First detection of Leishmania kDNA in canine cerumen samples by qPCR

Association of myocardial parasitic load with cardiac biomarkers and other selected variables in 10 dogs with advanced Canine Leishmaniasis

BACKGROUND

The association between myocardial parasitic load (MPL) and cardiac biomarkers in Canine Leishmaniasis (CanL) has not been studied.

METHODS

Dogs with advanced CanL were prospectively recruited and were included if they were euthanised. Prior to euthanasia these variables were assessed: hematocrit, globulin, creatinine, N-terminal-pro brain natriuretic peptide (NT-proBNP), cardiac troponin I (cTnI), blood pressure, urine protein/creatinine ratio and echocardiographic parameters. A left ventricular (LV) sample was taken for histopathology and MPL evaluation by quantitative PCR. Correlation of MPL with all variables was analysed. Dogs with lower and higher histopathology scores were compared.

RESULTS

Ten dogs were included. NT-proBNP was 6946 pmol/ (interquartile range [IQR] 3751-9268 pmol/L) and cTnI 4.56 ng/mL (IQR 0.46-13.1 ng/mL). In all dogs, echocardiography showed an increase in LV thickening, and histopathology revealed moderate to severe lympho-plasmocytic myocarditis and/or myocardial cell degeneration. MPL was 215.53 parasites/gram (IQR 21.2-1372.63 parasites/gram). A strong correlation (p < 0.001; R = 0.90; R² 0.81) with cTnI was observed but correlation with any of the other variables or differences between the two histopathological scores, were not detected.

CONCLUSIONS

MPL in dogs with advanced CanL shows variable but generally high levels. A strong association between MPL and cTnI was observed, which encourages the exploration of cTnI as a marker in CanL.

Method for Malaria Diagnosis Based on Extractions of Samples Using Non-Invasive Techniques: An Opportunity for the Nursing Clinical Practice

Malaria has been for millennia one of the best known and most destructive diseases affecting humans. Its high impact has aroused great interest for the development of new effective and reliable diagnostic techniques. Recently it has been recently published that hairs from mammal hosts are able to capture, hold and finally remove foreign DNA sequences of Leishmania parasites. The aim of this study was to check if Plasmodium falciparum (P. falciparum) DNA remains stable in blood samples deposited in Whatman paper after suffering different transport and storage conditions, and to compare the sensitivity of these results with those offered by thick a smear and Rapid Diagnostic Test, and besides to examine whether P. falciparum DNA would be detected and quantified by Real time quantitative PCR (qPCR) from hairs of people with different types of malaria. P. falciparum Histidine Repeat Protein II (pHRP-II) antigen detection and P. falciparum DNA were detected in 18 of 19 dry blood samples adhered to Whatman paper (94.74%), besides, Plasmodium DNA was also detected in seven out of 19 hair samples analyzed (36.84%), remaining stable until analysis for several months under the exposure to different environmental conditions. Although the sensitivity of PCR for the diagnosis of malaria in hair samples is not as high as blood analysis, the study of Plasmodium DNA presence in blood and hair could constitute a complementary tool with numerous advantages in sample collection, transport and storage. We suggest that the method could be also applied to medical, forensic and paleo-parasitological diagnosis, not only for malaria but also for searching many other pathogens in hair samples.

Noninvasive Biological Samples to Detect and Diagnose Infections due to Trypanosomatidae Parasites: A Systematic Review and Meta-Analysis

Unicellular eukaryotes of the Trypanosomatidae family include human and animal pathogens that belong to the Trypanosoma and Leishmania genera. Diagnosis of the diseases they cause requires the sampling of body fluids (e.g., blood, lymph, peritoneal fluid, cerebrospinal fluid) or organ biopsies (e.g., bone marrow, spleen), which are mostly obtained through invasive methods. Body fluids or appendages can be alternatives to these invasive biopsies but appropriateness remains poorly studied. To further address this question, we perform a systematic review on clues evidencing the presence of parasites, genetic material, antibodies, and antigens in body secretions, appendages, or the organs or proximal tissues that produce these materials. Paper selection was based on searches in PubMed, Web of Science, WorldWideScience, SciELO, Embase, and Google. The information of each selected article (n = 333) was classified into different sections and data were extracted from 77 papers. The presence of Trypanosomatidae parasites has been tracked in most of organs or proximal tissues that produce body secretions or appendages, in naturally or experimentally infected hosts. The meta-analysis highlights the paucity of studies on human African trypanosomiasis and an absence on animal trypanosomiasis. Among the collected data high heterogeneity in terms of the I2 statistic (100%) is recorded. A high positivity is recorded for antibody and genetic material detection in urine of patients and dogs suffering leishmaniasis, and of antigens for leishmaniasis and Chagas disease. Data on conjunctival swabs can be analyzed with molecular methods solely for dogs suffering canine visceral leishmaniasis. Saliva and hair/bristles showed a pretty good positivity that support their potential to be used for leishmaniasis diagnosis. In conclusion, our study pinpoints significant gaps that need to be filled in order to properly address the interest of body secretion and hair or bristles for the diagnosis of infections caused by Leishmania and by other Trypanosomatidae parasites.

