Directions for the diagnosis, clinical staging, treatment and prevention of canine leishmaniosis

Comparison of four commercial serological tests for the detection of Leishmania infantum antibodies in dogs

Early detection and treatment of cases of Leishmania infantum infection are critical in controlling the spread of the disease in dogs. Several serological methods are available to support the diagnosis of canine leishmaniosis. The immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) are the main tests used by clinicians. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. Conversely, the presence of low antibody levels is not necessarily indicative of disease and may be more difficult to detect by serological tests. The aim of this study was to evaluate and compare the diagnostic performance of four commercially available serological tests, including ELISAs (CIVTEST® CANIS LEISHMANIA short and standard protocols), LEISHMANIA-ELISA DOG®, ELISA/S7® and MegaFLUO®LEISH IFAT, for the detection of specific antibodies against L. infantum antigens in dogs in different states of infection. Canine sera samples from seropositive sick infected dogs (n = 75), seropositive apparently healthy dogs (n = 48), and seronegative apparently healthy dogs from a high endemic area (Cadiz, n = 40) and seronegative apparently healthy dogs from very low endemic area of L. infantum infection (Asturias, n = 40) were classified based on the results of an in-house UAB ELISA as a reference test. The positive percent of agreement (PPA) and negative percent of agreement (NPA) observed for each test were as follows: CIVTEST® standard (93.4 %, 100 %) on 202 samples tested, CIVTEST® short (84.4 %, 100 %) on 202 samples tested, LEISHMANIA-ELISA DOG® (81.8 %, 72.2 %) on 138 samples tested, ELISA/S7® (34.8 %, 45 %) on 195 samples tested and MegaFLUO®LEISH IFAT (100 %, 100 %) on 203 samples tested, respectively. The accuracy was as follows: CIVTEST® standard (0.96), CIVTEST® short (0.91), LEISHMANIA-ELISA DOG® (0.77), ELISA/S7® (0.39), and MegaFLUO®LEISH IFAT (1). The Cohen´s Kappa index (K) from best to worst was: MegaFLUO®LEISH IFAT (K = 1), CIVTEST® standard (K = 0.92), CIVTEST® short (K=0.81), LEISHMANIA-ELISA DOG® (K =0.54), and ELISA/S7® (K=-0.19). Finally, the area under the receiver operating characteristic curve (AUC-ROC), in the ELISAs test, ordered from the maximum to the minimum value was: CIVTEST® short (1), CIVTEST® standard (0.99), LEISHMANIA-ELISA DOG® (0.87), and S7® (0.37). In conclusion, this study demonstrated that the diagnostic performance of the commercially available ELISA tests against L. infantum antigen can vary widely. Moreover, it highlights the fact that CIVTEST® CANIS LEISHMANIA is a reliable test to support the diagnosis of canine leishmaniosis in clinical settings.

Validation of an improved reference freeze-dried direct agglutination test for detecting leishmaniasis in the canine reservoir

Introduction. Proper identification and management of post-kala-azar dermal leishmaniasis (PKDL) and canine leishmaniasis (CanL) cases are among the prerequisites to the effective control of visceral leishmaniasis worldwide. Unlike PKDL, CanL still awaits effective improvement because of its cryptic nature, absence of Leishmania parasites in lesions or lymph nodes and not complete sensitivity of some diagnostic tools in use. Because of the need for certain skills and equipment, both the liquid direct agglutination test and freeze-dried direct agglutination test (FD-DAT) versions are, in comparison with the indirect immunofluorescence antibody test (IFAT) or enzyme-linked immunosorbent assay (ELISA), practical and feasible diagnostic alternatives. Aim. Validate the performance of an improved FD-DAT to suit routine and large-scale applications in CanL endemic areas. Methodology. Introducing citrate-saline formaldehyde (CSF) as an anti-clumping agent to replace normal saline for antigen reconstitution and drastically, however, eligibly lower the concentration of promastigotes (1.4×107) in comparison with the original FD-DAT reference (>5×107 ml-1). To ensure optimal safety, β-mercaptoethanol was replaced by urea or SDS as a serum-reducing agent. Results. By improving the procedure for reconstitution of FD-DAT antigen with CSF, a 150% reduction in the test application cost was achieved. Expired test batches (±4 years earlier) were successfully revitalized to full validity. As compared to the 48 h shelf-life time for the original, an FD-DAT batch reconstituted here with CSF maintained stability for ±12 months. Conclusions. The highly concordant results with IFAT and ELISA (one-way ANOVA test, P=0.142, homogeneity of variances P=0.009) as routine CanL diagnostics further motivate the application of the improved FD-DAT for the detection of the disease in endemic areas.

Performance of Culture Using a Semi-Automatic Needle as a Novel Tool for Collecting Lymph Node Samples for the Diagnosis of Canine Visceral Leishmaniasis

Zoonotic visceral leishmaniasis is caused by Leishmania (Leishmania) infantum and dogs are the main domestic reservoir. This study compared the performance of parasitological tests using semi-automatic needle puncture (SANP) for collecting popliteal lymph node samples with samples collected from the same lymph node by fine needle aspiration puncture (FNAP) and by necropsy for the diagnosis of canine visceral leishmaniasis (CVL). Popliteal lymph node samples were collected from 30 CVL-seropositive dogs from an endemic region in Brazil. After clinical examination and euthanasia, samples were collected from the same lymph node by SANP, FNAP, and necropsy. The reference tests were culture, immunohistochemistry, and histopathology. Positivity for Leishmania spp. was 70% for immunohistochemistry and 33.3% for histopathology. Culture positivity using the different sampling techniques was 77% for necropsy (87% in the first week), 73% for FNAP (82% in the first week), and 63% for SANP (95% in the first week). The combination of SANP and culture proved to be an alternative for the diagnosis of Leishmania spp. in the lymph node samples of dogs because of its high positivity rate and because it is more practical and faster and has a shorter time to positivity by culture when compared to FNAP and necropsy sampling.

Updating the epidemiology of canine leishmaniosis in the United Kingdom through the use of electronic health data

Dogs infected with Leishmania infantum have been increasingly reported in the UK mostly related to imported/travelled dogs. Up-to-date epidemiologic data are essential for a better control of this zoonotic disease in such emerging areas. This study aimed for the first time, to estimate the percentage and temporal variation of dog and cat samples testing positive for L. infantum infection at commercial diagnostic laboratories, and to describe the travel history of positive dogs and cats positive to leishmaniosis in a network of UK veterinary practices. Leishmania infantum serology and PCR data were collected by the Small Animal Veterinary Surveillance Network (SAVSNET) from five UK national veterinary diagnostic laboratories between 2010 and 2022 and were analysed. In addition, electronic health records (EHRs) were collected from 251 veterinary practices across the UK between March 2014 and September 2022. Text mining tools were used to identify cases compatible with clinical leishmaniosis as recorded in the clinical narratives; these were subsequently manually validated. Data from a total of 25,327 diagnostic samples (25,201 from dogs and 126 from cats) were analysed including 20,517 sera tested by either quantitative ELISA or IFAT, and 4810 by PCR. Leishmania infantum antibodies were detected in 39.7 % of tested dog samples and 1.07 % of cat samples. In dogs, seropositivity increased from 2013 to 2022. Leishmania DNA was only detected by PCR in samples from dogs (11.8 %). A total of 368 dogs with canine leishmaniosis (CanL) were identified from clinical narratives. Of these, 189 had either visited, or were rescued/imported from, Spain, Greece, Cyprus and other southern European countries. Among factors associated with CanL in the UK canine population, dogs between 3 and 6 years of age were 4.71 times more likely to have CanL than those two years or younger. In addition, there was an increased risk of having recorded CanL clinical cases from 2017 to 2022, compared to 2014. Southeast of England was the UK region that accounted for the highest number of CanL cases (34.51 %). This study provides recent trends in Leishmania infection in dogs in the UK, identifies risk factors and countries likely associated with imported cases, and provides important insights to help plan and monitor national intervention strategies.

Epidemiology and clinical management of canine Leishmaniasis in northeastern Algeria: A preliminary study

Canine leishmaniasis (CanL) caused by Leishmania infantum is a prevalent vector-borne disease in the Mediterranean region, notably Algeria. This research aims to assess the epidemiology and the clinical management practices of CanL employed by veterinarians in the Skikda and Constantine regions in the northeastern part of Algeria. A retrospective survey comprising 37 open and closed questions was distributed to 139 veterinary clinics between 2022 and 2023. The objective was to collect comparable epidemiological information on clinical presentations, diagnostic approaches, treatment protocols, preventive strategies, and awareness of the disease's public health implications. The findings from this study have revealed a notable prevalence of CanL in both regions, accompanied by similar clinical manifestations. Serological techniques, particularly rapid detection kits, are predominantly utilized alongside direct methods, while euthanasia remains the primary approach to combat the disease. The results show that only a few veterinarians educate pet owners about zoonotic diseases and prevention measures (32,79 %), while most do not provide this information. This investigation sheds more light on the current status of CanL in the selected studied area and suggests the need for standardizing diagnosis and treatment of CanL using evidence-based medicine criteria to enhance disease management. This will provide a proper way of conducting a more comprehensive epidemiological assessment of the condition for improving the handling and management of CanL in Algeria.

Comparison of ELISA and IFAT for Leishmania infantum by European and Middle Eastern diagnostic laboratories

BACKGROUND

Visceral leishmaniosis (VL) is the most severe form of human leishmaniosis, with an estimated 95% case fatality if left untreated. Dogs act as peridomestic reservoir hosts for the protozoan parasite Leishmania infantum, a causative agent for human leishmaniosis, endemic throughout the Mediterranean basin. To assure consistent and accurate surveillance of canine infection and prevent transmission to people, consistent diagnosis of canine L. infantum infection across this region is essential for protecting both human and animal health. Our goal was to compare the accuracy, sensitivity and specificity of enzyme-linked immunosorbent assays (ELISA) and immunofluorescence antibody tests (IFAT), performed at seven academic veterinary diagnostic centres across southern Europe and Israel.

METHODS

We performed a known sample "ring" trial to compare L. infantum quantitative serological tests. Two hundred seventy-two (n = 272) canine serum samples of known serological status were chosen from these sites, representative of the region. In-house or commercial ELISA and IFAT were performed according to each laboratory's specifications. Latent Class Analysis (LCA) was used to determine sensitivity and specificity of each test. True and false positives were calculated to determine the probability of identifying samples.

