Urinary proteome of dogs with renal disease secondary to leishmaniosis.

Canine leishmaniosis is frequently associated with the development of renal disease. Its pathogenesis is complex and not fully understood. For this reason, this study aimed to describe the urinary proteome, and identify possible new biomarkers in dogs with kidney disease secondary to leishmaniosis. Urine samples were collected from 20 dogs, 5 from healthy dogs, and 15 from stages Leishvet III and IV. Urine samples were analyzed by UHPLC-MS/MS. The data are available via ProteomeXchange with identifier PXD029165. A total of 951 proteins were obtained. After bioinformatic analysis, 93 urinary proteins were altered in the study group. Enrichment analysis performed on these proteins showed an overrepresentation of the complement activation pathway, among others. Finally, 12 discriminant variables were found in dogs with renal disease secondary to leishmaniosis, highlighting C4a anaphylatoxin, apolipoprotein A-I, haptoglobin, leucine-rich alpha-2-glycoprotein 1, and beta-2-microglobulin. This study is the first to describe the urinary proteomics of dogs with renal disease caused by leishmaniosis, and it provides new possible biomarkers for the diagnosis and monitoring of this disease.

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.

Strength and medium-term impact of HisAK70 immunization in dogs: Vaccine safety and biomarkers of effectiveness for ex vivo Leishmania infantum infection.

HisAK70 candidates have successfully been tested in cutaneous (CL) and visceral leishmaniosis (VL) mouse models. Here, we analyse different biomarkers in dog trials after a heterologous immunization strategy with a HisAK70 candidate (plasmid DNA plus adoptive transfer of peripheral blood-derived dendritic cells (DCs) pulsed with the same pathoantigen and CpG ODN as an adjuvant) to explore the antileishmanial activity in an ex vivo canine co-culture system in the presence of Leishmania infantum parasites. In the canine model, the heterologous HisAK70 vaccine could decrease the infection index in the DC-T cell co-culture system by up to 54% after 30 days and reach almost 67% after 100 days post-immunization, respectively, compared to those obtained in the control group of dogs. The observed security and potential to fight ex vivo L. infantum infection highlight a HisAK70 heterologous immunization strategy as a promising alternative to evaluate its effectiveness against canine VL.

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.

A large-scale field randomized trial demonstrates safety and efficacy of the vaccine LetiFend® against canine leishmaniosis.

Canine leishmaniosis is a zoonotic disease caused by Leishmania infantum. Extensive research is currently ongoing to develop safe and effective vaccines to protect from disease development. The European Commission has granted a marketing authorization for LetiFend®, a new vaccine containing recombinant Protein Q. The efficacy of LetiFend® vaccination in a large-scale dog population of both sexes, different breeds and ages in endemic areas is reported in this multicenter, randomized, double-blind, placebo-controlled field trial. Dogs (n = 549) living in France and Spain were randomly selected to receive a single subcutaneous dose of LetiFend® or placebo per year, and were naturally exposed to two L. infantum transmission seasons. Clinical examinations, blood and lymphoid organ sampling to evaluate serological, parasitological and disease status of the dogs were performed at different time points during the study. LetiFend® was very well tolerated and clearly reduced the incidence of clinical signs related to leishmaniosis. The number of confirmed cases of leishmaniosis was statistically significantly lower in the vaccine group. The number of dogs with parasites was close to be significantly reduced in the vaccine group (p = 0.0564). Re-vaccination of seropositive dogs demonstrated to be safe and not to worsen the course of the disease. The likelihood that a dog vaccinated with LetiFend® develops a confirmed case or clinical signs of leishmaniosis in areas with high pressure is, respectively, 5 and 9.8 time less than that for an unvaccinated dog. Thus, the overall efficacy of the LetiFend® vaccine in the prevention of confirmed cases of leishmaniosis in endemic areas with high disease pressure was shown to be 72%. In conclusion, this field trial demonstrates that LetiFend® is a novel, safe and effective vaccine for the active immunization of non-infected dogs from 6 months of age in reducing the risk of developing clinical leishmaniosis after natural infection with Leishmania infantum.

First detection of Leishmania kDNA in canine cerumen samples by qPCR.

Nowadays, searching for alternative non-invasive methods for molecular diagnosis of canine visceral leishmaniosis is getting increasingly important. We previously described the presence of Leishmania kinetoplast DNA (kDNA) in canine hair; in this case we hypothesized whether foreign DNA might be present in cerumen of dogs with leishmaniosis, and be detected by Real time quantitative PCR (qPCR). A population of 38 dogs that lived in Leishmania endemic areas was divided in two groups: A (33 dogs with confirmed leishmaniosis by serological techniques) and B (5 healthy dogs). Blood, lymph node, bone marrow and cerumen samples from all animals were tested for the presence of parasite kDNA. Our method was 100% specific, and in dogs from group A, Leishmania infantum kDNA was detected and quantified in the 100% of lymph node samples, in 90.9% of cerumen samples, in 88.5% of the bone marrow samples and in 57.6% of the blood samples. The qPCR-cerumen is a new non-invasive method that shows a high potential for the diagnosis of zoonotic visceral leishmaniosis.

