Malaria-Cutaneous Leishmaniasis Co-infection: Influence on Disease Outcomes and Immune Response

Cutaneous Manifestations of Malaria and Their Prognostic Windows: A Narrative Review

Malaria is a vector-borne tropical infection caused by protozoa of the genus Plasmodium and is transmitted by the bite of an infected Anopheles mosquito. The disease is commonly characterized by fever, edema, thrombocytopenia, hypoglycemia, anemia, and myalgias; however, the infection's cutaneous presentations are not commonly emphasized and tend to be overlooked. A literature search was conducted that focused on the various skin pathologies that malaria patients have been noted to present with using case reports and currently available literature. We describe the various skin manifestations associated with malaria, such as purpura fulminans, febrile urticaria, cutaneous leishmaniasis co-infections, urticaria infectiosum, vivax-induced severe thrombocytopenia petechiae, acral skin necrosis, and reticulated erythema, and how each of these skin manifestations may provide insight into the patient's prognosis. Documentation and vigilance regarding these cutaneous manifestations must be emphasized as they may lead to better patient outcomes and a stronger understanding of the patient's underlying malaria.

Clinical features, immunological interactions and household determinants of visceral leishmaniasis and malaria coinfections in West Pokot, Kenya: protocol for an observational study

INTRODUCTION

Visceral leishmaniasis (VL) and malaria are two deadly parasitic diseases that coexist in West Pokot County, Kenya. The local population is at considerable risk of coinfection with VL and malaria; however, few studies have described the clinical implications of this comorbidity. Questions remain regarding the immune responses responsible for possible predisposing or protective effects. Moreover, characterisation of environmental and household risk factors for co-acquiring VL and malaria is warranted to increase awareness and guide implementation of targeted control strategies. This protocol intends to address these knowledge gaps concerning VL-malaria coinfections.

METHODS AND ANALYSIS

This observational research project will have a multimethod approach, starting with a cross-sectional study at Kacheliba Sub-County Hospital in West Pokot, Kenya. Patients with laboratory confirmation of a VL and/or malaria infection will be clinically assessed and symptomatology of monoinfections and coinfections will be compared. Second, a questionnaire will be addressed to all included patients and to healthy controls in local communities. This case-control study will aim to describe household and environmental determinants associated with VL-malaria coinfection. Lastly, blood samples will be collected from a small cohort of VL and malaria monoinfected and coinfected patients during treatment of their infection(s), and from healthy controls and asymptomatic VL and malaria cases recruited in local communities. These specimens will be used for serum cytokine measurements and molecular quantitation of Plasmodium and Leishmania. In this way, the immune response and parasite dynamics during VL-malaria coinfection will be characterised longitudinally and compared with those observed in clinical and asymptomatic monoinfections.

ETHICS AND DISSEMINATION

Ethical approval was obtained from the Ethics and Scientific Research Committee of Amref Health Africa. The study findings will be presented at international conferences and published in open-access, peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN Registry (ISRCTN15023306).

Malaria and leishmaniasis: Updates on co-infection

Malaria and leishmaniasis are endemic parasitic diseases in tropical and subtropical countries. Although the overlap of these diseases in the same host is frequently described, co-infection remains a neglected issue in the medical and scientific community. The complex relationship of concomitant infections with Plasmodium spp. and Leishmania spp. is highlighted in studies of natural and experimental co-infections, showing how this "dual" infection can exacerbate or suppress an effective immune response to these protozoa. Thus, a Plasmodium infection preceding or following Leishmania infection can impact the clinical course, accurate diagnosis, and management of leishmaniasis, and vice versa. The concept that in nature we are affected by concomitant infections reinforces the need to address the theme and ensure its due importance. In this review we explore and describe the studies available in the literature on Plasmodium spp. and Leishmania spp. co-infection, the scenarios, and the factors that may influence the course of these diseases.

Prevalence and characteristics of malaria co-infection among individuals with visceral leishmaniasis in Africa and Asia: a systematic review and meta-analysis

Background

Malaria and visceral leishmaniasis (VL) co-infection can occur due to the overlapping geographical distributions of these diseases; however, only limited data of this co-infection have been reported and reviewed. This study aimed to explore the pooled prevalence and characteristics of this co-infection using a systematic review approach.

