Mixed Mucosal Leishmaniasis Infection Caused by Leishmania tropica and Leishmania major

Mixed infections with different Leishmania species could explain differences in the clinical courses of these infections. On identification of Leishmania parasites from Iranian patients with mucosal leishmaniasis (ML), a patient with both oral and nasal lesions was found to be concomitantly infected with Leishmania tropica and L. major. Mixed infection was identified by PCR amplification of Leishmania kinetoplast DNA on scraping of cytological smears and histopathological sections. L. major and L. tropica were isolated from the nasal and oral lesions, respectively. These species were also confirmed by immunohistochemistry. This seems to be the first reported case of concurrent ML infection with two Leishmania species. It indicates that, at least in this patient, previous infection with one of these Leishmania species did not protect against infection with the other. This result has important implications for the development of vaccines against leishmaniases and implies careful attention in the treatment of this infectious disease.     

Leishmaniasis in immunosuppressed individuals

Leishmaniasis is a vector-born chronic infectious disease caused by a group of protozoan parasites of the genus Leishmania. Whereas most immunocompetent individuals will not develop disease after Leishmania infection, immunosuppression is a well-established risk factor for disease. The most severe form is visceral leishmaniasis (VL), which is typically fatal if untreated. Whereas human immunodeficiency virus (HIV) co-infection (VL–HIV) was initially mainly reported from southern Europe, it is now emerging in other regions, including East Africa, India, and Brazil. VL has also been found in a wide range of non-HIV-related immunosuppressive states, mainly falling under the realm of transplantation medicine, rheumatology, haematology, and oncology. Clinical presentation can be atypical in immunosuppressed individuals, being easily misdiagnosed or mistaken as a flare-up of the underlying disease. The best diagnostic approach is the combination of parasitological and serological or molecular methods. Liposomal amphotericin B is the drug of choice. Treatment failure and relapse rates are particularly high in cases of HIV co-infection, despite initiation of antiretroviral treatment. Primary prophylaxis is not recommended, but secondary prophylaxis is recommended when the patient is immunosuppressed. Cutaneous leishmaniasis can have a number of particular features in individuals with immunosuppression, especially if severe, including parasite dissemination, clinical polymorphism with atypical and often more severe clinical forms, and even visceralization. Mucosal leishmaniasis is more common. Treatment of cutaneous and mucosal leishmaniasis can be challenging, and systemic treatment is more often indicated. With globally increased travel and access to advanced medical care in developing countries, the leishmaniasis burden in immunosuppressed individuals will probably continue to rise, warranting increased awareness and enhanced surveillance systems.     

CCR5 and CCR3 expression on T CD3+ lymphocytes from HIV/<Emphasis Type="Italic">Leishmania</Emphasis> co-infected subjects

CC chemokine receptor 5 (CCR5) and CC chemokine receptor 3 (CCR3) are membrane-bound proteins involved in HIV-1 entry into susceptible cells. All T lymphocyte subsets display CCR5 and CCR3 on their membrane surface. T helper 1 cells are known to express CCR5 but not CCR3, and most of T cells expressing CCR3 are T helper 2. This study aimed to assess the expression of CCR5 and CCR3 on peripheral blood CD3+ T lymphocytes of HIV-Leishmania co-infected individuals. A total of 36 subjects were enrolled; nine had HIV-Leishmania co-infection; nine were HIV-infected without Leishmania, nine had visceral leishmaniasis without HIV co-infection and nine were healthy blood donors. HIV-Leishmania co-infected subjects showed a significantly higher rate of CCR5+CD3+ T lymphocytes in comparison with the other studied groups. The higher rate of CD3+ T-cells expressing CCR5 found in HIV-Leishmania co-infected subjects may be related to the role of Leishmania as an enhancer of the progression to AIDS.     

