Real-time PCR for Leishmania species identification: Evaluation and comparison with classical techniques

Identification of infection by Leishmania spp. in wild and domestic animals in Brazil: a systematic review with meta-analysis (2001-2021)

Leishmaniasis is a zoonosis caused by protozoan species of the genus Leishmania. It generates different clinical manifestations in humans and animals, and it infects multiple hosts. Leishmania parasites are transmitted by sandfly vectors. The main objective of this systematic review was to identify the host, or reservoir animal species, of Leishmania spp., with the exception of domestic dogs, that were recorded in Brazil. This review included identification of diagnostic methods, and the species of protozoan circulating in the country. For this purpose, a literature search was conducted across index journals. This study covered the period from 2001 to 2021, and 124 studies were selected. Eleven orders possible hosts were identified, including 229 mammalian species. Perissodactyla had the highest number of infected individuals (30.69%, 925/3014), with the highest occurrence in horses. In Brazil, the most commonly infected species were found to be: horses, domestic cats, rodents, and marsupials. Bats, that were infected by one or more protozoan species, were identified as potential reservoirs of Leishmania spp. Molecular tests were the most commonly used diagnostic methods (94 studies). Many studies have detected Leishmania spp. (n = 1422): Leishmania (Leishmania) infantum (n = 705), Leishmania (Viannia) braziliensis (n = 319), and Leishmania (Leishmania) amazonensis (n = 141). Recognizing the species of animals involved in the epidemiology and biological cycle of the protozoan is important, as this allows for the identification of environmental biomarkers, knowledge of Leishmania species can improve the control zoonotic leishmaniasis.

Evaluation of Molecular Methods to Identify Chagas Disease and Leishmaniasis in Blood Donation Candidates in Two Brazilian Centers

In Brazil, blood donation is regulated by the Brazilian Ministry of Health, and all States follow the same protocol for clinical and laboratory screening. Brazil is an endemic country for Chagas disease (CD), caused by Trypanosoma cruzi, and for leishmaniasis, caused by a species of Leishmania spp. Screening for leishmaniosis is not routinely performed by blood banks. Given the antigenic similarity between T. cruzi and Leishmania spp., cross-reactions in serological tests can occur, and inconclusive results for CD have been found. The objective of this study was to apply molecular techniques, e.g., nPCR, PCR, and qPCR, to clarify cases of blood donation candidates with non-negative serology for CD and to analyze the difference between the melting temperature during real-time PCR using SYBR Green. Thirty-seven cases that showed non-negative results for CD using chemiluminescent microparticle immunoassay (CMIA) tests from blood banks in Campo Grande, MS, and Campinas, SP, were analyzed. In the serum samples, 35 samples were evaluated by ELISA, and 24.3% (9/35) showed positive results for CD. nPCR was able to detect 12 positive results in 35 samples (34.28%). qPCR for T. cruzi was quantifiable in the samples that showed a value ≥0.002 par eq/mL (parasite equivalents per milliliter), and in 35 samples, 11 (31.42%) were positive. Of all evaluated samples using the described tests (CMIA, ELISA, nPCR, and qPCR), 18 (48.6%) were positive for CD. For MCA by qPCR, the melting temperature was 82.06 °C ± 0.46 for T. cruzi and 81.9 °C ± 0.24 for Leishmania infantum. The Mann-Whitney test showed a significant value of p < 0.0001. However, the differentiation between T. cruzi and L. infantum could not be considered due to temperature overlap. For leishmaniasis, of the 35 samples with non-negative serology for CD tested by the indirect fluorescent antibody test (IFAT), only one sample (2.85%) was positive (1:80). The PCR for Leishmania spp. was performed on 36 blood samples from donation candidates, and all were negative. qPCR for L. infantum showed 37 negative results for the 37 analyzed samples. The data presented here show the importance of performing two different tests in CD screening at blood banks. Molecular tests should be used for confirmation, thereby improving the blood donation system.