Methods

The PubMed, Web of Science and Scopus databases were searched for relevant studies. The quality of these studies was assessed in accordance with strengthening the reporting of observational studies in epidemiology (STROBE) guidelines. The numbers of individuals co-infected with Plasmodium and VL and the total numbers of individuals with VL were used to estimate the pooled prevalence using random-effects models. Differences in age, sex and the presence of anemia and malnutrition on admission were compared between co-infected individuals and individuals with VL using a random-effects model; the results are presented as odds ratios (ORs) and 95% confidence intervals (CIs). Heterogeneity among the included studies was assessed and quantified using Cochrane Q and I² statistics.

Results

Of the 3075 studies identified, 12 met the eligibility criteria and were included in this systematic review. The pooled prevalence of Plasmodium infection among the 6453 individuals with VL was 13%, with substantial heterogeneity of the data (95% CI 7–18%, I² 97.9%). Subgroup analysis demonstrated that the highest prevalence of co-infection occurred in African countries, whereas the lowest prevalence occurred in Asian countries. Patients aged < 5 years had higher odds of having co-infection than having VL (co-infection, n = 202; VL, n = 410) (OR 1.66, 95% CI 1.37–2.01, I² 0%; P < 0.0001), whereas patients aged 20–29 years had lower odds of having co-infection than having VL (co-infection, n = 170; VL, n = 699) (OR 0.75, 95% CI 0.60–0.93, I² 18%; P = 0.01). Male patients had equivalent odds of having co-infection and having VL (co-infection, n = 525; VL, n = 2232) (OR 0.92, 95% CI 0.078–1.08, I² 0%; P = 0.29). Patients with co-infection had lower odds of having anemia at admission than those with VL (co-infection, n = 902; VL, n = 2939) (OR 0.64, 95% CI 0.44–0.93, I² 0%; P = 0.02). No difference in malnutrition at admission was found in the meta-analysis.

Conclusions

The prevalence of malaria co-infection among individuals with VL was heterogeneous and ranged from 7 to 18%, depending on geographical area. Age and anemia at admission were associated with co-infection status. Further longitudinal studies are needed to determine if co-infection with malaria has an impact on the severity of VL.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05045-1.

Cross-protective efficacy of immuno-stimulatory recombinant Brugia malayi protein HSP60 against the Leishmania donovani in BALB/c mice

Coinfection of Leishmania with bacteria, viruses, protozoans, and nematodes alter the immune system of the host, thereby influencing the disease outcomes. Here, we have determined the immunogenic property and protective efficacy of the cross-reactive molecule HSP60 of filarial parasite B. malayi against the L. donovani in BALB/c mice. Parasitological parameters results showed a significant decrease in the parasite burden (~59%; P < 0.001) and also a substantial increase in the delayed-type hypersensitivity (DTH) response (P < 0.001) in mice immunized with 10 μg of rBmHSP60. Protection against L. donovani in mice immunized with rBmHSP60 resulted from activation of the T cells, which is characterized by higher levels of nitric oxide (NO) production, enhanced cell proliferation, higher levels (expression and release) of IFN- γ, TNF- α, and IL-12, also, higher production of IgG and IgG2a antibodies. This strong Th1 immune response creates an inflammatory domain for L. donovani and protects the host from VL.

Infection-Associated Thymic Atrophy

The thymus is a vital organ of the immune system that plays an essential role in thymocyte development and maturation. Thymic atrophy occurs with age (physiological thymic atrophy) or as a result of viral, bacterial, parasitic or fungal infection (pathological thymic atrophy). Thymic atrophy directly results in loss of thymocytes and/or destruction of the thymic architecture, and indirectly leads to a decrease in naïve T cells and limited T cell receptor diversity. Thus, it is important to recognize the causes and mechanisms that induce thymic atrophy. In this review, we highlight current progress in infection-associated pathogenic thymic atrophy and discuss its possible mechanisms. In addition, we discuss whether extracellular vesicles/exosomes could be potential carriers of pathogenic substances to the thymus, and potential drugs for the treatment of thymic atrophy. Having acknowledged that most current research is limited to serological aspects, we look forward to the possibility of extending future work regarding the impact of neural modulation on thymic atrophy.