Prevalence of and Factors Associated with Visceral Leishmaniasis in Human Immunodeficiency Virus Type 1-Infected Patients in Southern Spain

The actual prevalence of visceral leishmaniasis among human immunodeficiency type 1 (HIV-1)-infected patients in the Mediterranean basin remains unknown. There is also controversy about the risk factors for Leishmania infantum and HIV-1 coinfection. To appraise the prevalence of visceral leishmaniasis in patients infected with HIV-1 in southern Spain and to identify factors associated with this disease, 291 HIV-1 carriers underwent a bone marrow aspiration, regardless of their symptoms. Giemsa-stained samples were searched for Leishmania amastigotes. Thirty-two (11%) patients showed visceral leishmaniasis. Thirteen (41%) patients had subclinical cases of infection. Centers for Disease Control and Prevention (CDC) clinical category C was the factor most strongly associated with this disease (adjusted odds ratio [OR], 1.88 [95% confidence interval, 1.22 to 2.88]), but patients with subclinical cases of infection were found in all CDC categories. Female sex was negatively associated with visceral leishmaniasis (adjusted OR, 0.42 [95% confidence interval, 0.18 to 0.97]). Intravenous drug users showed a higher prevalence than the remaining patients (13.3 versus 4.9%; P = 0.04), but such an association was not independent. These results show that visceral leishmaniasis is a very prevalent disease among HIV-1-infected patients in southern Spain, with a high proportion of cases being subclinical. Like other opportunistic infections, subclinical visceral leishmaniasis can be found at any stage of HIV-1 infection, but symptomatic cases of infection appear mainly when a deep immunosuppression is present. There is also an association of this disease with male sex and intravenous drug use.     

Co-cutaneous infection in a dog: PCR-reverse identification of Candida tropicalis on skin biopsy

Canine leishmaniasis is a very common disease in all countries of the Mediterranean area. In these territories, Leishmania infantum MONT-1 is the species producing visceral infections in humans and visceral-cutaneous infections in dogs, the principal domestic reservoir. The alterations of the immune response during leishmaniasis could predispose the host to other infectious, parasitic or mycologic diseases. In the domain of mycology, concurrent infections by dermatophytes and Aspergillus were reported. It is reported a clinical case of Candida tropicalis and L. infantum co-infection in a dog with skin lesions; it could be the first report of a such co-infection. The animal is a 10-year-old mongrel male dog showing, since about 1 year, a diffuse dermatitis on the face, the back and the flanks, characterized by alopecia and scaling. Serological tests for ehrlichiosis and rickettsiosis gave negative result, while indirect immunofluorescence test for IgG anti-L. infantum antibodies gave a positive titre of 1:640. Due to the severity of the lesions euthanasia of the dog was decided. Histopathology and immunochemistry performed on skin biopsies confirmed the positivity for Leishmania; by mycological culture and PCR-reverse hybridization assay on skin biopsies C. tropicalis was identified as associated to the protozoan. An impaired immune function and skin lesions caused by L. infantum could have played a direct role in the development of C. tropicalis.     

Molecular, cytological, and immunocytochemical study and kDNA sequencing of laryngeal Leishmania infantum infection

Mucosal leishmaniasis is a well-known clinical manifestation of infections mainly caused by New World Leishmania species, especially Leishmania braziliensis (Viannia) in Central and South America. It is extremely uncommon in the world, even in the endemic areas such as Fars Province, Southern Iran. Two male immunocompetent subjects who developed Leishmania mucosal lesion mimicking a laryngeal tumor presented with a several-months history of dysphonia, dyspnea, hoarseness, and odynophagia. Multiple smears from the lesions showed structures resembling the amastigote form of Leishmania. Nested PCR analysis to amplifying a fragment of Leishmania infantum kinetoplastid DNA from the Giemsa-stained smear resulted in a fragment of 680 bp. Sequence analysis of one of the strains showed 98 % similarity to L. infantum strain IranJWinf (GenBank accession no. AB678348.1) and 96 % similarity to L. infantum isolate MCAN/ES/98/10445 (GenBank accession no. EU437407.1), while another strain showed 97 % similarity with two L. infantum strains from kala-azar patient (GenBank accession nos. AJ223725.1 and AF027577.1). Immunocytochemical staining with anti-L. infantum mAb (D2) was positive. Primary mucosal leishmaniasis (ML) may occur in the immunocompetent patients who reside in or travel to endemic areas of leishmaniasis. Mucosal leishmaniasis contracted in endemic areas, such as Iran, has to be considered in the differential diagnosis of lesions in the other mucosa and may occur in previously healthy persons. Therefore, cytology, PCR, and immunocytochemistry-based methods with anti-Leishmania mAb are helpful in the diagnosis of ML.     