RESULTS

Sensitivity and specificity for ELISA ranged from 95 to 99% and 92% to 97%, respectively, with moderate variability from one site. Sensitivity and specificity for IFAT ranged from 89 to 99% and 83% to 94%, respectively, with increased variability compared to ELISA. Overall test agreement was 78% with a pair-wise agreement between 65 and 89%.

CONCLUSIONS

All sites demonstrated substantial comparative diagnostic accuracy, with good agreement based on known seropositive and seronegative samples. Studies and interventional trials that use these tests will remain valid because of high diagnostic agreement between sites.

Relationship between urinary neutrophil gelatinase-associated lipocalin and selected biochemical and urinary parameters in dogs naturally infected with Leishmania infantum

Background and Aim

Leishmania infantum infection in dogs has several clinical manifestations. Glomerulonephritis, caused by circulating immune complexes, may cause proteinuria and progress to kidney failure, which is the primary cause of death in dogs with canine leishmaniasis (CanL). Renal proteinuria can be monitored in dogs with CanL for the early detection of renal involvement. Neutrophil gelatinase-associated lipocalin (NGAL) is a neutrophil-derived protein that is filtered by glomeruli and reabsorbed by proximal tubular cells. Urinary NGAL (uNGAL) is a sensitive marker of acute and chronic kidney disease in dogs. This study aimed to evaluate uNGAL concentrations in dogs naturally affected by CanL, to determine whether uNGAL concentration differs depending on the stage of disease based on the LeishVet and International Renal Interest Society (IRIS) classification systems, to compare uNGAL concentration with selected urinary and biochemical parameters related to kidney function, and to assess the clinicopathological status of dogs affected by CanL.

Materials and Methods

We assessed uNGAL concentrations in 37 privately owned dogs naturally affected by CanL, in which urinary tract infections were excluded based on negative urine culture. No dog exhibited clinical signs related to impaired renal function. uNGAL concentration evaluated in dogs affected by CanL was compared to the one previously analyzed in the control group. Furthermore, the uNGAL concentration was compared between leishmaniasis dogs with biochemical and urinary parameters inside or outside the normal range and between dogs with different clinical stages of leishmaniasis based on the LeishVet clinical staging guidelines and IRIS classification.

Results

The median uNGAL concentration in affected dogs was 50.2 ng/mL, which was significantly higher than that in healthy dogs (9.74 ng/mL [p = 0.0025]). uNGAL concentration was significantly higher in proteinuric leishmaniosis dogs than in non-proteinuric leishmaniosis dogs (p = 0.0001). Dogs classified as LeishVet clinical stage III had a higher mean uNGAL concentration than those classified as stage II (p = 0.0001) and median uNGAL concentration was statistically higher in dogs classified as IRIS stage 1 than in dogs affected by CanL with no clinical and pathological signs of renal disease. The amount of proteinuria and urinary sediment hyaline cast per high-power field of the microscope and total serum protein concentrations were significantly correlated with uNGAL concentration.

Conclusion

To the best of our knowledge, only a few studies have measured uNGAL in dogs naturally affected by CanL. Although limited by the small number of cases, this study highlighted a significant increase in uNGAL levels in affected dogs compared with healthy dogs and confirmed the correlation between proteinuria and urinary excretion of uNGAL in dogs with leishmaniasis. This suggests that uNGAL can be used as a marker of kidney damage in dogs affected by CanL.

Standardization and Evaluation of the LAMP Technique for the Diagnosis of Canine Visceral Leishmaniasis in Conjunctival Swab Samples Using DNA Extracted by a Silica Column and Boiling

The diagnosis of canine visceral leishmaniasis (CVL) presents a challenge due to a variety of non-specific clinical signs. The available tests have low sensitivity. This study aimed to standardize and evaluate the loop-mediated isothermal amplification technique with K26 target (K26-LAMP) for diagnosis of CVL in conjunctival swab (CS) DNA samples extracted through a silica column commercial kit (SW-kit) and boiling (SW-DB) and to compare sensitivity with conventional PCR (kDNA-cPCR) and quantitative real-time PCR (18S-qPCR). Clinical samples of CSs were collected from 54 dogs after reactive serology tests. Positive parasitological and/or histological tests were used as inclusion criteria for a sensitivity analysis. A total of 79.2% (43/54) of dogs without clinical signs or with mild, moderate, or severe clinical signs were included in the study. The sensitivity results of K26-LAMP, kDNA-cPCR, and 18S-qPCR were 72.1%, 81.4%, and 80.5% with the SW-kit and 97.2%, 95.2%, and 57.1% with SW-DB, respectively. In all techniques, the proportion of positives was higher in the group with severe clinical disease, with statistically significant differences in the K26-LAMP and 18S-qPCR techniques being seen with the SW-kit. The results obtained with LAMP for CS samples are promising and its performance is similar to other techniques.

Detection of DNA of Leishmania infantum in the brains of dogs without neurological signs in an endemic region for leishmaniasis in the state of Rio Grande do Sul, Brazil

Canine visceral leishmaniasis (CVL) is a parasitic disease caused by the protozoan Leishmania infantum. Neurological infection occurs due to the parasite's ability to cross the blood-brain barrier. It is known that dogs can remain infected with a subclinical infection for life, potentially acting as reservoirs for L. infantum when bitten by sandflies. In this context, the objective of this study was to evaluate the occurrence of Leishmania spp. in the brains of dogs from the metropolitan region of Rio Grande do Sul, Brazil, without a history of neurological disease but residing in an endemic area for L. infantum. A total of 200 samples, from 2022 to 2023, were evaluated using conventional Polymerase Chain Reaction (PCR) with the primers Leishmini-F GGKAGGGGCGTTCTGC and Leishmini-R STATWTTACACCAACCCC, aiming to amplify a product of 120 base pairs for Leishmania spp. To identify the species, a multiplex PCR was used, differentiating L. braziliensis (127 bp), L. amazonensis (100 bp), and L. infantum (60 bp), with the molecular target being the conserved region of the kinetoplast DNA (kDNA) minicircle, specific to Leishmania spp. Of the 200 samples evaluated, 26.5% (53/200) tested positive in the conventional PCR reaction for Leishmania spp., with the PCR multiplex the only species detected was Leishmania infantum. The average age of the positive animals was 5.08 years, with 47.2% being females and 52.8% being males; among these, mixed-breed dogs were the most predominant, representing 43.4% of the total. Clinical signs varied: hepatomegaly in two dogs, pronounced neutrophilic hepatitis in one, splenomegaly in one with lymphoid hyperplasia, and glomerulonephritis and nephritis in two animals. Mild anemia and thrombocytopenia were found in eight, with pale mucous membranes in three, and diffuse alveolar edema in one case. Notable pathological findings included suspected distemper in one animal and lymphoplasmacytic meningitis in another. Histopathological findings revealed alveolar edema and acute renal failure. A third dog exhibited bilateral hydrocephalus and diffuse edema in the brain. Additional changes, such as mild inflammatory infiltrate and slight vacuolar degeneration, were observed in 11.3% of the analyzed brains. There was no clinical suspicion of leishmaniasis in any of the studied cases. Therefore, the detection of L. infantum DNA in the brains of dogs suggests that animals with subclinical infection may play a crucial role in the spread of leishmaniasis, and infection by Leishmania spp. should be considered as a differential diagnosis for neurological disease in endemic areas for the protozoan.

Clinical significance of blood cell ratios in healthy and sick Leishmania infantum-seropositive dogs

BACKGROUND

The accuracy of blood cell ratios (BCRs) as cost-effective and easily accessible diagnostic and prognostic markers of inflammatory conditions has been investigated in veterinary medicine in recent years.

METHODS

Neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), and platelet-to-lymphocyte (PLR) ratios were studied in 195 dogs clinically evaluated and tested for anti-Leishmania infantum (Li) antibodies (Li-seronegative (Li-), n = 10; Li-seropositive clinically healthy (Li+healthy), n = 100; Li-seropositive with clinical and/or clinicopathological abnormalities (Li+sick), n = 85). The Li+sick dogs were classified in LeishVet stages IIa/IIb (Li+IIa/IIb) (n = 66) and III/IV (Li+III/IV) (n = 19). BCR relationships with LeishVet clinical stage, antibody levels, and serum protein electrophoretic fraction concentrations were investigated.

RESULTS

Higher NLR values were found in Li+, Li+healthy, and Li+IIa/IIb sick dogs compared to Li- dogs (P < 0.001). Higher NLR and MLR were found in Li+sick (NLR, P < 0.001; MLR, P = 0.034) and Li+III/IV dogs (NLR, P < 0.001; MLR, P = 0.005) compared to Li- dogs, and in Li+III/IV dogs (NLR, P = 0.002; MLR, P < 0.001) compared to Li+healthy. All three BCRs were higher in Li+sick (NLR, MLR, P < 0.001; PLR, P = 0.023) and Li+IIa/IIb dogs (NLR P < 0.001; MLR P = 0.001; PLR, P = 0.012) compared to Li+healthy dogs. The BCRs failed to distinguish dogs with moderate (Li+IIa/IIb) and severe or very severe disease (Li+III/IV). BCRs demonstrated weak positive correlations with serum globulin fractions and antibody levels, and weak negative correlations with serum albumin level were found. Li+sick dogs presenting hypoalbuminemia showed higher MLR ratios (P = 0.001) than those with normal albumin values.

CONCLUSIONS

This study shows that BCR measures provide useful information for differentiating antibody-positive healthy and sick dogs at diagnosis. Dogs with hypoalbuminemia showed higher MLR values despite monocytosis being very rare.

Short Term Treatment Monitoring of Renal and Inflammatory Biomarkers with Naturally Occurring Leishmaniosis: A Cohort Study of 30 Dogs

Various inflammatory and renal biomarkers have already been assessed for monitoring the response to anti-leishmanial therapy in canine leishmaniosis. This study assessed the parasite load, various inflammatory and renal biomarkers pre- and post-treatment, and any association between the studied variables and the degree of disease severity at diagnosis. This is a prospective cohort study of 30 client-owned dogs with leishmaniosis, classified according to LeishVet's guidelines as stage I (n = 2), stage IIa (n = 7), stage IIb (n = 6), stage III (n = 8), and stage IV (n = 7). In addition to Leishmania real-time PCR in the bone marrow, blood and urine, previously studied biomarkers, and several inflammatory and renal markers never investigated in canine leishmaniosis, such as fibrinogen, antithrombin, urinary fractional excretion of sodium, and urinary amylase-to-creatinine ratio were measured pre- and post-treatment (meglumine antimoniate or miltefosine + allopurinol). A positive Leishmania real-time PCR in the blood at diagnosis predicted a positive Leishmania real-time PCR in the bone marrow post-treatment (p = 0.003). Following treatment, antithrombin and urinary amylase-to-creatinine ratio were significantly changed (p < 0.001, respectively). Urinary amylase-to-creatinine ratio, total iron-binding capacity, and antithrombin were the variables most strongly associated with disease severity (p < 0.005, respectively). Urinary amylase-to-creatinine ratio can be a useful marker to monitor treatment response and to classify the degree of disease severity.