The role of heparan sulfate in host macrophage infection by Leishmania species

The leishmaniases are a group of neglected tropical diseases caused by parasites from the Leishmania genus. More than 20 Leishmania species are responsible for human disease, causing a broad spectrum of symptoms ranging from cutaneous lesions to a fatal visceral infection. There is no single safe and effective approach to treat these diseases and resistance to current anti-leishmanial drugs is emerging. New drug targets need to be identified and validated to generate novel treatments. Host heparan sulfates (HSs) are abundant, heterogeneous polysaccharides displayed on proteoglycans that bind various ligands, including cell surface proteins expressed on Leishmania promastigote and amastigote parasites. The fine chemical structure of HS is formed by a plethora of specific enzymes during biosynthesis, with various positions (N-, 2-O-, 6-O- and 3-O-) on the carbon sugar backbone modified with sulfate groups. Post-biosynthesis mechanisms can further modify the sulfation pattern or size of the polysaccharide, altering ligand affinity to moderate biological functions. Chemically modified heparins used to mimic the heterogeneous nature of HS influence the affinity of different Leishmania species, demonstrating the importance of specific HS chemical sequences in parasite interaction. However, the endogenous structures of host HSs that might interact with Leishmania parasites during host invasion have not been elucidated, nor has the role of HSs in host-parasite biology. Decoding the structure of HSs on target host cells will increase understanding of HS/parasite interactions in leishmaniasis, potentiating identification of new opportunities for the development of novel treatments.

Tegumentary leishmaniasis and coinfections other than HIV

BACKGROUND

Tegumentary leishmaniasis (TL) is a disease of skin and/or mucosal tissues caused by Leishmania parasites. TL patients may concurrently carry other pathogens, which may influence the clinical outcome of TL.

METHODOLOGY AND PRINCIPAL FINDINGS

This review focuses on the frequency of TL coinfections in human populations, interactions between Leishmania and other pathogens in animal models and human subjects, and implications of TL coinfections for clinical practice. For the purpose of this review, TL is defined as all forms of cutaneous (localised, disseminated, or diffuse) and mucocutaneous leishmaniasis. Human immunodeficiency virus (HIV) coinfection, superinfection with skin bacteria, and skin manifestations of visceral leishmaniasis are not included. We searched MEDLINE and other databases and included 73 records: 21 experimental studies in animals and 52 studies about human subjects (mainly cross-sectional and case studies). Several reports describe the frequency of Trypanosoma cruzi coinfection in TL patients in Argentina (about 41%) and the frequency of helminthiasis in TL patients in Brazil (15% to 88%). Different hypotheses have been explored about mechanisms of interaction between different microorganisms, but no clear answers emerge. Such interactions may involve innate immunity coupled with regulatory networks that affect quality and quantity of acquired immune responses. Diagnostic problems may occur when concurrent infections cause similar lesions (e.g., TL and leprosy), when different pathogens are present in the same lesions (e.g., Leishmania and Sporothrix schenckii), or when similarities between phylogenetically close pathogens affect accuracy of diagnostic tests (e.g., serology for leishmaniasis and Chagas disease). Some coinfections (e.g., helminthiasis) appear to reduce the effectiveness of antileishmanial treatment, and drug combinations may cause cumulative adverse effects.

CONCLUSIONS AND SIGNIFICANCE

In patients with TL, coinfection is frequent, it can lead to diagnostic errors and delays, and it can influence the effectiveness and safety of treatment. More research is needed to unravel how coinfections interfere with the pathogenesis of TL.

Joint spatial time-series epidemiological analysis of malaria and cutaneous leishmaniasis infection

Malaria and leishmaniasis are among the two most important health problems of many developing countries especially in the Middle East and North Africa. It is common for vector-borne infectious diseases to have similar hotspots which may be attributed to the overlapping ecological distribution of the vector. Hotspot analyses were conducted to simultaneously detect the location of local hotspots and test their statistical significance. Spatial scan statistics were used to detect and test hotspots of malaria and cutaneous leishmaniasis (CL) in Afghanistan in 2009. A multivariate negative binomial model was used to simultaneously assess the effects of environmental variables on malaria and CL. In addition to the dependency between malaria and CL disease counts, spatial and temporal information were also incorporated in the model. Results indicated that malaria and CL incidence peaked at the same periods. Two hotspots were detected for malaria and three for CL. The findings in the current study show an association between the incidence of malaria and CL in the studied areas of Afghanistan. The incidence of CL disease in a given month is linked with the incidence of malaria in the previous month. Co-existence of malaria and CL within the same geographical area was supported by this study, highlighting the presence and effects of environmental variables such as temperature and precipitation. People living in areas with malaria are at increased risk for leishmaniasis infection. Local healthcare authorities should consider the co-infection problem by recommending systematic malaria screening for all CL patients.