Leishmaniases in Northern Greece: seroprevalence of the infection and incidence of the disease during the period 2001–2006

Increasing risk factors are making leishmaniases a growing public health concern for many countries around the world. The aim of this study was to assess the seroprevalence of Leishmania infantum infection in the general population and in HIV infected subjects of Northern Greece, bordering the Mediterranean basin where leishmaniasis is endemic. The clinical cases of the disease during the last 6 years (2001–2006) are also presented. A low frequency of L. infantum antibodies was found by IFA and ELISA in 1,525 healthy individuals (2.8%), aged 18–80 years, living in the 16 prefectures of Northern Greece (Macedonia and Thrace regions), and in 167 HIV positive subjects (0.6%). Fifty-seven clinical cases were diagnosed in the same area and an approximate annual incidence of 0.34/100,000 was estimated. No endemic foci were identified and the cases of the disease were sporadic. Most presented with the visceral form (VL), few with the cutaneous, and one with VL-HIV co-infection. A significant shift in the age of people at risk was observed, with children less affected than adults (children/adults ratio: 0.36). No relevant data from previous studies are available to demonstrate a possible change of the infection in Northern Greece. The results of this study could be used as a reference for leishmaniasis surveillance in the area.     

Immune cellular parameters of leprosy and human immunodeficiency virus-1 co-infected subjects

Leprosy and human immunodeficiency virus-1 (HIV-1) are examples of human infections where interactions between the pathogen and the host cellular immunity determine the clinical manifestations of disease. Hence, a significant immunopathological interaction between HIV-1 and leprosy might be expected. In the present study we explored several aspects of cellular immunity in patients co-infected with HIV-1 and Mycobacterium leprae. Twenty-eight individuals were studied, comprising four groups: healthy controls, HIV-1 and M. leprae co-infection, HIV-1 mono-infection, and M. leprae mono-infection. Subjects in the mono-infection and co-infection groups were matched as far as possible for bacillary load and HIV disease status, as appropriate. Peripheral blood mononuclear cells (PBMC) were analysed using six- and seven-colour flow cytometry to evaluate T-cell subpopulations and their activation status, dendritic cell (DC) distribution phenotypes and expression of IL-4 by T cells. The co-infected group exhibited lower CD4 : CD8 ratios, higher levels of CD8⁺ T-cell activation, increased Vδ1 : Vδ2 T cell ratios and decreased percentages of plasmacytoid DC, compared with HIV-1 mono-infected subjects. Across infected groups, IL-4 production by CD4⁺ T lymphocytes was positively correlated with the percentage of effector memory CD4⁺ T cells, suggesting antigenically driven differentiation of this population of T cells in both HIV-1 and M. leprae infections. Co-infection with M. leprae may exacerbate the immunopathology of HIV-1 disease. A T helper 2 (Th2) bias in the CD4⁺ T-cell response was evident in both HIV-1 infection and leprosy, but no additive effect was apparent in co-infected patients.     