Evaluation of urinary podocin and nephrin as markers of podocyturia in dogs with leishmaniosis

BACKGROUND

Renal disease is the main cause of death in canine leishmaniosis. Detection of an active glomerular injury is important to identify early renal damage and to prevent the development of chronic kidney disease. Podocyturia can indicate renal injury, and podocyte-associated molecules such as podocin and nephrin can be used to identify podocyturia. The purpose of the study was to evaluate urinary podocin and nephrin concentrations in dogs with leishmaniosis as markers of podocyturia.

METHODS

A total of 35 healthy dogs and 37 dogs with leishmaniosis were enrolled in the study. Dogs with leishmaniosis were classified according to the staging of the International Renal Interest Society (IRIS). Urinary podocin and nephrin concentrations were measured in all dogs with a validated enzyme-linked immunosorbent assay test and normalized to creatinine (uPoC and uNeC, respectively). The demographic, clinical, and laboratory data from both groups were analyzed and compared. Subsequently, the laboratory results were analyzed and compared according to IRIS staging in dogs in IRIS stage I and dogs in IRIS stage II + III + IV. The Pearson's correlation test evaluated the relationship between urinary markers of podocyturia.

RESULTS

Compared with healthy dogs, lower urinary podocin [median values (IQR): 15.10 (11.75-17.87) ng/ml versus 8.63 (7.08-13.56) ng/ml; P < 0.01] and nephrin [median values (IQR): 3.2 (3.62-5.43) ng/ml versus 2.67 (2.06-3.44) ng/ml; P < 0.01] were found in infected sick dogs. No significant differences were observed in the uPoC and uNeC between the two groups. Urinary nephrin and podocin concentrations were higher in healthy dogs and in dogs in IRIS stage I (both P < 0.05) compared with dogs in IRIS stages II + III + IV. No significant differences were found for uPoC and uNeC between healthy dogs and dogs with leishmaniosis in different IRIS clinical stages.

CONCLUSIONS

Dogs with leishmaniosis had a low concentration of podocin and nephrin in more advanced IRIS clinical stages, when kidney disease was more severe compared with healthy dogs and dogs in IRIS stage I with mild disease. Urinary nephrin was detectable for the first time in healthy non-infected dogs.

Canine vector-borne infections of working dogs of the Sri Lanka Air Force, and free roaming, and privately owned dogs

Canine vector-borne infections (CVBIs) are a global health problem. The military working dogs of Sri Lanka die at an early age, and CVBIs have been a leading speculated cause. We examined CVBIs in the working dogs of the Sri Lanka air force (SLAF) and free-roaming dogs (FRDs) and privately owned dogs (PODs) country-wide. Giemsa-stained smears were prepared and conventional PCR-positive DNA was subjected to sequencing and phylogeny. Of the 668 dogs sampled, 212 (31.7%) had one or more CVBIs. The prevalence of infections among the FRDs (40.0%) was significantly higher than SLAF working dogs (30.0%; χ2 = 10.5216; p = 0.0012) and PODs (26.2%; χ2 = 5.3414, p = 0.0208) but not between SLAF dogs and PODs (χ2 = 1.7655, p = 0.1838). Many infected dogs were asymptomatic (57.4%), which was higher among the FRDs. Seven infectious agents were identified: Babesia gibsoni, B. canis, Ehrlichia canis, Anaplasma platys, Leishmania sp., Hepatozoon canis, and filaria worms. The most common infection was B. gibsoni (13.8%), followed by E. canis (9.9%). Three tick species: Rhipicephalus linneai, Rhipicephalus haemaphysaloides and Haemophysalis bispinosa were found infesting the dogs. The SLAF dogs were thoroughly quarantined upon arrival, but the infection prevalence was similar to PODs.

Urinary neutrophil gelatinase-associated lipocalin as early biomarker for renal disease in dogs with leishmaniosis

Canine leishmaniosis (CanL), caused by Leishmania sp., presents a wide array of symptoms; renal dysfunction is frequently observed in these dogs and is associated with a poor prognosis and increased mortality. The traditional biomarkers namely urea and creatinine can detect renal damage but only in advanced stages of the disease. However, it has been shown that the symmetric dimethylarginine assay (SDMA) or the protein/creatinine ratio (UPC) and are early biomarkers of renal dysfunction. Their elevation occurs earlier than that of creatinine, but other novel biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL) are currently under investigation. Our objective was to determine whether the urine NGAL-creatinine ratio (uNGAL/c) can provide very early diagnosis of kidney disease in CanL. In total, 68 dogs were included in the study: 15 healthy dogs and 53 dogs with CanL who were classified according to International Renal Interest Society (IRIS) classification: IRIS 1 (N= 34), IRIS 2 (N= 9) and IRIS 3/4 (N= 10). IRIS 1 was subdivided according to proteinuria in IRIS 1NP (13 dogs with UPC < 0.2), IRIS 1BL (8 dogs with UPC = 0.2-0.5) and IRIS 1 P (13 dogs with UPC > 0.5). Blood samples were collected for complete hematological and biochemistry analysis including plasma NGAL. Urinalysis included specific gravity, UPC, CysC and NGAL expressed as a ratio with creatinine. The mean concentrations of pCysC and SDMA in CanL, show a statistically significant increase from IRIS 1NP, not being statistically significant for pCysC in the IRIS 1BL group. The UPC show a statistically significant increase from IRIS 1NP. In all groups with CanL for uCysC/c and uNGAL/c was observed a statistically significant increase. The uNGAL/c in the group proteinuric animals, presents a positive correlation with all renal biomarkers studied. In the group of non-proteinuric animals, the uNGAL/c presents a positive correlation with SDMA and UPC. The uNGAL/c can be considered a reliable indicator of renal disease in dogs diagnosed with CanL who are non-azotemic and non-proteinuric.

Fatal case of imported visceral leishmaniasis in a dog caused by Leishmania infantum in French Guiana

Here we described a case of fatal canine visceral leishmaniasis (VL) in French Guiana, a non-endemic VL Amazonian area. The dog was a 2-year-old pug imported from Brazil to French Guiana. Initially seen for a pruriginous lesion on the muzzle which healed after treatment, the dog was in a deteriorated condition and had sublingual, foreleg and eye ulcers, one month later. A visceral leishmaniasis was suspected by the veterinarian. The dog was hospitalized awaiting results, which revealed the presence of L. infantum. However, the dog succumbed suddenly before the results were returned. Few imported and scarce autochthonous canine VL cases have been previously reported in French Guiana, raising the need for local epidemiological surveillance, considering the possibility of unusual transmission routes of the parasite.

Unexpected Cytological Detection of Leishmania infantum within the Secretion of a Canine Mammary Carcinoma

Mammary tumors are one of the most common neoplasms in female dogs, and cytology represents a non-invasive diagnostic method. The protozoal pathogen Leishmania spp. was previously demonstrated in canine mammary glands. An eight-year-old, female-spayed Doberman was imported from Crete, Greece, three years before the first presentation. The dog was presented due to a mammary tumor two years after adoption. The clinical examination revealed fever and weight loss. Smears of the mammary secretion were investigated cytologically. Multiple atypical epithelial cells with moderate to marked criteria of malignancy were detected. Furthermore, amastigotes were visible intra- and extracellularly. The diagnosis of L. infantum infection was based on a positive PCR out of the cytological smear, and a positive serology. Mammary carcinoma and granulomatous inflammation with amastigotes were confirmed by histopathology. We aimed to provide a complete report of cytological, histopathological, hematological, and biochemistry findings in a dog with L. infantum in the mammary glands with focus on trans-mammary pathogen transmission as a potential alternative way of spreading Leishmania infections. Canine leishmaniasis should be a potential differential diagnosis in dogs with lesions and/or inflammation in the mammary glands and a history of presence in areas endemic for L. infantum, especially the Mediterranean in Europe.

Serum and urinary monocyte chemoattractant protein-1 as markers of inflammation and renal damage in dogs with naturally occurring leishmaniosis

BACKGROUND

Renal disease in canine leishmaniosis is of great importance owing to increased risk of mortality. In human visceral leishmaniosis, monocyte chemoattractant protein-1 (MCP-1) has been used as a marker of renal damage and inflammation. The purpose of this study was first to determine the serum MCP-1 and urinary MCP-1-to-creatinine ratio (uMCP-1/Cr) in healthy dogs and dogs with leishmaniosis at diagnosis, and second to determine whether these markers can differentiate disease severity at diagnosis.

METHODS

In total, 19 healthy seronegative dogs and 38 dogs with leishmaniosis were included in the study. Dogs with leishmaniosis were classified as LeishVet clinical staging and as International Renal Interest Society (IRIS) staging. Serum and urinary MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. A receiver operating characteristic (ROC) curve determined disease severity at diagnosis between two LeishVet groups (Stage II versus stage III and IV).

RESULTS

Dogs in Leishvet stages IIb, III, and IV had a median serum MCP-1 and uMCP-1/Cr concentration higher than healthy dogs (P < 0.0001). No statistical differences were found in serum MCP-1 and uMCP-1/Cr between dogs in LeishVet stage IIa and healthy dogs. The dogs in LeishVet stage IV had significantly higher serum MCP-1 and uMCP-1/Cr compared with the dogs in LeishVet stage IIa (P < 0.0001). Serum MCP-1 and uMCP-1 were significantly higher in dogs in IRIS stage I and II + III + IV compared with healthy dogs. Dogs stage II + III + IV of IRIS had a significantly higher serum MCP-1 compared with dogs in IRIS stage I (P < 0.0001). The area under the ROC curve for serum MCP-1 was 0.78 [95% confidence interval (CI) 0.64-0.93] and for uMCP-1/Cr it was 0.86 (95% CI, 0.74-0.99). The optimal cutoff value for serum MCP-1 and uMCP-1/Cr was 336.85 pg/ml (sensitivity of 79% and specificity of 68%) and 6.89 × 10-7 (sensitivity of 84% and specificity of 79%), respectively.

CONCLUSIONS

Serum MCP-1 and uMCP-1/Cr are increased in dogs with leishmaniosis compared with healthy dogs, suggesting the presence of inflammation and renal injury. Serum MCP-1 and uMCP-1/Cr were more elevated in the advanced stages of the disease compared with the moderate stages and, therefore, can be markers of the severity of the disease process.