Laboratory diagnostics for human Leishmania infections: a polymerase chain reaction-focussed review of detection and identification methods

Leishmania infections span a range of clinical syndromes and impact humans from many geographic foci, but primarily the world's poorest regions. Transmitted by the bite of a female sand fly, Leishmania infections are increasing with human movement (due to international travel and war) as well as with shifts in vector habitat (due to climate change). Accurate diagnosis of the 20 or so species of Leishmania that infect humans can lead to the successful treatment of infections and, importantly, their prevention through modelling and intervention programs. A multitude of laboratory techniques for the detection of Leishmania have been developed over the past few decades, and although many have drawbacks, several of them show promise, particularly molecular methods like polymerase chain reaction. This review provides an overview of the methods available to diagnostic laboratories, from traditional techniques to the now-preferred molecular techniques, with an emphasis on polymerase chain reaction-based detection and typing methods.

DEFINITION OF THE MAIN VECTOR OF CUTANEOUS LEISHMANIASIS: ECOLOGY AND MAPPING IN ENDEMIC AREA OF NORTHEAST BRAZIL

Cutaneous leishmaniasis is endemic in Pernambuco. Aiming to determine the vector species of cutaneous leishmaniasis in an endemic area of the Northeast region of Brazil, this study aimed to use the spatial mapping of human cases of CL and correlate with ecological studies of the vectors in the municipality of Timbaúba, Pernambuco, Brazil. Individuals infected with CL were recruited through active search in their homes and clinically and serologically diagnosed during the period from 2018 to 2019. Sandflies were captured with CDC-type light traps in peridomiciliary environments and these were identified at the species level. Females were separated for DNA extraction and subsequent analysis by PCR. The points of collection of phlebotomes and the residences of individuals with lesions were marked with GPS. During the study period, 60 cases of CL were diagnosed. A higher concentration of CL cases was observed in proximity to Atlantic forest remnants confirmed by heat map. A total of 3,744 sandflies was captured and five distinct species were identified, with the predominance of Nyssomyia whitmani. From the females separated for the identification of Leishmania braziliensis DNA, a rate of 0.68% of infected sandflies was obtained. It was concluded that cutaneous leishmaniasis continues to be a rural feature of the area. And from this study, it is concluded that Ny. whitmani is the carrier species of CL in the municipality of Timbaúba, Pernambuco. This is due to abundance in catching, specialization of species and PCR positivity for Leishmania braziliensis.

Liver- and Spleen-Specific Immune Responses in Experimental Leishmania martiniquensis Infection in BALB/c Mice

Leishmania martiniquensis is a neglected cause of an emerging leishmaniasis in many countries, including France, Germany, Switzerland, the United States of America, Myanmar, and Thailand, with different clinical manifestations ranging from asymptomatic, cutaneous (CL), visceral (VL), and atypically disseminated CL and VL. The persistence of parasites and the recurrence of the disease after treatment are challenges in controlling the disease. To explore efficient prophylaxis and therapy, this study aimed to investigate infection outcome and organ-specific immune responses after inoculation with L. martiniquensis (MHOM/TH/2011/PG; 5 x 10⁶ promastigotes) in BALB/c mice via intravenous and intraperitoneal routes. A quantitative PCR technique, targeting L. martiniquensis ITS1, was primarily established to estimate the parasite burden. We found that the infection in the liver resolved; however, persistent infection was observed in the spleen. Histopathology with Leishmania-specific immunostaining revealed efficient hepatic granuloma formation, while splenic disorganization with parasitized macrophages at different locations was demonstrated. The mRNA expression of Th1 cytokines (IFN-γ, TNF-α, IL-12p40) and iNOS in the liver and spleen was upregulated. In addition, high expression of IL-10 was observed in the spleen in the chronic phase, revealing a significant moderate correlation with the parasite persistence [r₍₁₂₎ = 0.72, P = 0.009]. Further clarification of the mechanisms of persistent infection and experimental infection in immunosuppressed murine models are warranted.

In silico and in vitro evaluation of primers for molecular differentiation of Leishmania species

Leishmaniasis is a zoonotic disease caused by over 20 species of protozoan parasites of the genus Leishmania. Infection is commonly spread by sandflies and produces a wide spectrum of clinical signs and symptoms. Therefore, from an epidemiological and therapeutic standpoint, it is important to detect and differentiate Leishmania spp. The objective of this study was to combinate in silico and in vitro strategies to evaluate the analytical specificity of primers previously described in the literature. According to electronic PCR (e-PCR) analysis, 23 out of 141 pairs of primers selected through literature search matched their previously reported analytical specificity. In vitro evaluation of nine of these primer pairs by quantitative PCR (qPCR) confirmed the analytical specificity of five of them at the level of Leishmania spp., L. mexicana complex or Leishmania and Viannia subgenera. Based on these findings, the combination of e-PCR and qPCR is suggested to be a valuable approach to maximize the specificity of new primer pairs for the laboratory diagnosis of infections with Leishmania spp.