HIV and co-infections

Despite significant reductions in morbidity and mortality secondary to availability of effective combination anti-retroviral therapy (cART), human immunodeficiency virus (HIV) infection still accounts for 1.5 million deaths annually. The majority of deaths occur in sub-Saharan Africa where rates of opportunistic co-infections are disproportionately high. In this review, we discuss the immunopathogenesis of five common infections that cause significant morbidity in HIV-infected patients globally. These include co-infection with Mycobacterium tuberculosis, Cryptococcus neoformans, hepatitis B virus, hepatitis C virus, and Plasmodium falciparum. Specifically, we review the natural history of each co-infection in the setting of HIV, the specific immune defects induced by HIV, the effects of cART on the immune response to the co-infection, the pathogenesis of immune restoration disease (IRD) associated with each infection, and advances in the areas of prevention of each co-infection via vaccination. Finally, we discuss the opportunities and gaps in knowledge for future research.     

The therapeutic potential of immune cross-talk in leishmaniasis

Veterans of infection, Leishmania parasites have been plaguing mammals for centuries, causing a morbidity toll second only to that of malaria as the most devastating protozoan parasitic disease in the world. Cutaneous leishmaniasis (CL) is, by far, the most prevalent form of the disease, with symptoms ranging from a single self-healing lesion to chronic metastatic leishmaniasis (ML). In an increasingly immunocompromised population, complicated CL is becoming a more likely outcome, characterized by severely inflamed, destructive lesions that are often refractory to current treatment. This is perhaps because our ageing arsenal of variably effective antileishmanial drugs may be directly or indirectly immunomodulatory and may thus have variable effects in each type and stage of CL. Indeed, widely differing immune biases are created by the various species of Leishmania, and these immunological watersheds are further shifted by extrinsic disturbances in immune homeostasis. For example, we recently showed that a naturally occurring RNA virus (Leishmania RNA virus (LRV)) within some Leishmania parasites creates hyperinflammatory cross-talk, which can predispose to ML: a case of immunological misfire that may require a different approach to immunotherapy, whereby treatments are tailored to underlying immune biases. Understanding the intersecting immune pathways of leishmaniasis and its co-infections will enable us to identify new drug targets, and thereby design therapeutic strategies that work by untangling the immunological cross-wires of pathogenic cross-talk.     

The role of HSV in the transmission and progression of HIV

Herpes simplex virus (HSV) is a common co-infection in persons infected with human immunodeficiency virus type 1 (HIV-1). Chronic perianal ulceration from herpes simplex virus type 2 (HSV-2) was one of the first opportunisitc infections identified among patients with AIDS. Subsequent research has established that the natural history of HSV-2 is altered in co-infected persons as they experience more frequent clinical and subclinical reactivation of HSV than persons infected only with HSV-2. In addition, there are accumulating data to suggest a significant biological interaction between these two viruses that result in more efficient sexual transmission of HIV-1 and an increased rate of HIV replication during both clinical and subclinical HSV reactivation.     

Asymptomatic carriage of Leishmania in family members of patients with visceral leishmaniasis in Central Tunisia

Introduction

In Tunisia, asymptomatic carriage of Leishmania is poorly documented.

Objective

The aim of the present study was to estimate the frequency of asymptomatic infection among the family members of patients with patent visceral leishmaniasis by using the Western blotting kit based on 14 and 16 kDa bands.

Material and methods

We tested 94 sera collected from 24 patients with patent visceral leishmaniasis and 70 from their families’ members.

Results

The rate of seropositivity was 100% in the group of patients and 54.3% in the group of families’ members. The analysis of the Western blotting patterns showed that the 33 kDa, 24 kDa and to a lesser extent the 22 kDa band were very indicative of patent visceral leishmaniasis in contrast to asymptomatic infection where these bands were very rarely detected.

Conclusion

The results reported herein showed the high frequency of asymptomatic carriers of Leishmania among the families’ members of visceral leishmaniasis cases and the usefulness of the Western blotting as a screening technique and in distinguishing between patent visceral leishmaniasis and the asymptomatic carriage of Leishmania.     