Relapses in canine leishmaniosis: risk factors identified through mixed-effects logistic regression

BACKGROUND

Canine leishmaniosis (CanL), caused by Leishmania infantum, is an important vector-borne parasitic disease in dogs with implications for human health. Despite advancements, managing CanL remains challenging due to its complexity, especially in chronic, relapsing cases. Mathematical modeling has emerged as a powerful tool in various medical fields, but its application in understanding CanL relapses remains unexplored.

METHODS

This retrospective study aimed to investigate risk factors associated with disease relapse in a cohort of dogs naturally infected with L. infantum. Data from 291 repeated measures of 54 dogs meeting the inclusion criteria were included. Two logistic mixed-effects models were created to identify clinicopathological variables associated with an increased risk of clinical relapses requiring a leishmanicidal treatment in CanL. A backward elimination approach was employed, starting with a full model comprising all potential predictors. Variables were iteratively eliminated on the basis of their impact on the model, considering both statistical significance and model complexity. All analyses were conducted using R software, primarily employing the lme4 package, and applying a significance level of 5% (P < 0.05).

RESULTS

This study identified clinicopathological variables associated with an increased risk of relapses requiring a leishmanicidal treatment. Model 1 revealed that for each 0.1 increase in the albumin/globulin ratio (A/G) ratio, the odds of requiring treatment decreased by 45%. Conversely, for each unit increase in the total clinical score (CS), the odds of requiring treatment increase by 22-30%. Indirect immunofluorescence antibody test (IFAT) was not a significant risk factor in model 1. Model 2, incorporating individual albumin and globulins values, showed that dogs with high IFAT titers, hyper beta-globulinemia, hypoalbuminemia, anemia, and high CS were at increased risk of relapse. Both models demonstrated a good fit and explained a substantial amount of variability in treatment decisions.

CONCLUSIONS

Dogs exhibiting higher CS, dysproteinemia, anemia, and high IFAT titers are at increased risk of requiring leishmanicidal treatment upon clinical relapse in CanL. Regular monitoring and assessment of risk factors prove essential for early detection of relapses and effective intervention in CanL cases. The contrasting findings between the two models highlight the complexity of aspects influencing treatment decisions in this disease and the importance of tailored management strategies to improve outcomes for affected dogs.

Feline leishmaniosis in the Mediterranean Basin: a multicenter study

BACKGROUND

Cats are now recognized as competent hosts for Leishmania infantum and a blood source for sand fly vectors. Although canine leishmaniosis (CanL) is endemic in Mediterranean Basin countries, large-scale epidemiological studies are lacking for feline leishmaniosis (FeL). This study aimed to assess the prevalence of L. infantum infections, associated risk factors, clinical signs, and clinicopathological abnormalities in domestic cat populations from six Mediterranean Basin countries.

METHODS

From 2019 to 2022, blood and serum samples of cats (n = 2067) living in Italy (n = 300), Greece (n = 297), Portugal (n = 295), France (n = 231), Israel (n = 313), and Spain (n = 631) were collected along with animal data (i.e., age, sex, breed, housing conditions, and geographical origin), clinical signs, and laboratory blood test parameters. Cats were grouped according to their age as kittens (up to 1 year), young (older than 1 and younger than 7 years), mature (between 7 and 10 years), and senior (older than 10 years). Serum samples were tested for L. infantum by immunofluorescence antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA), and blood samples of seropositive cats were tested for L. infantum kinetoplast deoxyribonucleic acid (kDNA). Viral infection by feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) was molecularly addressed in all cats enrolled. Statistical analysis was performed to evaluate the association between the risk of L. infantum infection and independent variables, and among co-infection of L. infantum with FIV and/or FeLV, clinical signs, and clinicopathological abnormalities.

RESULTS

Overall, 17.3% (358/2067) of cats scored positive for L. infantum by serological tests. Specifically, 24.7% were from Portugal, 23.2% from Greece, 16.6% from Israel, 15% from Spain, 13.3% from France, and 12.6% from Italy. Leishmania infantum DNA was detected in 15 seropositive animals. Housing condition and FIV infection proved to be risk factors for FeL. Leishmania seropositivity was significantly associated with weight loss, lymphadenomegaly, gingivostomatitis, and oral ulcers, as well as with reduced albumin and albumin/globulin ratio, increased total globulins and total proteins, leukocytosis, and thrombocytosis.

CONCLUSIONS

This study provides, for the first time, a large-scale epidemiological survey on FeL and its clinical presentation, revealing that L. infantum circulates among domestic cats, especially shelter/free-roaming and FIV-infected animals, living in CanL endemic countries of the Mediterranean Basin.

Seroprevalence of zoonotic pathogens in stray cats in an urban area of northeast Spain

The feline population is extensive in urban areas worldwide, comprising stray and domestic cats. Cats, acting as reservoirs, can transmit various zoonotic organisms to humans, which can cause significant public health issues. We evaluated the seroprevalence of zoonotic pathogens in stray cats in an urban area of northeast Spain (the city of Zaragoza) to assess potential risks to human health. A total of 88 sampled cats (52 females and 36 males) underwent antibody evaluation using the indirect immunofluorescence technique. Seroprevalence rates were determined for IgG antibodies to Bartonella henselae (36.3%), Toxoplasma gondii (31.8%), Rickettsia felis (14.7%), Rickettsia typhi (9%), and Leishmania infantum (10.2%). Our results confirmed the presence in stray cats of antibodies against all those pathogens, indicating that they all circulate in the feline population in Zaragoza. Male cats exhibited a higher predisposition to T. gondii, whereas females showed an increased likelihood of contracting B. henselae. This difference may be attributed to distinct behaviors according to sex. Our findings underscore the importance of maintaining and intensifying surveillance coupled with preventive measures against zoonotic pathogens in cats. They highlight the need for comprehensive control strategies designed to mitigate public health risks associated with feline populations.

A compared histopathological study on kidneys and eye bulbs in distinct clinical presentations of canine leishmaniasis by Leishmania infantum

Canine leishmaniasis (CanL) caused by Leishmania infantum commonly progresses with renal and ophthalmic lesions associated with active systemic disease. As chronic inflammation related to immune complex deposits is a pathophysiological factor in the development of both glomerulonephritis and uveitis, we aimed to evaluate renal and ocular histopathological lesions and analyze whether they were related to each other and the clinical degree of the disease. For that, we evaluated 15 dogs from CanL-endemic areas. L. infantum PCR-positive dogs were studied according to disease severity into two different groups: Group-1 (G1) had data from seven dogs with mild to moderate CanL and no history of treatment, and G2 was formed with eight dogs with severe to terminal disease that had not responded to CanL treatment. Histopathological analysis of kidneys showed higher frequencies and intensities of glomerular basement membrane thickening (p = 0.026), deposits in glomeruli (p = 0.016), epithelial necrosis (p = 0.020), tubular dilatation (p = 0.003) and interstitial fibrosis (p = 0.04) in G2 dogs than in G1 dogs. Surprisingly, the histopathology of eye bulbs showed a higher frequency and intensity of retinitis (p = 0.019) in G1 dogs than in G2 dogs. The comparative analysis showed that there was no correspondence between histopathological findings in kidneys versus eyes in milder or more severe CanL. Our findings suggested that (1) clinically undetectable eye alterations can be more precocious than those in kidneys in the development of CanL, and (2) the lower frequency of eye lesions and higher frequency of renal lesions in dogs with terminal disease even after treatment indicate that therapy may have been effective in reducing CanL-associated ophthalmic disease but not proportionally in reducing kidney disease.

Owners' experiences of administering meglumine antimoniate injections to dogs with leishmaniosis: An online questionnaire study

BACKGROUND

This study examined the experiences of owners of dogs with leishmaniosis who treated their dogs with daily subcutaneous meglumine antimoniate injections. The owners' perceived ease of administering the injections, the occurrence of problems and the effects on the owners and on the dog‒owner bond were evaluated.

METHODS

Dogs prescribed meglumine antimoniate as a treatment for leishmaniosis were identified using the database of the veterinary pharmacy of the Faculty of Veterinary Medicine, Utrecht University. An online questionnaire was sent to the owners of these dogs to evaluate the perceived ease of administering the injections, the occurrence of problems and the effects on the owner and the dog-owner bond.

RESULTS

Responses were received from 64 dog owners. Most respondents (78%) reported that administering the injections was not difficult. Pain or the development of nodules at the injection site was reported in 50% and 40% of the dogs, respectively. Polyuria was reported in 44% of the dogs. Some owners reported that administering the injections had a negative impact on their psychological wellbeing (20%), and some would have liked more veterinary support (11%).

LIMITATIONS

Some questions were answered by a limited number of people, and their responses may not be representative.

CONCLUSION

Dog owners remain highly motivated to persevere with meglumine antimoniate treatment and are willing to administer the injections themselves. The availability of active support when needed during the therapy cycle may further improve their acceptance of and confidence in giving the injections.

Global Distribution of Canine Visceral Leishmaniasis and the Role of the Dog in the Epidemiology of the Disease

Visceral leishmaniasis is a disease caused by protozoa of the species Leishmania (Leishmania) infantum (syn = Leishmania chagasi) and Leishmania (Leishmania) donovani, which are transmitted by hematophagous insects of the genera Lutzomyia and Phlebotomus. The domestic dog (Canis familiaris) is considered the main urban reservoir of the parasite due to the high parasite load on its skin, serving as a source of infection for sandfly vectors and, consequently, perpetuating the disease in the urban environment. Some factors are considered important in the perpetuation and spread of canine visceral leishmaniasis (CVL) in urban areas, such as stray dogs, with their errant behavior, and houses that have backyards with trees, shade, and organic materials, creating an attractive environment for sandfly vectors. CVL is found in approximately 50 countries, with the number of infected dogs reaching millions. However, due to the difficulty of controlling and diagnosing the disease, the number of infected animals could be even greater. In the four continents endemic for CVL, there are reports of disease expansion in endemic countries such as Brazil, Italy, Morocco, and Tunisia, as well as in areas where CVL is not endemic, for example, Uruguay. Socio-environmental factors, such as migration, drought, deforestation, and global warming, have been pointed out as reasons for the expansion into areas where it had been absent. Thus, the objective of this review is to address (i) the distribution of CVL in endemic areas, (ii) the role of the dog in the visceral leishmaniasis epidemiology and the factors that influence dog infection and the spread of the disease, and (iii) the challenges faced in the control of CVL.