Analysis of the IGS rRNA Region and Applicability for Leishmania (V.) braziliensis Characterization

The causative species is an important factor influencing the evolution of American cutaneous leishmaniasis (ACL). Due to its wide distribution in endemic areas, Leishmania (V.) braziliensis is considered one of the most important species in circulation in Brazil. Molecular targets derived from ribosomal RNA (rRNA) were used in studies to identify Leishmania spp.; however, the Intergenic Spacer (IGS) region has not yet been explored in parasite species differentiation. Besides, there is a shortage of sequences deposited in public repositories for this region. Thus, it was proposed to analyze and provide sequences of the IGS rRNA region from different Leishmania spp. and to evaluate their potential as biomarkers to characterize L. braziliensis. A set of primers was designed for complete amplification of the IGS rRNA region of Leishmania spp. PCR products were submitted to Sanger sequencing. The sequences obtained were aligned and analyzed for size and similarity, as well as deposited in GenBank. Characteristics of the repetitive elements (IGSRE) present in the IGS rRNA were also verified. In addition, a set of primers for L. braziliensis identification for qPCR was developed and optimized. Sensitivity (S), specificity (σ), and efficiency (ε) tests were applied. It was found that the mean size for the IGS rRNA region is 3 kb, and the similarity analysis of the sequences obtained demonstrated high conservation among the species. It was observed that the size for the IGSRE repetitive region varies between 61 and 71 bp, and there is a high identity between some species. Fifteen sequences generated for the IGS rRNA partial region of nine different species were deposited in GenBank so far. The specific primer system for L. braziliensis showed S = 10 fg, ε = 98.08%, and logσ = 10³ for Leishmania naiffi; logσ = 10⁴ for Leishmania guyanensis; and logσ = 10⁵ for Leishmania shawi. This protocol system can be used for diagnosis, identification, and quantification of a patient's parasite load, aiding in the direction of a more appropriate therapeutic management to the cases of infection by this etiological agent. Besides that, the unpublished sequences deposited in databases can be used for multiple analyses in different contexts.

Duplex qPCR for Leishmania species identification using lesion imprint on filter paper

BACKGROUND

American cutaneous leishmaniasis (ACL) is caused by different Leishmania parasites, which stimulate and direct the immune response against the infection.

OBJECTIVE

To evaluate the TaqMan probe technology applicability to diagnose and identifying of Leishmania spp. related to the ACL etiology.

METHODOLOGY

Through the MEGA 6.0 software, performed an in silico analysis using multiple alignments of Leishmania spp. which were available on GenBank for different genomic targets. The efficiency (e), specificity and detection limit (DL) were calculated for each system, these were associated to compose a duplex-qPCR (DqPCR). The samples of blood, lesion biopsy and lesion imprint on filter paper from patients residing in states of Amazonas (AM) and Pernambuco (PE)-Brazil, (cases and controls) were used to perform the DqPCR technique. The capacity to identify the Leishmania species was determined by comparison with isoenzymes method and sequencing analysis.

RESULTS

Internal Transcribed Spacer 1 (rDNA) was the target selected. Two sets of primers and probes were designed and combined: SVS for subgenus Viannia and LaS for L. (L.) amazonensis. The results were: SVSe = 93.24%, SVS DL = 50 fg/μL; LaSe = 89.3%, LaSLD = 5 fg/μL presented 100% of specificity. In total, 236 individuals participated of the present study, wherein were 101 blood samples, 33 biopsies and 147 lesion imprints. The imprint was the most sensitive sample, showing 83.06% of sensitivity, 86.96% of specificity and substantial agreement between the techniques analysis (k = 0.531; p < 0,001). Regarding the species identification, DqPCR and sequencing/isoenzymes have agreed at 100%, since the infection is caused by a single Leishmania species.

CONCLUSION

The DqPCR technique was applicable in diagnosis and identification of Leishmania spp. (subgenus Viannia and L. amazonensis). Furthermore, the lesion imprint is less invasive, allowing a fewer discomfort and greater acceptance by the patients, in addition of being low cost and easy handling.

