Prognosis and monitoring of leishmaniasis in dogs: A working group report

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.

Clinical and Clinico-Pathological Observations of the Erythrocyte Sedimentation Rate in Dogs Affected by Leishmaniosis and Other Inflammatory Diseases

The erythrocyte sedimentation rate (ESR) has been used in canine medicine in several disorders, above all, to evaluate levels of inflammation. This study evaluated the ESR in canine leishmaniosis (CanL) and other inflammatory conditions. Three groups of dogs were examined: CanL affected dogs without clinical signs (INFECTED group, #25) or with clinical signs (SICK group, #43) and dogs affected by acute or acute-on-chronic conditions (OTHER DISEASE group, #65). The ESR was compared with acute phase proteins or reactants either positive or negative (leukogram, fibrinogen, iron, unsaturated iron binding capacity, ferritin, haptoglobin, and albumin) and immunological markers (gamma-globulins, IgG, and IgM). The ESR was higher in the SICK group than in the INFECTED group (median 39 vs. 11 mm/h; p < 0.0001), as well as in the OTHER DISEASE than in the INFECTED groups (median 41 vs. 11 mm/h; p < 0.0001). The ESR appeared outside the reference range for all dogs in the SICK and OTHER DISEASE groups and almost with similar values (mm/h; median 39, 95% CI 31-51 vs. 41, 95% CI 12-87; p > 0.05). The extent of changes in ESR can help to establish the severity of CanL and other inflammatory disorders. As a point-of-care test, the ESR can be used to screen dogs for unhealthy conditions, and its values correlate with the severity of any disease, including CanL.

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.

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.

Proteomic research on new urinary biomarkers of renal disease in canine leishmaniosis: Survival and monitoring response to treatment

The objective of our study was to search for survival biomarkers (SB) and treatment response monitoring biomarkers (TRMB) in the urinary proteome of dogs with renal disease secondary to canine leishmaniosis (CanL), using UHPLC-MS/MS. The proteomic data are available via ProteomeXchange with identifier PXD042578. Initially, a group of 12 dogs was evaluated and divided into survivors (SG; n = 6) and nonsurvivors (NSG; n = 6). A total of 972 proteins were obtained from the evaluated samples. Then, bioinformatic analysis reduced them to 6 proteins like potential SB increased in the NSG, specifically, Haemoglobin subunit Alpha 1, Complement Factor I, Complement C5, Fibrinogen beta chain (fragment), Peptidase S1 domain-containing protein, and Fibrinogen gamma chain. Afterwards, SG was used to search for TRMB, studying their urine at 0, 30, and 90 days, and 9 proteins that decreased after treatment were obtained: Apolipoprotein E, Cathepsin B, Cystatin B, Cystatin-C-like, Lysozyme, Monocyte differentiation CD14, Pancreatitis-associated precursor protein, Profilin, and Protein FAM3C. Finally, enrichment analysis provided information about the biological mechanisms in which these proteins are involved. In conclusion, this study provides 15 new candidate urinary biomarkers and an improved understanding of the pathogenesis of kidney disease in CanL.

Survival time and prognostic factors in canine leishmaniosis in a non-endemic country treated with a two-phase protocol including initial allopurinol monotherapy

BACKGROUND

Leishmania infantum is an intracellular protozoan parasite which is endemic in countries of the Mediterranean Basin. Leishmaniosis is increasingly diagnosed in non-endemic areas due to the relocation of dogs from endemic areas and the travel of dogs to and from these areas. The prognosis of leishmaniosis in these dogs may differ from that of those in endemic areas. The aims of this study were (1) to determine the Kaplan-Meier estimated survival time for dogs with leishmaniosis in the Netherlands (a non-endemic country), (2) to determine if clinicopathological variables at the time of diagnosis predicted the survival of these dogs, and (3) to evaluate the effect of a two-phase therapy protocol of allopurinol monotherapy followed by meglumine antimoniate and/or miltefosine in the case of incomplete remission or relapse.