Diagnostic performance of a qPCR for Leishmania on stained cytological specimens and on filter paper impressions obtained from cutaneous lesions suggestive of canine leishmaniosis

BACKGROUND

Detection of Leishmania in cutaneous lesions is possible by visualization of amastigotes. Detection of Leishmania DNA by PCR presents greater sensitivity, and PCR has been used to diagnose cutaneous leishmaniosis in humans using noninvasive clinical specimens.

OBJECTIVES

Study I: to determine if Leishmania DNA could be efficiently extracted and amplified from archived Diff-Quik^® -stained slides of cytological specimens from canine cutaneous lesions. Study II: to evaluate the diagnostic performance of a Leishmania-quantitative (q)PCR on stained cytological specimens and on filter paper impressions (FPI) obtained from cutaneous lesions suggestive of canine leishmaniosis (CanL).

ANIMALS

Samples from cutaneous lesions of 54 dogs.

METHODS AND MATERIALS

Study I: Leishmania-qPCR was performed on 19 glass slides (from nine dogs) with cytologically visible amastigotes. Fifteen slides with no visible amastigotes, obtained from 12 dogs seronegative for Leishmania by ELISA, served as controls. Study II: Leishmania-qPCR was performed on glass slides and FPI from cutaneous lesions compatible with clinical leishmaniosis in 33 dogs.

RESULTS

Study I: all slides with visible amastigotes had positive qPCR, whereas all control slides yielded negative results. Study II: of 13 dogs definitively diagnosed with clinical leishmaniosis, eight had visible amastigotes on cytology, whereas Leishmania-qPCR was positive on 11 glass slides and 13 FPI. Leishmaniosis was ruled out by standard methods in 20 dogs, four of which yielded positive qPCR on FPI and/or glass slides.

CONCLUSIONS AND CLINICAL IMPORTANCE

Leishmania-DNA can be detected efficiently by qPCR from cutaneous cytological specimens and FPI to diagnose Leishmania infection in dogs with cutaneous lesions suggestive of CanL.

Application of qPCR method to hair and cerumen samples for the diagnosis of canine leishmaniosis in Araçatuba, Brazil

Visceral leishmaniosis (VL) remains a serious public health problem in Brazil. Dogs are the main hosts of the parasite, developing canine leishmaniosis (CanL), hence the importance of an accurate diagnosis of the animals. Recently, the application of qPCR method to non-invasive samples obtained from dogs with CanL has shown high sensitivity. Thus, we analyzed by qPCR blood, hair (from healthy zones and cutaneous lesions) and cerumen of 16 dogs with confirmed leishmaniosis from Araçatuba, a Brazilian endemic area. Cerumen-qPCR showed the highest sensitivity (87.5%), followed by hair (lesions: 78.57%, healthy skin: 62.5%), and blood (68.75%). We also analyzed blood, hair and cerumen of 5 healthy dogs from a non-endemic area, obtaining 100% of specificity in all samples. The use of cerumen and hair for qPCR analysis provides high reliability, taking into account the sensitivity and total specificity of the method. The non-invasive sampling procedure without the need of specific conditions of storage and transport support the usefulness of hair and cerumen for the diagnosis of CanL.

Diagnostic Challenges in the Era of Canine Leishmania infantum Vaccines

The diagnosis of canine leishmaniosis (CanL) is complex due to its variable clinical manifestations and laboratory findings. The availability of vaccines to prevent CanL has increased the complexity of diagnosis, as serological tests may not distinguish between naturally infected and vaccinated dogs. Current practices of prevaccination screening are not sufficiently sensitive to detect subclinically infected dogs, resulting in the vaccination of infected animals, which may lead to disease in vaccinated dogs that are also infectious to sand flies. This review evaluates the current techniques for diagnosing CanL, and focuses on new challenges raised by the increasing use of vaccines against this disease. Important gaps in knowledge regarding the diagnosis of CanL are underscored to highlight the need for novel diagnostic test development.

Detection of high Leishmania infantum loads in Phlebotomus perniciosus captured in the leishmaniasis focus of southwestern Madrid region (Spain) by real time PCR

Since 2010 a human leishmaniasis outbreak has been notified in southwestern Madrid region that still remains active. Entomological surveys have been carried out in the affected area in order to obtain information about species diversity, distribution, and density of sand flies. Moreover, molecular identification of blood meal preferences of sand flies and molecular detection of Leishmania infantum has been performed. In this work, we optimized a real time PCR assay in order to determine parasite loads in unfed and blood-fed Phlebotomus perniciosus female sand flies caught in the focus area. Results showed elevated parasite loads in nearly 70% of the studied positive sand flies. Furthermore, significantly higher parasite loads were observed in females without blood in their guts. In conclusion, high L. infantum loads found in P. perniciosus sand flies from the Madrid focus support the exceptional characteristics of this outbreak.