Application of Quantitative PCR in the Diagnosis and Evaluating Treatment Efficacy of Leishmaniasis

Leishmaniasis is still a serious neglected tropical disease that may cause death in infected individuals. At present, the clinical diagnosis and treatment monitoring still rely on parasitological culture and microscopy that needs experienced technicians. The low sensitivity and inconvenience of microscopic examination could cause misdiagnosis and relapse of leishmaniasis. There is an urgent need for developing a sensitive and easily operated diagnostic method for the diagnosis and disease management of leishmaniasis. Thus, a quantitative real-time PCR (qPCR) based on the conversed regions of kinetoplast minicircle DNA (mkDNA) of Leishmania spp. was developed to detect different species of Leishmania. The designed mkDNA-based qPCR was able to detect as low as one copy of Leishmania mkDNA or DNA from single parasite. It also detected Pan-Leishmania protozoa including Leishmania donovani, Leishmania infantum and Leishmania major without cross-reaction with other pathogen DNAs available in our lab. This method was clinically applied to quantitatively detect skin lesion samples from 20 cutaneous leishmaniasis (CL) and bone marrow and/or PBMC samples from 30 current and cured visceral leishmaniasis (VL) patients, and blood samples from 11 patients with other infections and 5 normal donors as well. Total 20 skin lesion samples from current CL patients and 20 bone marrow and/or PBMC samples from current VL patients were all detected as positive with qPCR without cross-reaction with samples from patients with malaria, brucellosis and dengue or normal donors. Two VL patients with parasite converted to microscopically negative after treatment were detected positive with qPCR. The patients with bigger skin lesion in CL and higher level of immunoglobulin or splenomegaly in VL, had the higher parasite load detected by qPCR. The parasite load was significantly reduced after treatment. In conclusion, the mkDNA-based qPCR assay that we developed in this study can be used not only for diagnosis of both cutaneous and visceral leishmaniasis with high sensitivity and specificity, but also for evaluating the severity and treatment efficacy of this disease, presenting a rapid and accurate tool for clinical surveillance, treatment monitoring and the end point determination of leishmaniasis.

Identification of Clinical Infections of Leishmania Imported into Australia: Revising Speciation with Polymerase Chain Reaction-RFLP of the Kinetoplast Maxicircle

Leishmaniasis is a vector-borne disease caused by protozoan parasites of the Leishmania genus. In Australia, leishmaniasis is an imported disease that is presenting itself at increased rates because of international travel, the influx of immigrants, and deployment of military operations to endemic regions. Although Leishmania species are morphologically indistinguishable, there is a strong correlation between some causative species of leishmaniasis and the subsequent response to the treatments available and patient outcome. Consequently, identification of the infective species is imperative as misidentification can result in the administering of an ineffective drug. The aim of this study was to develop a simple diagnostic tool with high sensitivity and specificity, which is capable of detecting the presence of the parasite and accurately differentiating the causative species in question. Using the advantageous properties of the maxi-circle kinetoplast DNA, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) targeting the ND7 gene was developed for the analysis of imported cases of human leishmaniasis in Australia. Designed as a dual analysis, concurrent PCR of Leishmania maxi-circle DNA and digestion with two separate enzymes (NlaIII and HpyCH4IV), this study provides an appraisal on 24 imported cases of leishmaniasis between 2008 and 2017. Five Leishmania species were reported, with members of the Viannia subgenus being the most common. The implementation of novel diagnostic procedures for leishmaniasis such as the one reported here is needed to establish a gold standard practice for the diagnosis and treatment of leishmaniasis.

Development of a Multilocus sequence typing (MLST) scheme for Pan-Leishmania

Since the description of the Leishmania genus, its identification and organization have been a challenge. A high number of molecular markers have been developed to resolve phylogenetic differences at the species level and for addressing key epidemiological and population genetics questions. Based on Multilocus enzyme electrophoresis (MLEE), Multilocus sequence typing (MLST) schemes have been developed using different gene candidates. From 38 original gene targets proposed by other authors, 27 of them were chosen. In silico selection was made by analyzing free access genomic sequence data of 33 Leishmania species, one Paraleishmania representative, and one outgroup, in order to select the best 15 loci. De novo amplifications and primers redesign of these 15 genes were analyzed over a panel of 20 reference strains and isolates. Phylogenetic analysis was made at every step. Two MLST schemes were selected. The first one was based on the analysis of three-gene fragments, and it is suitable for species assignment as well as basic phylogenetic studies. By the addition of seven-genes, an approach based on the analysis of ten-gene fragments was also proposed. This is the first work that two optimized MLST schemes have been suggested, validated against a phylogenetically diverse panel of Leishmania isolates. MLST is potentially a powerful phylogenetic approach, and most probably the new gold standard for Leishmania spp. characterization.