Critically Appraised Topic on Canine Leishmaniosis: Does Treatment with Antimonials and Allopurinol Have the Same Clinical and Clinicopathological Efficacy as Treatment with Miltefosine and Allopurinol, after One Month of Treatment?

The treatment of canine leishmaniosis commonly involves meglumine antimoniate with allopurinol or miltefosine with allopurinol. This study aims to compare the clinical and clinicopathological efficacy at 28-30 days of conventional dosing regimens for both treatments using the critically appraised topic methodology. A comprehensive search across three databases (PubMed, CAB Abstracts, and Web of Science) from March 2004 to September 2023 yielded 16 relevant articles, encompassing 325 ogs treated with meglumine antimoniate and allopurinol, and 273 dogs treated with miltefosine and allopurinol. The findings indicated a significantly higher rate of complete clinical cure in the group treated with meglumine antimoniate and allopurinol. Most dogs in both groups exhibited improvement in clinicopathological alterations after one month of treatment. No significant difference was observed in the number of dogs that showed a negative Leishmania qPCR between the two groups, one month post-treatment. However, quantitative serology results were not commonly reported in the available data and therefore this aspect could not be compared.

Fibroblast growth factor-23 and Alpha-Klotho concentrations in dogs with canine Leishmaniasis

This study aimed to assess the concentrations of Fibroblast Growth Factor-23 (FGF-23) and α-Klotho in healthy dogs and dogs at different stages of Canine Leishmaniasis (CanL), and investigate the changes of these parameters in relation to renal function and calcium‑phosphorus metabolism. A total of 74 dogs (22 healthy and 52 with CanL) of varying ages, sexes, and medium-sized breeds were included. Dogs with CanL were categorized into different stages (Stage I-IV) based on Leishvet recommendations. In addition to routine hematological parameters, plasma FGF-23, serum α-Klotho, urea, creatinine, phosphorus, calcium, parathormone, vitamin D concentrations, and urine protein/creatinine ratio were measured. Data from healthy dogs were compared to dogs with CanL overall and by stage. Dogs with CanL exhibited higher concentrations of FGF-23 (p < 0.05), α-Klotho, and parathormone (p < 0.001), as well as lower concentrations of vitamin D and calcium (p < 0.001). FGF-23 concentration was particularly elevated in Stage IV compared to other stages. However, no significant differences in α-Klotho levels were observed among the stages. FGF-23 levels showed a weak positive correlation with urea and creatinine concentrations and a moderate positive correlation with urine protein/creatinine ratio. This study demonstrated increased levels of FGF-23 and α-Klotho in dogs with CanL for the first time. The increase in FGF-23 levels was more prominent in advanced stages of the disease and correlated with higher urea and creatinine concentrations. These findings may serve as a basis for future diagnostic and therapeutic investigations, contributing to the understanding of the pathophysiology of kidney disease in CanL.

Alternative hosts of Leishmania infantum: a neglected parasite in Europe

Multi-host pathogens that infect various animal species and humans are considered of great importance for public and animal health. Leishmania spp. parasites are a characteristic example of such pathogens. Although leishmaniosis in humans is endemic for about 100 countries around the world it is classified as a neglected tropical disease. There are three main forms of leishmaniosis in humans: cutaneous (CL), visceral (VL) and mucocutaneous leishmaniosis (MCL). Each year, about 30,000 new cases of VL and more than 1 million new cases of CL are recorded. In Europe L. infantum is the dominant species with dogs being reservoir hosts. Apart from dogs, infection has been recorded in various animals, which suggests that other species could play a role in the maintenance of the parasite in nature. Herein we provide an in-depth review of the literature with respect to studies that deal with Leishmania infantum infections in domestic and wild animal species in Europe. Given the fact that domesticated and wild animals could contribute to the incidences of leishmaniosis in humans, the aim of this paper is to provide a comprehensive review which could potentially be used for the development of measures when it comes to the control of the Leishmania infantum parasite.

Leishmania Infection in Wild Lagomorphs and Domestic Dogs in North-East Spain

Leishmania infantum is a zoonotic protozoan parasite distributed worldwide that is transmitted by phlebotomine sandflies. Dogs are the main reservoir for human infections. However, in recent years, the capacity of lagomorphs to contribute to Leishmania transmission has been confirmed. The present study aimed to assess Leishmania spp. exposure and infection in lagomorphs and sympatric domestic dogs in NE Spain. Sera from European hares, European rabbits, and rural dogs were tested for antibodies against L. infantum using an in-house indirect ELISA. PCR analysis targeting Leishmania spp. was performed in spleens from L. europaeus. Antibodies against Leishmania spp. were detected in all the species analyzed. Total sample prevalence was significantly higher in O. cuniculus (27.9%) than in L. europaeus (2.0%). Results of the PCR were all negative. The present study expands knowledge about Leishmania infections in free-ranging lagomorphs in the Iberian Peninsula, suggesting a more important role of O. cuniculus in the study area. Given the strong correlation between lagomorph densities and human leishmaniasis outbreaks in Spain, the high rabbit and human densities in NE Spain, and the high Leishmania spp. seroprevalence in rabbits, it becomes imperative to establish surveillance programs for lagomorphs in this region.

[Overview on utility of in-house tests for detection of systemic infectious diseases in dogs]

For detection of infectious diseases, several point-of-care (POC) tests are on the market in addition to methods performed in commercial laboratories. These POC tests are based on enzyme-linked immunosorbent assay (ELISA) or other immunochromatographic technologies and present results within few minutes in veterinary practice. This article gives an overview of the utility of numerous POC tests of different manufacturers for detection of parvovirus antigen in feces, Dirofilaria (D.) immitis antigen in blood as well as antibodies against Borrelia (B.) burgdorferi, Anaplasma (A.) spp., Ehrlichia (E.) spp., Leptospira (L.) spp. and Leishmania (L.) infantum in blood (single or in different combinations). Sensitivity and specificity of these tests are important for their usefulness in veterinary practice. Furthermore, presence of antibodies or detection of antigen has to correlate with the presence of clinical signs. POC tests for detection of canine parvovirus antigen have a very high specificity, the sensitivity of all evaluated POC tests, however, is very low. POC tests for detection of D. immitis antigen have a very high sensitivity and specificity. As they detect antigen from the uterus of female adult parasites, test results are negative when only very few female or only male adults are present. POC tests for detection of antibodies against B. burgdorferi only indicate contact with Borrelia spp. and do not prove clinical Lyme disease, as the infection only extremely rarely causes clinical signs. POC tests for detection of antibodies against A. phagocytophilum are also not suitable for diagnosis of clinical anaplasmosis. Infections with A. phagocytophilum only lead to clinical disease in very rare cases and in these, clinical signs occur before the development of antibodies. POC tests for detection of antibodies against E. canis have a very high sensitivity as well as specificity. POC tests for detection of antibodies against L. infantum and Leptospira species (spp.) show a very high specificity and a high sensitivity. However, Leptospira spp. antibody-positive results may occur following vaccination, as the POC tests cannot distinguish between field and vaccination strains.

Challenges of animals shelters in caring for dogs infected with Leishmania and other pathogens

The incidence of human Visceral Leishmaniasis (VL) has decreased in Brazil; however, the number of areas reporting human and canine cases has increased, with Leishmania infantum usually preceding human infection. This study aimed to analyze the profile of infectious diseases that are endemic for both human and canine VL, in dogs housed in a shelter located in the state of Rio Grande do Norte, Northeast Brazil. Data was obtained between November/2021 to April/2022. All dogs residing at the shelter (98 dogs) were examined and blood was collected for testing for L. infantum, Ehrlichia canis, and Babesia sp. Statistical analyses considered the clinical and laboratory findings. Of the 98 animals, approximately 43% were positive for L. infantum antibodies, 19% were positive for L. infantum kDNA, and 18% were L. infantum positive by culture. Greater levels of anti-leishmania antibodies were observed in dogs with symptoms suggestive of VL. The dogs tested positive for E. canis (19/98) and B. canis (18/98). Lutzomyia longipalpis was captured inside the shelter, representing 74.25% (n = 225) of whole sandflies in the dog shelter. Concomitant infection by L. infantum and E. canis increased the odds of death. Treatment of VL included the use of allopurinol (n = 48) and miltefosine (n = 8). Treated animals showed more signs of Leishmania infection. Tickborn parasites and Leishmania were prevalent in sheltered dogs in a VL-endemic area, which increases the odds of death and poses an additional challenge for caring for abandoned dogs and at the same time setting protocols to manage reservoirs of L. infantum.

Clinical validation of circulating immune complexes for use as a diagnostic marker of canine leishmaniosis

Introduction

Canine leishmaniosis (CanL) is a systemic disease that affects dogs. When multiplication of the parasite cannot be controlled, dogs consistently show high levels of antigen and IgG antibodies, which lead to the formation of circulating immune complexes (CIC). Timely intervention to reduce the parasite load and CIC levels is crucial for preventing irreversible organ damage. However, a diagnostic test to quantify CIC levels is currently lacking.

Methods

In this real-world study, we aimed to examine the performance of a new ELISA to measure CIC levels in dogs naturally infected with Leishmania infantum. Thirty-four dogs were treated according to their clinical condition and followed for 360 days. Before (day 0) and after treatment (days 30, 90, 180, 270, and 360), all dogs underwent a physical examination, and blood samples were obtained for CBC, biochemical profile, serum protein electrophoresis and IFAT. Serum PEG-precipitated CIC were determined by ELISA.

Results

Our results indicate higher CIC levels in dogs in advanced disease stages showing higher antibody titres (p < 0.0001, r = 0.735), anemia (p < 0.0001), dysproteinemia (p < 0.0001), and proteinuria (p = 0.004). Importantly, dogs responding well to treatment exhibited declining CIC levels (p < 0.0001), while in poor responders and those experiencing relapses, CIC were consistently elevated. CIC emerged as a robust discriminator of relapse, with an area under the curve (AUC) of 0.808. The optimal cut-off to accurately identify relapse was an optical density of 1.539.

Discussion

Our findings suggest that declining CIC levels should be expected in dogs showing a favorable treatment response. Conversely, in dogs displaying a poor response and recurrent clinical relapses, CIC levels will be high, emphasizing the need for vigilant monitoring. These findings suggest that CIC could serve as a valuable biomarker for disease progression, treatment efficacy, and relapse detection in CanL. Our study contributes to enhancing diagnostic approaches for CanL and underscores the potential of CIC as a complementary tool in veterinary practice. As we move forward, larger studies will be essential to confirm these findings and establish definitive cut-offs for clinical application.