First detection of Leishmania infantum kinetoplast DNA in hair of wild mammals: application of qPCR method to determine potential parasite reservoirs.

The data presented in this paper describe the application of a method for a reliable and non-invasive diagnosis of leishmaniosis in wild reservoirs, based on the detection of Leishmania infantum kinetoplast DNA (kDNA) in hair samples by Real Time PCR (qPCR). The study has been performed on 68 ear/leg hair samples from 5 different wild species (Vulpes vulpes, Canis lupus, Martes foina, Rattus norvegicus and Erinaceus europaeus) from several geographic areas of West and North Spain. The presence of Leishmania kDNA was detected in 14 of the 68 analyzed samples, being the highest quantity of DNA observed in foxes. This is the first report of the presence of Leishmania in a hedgehog. The kDNA remained stable under the exposure of hair to different environmental conditions (freezing or high temperature, ultraviolet rays or treatment with tanning salts). This detection method could constitute a suitable alternative for the search of the parasite in wild hosts, due to the numerous advantages that hair samples present for collection, transport and storage processes.

Detection and chronology of parasitic kinetoplast DNA presence in hair of experimental Leishmania major infected BALB/c mice by Real Time PCR.

Hair can accumulate foreign chemical or biological substances. Recently, it has been reported that parasite DNA can also be detected in the hair of Leishmania infantum infected dogs. The aim of this work has been to find out whether parasite DNA incorporates in the hair of Leishmania major experimentally infected animals. For this purpose, a group of 4 BALB/c mice, intradermally inoculated in both ears with 1000 L. major V1 strain promastigote forms, was monitored for parameters associated to the infection during 35 days. Weekly, ear swelling was measured, and hair samples from ears and leg were collected. Blood samples were obtained before challenge and at day 35 post infection, when parasite load was measured in ear, lymph node and spleen by limit dilution. Ear swelling and other parameters observed in the infected mice were consistent with those described for this model. The presence of parasite kinetoplast DNA (kDNA) was detected by Real Time PCR in all ear and leg hair samples at the final timepoint. These data suggests that hair is a specialized tissue in the sequestration and removal of foreign DNA. Detection of DNA in hair could be, therefore, a useful tool to chronologically record the infection process during experimental mice assays.

Detection of Leishmania infantum kinetoplast minicircle DNA by Real Time PCR in hair of dogs with leishmaniosis.

It is known that hair can accumulate environmental toxics and excrete foreign chemical or biological substances. In this context, we hypothesized that foreign DNA could be found in the hair of an infected organism, and thus, be detected by Real Time PCR in the hair of Leishmania infantum naturally infected dogs. A population of 28 dogs living in Leishmania endemic areas was divided into two groups: A (13 Leishmania infected dogs) and B (15 healthy dogs). Blood, lymph node and ear hair samples from all of them were tested for the presence of parasite kinetoplast DNA (kDNA). For the same purpose, hair of several body areas and hair sections of two infected dogs were also analyzed. Epidermal keratinocytes from an infected animal were also analyzed for reactivity against Leishmania antigens by ELISA and for the presence of kDNA. Regarding to dogs from group A, parasite kDNA was detected in the 100% of lymph node samples. The sensitivity of Real Time PCR in ear hair was similar to that obtained in blood (9 positive out of 13 versus 8 positive out of 13, respectively). Moreover, the presence of L. infantum kDNA was also detected in the hair of all the analyzed body zones, in all hair sections and in epidermal keratinocytes. In infected dogs, parasite kDNA could be detected and quantified from just one single hair, whereas it was not detected in any of the samples of the healthy dogs. This work describes a new method for a reliable and non-invasive diagnosis of canine leishmaniosis using hair samples of infected animals. The data presented also provide some insights for the understanding of the physiology of keratinocytes and the role of hair as a specialized tissue in the kidnapping and removal of foreign DNA.

Leishmania major infection in susceptible and resistant mice elicit a differential humoral response against a total soluble fraction and defined recombinant antigens of the parasite.

In the present work, we analyzed the humoral response of Leishmania major experimentally infected BALB/c and C57BL/6 mice against three Leishmania antigens: total soluble antigen (soluble leishmania antigen(SLA)), a chimerical recombinant protein formed by the genetic fusion of four cytoplasmic proteins (PQ), and a kinetoplastic membrane protein (Kmp-11). We determined the correlation between the immune response against these proteins and the histopathological changes induced in the susceptible and resistant mice after infection. The data showed the existence of wide differences in the recognition of SLA, PQ, and Kmp-11 by the sera from both strains. The anti-SLA titer of BALB/c was 100 times higher than that of C57BL/6 mice. Antibodies against the recombinant Kmp-11 were detected only in infected BALB/c during the first stage of the infection. In contrast, the PQ protein was recognized by the sera from infected BALB/c mice but exclusively when they were in a late-lesion period. The data suggest that the response against the membrane Kmp-11 protein is transient and correlates with early developmental stages of the infection, whereas the response against cytoplasmic proteins as those present in PQ is sustained and could be considered as a marker of an advanced stage of the infection and disease.