Prevalence of Leishmania species among patients with cutaneous leishmaniasis in Qassim province of Saudi Arabia

Background

Leishmaniasis is a parasitic infection endemic in more than ninety countries of the world. The cutaneous leishmaniasis (CL) is a most common form of leishmaniasis and it remains to be a major public health issue in Saudi Arabia. This study was undertaken to investigate the Leishmania species responsible for CL infection in different provinces of Qassim, Saudi Arabia.

Methods

Skin biopsies were obtained from CL patients and DNA was extracted using the Magna pure system. Leishmania species were identified by highly specific/sensitive quantitative and qualitative PCR.

Results

Out of total 206 CL biopsies, 49.5% biopsies were found to be positive for Leishmania major (L. major), 28.6% biopsies were positive for Leishmania tropica (L. tropica), 3.9% were found to be positive for Leishmania infantum/donovani (L. infantum/donovani). Not only have these, all tested CL biopsies showed negative test for Leishmania mexicana (L. mexicana) and Leishmania viannia (L. viannia).

Conclusions

This is the first comprehensive study that shows the majority of CL in Qassim was caused by L. major and L. tropica. To the best of our knowledge, this is the very first report that shows the occurrence of L. infantum/donovani in Saudi Arabia. This requires higher alert to the Ministry of Health of Saudi Arabia to take proactive actions in preventing the onset of L. major, L. tropica, L. infantum and L. donovani infections.

The applicability of real-time PCR in the diagnostic of cutaneous leishmaniasis and parasite quantification for clinical management: Current status and perspectives

Cutaneous leishmaniasis (CL) is spread worldwide and is the most common manifestation of leishmaniasis. Diagnosis is performed by combining clinical and epidemiological features, and through the detection of Leishmania parasites (or DNA) in tissue specimens or trough parasite isolation in culture medium. Diagnosis of CL is challenging, reflecting the pleomorphic clinical manifestations of this disease. Skin lesions vary in severity, clinical appearance, and duration, and in some cases, they can be indistinguishable from lesions related to other diseases. Over the past few decades, PCR-based methods, including real-time PCR assays, have been developed for Leishmania detection, quantification and species identification, improving the molecular diagnosis of CL. This review provides an overview of many real-time PCR methods reported for the diagnostic evaluation of CL and some recommendations for the application of these methods for quantification purposes for clinical management and epidemiological studies. Furthermore, the use of real-time PCR for Leishmania species identification is also presented. The advantages of real-time PCR protocols are numerous, including increased sensitivity and specificity and simpler standardization of diagnostic procedures. However, despite the numerous assays described, there is still no consensus regarding the methods employed. Furthermore, the analytical and clinical validation of CL molecular diagnosis has not followed international guidelines so far. A consensus methodology comprising a DNA extraction protocol with an exogenous quality control and an internal reference to normalize parasite load is still needed. In addition, the analytical and clinical performance of any consensus methodology must be accurately assessed. This review shows that a standardization initiative is essential to guide researchers and clinical laboratories towards the achievement of a robust and reproducible methodology, which will permit further evaluation of parasite load as a surrogate marker of prognosis and monitoring of aetiological treatment, particularly in multi-centric observational studies and clinical trials.

Real-time PCR applications for diagnosis of leishmaniasis

Leishmaniasis is a vector-borne disease caused by many Leishmania species, which can infect both humans and other mammals. Leishmaniasis is a complex disease, with heterogeneous clinical manifestations ranging from asymptomatic infections to lesions at cutaneous sites (cutaneous leishmaniasis), mucosal sites (mucocutaneous leishmaniasis) or in visceral organs (visceral leishmaniasis), depending on the species and host characteristics. Often, symptoms are inconclusive and leishmaniasis can be confused with other co-endemic diseases. Moreover, co-infections (mainly with HIV in humans) can produce atypical clinical presentations. A correct diagnosis is crucial to apply the appropriate treatment and the use of molecular techniques in diagnosis of leishmaniasis has become increasingly relevant due to their remarkable sensitivity, specificity and possible application to a variety of clinical samples. Among them, real-time PCR (qPCR)-based approaches have become increasingly popular in the last years not only for detection and quantification of Leishmania species but also for species identification. However, despite qPCR-based methods having proven to be very effective in the diagnosis of leishmaniasis, a standardized method does not exist. This review summarizes the qPCR-based methods in the diagnosis of leishmaniasis focusing on the recent developments and applications in this field.