Refinement of the rKLi8.3-Based Serodiagnostic ELISA Allows Detection of Canine Leishmaniosis in Dogs with Low Antibody Titers

The diagnosis of canine leishmaniasis (CanL) still represents a challenge due to the variable clinical manifestations and the large number of asymptomatic dogs. Serological tests are most commonly used to detect infected animals, revealing anti-Leishmania antibodies, mainly of the IgG isotype. Recently, a new diagnostic antigen, rKLi8.3, containing 8.3 kinesin tandem repeats (TR) from a Leishmania infantum strain from Sudan, has been shown to provide excellent specificity and sensitivity for the detection of Leishmania-infected humans and dogs. However, asymptomatic animals with very low antibody titers are often difficult to detect by serodiagnosis. Thus, we wondered whether the addition of an anti-IgG-enhancing step in the protein A/G-based rKLi8.3-ELISA will improve the diagnostic performance without decreasing the specificity. For this, parasitologically confirmed CanL cases with low or high clinical scores, uninfected healthy controls and dogs with other infections were tested by rKLi8.3-ELISA as well as two different immunochromatographic rapid tests, rKLi8.3-lateral flow test (LFT) and Dual Path Platform (DPP®) based on the rK28 antigen. Our results show that the diagnostic accuracies of the rKLi8.3-ELISA and LFT were similar to that of DPP, missing several asymptomatic animals. However, the addition of a secondary, amplifying anti-dog IgG antibody in the protein A/G-based rKLi8.3-ELISA enabled the detection of nearly all asymptomatic dogs without compromising its specificity.

Diagnostic benefits of platelet-to-lymphocyte, neutrophil-to-lymphocyte, and albumin-to-globulin ratios in dogs with nasal cavity diseases

BACKGROUND

A multimodal approach for diagnostic tests under anesthesia is required to diagnose nasal cavity pathology (NP) reliably in dogs. Blood test results may provide clues to the suspected NP.

METHODS

This prospective blinded study assessed 72 dogs with chronic nasal discharge due to NPs, and 10 healthy dogs as the control group (CG). NPs were diagnosed using whole-body computed tomography (CT), upper airway endoscopy, examination of nasal mucosal swabs by bacterial and fungal culture, and histopathological examination of nasal mucosa biopsies. The exclusion criteria were the presence of any additional diseases or corticosteroid pre-treatment. In consideration of these exclusion criteria, 55 dogs entered the study. Dogs were classified into benign (benign tumors, idiopathic rhinitis (IR), and others) and malignant (carcinomas and sarcomas) NP groups. Blood count and blood chemistry tests were performed. The neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and albumin-to-globulin ratio (AGR) were calculated and compared.

RESULTS

25 dogs with malignant NP (13 and 12 with carcinomas and sarcomas, respectively) and 30 dogs with benign NP (seven with benign tumors,13 with IR, and 10 others) were included. In general, in dogs with NP there were only slight abnormalities in complete blood count. However, PLR was significantly higher in dogs with malignant NP (carcinoma and sarcoma) than in those with benign NP and in the CG. Compared with the CG, the NLR was significantly increased in all dogs with NP, and the AGR was mild but significantly lower, except in dogs with sarcomas and benign tumors.

CONCLUSIONS

In dogs with nasal disease alone, there are usually no marked abnormalities in blood count. However, while mildly increased NLR and decreased AGR can be observed in almost all NPs, an increased PLR may indicate a malignant NP and can be used as an additional screening tool in dogs with nasal discharge due to nasal cavity pathology.

Comparative Study of a Novel Lateral Flow Rapid Test with Conventional Serological Test Systems for the Diagnosis of Canine Leishmaniosis in Croatia and Brazil

Control of canine infections with Leishmania infantum (L. infantum), a major zoonotic disease in Brazil and southern Europe, is becoming increasingly important due to its close proximity to humans, the increasing import of dogs from endemic regions and the impact of climate change on vector spreading. Simple, rapid and reliable diagnostic tests are therefore needed to detect infected dogs. Here, we re-evaluated different serological methods for the diagnosis of canine leishmaniosis (CanL) in Croatia and Brazil. The diagnostic performance of the indirect fluorescent antibody test (IFAT) and the VetLine® Leishmania ELISA (GSD Frankfurt, Germany) was compared with three rKLi8.3-based diagnostic test systems, the rKLi8.3 ELISA (GSD Frankfurt, Germany), the INgezim® Leishma CROM (GSD Madrid, Spain) lateral flow test (LFT) and the VetBlot®Leishmania LineBlot (GSD Frankfurt, Germany). CanL symptomatic dogs were efficiently diagnosed by all tests, except the VetLine® Leishmania ELISA, which is based on whole Leishmania antigens. The advantage of rKLi8.3 was also observed in oligo- and asymptomatic dogs from Brazil and Croatia, although with reduced diagnostic efficiency compared to symptomatic dogs. Similar to IFAT and rKLi8.3 ELISA, the LFT did not cross-react with other common canine pathogens; it showed very high specificity for healthy dogs from endemic regions in both countries and did not react with healthy, vaccinated dogs in Brazil. In conclusion, serodiagnostic tests based on the rKLi8.3 antigens are superior to whole parasite antigens, and the LFT has the advantage of providing a laboratory-independent, rapid and specific diagnosis of CanL.

Pilot Study on QTc Interval in Dogs Treated with Domperidone

Domperidone is used as an immunomodulatory drug for Leishmania infantum infection and disease in dogs. However, a pro-arrhythmic side effect, caused by prolonged QT intervals, is reported in humans. This pilot study evaluated the corrected QT (QTc) interval in dogs treated with domperidone for preventive or therapeutic management of leishmaniosis. The electrocardiogram and blood concentration of creatinine, urea nitrogen, sodium, potassium, and chloride were evaluated seven days before the start and on the last day of therapy in 17 dogs receiving domperidone for four weeks. In two dogs, the QTc interval was measured before and 2 h, 3 h, and 12 h after administration of the drug on the first day of treatment. After treatment, QTc measures and chloride concentrations increased significantly, although the QTc value slightly exceeded the upper reference limit only in one dog, and chloride concentrations were always normal. Creatinine concentrations significantly decreased after therapy. In the two dogs monitored at different times on the first day of treatment, QTc values were always normal. Domperidone caused a slight prolongation of QTc interval, and further studies should be made for a risk assessment in dogs with cardiac diseases, electrolytic imbalance, and in those receiving drugs increasing QT interval or competing with domperidone metabolism.

MicroRNA-194 regulates parasitic load and IL-1β-dependent nitric oxide production in the peripheral blood mononuclear cells of dogs with leishmaniasis

Domestic dogs are the primary urban reservoirs of Leishmania infantum, the causative agent of visceral leishmaniasis. In Canine Leishmaniasis (CanL), modulation of the host's immune response may be associated with the expression of small non-coding RNAs called microRNA (miR). miR-194 expression increases in peripheral blood mononuclear cells (PBMCs) of dogs with leishmaniasis with a positive correlation with the parasite load and in silico analysis demonstrated that the TRAF6 gene is the target of miR-194 in PBMCs from diseased dogs. Here, we isolated PBMCs from 5 healthy dogs and 28 dogs with leishmaniasis, naturally infected with L. infantum. To confirm changes in miR-194 and TRAF6 expression, basal expression of miR-194 and gene expression of TRAF6 was measured using qPCR. PBMCs from healthy dogs and dogs with leishmaniasis were transfected with miR-194 scramble, mimic, and inhibitor and cultured at 37° C, 5% CO2 for 48 hours. The expression of possible targets was measured: iNOS, NO, T-bet, GATA3, and FoxP3 were measured using flow cytometry; the production of cytokines IL-1β, IL-4, IL-6, IL-10, TNF-α, IFN-γ, and TGF-β in cell culture supernatants was measured using capture enzyme-linked immunosorbent assays (ELISA). Parasite load was measured using cytometry and qPCR. Functional assays followed by miR-194 inhibitor and IL-1β blockade and assessment of NO production were also performed. Basal miR-194 expression was increased in PBMC from dogs with Leishmaniasis and was negatively correlated with TRAF6 expression. The mimic of miR-194 promoted an increase in parasite load. There were no significant changes in T-bet, GATA3, or FoxP3 expression with miR-194 enhancement or inhibition. Inhibition of miR-194 increased IL-1β and NO in PBMCs from diseased dogs, and blockade of IL-1β following miR-194 inhibition decreased NO levels. These findings suggest that miR-194 is upregulated in PBMCs from dogs with leishmaniasis and increases parasite load, possibly decreasing NO production via IL-1β. These results increase our understanding of the mechanisms of evasion of the immune response by the parasite and the identification of possible therapeutic targets.

Analysis of exotic pathogens found in a large group of imported dogs following an animal welfare investigation

BACKGROUND

Increased dog relocation can cause dissemination of pathogen and vector populations, and this is being recognised in countries across Northern Europe, including the UK. Data regarding the prevalence of exotic infections in dogs entering the UK would be beneficial to veterinarians to help assess pets entering the UK from abroad and to help calculate the risk of establishment of novel pathogens. This study reports the findings from a group of imported dogs that was seized as part of a Royal Society for the Prevention of Cruelty to Animals (RSPCA)-led animal welfare investigation and subsequently blood tested for exotic pathogens.

METHODS

As part of the RSPCA investigation, 151 dogs were removed from the site. Blood tests were performed for Babesia canis, Ehrlichia canis, Hepatozoon canis and Leishmania infantum by PCR, Brucella canis by antibody serology and Dirofilaria immitis by blood antigen. In addition to pathogen screening, a serology titre for rabies was measured for each dog. A clinical examination was performed by a veterinary surgeon, and clinical signs were recorded.

RESULTS

Overall, 24% (32/133) of the dogs tested positive for an infection with one or more exotic pathogens. Two dogs were positive for Br. canis antibodies and had no clinical signs indicative of infection. Leishmania was identified in 10.5% (14/133) of dogs, and all but two of these were implanted with microchips of Romanian origin. H. canis was identified in 9.6% (10/104) of dogs, all of whom had a Romanian microchip. D. immitis was identified in 4.1% (5/121) of dogs, B. canis in 2.3% (3/129) of dogs and E. canis in only 1.5% (2/131) of dogs tested. Only four dogs were found to have co-infections. No significant association was found between the pathogens detected and presenting clinical signs.

LIMITATIONS

This was a group of rescued dogs that were tested for a range of pathogens. They were not randomly selected and as such do not represent the true prevalence of these pathogens in dogs imported into the UK.