Real-time in vivo green fluorescent protein imaging of a murine leishmaniasis model as a new tool for Leishmania vaccine and drug discovery

Leishmania species are obligate intracellular protozoan parasites that cause a broad spectrum of clinical diseases in mammalian hosts. The most frequently used approach to quantify parasites in murine model systems is based on thickness measurements of the footpad or ear after experimental infection. To overcome the limitations of this method, we used a Leishmania mutant episomally transfected with enhanced green fluorescent protein, enabling in vivo real-time whole-body fluorescence imaging, to follow the progression of Leishmania infection in parasitized tissues. Fluorescence correlated with the number of Leishmania parasites in the tissue and demonstrated the real-time efficacy of a therapeutic vaccine. This approach provides several substantial advantages over currently available animal model systems for the in vivo study of immunopathogenesis, prevention, and therapy of leishmaniasis. These include improvements in sensitivity and the ability to acquire real-time data on progression and spread of the infection.     

Low Sensitivity of Peripheral Blood Smear for Diagnosis of Subclinical Visceral Leishmaniasis in Human Immunodeficiency Virus Type 1-Infected Patients

The peripheral blood smear is an easy method for the diagnosis of symptomatic visceral leishmaniasis (VL) in human immunodeficiency virus type 1 (HIV-1)-infected patients. However, its efficiency in diagnosing subclinical VL remains unknown. In this study, Leishmania amastigotes were seen in blood smears from 1 of 13 HIV-1-positive individuals with subclinical VL. This shows that this procedure is not suitable for subclinical-VL diagnosis.     

Seroprevalence of cytomegalovirus infection in children born to HIV-1 infected women

Cytomegalovirus (CMV) is a frequent opportunistic infectious agent in children infected with human immunodeficiency virus type 1 (HIV-1). It has been implicated as a factor in the progression of HIV-1 disease. The aim of the present study was to evaluate the prevalence of CMV infection in Thai children born to HIV-1 infected women. The prevalence of CMV infection was 13, 89 and 84% in HIV-infected children and 9, 61 and 75% in HIV uninfected at age ranges of 0-12, 13-36 and 37-79 months, respectively. The prevalence of CMV infection was significantly different between HIV infected children (89%) and HIV uninfected (61%) at the age of 13-36 months (p < 0.05). The presence of CMV IgM in some children of age < 1 year suggested that CMV infection could occur early in life. Early co-infection may be important as they remain a risk factor for reactivation of latent CMV infection throughout the course of the HIV diseases. Clinical monitoring and appropriate work up may be of benefit in the early diagnosis and treatment of CMV disease.     

Biomarkers for intracellular pathogens: establishing tools as vaccine and therapeutic endpoints for visceral leishmaniasis

Visceral leishmaniasis in South Asia is a serious disease affecting children and adults. Acute visceral leishmaniasis develops in only a fraction of those infected individuals, the majority being asymptomatic with the potential to transmit infection and develop disease. We followed 56 individuals characterized as being asymptomatic by seropositivity with rk39 rapid diagnostic test in a hyperendemic district of Bangladesh to define the utility of Leishmania-specific antibodies and DNA in identifying infection. At baseline, 54 of the individuals were seropositive with one or more quantitative antibody assays and antibody levels persisted at follow up. Most seropositive individuals (47/54) tested positive by quantitative PCR at baseline, but only 16 tested positive at follow up. The discrepancies among the different tests may shed light on the dynamics of asymptomatic infections of Leishmania donovani, as well as underscore the need for standard diagnostic tools for active surveillance as well as assessing the effectiveness of prophylactic and therapeutic interventions.     

