Is Leishmania (Viannia) braziliensis parasite load associated with disease pathogenesis?

Pereira, Luiza de Oliveira Ramos; Moreira, Regina Barbosa; Oliveira, Márcia Pereira de; Reis, Soraya de Oliveira; Neto, Manoel Paes de Oliveira; Pirmez, Claude

doi:10.1016/j.ijid.2017.01.036

Cited by 31 publications

(21 citation statements)

References 25 publications

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“…The Lb/IGS primer system presented a satisfactory performance in optimization tests and exhibited a high sensitivity for the detection of L. braziliensis in assays with 98.08% analytical efficiency. These results showed a higher efficiency when compared to other similar studies [ 10 , 46 ]. The cross reaction obtained only for species of the Viannia subgenus emphasizes the high genetic similarities among them.…”

Section: Discussionsupporting

confidence: 50%

“…The infections caused by L. braziliensis correspond to lesions with scarce parasites. In this case, qPCR might be useful to confirm the diagnosis, besides evaluating the parasitic load, providing advantages once infections caused by this species may evolve to mucocutaneous form, which requires differentiated clinical and therapeutic management [ 46 ].…”

Section: Discussionmentioning

confidence: 99%

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

Goes¹,

Morais²,

Melo³

et al. 2020

Journal of Parasitology Research

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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.

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Section: Discussionsupporting

confidence: 50%

Section: Discussionmentioning

confidence: 99%

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

Goes¹,

Morais²,

Melo³

et al. 2020

Journal of Parasitology Research

View full text Add to dashboard Cite

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“…requires the quantification of both parasites and the host cells (by means of another qPCR for a single copy host gene). The comparison of the two qPCR results allows to obtain the number of parasites/number of host cells [ 13 , 33 , 34 , 48 , 76 , 77 ]. Alternatively, if yield of DNA extraction is reproducible among different samples and the amount of DNA can be accurately determined, the number of parasites could also be normalized to μg of tissue DNA [ 78 ].…”

Section: Qpcr Assays For Parasite Detection and Quantificationmentioning

confidence: 99%

Real-time PCR applications for diagnosis of leishmaniasis

et al. 2018

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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.

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“…Although studies on experimental infection showed initial inocula impacted on clinical course, the parasite burden detected in established lesion may not influence the therapeutic response since Pereira et al (2017) demonstrated high parasitism in good responders when compared with the poor ones ( Pereira et al, 2017 ). However, there was an increase in parasite burden with recurrent relapses which suggests a failure of the immune system in controlling the parasite replication ( Pereira et al, 2017 ).…”

Section: Parasite Point Of View: Do Parasites Influence the Therapeutmentioning

confidence: 99%

The Binomial Parasite-Host Immunity in the Healing Process and in Reactivation of Human Tegumentary Leishmaniasis

2018

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Leishmaniasis is a vector-borne infectious disease caused by different species of protozoa from the Leishmania genus. Classically, the disease can be classified into two main clinical forms: Visceral (VL) and Tegumentary (TL) leishmaniasis. TL is a skin/mucosal granulomatous disease that manifests mainly as cutaneous localized or disseminated ulcers, papules diffusely distributed, mucosal lesions or atypical lesions. Once the etiology of the infection is confirmed, treatment can take place, and different drugs can be administered. It has already been shown that, even when the scar is clinically evident, inflammation is still present in the native tissue, and the decrease of the inflammatory process occurs slowly during the 1st years after clinical healing. The maintenance of residual parasites in the scar tissue is also well documented. Therefore, it is no longer a surprise that, under some circumstances, therapeutic failure and/or lesion reactivation occurs. All over the years, an impressive amount of data on relapses, treatment resistance and lesion reactivation after healing has been collected, and several factors have been pointed out as having a role in the process. Different factors such as Leishmania species, parasite variability, Leishmania RNA virus 1, parasite load, parasite persistence, age, nutritional status, gender, co-morbidities, co-infection, pregnancy, immunosuppression, lesion duration, number and localization of lesions, drug metabolism, irregular treatment and individual host cellular immune response were described and discussed in the present review. Unfortunately, despite this amount of information, a conclusive understanding remains under construction. In addition, multifactorial influence cannot be discarded. In this context, knowing why leishmaniasis has been difficult to treat and control can help the development of new approaches, such as drugs and immunotherapy in order to improve healing maintenance. In this sense, we would like to highlight some of the findings that may influence the course of Leishmania infection and the therapeutic response, with an emphasis on TL.

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Is Leishmania (Viannia) braziliensis parasite load associated with disease pathogenesis?

Cited by 31 publications

References 25 publications

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

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

Real-time PCR applications for diagnosis of leishmaniasis

The Binomial Parasite-Host Immunity in the Healing Process and in Reactivation of Human Tegumentary Leishmaniasis

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