CONCLUSIONS

This study demonstrates a range of exotic pathogens entering the UK, including Br. canis, and demonstrates the importance of screening imported dogs. The emphasis on early recognition of exotic pathogens in imported dogs has relied on screening based on relevant clinical signs and the country of origin. While these factors are useful, this study demonstrated no significant association between presenting clinical signs and the pathogens carried.

A blinded, randomized and controlled multicenter clinical trial to assess the efficacy and safety of Leisguard® as an immunotherapeutic treatment for healthy Leishmania infantum-seropositive dogs

BACKGROUND

Domperidone (Leisguard®) is an immunomodulatory drug used as a preventive measure in healthy dogs. However, no studies have been published in healthy Leishmania infantum-seropositive dogs. The aim of this study was to evaluate the clinical efficacy and safety of domperidone as immunotherapy in Leishmania-seropositive healthy dogs.

METHODS

Sixty-seven dogs were treated with domperidone at 0.5 mg/kg and 44 dogs received placebo, once daily for 4 consecutive weeks. Monthly treatments were repeated every 4 months until the end of the 1-year follow-up period. Veterinary examinations were performed on days 0, 30, 120, 150, 240, 270 and 360. Samples of blood and urine were collected on days 0, 120, 240 and 360 for routine laboratory tests and quantitative in-house ELISA for the detection of L. infantum-specific antibodies. Furthermore, Leishmania real-time PCR and IFN-γ ELISA were performed at day 0 and the end of the study. Dogs that developed disease were withdrawn from the study and classified as sick dogs. Adverse drug reactions were reported.

RESULTS

Thirty dogs developed disease during the follow-up period: 13/67 (19.4%) in the group treated with domperidone and 17/44 (38.6%) in the placebo-treated group (P = 0.03). Low-seropositive dogs treated with domperidone (4/40, 9.1%) were significantly less likely to develop disease compared to low-seropositive dogs treated with placebo (7/24, 29.2%; P = 0.04), while no differences were found between domperidone (9/23, 39.1%) and placebo (10/20, 50%) in medium- to high-seropositive dogs. At the end of the study, a higher proportion of Leishmania PCR-positive dogs was observed in the placebo-treated group (16/33, 48.5%) compared to the domperidone group (13/51, 25.5%; P = 0.04). Furthermore, low-seropositive dogs treated with domperidone with an increase of IFN-γ concentration presented a higher increase than those treated with placebo at the end of the study. Four dogs treated with domperidone presented self-limiting diarrhea.

CONCLUSIONS

Healthy dogs with low L. infantum antibody levels treated with domperidone were less likely to develop disease compared to placebo-treated dogs. Furthermore, domperidone presented a good safety profile.

Clinical findings and prognostic factors for mortality in hospitalized dogs with leishmaniosis: aretrospective study

This retrospective study evaluated factors responsible for mortality of dogs hospitalized for Canine Leishmaniosis. Medical records of 31 dogs with leishmaniosis from a Portuguese Veterinary Teaching Hospital were examined between August 2018 and January 2022. Females (n = 18) and pure breed dogs (n = 27) were overrepresented, with higher frequency of Labrador Retriever (n = 4). Median age was 7 years (interquartile range=7). Most had historical findings of lethargy (n = 26) and the commonest clinicopathological abnormality was hypoalbuminemia (n = 26). Eleven dogs were classified as LeishVet stage II, 10 stage III and 10 stage IV. Fourteen dogs (45.2%) died or were euthanized, with azotemia, leukocytosis, stage IV, absence of diagnosis before hospitalization and lack of leishmaniosis specific treatment during hospitalization contributing to mortality. Absence of hypoalbuminemia and stages II/III increased survival. Mean hospitalization length prior to discharge was 5.41days ( ± 1.84) and diarrhea prolonged hospital stay.

Serological survey of Leishmania infantum in apparently healthy dogs in different areas of Spain

BACKGROUND

Canine leishmaniosis caused by Leishmania infantum is an endemic disease in Spain. The dog is considered the main reservoir, and the detection of specific serum antibodies against L. infantum antigen is the most used technique for diagnosing this infection. The LEISCAN LEISHMANIA ELISA test is a commercialized enzyme-linked immunosorbent assay for the detection and measurement of canine anti-Leishmania serum antibodies.

OBJECTIVES

The aim of this study was to assess seroprevalence results of apparently healthy dogs in different areas of Spain using LEISCAN.

METHODS

Collection of sera from 5451 apparently healthy dogs was performed between 2020 and 2021 in different areas of Spain. Dogs were of adult age (≥12 months), were not previously diagnosed with clinical leishmaniosis or vaccinated against Leishmania and did not present clinical signs compatible with L. infantum infection. LEISCAN was performed following the manufacturer's protocol.

RESULTS

The overall seroprevalence was 5.5%. The highest seroprevalences were found in the Southeast of Spain: Comunidad Valenciana (14%) and Región de Murcia (14%), whereas the lowest seroprevalences were found in Northern Spain: Galicia (1%), Navarra (2%) and Castilla y León (2%) (p-value <0.001).

CONCLUSIONS

In conclusion, the seroprevalence for L. infantum in apparently healthy dogs in Spain varied from almost no infection to being over 10%.

Same parasite, different outcomes: unraveling the epidemiology of Leishmania infantum infection in Brazil and Spain

Human leishmaniosis caused by Leishmania infantum is an important health problem worldwide. One of the main aspects arousing interest is the epidemiological scenario surrounding Le. infantum infection in the New World (NW) and Old World (OW). This parasite was introduced to the Americas during European colonization leading to different epidemiology outcomes, even more enigmatic in the face of global changes. Thus, this review aims to highlight the differences and similarities between Le. infantum epidemiology between Brazil (NW) and Spain (OW), as both countries are leading the total number of leishmaniosis cases in their respective continents. Grounded on a systemic view, this article also draws attention to possible common innovative strategies to rethink ways of controlling infections caused by Le. infantum.

Dogs with canine visceral leishmaniasis have a boost of extracellular vesicles and miR-21-5p up-expression

This retrospective cohort study analysed extracellular vesicles (EVs) and microRNAs (miRNAs) excreted in canine sera from dogs with canine visceral leishmaniasis (CanVL). A total of 56 canine sera were divided into Group I (28, from healthy dogs) and Group II (28, from the same dogs, but already with CanVL). CanVL was determined by clinical and laboratory diagnoses. Canine sera were ultra-centrifuged to recover EVs (Can-EVs). Analyses by transmission electron microscopy, nanoparticle tracking analysis (NTA), sodium dodecyl sulfate-poli-acrylammide gel eletroforesis (SDS-PAGE) and, Immunoblot confirmed the presence of (i) microvesicles/exosomes and (ii) the tetraspanins CD63 and CD9. EVs secreted by Leishmania (Leishmania) infantum-EVs were reactive against sera from dogs with CanVL (performed by ELISA and Immunoblot). NTA analyses exhibited that concentrations of Can-EVs from dogs with CanVL (7.78 × 1010 Can-EVs/mL) were higher (p < .0001) than the non-infected dogs (mean: 1.47 × 1010 Can-EVs/mL). These results suggested that concentrations of Can-EVs were able to distinguish dogs with CanVL from healthy dogs. The relative expressions of 11 miRNAs species (miR-21-5p, miR-146a-5p, miR-125b-5p, miR-144-3p, miR-194-5p, miR-346, miR-29c-3p, miR-155-5p, miR-24-3p, miR-181a-5p, and miR-9-5p) were estimated in purified miRNAs of 30 canine sera. Dogs with CanVL up-expressed miR-21-5p and miR-146a-5p when compared with healthy dogs. The other miRNA species were poorly or not expressed in canine sera. In conclusion, this study suggests that CanVL induces changes in size and concentration of Can-EVs, as well as, the up-expression of miR-21-5p and miR-146a-5p in infected dogs.

First reported case of leishmaniasis in a cat in Trinidad and Tobago

A 3-year-old, female, domestic shorthair cat, was presented to the Veterinary Teaching Hospital at the School of Veterinary Medicine (SVM), Trinidad and Tobago for a swollen nose, and multiple, variably sized small masses on both ears. The initial diagnostic tests included a CBC, serum biochemistry profile, cytological evaluation of masses on the ear and nose, and FeLV/FIV testing. The CBC and biochemistry results were unremarkable except for a hyperproteinaemia and hyperglobulinemia. Cytology of the nose and ear lesions revealed mixed inflammation and high numbers of intracellular and extracellular organisms consistent with Leishmania amastigotes. The cat was FeLV/FIV negative. Histopathology and Leishmania IFA and PCR analysis were subsequently performed, confirming the Leishmania diagnosis. The PCR, DNA sequencing and phylogenetic tree analyses identified L. amazonensis. This is the first reported case of L. amazonensis infection in a domestic animal in Trinidad with molecular characterization indicating it exists in the region and is likely being transmitted by sandflies.

Effect of Local Administration of Meglumine Antimoniate and Polyhexamethylene Biguanide Alone or in Combination with a Toll-like Receptor 4 Agonist for the Treatment of Papular Dermatitis due to Leishmania infantum in Dogs

Papular dermatitis is a cutaneous manifestation of canine Leishmania infantum infection associated with mild disease. Although it is a typical presentation, nowadays, there is still no established treatment. This study evaluated the safety and clinical efficacy of local meglumine antimoniate, locally administered polyhexamethylene biguanide (PHMB) alone or PHMB in combination with a Toll-like receptor 4 agonist (TLR4a) for the treatment of papular dermatitis due to L. infantum and assessed parasitological and immunological markers in this disease. Twenty-eight dogs with papular dermatitis were divided randomly into four different groups; three of them were considered treatment groups: PHMB (n = 5), PHMB + TLR4a (n = 4), and meglumine antimoniate (n = 10)), and the remaining were considered the placebo group (n = 9), which was further subdivided into two sub-groups: diluent (n = 5) and TLR4a (n = 4). Dogs were treated locally every 12 h for four weeks. Compared to placebo, local administration of PHMB (alone or with TLR4a) showed a higher tendency towards resolution of papular dermatitis due to L. infantum infection at day 15 (χ² = 5.78; df = 2, p = 0.06) and day 30 (χ² = 4.; df = 2, p = 0.12), while local meglumine antimoniate administration demonstrated the fastest clinical resolution after 15 (χ² = 12.58; df = 2, p = 0.002) and 30 days post-treatment (χ² = 9.47; df = 2, p = 0.009). Meglumine antimoniate showed a higher tendency towards resolution at day 30 when compared with PHMB (alone or with TLR4a) (χ² = 4.74; df = 2, p = 0.09). In conclusion, the local administration of meglumine antimoniate appears to be safe and clinically efficient for the treatment of canine papular dermatitis due to L. infantum infection.