Immunopathogenesis of non-healing American cutaneous leishmaniasis and progressive visceral leishmaniasis

The outcomes of Leishmania infection are determined by host immune and nutrition status, parasite species, and co-infection with other pathogens. While subclinical infection and self-healing cutaneous leishmaniasis (CL) are common, uncontrolled parasite replication can lead to non-healing local lesions or visceral leishmaniasis (VL). It is known that infection control requires Th1-differentiation cytokines (IL-12, IL-18, and IL-27) and Th1 cell and macrophage activation. However, there is no generalized consensus for the mechanisms of host susceptibility. The recent studies on regulatory T cells and IL-17-producing cells help explain the effector T cell responses that occur independently of the known Th1/Th2 cell signaling pathways. This review focuses on the immunopathogenesis of non-healing American CL and progressive VL. We summarize recent evidence from human and animal studies that reveals the mechanisms of dysregulated, hyper-responses to Leishmania braziliensis, as well as the presence of disease-promoting or the absence of protective responses to Leishmania amazonensis and Leishmania donovani. We highlight immune-mediated parasite growth and immunopathogenesis, with an emphasis on the putative roles of IL-17 and its related cytokines as well as arginase. A better understanding of the quality and regulation of innate immunity and T cell responses triggered by Leishmania will aid in the rational control of pathology and the infection.     

Contribution of molecular diagnosis to the management of cutaneous leishmaniasis in travellers

Cutaneous leishmaniasis is one of the most frequent skin diseases occurring after travelling in endemic areas. Optimal management requires identification of the species of Leishmania involved. In this study we aimed to evaluate the use of molecular diagnosis as routine, in comparison with direct examination and culture. Thirty positive diagnoses were carried out between 2007 and 2013. Classical PCR enabled 11 positive cases to be identified that were found to be negative by conventional methods. Sequencing led to the identification of eight different species. Routine use of PCR and sequencing appears very efficient in the management of cutaneous leishmaniasis.     

Malaria and HIV co-infection and their effect on haemoglobin levels from three health-care institutions in Lagos,southwest Nigeria

Background

Malaria and human immunodeficiency virus (HIV) are two major infections with enormous public health consequence. Together, they are endemic in many developing countries with anaemia being the most frequent haematological consequence of the infections.

Objectives

To determine the prevalence of malaria and HIV co-infection as well as anaemia among selected patients from three health-care institutions in Lagos, Nigeria.

Methods

A cross-sectional study of 1080 patients was carried out to determine the prevalence of malaria and HIV co-infection as well as anaemia. Blood sera from each of the patients were screened for malaria parasites, HIV-1 and HIV-2 using Giemsa stain, Cambridge Biotech Recombigen HIV-1/HIV-2 rapid device, respectively while haemoglobin estimation was performed using cyanmethemoglobin method.

Results

Our data showed that the total number of malaria infected patients were significantly higher in HIV sero-positive patients 47.7% (31/65) when compared with their HIV sero-negative counterparts 25.8% (262/1015) P = 0.047. The result also revealed that 25.8% (8/31) of the patients co-infected with malaria and HIV had anaemia as compared to 11.1% (29/262) infected with malaria alone. Multivariable logistic regression analysis showed that patients with dual infection of malaria and HIV were twice likely to be anaemic than those infected with malaria alone [adjusted OR 2.4, 95% CI, 1.3 to 2.7, P = 0.014].

Conclusions

Our data indicated a higher prevalence of malaria in HIV infected patients and also revealed that patients co-infected with malaria and HIV were more likely to be anaemic.     

Molecular identification of the parasites causing cutaneous leishmaniasis on the Caribbean coast of Colombia

All clinical manifestations of leishmaniasis exist in Colombia, the cutaneous form being the most frequent in the department of Sucre, where the Leishmania species associated with cutaneous leishmaniasis (CL) is unknown. This study was carried out to determine which Leishmania species was responsible for CL in Sucre, based on amplification and sequencing of the Cyt b gene. Isolates of Leishmania were obtained after CL diagnosis of eight patients who received attention in several health care centers of the study area. The nucleotide sequences obtained from patients were compared to Leishmania reference strains and six of the isolates identified as Leishmania (Viannia) braziliensis, the remaining two being identified as Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis. This represents the first report of the presence of L. (V.) guyanensis on the Caribbean coast of Colombia.