[Molecular typing of Leishmania (Leishmania) amazonensis and species of the subgenus Viannia associated with cutaneous and mucosal leishmaniasis in Colombia: A concordance study]

INTRODUCTION

Multilocus enzyme electrophoresis (MLEE) is the reference standard for the characterization of Leishmania species. The test is restricted to specialized laboratories due to its technical complexity, cost, and time required to obtain results. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) is used to identify Leishmania species.

OBJECTIVE

To establish the concordance between the two tests as identifying methods for circulating species in Colombia.

MATERIALS AND METHODS

A total of 96 isolates from patients with cutaneous or mucosal leishmaniasis were selected and identified by MLEE and PCR-RFLP with miniexon and hsp70 as the molecular targets, which were used sequentially. Restriction enzymes HaeIII and BccI were similarly applied. Cohen's kappa coefficient and the 95% confidence interval (CI) were calculated.

RESULTS

The kappa coefficient and the 95% CI between MLEE and PCR-RFLP displayed "very good" concordance with a coefficient of 0.98 (CI95%: 0.98 to 1.00). The identified species were Leishmania Viannia braziliensis, Leishmania Viannia panamensis, Leishmania Viannia guyanensis and Leishmania Leishmania amazonensis. A total of 80 of the 96 isolates were sequenced and the results obtained by PCR-RFLP were confirmed.

CONCLUSION

Due to the concordance obtained between tests results with the amplification of the genes miniexon and hsp70, PCR-RFLP is proposed as an alternative for identifying circulating Leishmania species in Colombia.

DNA Microarray Detection of 18 Important Human Blood Protozoan Species

Background

Accurate detection of blood protozoa from clinical samples is important for diagnosis, treatment and control of related diseases. In this preliminary study, a novel DNA microarray system was assessed for the detection of Plasmodium, Leishmania, Trypanosoma, Toxoplasma gondii and Babesia in humans, animals, and vectors, in comparison with microscopy and PCR data. Developing a rapid, simple, and convenient detection method for protozoan detection is an urgent need.

Methodology/Principal Findings

The microarray assay simultaneously identified 18 species of common blood protozoa based on the differences in respective target genes. A total of 20 specific primer pairs and 107 microarray probes were selected according to conserved regions which were designed to identify 18 species in 5 blood protozoan genera. The positive detection rate of the microarray assay was 91.78% (402/438). Sensitivity and specificity for blood protozoan detection ranged from 82.4% (95%CI: 65.9% ~ 98.8%) to 100.0% and 95.1% (95%CI: 93.2% ~ 97.0%) to 100.0%, respectively. Positive predictive value (PPV) and negative predictive value (NPV) ranged from 20.0% (95%CI: 2.5% ~ 37.5%) to 100.0% and 96.8% (95%CI: 95.0% ~ 98.6%) to 100.0%, respectively. Youden index varied from 0.82 to 0.98. The detection limit of the DNA microarrays ranged from 200 to 500 copies/reaction, similar to PCR findings. The concordance rate between microarray data and DNA sequencing results was 100%.

Conclusions/Significance

Overall, the newly developed microarray platform provides a convenient, highly accurate, and reliable clinical assay for the determination of blood protozoan species.

More than 1 billion people are infected with blood protozoan diseases worldwide. The most common blood protozoa in humans, animals, and vectors include Plasmodium, Leishmania, Trypanosoma, Toxoplasma gondii and Babesia. Due to similar morphology among different blood protozoan species, misdiagnosis always occurs. Most molecular techniques are only carried out in laboratories, with a small number of samples detected simultaneously. Meanwhile, common detection methods may not be convenient for field investigation of large amounts of samples. In order to better manage blood protozoan infection, proper tools are required for the monitoring of these pathogens. Here, a comprehensive and sensitive DNA microarray was developed and tested, which allowed the parallel detection of 18 blood protozoan species.