Leishmaniosis in Greece: The Veterinary Perspective

Leishmaniosis caused by the protozoon Leishmania infantum that is transmitted through the bites of infected phlebotomine sandflies is of major veterinary concern in Greece. The country is endemic with particularly favourable environmental conditions for the spread of this infection. Moreover, Greece remains a popular touristic destination, and the continuous travel of pets raises concern regarding the possible dissemination of infection from endemic to non-endemic areas. Dogs are the main reservoir host, although other animal species, including humans, may also be infected. Canine leishmaniosis manifests as a visceral disease that can result in death if left untreated. Serological and molecular epizootiological studies have confirmed circulation of the parasite in Greek canine and feline populations as well as in other mammals. As a result, constant surveillance and identification of high-risk localities are necessary to establish chemoprophylactic protocols for travelling animals to safeguard animal and public health.

MiR-150 regulates the Leishmania infantum parasitic load and granzyme B levels in peripheral blood mononuclear cells of dogs with canine visceral leishmaniosis

Leishmania infantum causes visceral leishmaniosis, a neglected tropical disease that can modulate the host immune response by altering the expression of small non-coding RNAs called microRNAs (miRNAs). Some miRNAs are differentially expressed in peripheral blood mononuclear cells (PBMCs) of dogs with canine visceral leishmaniosis (CanL), like the down-regulated miR-150. Even though miR-150 is negatively correlated with L. infantum parasitic load, it is unclear if miR-150 directly affects L. infantum parasitic load and (if so) how this miRNA would contribute to infection. Here, we isolated PBMCs from 14 naturally infected dogs (CanL group) and six healthy dogs (Control group) and treated them in vitro with miR-150 mimic or inhibitor. We measured L. infantum parasitic load using qPCR and compared treatments. We also measured miR-150 in silico predicted target protein levels (STAT1, TNF-α, HDAC8, and GZMB) using flow cytometry or enzyme-linked immunosorbent assays. Increasing miR-150 activity diminished L. infantum parasitic load in CanL PBMCs. We also found that inhibition of miR-150 reduced GZMB (granzyme B) levels. These findings demonstrate that miR-150 plays an important role in L. infantum infection in canine PBMCs, and they merit further studies aiming at drug development.

Evaluation of heart fatty acid-binding protein as a biomarker for canine leishmaniosis

BACKGROUND

Myocarditis frequently occurs in canine leishmaniosis (CanL). Heart fatty acid-binding protein (HFABP) is a biomarker of myocardial damage.

METHODS

This study aimed to compare HFABP concentration (HFABPc) in healthy dogs and dogs at different stages of CanL and evaluate the correlation of this biomarker with several clinicopathological and echocardiographic variables. Thirty-one dogs diagnosed with CanL and 10 healthy dogs were included.

RESULTS

HFABPc was not statistically different (p > 0.05) between groups of dogs at different LeishVet stages of CanL or between groups with high versus low to intermediate serology titres. In 70% of CanL dogs, HFABPc was within the 95% confidence interval limits of the mean of healthy dogs. A moderate negative correlation with globulin (r = -0.519; p = 0.03) and haematocrit (HCT) (r = -0.538; p = 0.02) was observed. No other significant correlation (p > 0.05) was observed with any other variable.

LIMITATIONS

Many statistical tests were performed, and therefore, type I error cannot be ruled out.

CONCLUSION

HFABPc is not consistently elevated in dogs with CanL and is not associated with the severity of the disease, or most echocardiographic or clinicopathological variables studied. The correlation with globulin and HCT was not strong and not considered clinically significant. HFABPc lacks sufficient predictive capacity in dogs with CanL, discouraging further research or clinical use of this biomarker in this disease.

Signalment, Immunological and Parasitological Status and Clinicopathological Findings of Leishmania-Seropositive Apparently Healthy Dogs

Canine leishmaniosis caused by Leishmania infantum is a disease with a wide range of clinical manifestations. Epidemiological serosurveys performed in Europe often lack a thorough assessment of clinical health status of studied dogs. The aim of this study was to evaluate signalment, immunological and parasitological status and clinicopathological findings of L. infantum-seropositive apparently healthy dogs (n = 212) living in endemic areas. Routine laboratory tests, endpoint in-house ELISA to quantify the anti-Leishmania antibodies, blood Leishmania qPCR and IFN-γ ELISA were performed. All dogs enrolled were L. infantum-seropositive and were classified as healthy (n = 105) or sick (n = 107) according to LeishVet guidelines. The sick group presented a higher proportion of medium to high antibody levels and positive qPCR and lower IFN-γ concentration compared to the healthy group. Sick dogs were mostly classified in LeishVet stage IIa. Biochemical alterations (98%) were the most common clinicopathological findings, with fewer urinary tract (46%) and hematological (40%) alterations. Apparently healthy L. infantum-seropositive dogs can be classified between truly healthy dogs and sick dogs with clinicopathological findings. Sick dogs presented medium to high seropositivity and parasitemia and low IFN-γ concentrations, and their most common clinicopathological abnormalities were serum protein alterations followed by proteinuria and lymphopenia.

Urinary cystatin C and N-acetyl-beta-D-glucosaminidase (NAG) as early biomarkers for renal disease in dogs with leishmaniosis

Canine leishmaniasis (CanL) is a disease caused by Leishmania infantum that can vary from a subclinical infection to a severe disease. Dogs affected with CanL present varying degrees of renal dysfunction. Unfortunately, traditional biomarkers such as urea and creatinine detect renal damage in advanced stages of the disease, so more accurate biomarkers are needed. Hence, we aimed to study how urinary cystatin C (CysC) and N-acetyl-beta-D-glucosaminidase (NAG), behave in dogs with CanL at different stages of the disease. Eighty-six CanL infected dogs were classified according to LeishVet stages: LI (16 dogs), LIIa (12 dogs), LIIb (12 dogs), LIII (16 dogs) and LIV (30 dogs); as a control, 17 healthy dogs were studied. Blood samples were collected for complete haematological and biochemistry analysis including plasma cystatin C. Urine analysis included urine specific gravity (USG), urine protein to creatinine ratio (UPC), CysC and NAG expressed as a ratio with creatinine uCysCc (μg/g) and uNAGc (IU/g). The haematological, biochemical and urinary analysis coincided with the LeishVet guidelines. The statistical study of the uCysCc ratio and the uNAGc, showed significant increase when compared against control starting from group LI (p < 0.05). Interestingly, when the cut-off values were calculated using the ROC curve, uCysCc (258.85 µg/g) and uNAGc (2.25 IU/g) 75 % of the dogs included in LI groups surpassed the threshold. Hence our study indicates that uCysCc and uNAGc, could help to detect early renal damage in CanL affected dogs.

Arginine, symmetric and asymmetric dimethylarginine levels in canine leishmaniasis

The study aimed to investigate the levels of arginine, symmetric dimethylarginine (SDMA), and asymmetric dimethylarginine (ADMA) in dogs with canine leishmaniasis (CanL) and their relationship with some renal and cardiovascular parameters. A total of 60 dogs were enrolled, including 40 with CanL and 20 healthy controls. The CanL group was divided into four stages based on clinical and laboratory findings. The levels of plasma arginine, SDMA, and ADMA were determined by high performance liquid chromatography (HPLC). The data from the healthy group were compared with those from the CanL group, and according to the stages. In dogs with CanL, systolic and diastolic blood pressure, plasma creatinine, cystatin-C, phosphorus, potassium, and low-density lipoprotein concentrations, the urine protein/creatinine ratio, the amount of nitric oxide, and creatine kinase-MB activity were higher, while the high-density lipoprotein concentration was lower compared to healthy controls. The concentration of arginine was low (p < 0.05) and the levels of ADMA (p < 0.001) and SDMA (p < 0.05) were high in dogs with CanL. There were no statistically significant differences in arginine concentration among the different stages of CanL. However, the concentration of plasma ADMA was higher in all stages of CanL compared to the healthy group, and the concentration of plasma SDMA was higher in Stage IV compared to the healthy group and Stage III. The present study demonstrates for the first time a decrease in arginine concentration and an increase in ADMA concentration in dogs with CanL. The increase in SDMA concentration in dogs with CanL was consistent with previous studies. However, compared to other renal parameters, SDMA exhibited limited performance distinguishing between clinical stages of CanL. These findings could be a source for future diagnostic and therapeutic studies to explain the renal and cardiovascular pathophysiology of CanL. Additional clinical studies that include treatment and patient follow-up with an assessment of the acute phase response are needed to provide a more detailed understanding of the changes observed in dogs with CanL.

Vector-Borne Pathogens in Guard Dogs in Ibadan, Nigeria

Canine vector-borne diseases are of great relevance not only regarding animal welfare but also in relation to the One Health concept. Knowledge concerning the most relevant vector-borne pathogens in dogs is scarce and limited to stray dogs in most western African regions, and there is virtually no information about the situation in kept dogs presenting (regularly) to vets. Therefore, the blood samples of 150 owned guard dogs in the Ibadan area—in the southwest of Nigeria—were collected and analyzed for the DNA of Piroplasmida (Babesia, Hepatozoon, Theileria), Filarioidea (e.g., Dirofilaria immitis, Dirofilaria repens), Anaplasmataceae (e.g., Anaplasma, Ehrlichia), Trypanosomatidae (e.g., Leishmania, Trypanosoma), Rickettsia, Bartonella, Borrelia and hemotropic Mycoplasma using molecular methods. Overall, samples from 18 dogs (12%) tested positive for at least one pathogen. Hepatozoon canis (6%) was the most prevalent blood parasite, followed by Babesia rossi (4%). There was a single positive sample each for Babesia vogeli (0.6%) and Anaplasma platys (0.6%). Moreover, one mixed infection with Trypanosoma brucei/evansi and Trypanosoma congolense kilifi was confirmed (0.67%). Generally, the prevalence of vector-borne pathogens in this sample group of owned dogs in southwest Nigeria was lower than in prior studies from the country and in other parts of Africa in total. This leads to the assumption that, firstly, the exact geographical location has a major influence on the incidence of vector-borne diseases, and, secondly, it seems to make a difference if the dogs are owned and, therefore, regularly checked at a veterinary clinic. This study should raise awareness of the importance of routine health check-ups, tick and mosquito prophylaxis, and a well-managed infectious disease control program to prevent vector-borne diseases in canines.