data on selective cytotoxicity of different cell-free culture media encourage us to forecast that the recently discovered "easy-PACId" research strategy is suitable for constructing entomopathogenic-bacterium (EPB) strains producing and releasing single, harmless, non-ribosomal templated anti-microbial peptides with considerable drug, (probiotic)-candidate potential.

Temporal trend in the incidence of human visceral leishmaniasis in Brazil

It is an ecological study that analyzed the time trend of visceral leishmaniasis incidence rates in Brazil using segmented time regression by joinpoints. There was a decreasing incidence rate of this disease in the country with an average annual percent change (AAPC) of -5 (CI95%: -9.1; -0.6) and a reduction of 1.69 cases/100 thousand inhabitants in 2007, and 0.91/100 thousand inhabitants in 2020. The Central-West region showed the highest reduction percent (AAPC: -9.1; CI95%: -13.8; -4.3), followed by the Southeast region (AAPC: -8.7; -14.6; -2.5). The North and South regions showed the largest number of joinpoints in the time series. The highest incidences were recorded in the male population, however, stable (AAPC: 2.14; CI95%: -8.3; 0). In the age group analysis, the trend was decreasing for the groups from 0 to 4 years old (AAPC: -7.7; CI95%: -12.6; -2.4), 5 to 9 years old (AAPC: -7.3; CI95%: -13.6; -0,4) and 10 to 14 years old (AAPC: -5.5; CI95%: -10.3; -0.3). It was found that although Visceral Leishmaniasis is an endemic disease in Brazil, there was a decrease in its incidence rate from 2007 to 2020.

Kala-Azar: A Case Report

Leishmaniasis is a zoonosis caused by unicellular protozoans Leishmania. The transmission can be zoonotic or anthroponotic, depending on the species, and the main vector is the phlebotomine sandfly. The disease is endemic in the tropics of Asia and Africa but is considered rare in Portugal, especially in immunocompetent hosts. Its main clinical syndromes constitute cutaneous leishmaniasis, mucocutaneous disease, and visceral leishmaniasis. The latter is also known as kala-azar and is caused by the infection of the phagocytes of the reticuloendothelial system, causing the typical symptoms: fever, hepatosplenomegaly, and pancytopenia. The clinical manifestations are non-specific, frequently causing a delay in the diagnosis, especially in nonendemic areas and immunocompetent hosts. Early diagnosis and treatment are essential, given the high mortality rate in untreated patients. The diagnosis is based on the direct visualization of the protozoan and molecular methods, such as polymerase chain reaction tests. Amphotericin B is considered the first-line treatment. We present a case of visceral leishmaniasis in an immunocompetent patient with fever, hepatosplenomegaly, and pancytopenia.

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.

Histological and neuronal changes in the duodenum of hamsters infected with Leishmania (Leishmania) infantum

Visceral leishmaniasis is a neglected tropical disease caused by parasites belonging to the Leishmania genus that infect macrophages in different tissues such as the spleen, liver, lymph nodes, bone marrow, and intestine. Therefore, this study aimed to investigate the integrity of the intestinal tract and the nitrergic (NADPH-dp) and metabolically active (NADH-dp) myenteric neurons of the duodenum of golden hamsters infected with L. (L.) infantum. Therefore, thirty golden hamsters were divided into six groups (n = 5); three of them were infected with 2 × 10⁷ promastigote forms of L. (L.) infantum by intraperitoneal route (Infected Group - IG) and three were inoculated with saline solution (control group - CG). After 30, 60 and 90 days post-infection (DPI) infected animals were euthanized and the liver, spleen and duodenum were collected to analyze tissue parasitism. The duodenum was processed using usual histological techniques to analyze the main changes that occurred during infection and histochemical techniques to phenotype myenteric neurons. Amastigote forms were observed in the spleen, liver, and duodenum during all experimental periods, and tissue parasitism in these organs increased significantly over time. At 30 DPI, reduction in muscle tunic, increase in the total intestinal wall and the number of goblet cells PAS+ was observed. At 60 DPI, an increase in intestinal crypts and intraepithelial lymphocytes was observed, and a reduction in intestinal villi was observed at 90 DPI, along with an increase in crypt size. Regarding neurons, an increase in the density of the NADPH-dp population was observed at 30 DPI, but at 60 and 90 DPI a significant reduction of this population was observed. In general, infection progression was observed to cause significant morphofunctional changes in the duodenum of infected hamsters.

Epidemiological Aspects and High Magnitude of Human Visceral Leishmaniasis in Ceará, Northeast of Brazil, 2007-2021

BACKGROUND

Human visceral leishmaniasis HVL is endemic to 75 countries. The state of Ceará, the Northeast region of Brazil, is of great sanitary importance for the transmission of HVL, and it stands out as an area of interest for epidemiological aspects and control strategies. This study aimed to characterize HVL in relation to epidemiological aspects, composite incidence, and mortality rates in the state of Ceará, Brazil, from 2007 to 2021.

METHODS

This ecological study used temporal and spatial cuts of HVL data from the notifiable diseases information system. Epidemiological indicators such as incidence, mortality, and composite indices of incidence and mortality were calculated according to the Ministry of Health standardization.

RESULTS

There were 6,775 confirmed cases, with high incidence coefficients in 2009 6.96 cases/100,000 inhabitants and 2011 9.83 cases/100,000 inhabitants, and the highest mortality rate in 2011 6.96 deaths/100,000 inhabitants. The composite index of incidence and mortality identified municipalities in the Northern, Northwestern, and Southern regions of Ceará as having the highest risk of HVL.

CONCLUSIONS

HVL remained endemic throughout the study period, with epidemiological indicators and risk of transmission expressing high magnitude, mainly in the Northeast, Northwest, and South regions of Ceará.

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

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