METHODS

The database of the Department of Clinical Sciences of Companion Animals of the Faculty of Veterinary Medicine, Utrecht University was investigated for leishmaniosis patients. Patient records were reviewed for signalment and clinicopathological data at the time of diagnosis. Only treatment-naive patients were included. Follow-up was performed during the study by phone contact and included treatment received and date and cause of death. Univariate analysis was performed using the Cox proportional hazards regression model.

RESULTS

The estimated median Kaplan-Meier survival time was 6.4 years. In the univariate analysis, increases in monocyte, plasma urea and creatinine concentrations, and urine protein to creatinine ratio were all significantly associated with decreased survival time. The majority of patients only received allopurinol monotherapy.

CONCLUSIONS

Canine leishmaniosis patients in our study population in the Netherlands, which is non-endemic for the disease, had an estimated Kaplan-Meier median survival time of 6.4 years, which is comparable to the outcome of other reported therapy protocols. Increased plasma urea and creatinine concentrations and monocyte concentration were statistically associated with an increased risk of death. We conclude that initial allopurinol monotherapy for 3 months should be effective in more than half of canine leishmaniosis cases, provided there is adequate follow-up, and that meglumine antimoniate or miltefosine therapy should be started as the second phase of the protocol in cases where remission is incomplete or there is a relapse.

Laboratory validation of an ELISA method to measure circulating immune complexes levels in canine visceral leishmaniasis

Susceptible dogs suffering from canine leishmaniasis (CanL) develop an ineffective humoral immune response that leads to the formation of circulating immune complexes (CIC). These CIC are aggregates of Leishmania proteins and anti-Leishmania immunoglobulins. Their deposition in different tissues is considered the main cause of mortality. For this reason, CIC have been suggested as an excellent CanL biomarker for measuring the progression of the disease and the effectiveness of specific treatments. The present study aims to perform a laboratory validation of a Leishmania-specific method to isolate and quantify CIC in dog serum samples. CIC isolated from serum samples of infected dogs, grouped according to the LeishVet classification, were quantified following a PEG-ELISA procedure. The validation established a cut-off of 0.274 OD. All the parameters analyzed (including linearity, specificity, precision, and robustness) fulfilled the defined criteria, confirmed by statistical analyses. The results also proved the reproducibility and reliability of the method when samples were tested under the same conditions, and the consistency and usefulness of the method for an optimal staging of infected dogs. In conclusion, the laboratory validated method offers a potent tool to clinicians for a proper CanL management and to measure the progression of the disease.

Ein Update zur Leishmaniose des Hundes: Diagnostik, Therapie und Monitoring

Aufgrund von steigenden Importzahlen von Hunden aus dem Ausland, zunehmendem Reiseverkehr sowie den Veränderungen klimatischer Bedingungen in Europa gewinnen Infektionen mit Leishmania (L.) infantum bei Hunden in Deutschland zunehmend an Bedeutung. Daher sollten auch Hunde aus dem Ausland, die keine klinischen Symptome zeigen, direkt nach Import sowie erneut 6 Monate später auf vektorübertragene Infektionserreger getestet werden. Bei Hunden mit klinischer Symptomatik, die hinweisend auf eine Leishmaniose sind, werden direkte und indirekte Nachweisverfahren sowie eine hämatologische und biochemische Untersuchung unter Einbezug von Serumeiweißelektrophorese sowie Bestimmung des C-reaktiven Proteins empfohlen. Als Leitfaden für die Therapie sowie das Monitoring stehen die LeishVet-Guidelines zur Verfügung. Es stehen leishmanizide und leishmaniostatische Wirkstoffe zur Verfügung, die in first-line, second-line und third-line unterschieden werden. Zur Anpassung der Allopurinol-Dosierung wird der Stufenplan empfohlen. Aufgrund der Veränderung der klimatischen Bedingungen kommt es zu einer Ausbreitung der Habitate von Sandmücken, die als Vektoren der Leishmaniose bekannt sind. Als weitere Infektionsquellen sind Deckakte, transplazentare Infektionen, Bisswunden und Bluttransfusionen beschrieben. Leishmania infantum hat zoonotisches Potential und ist daher auch in Hinblick auf den „One-Health“-Gedanken bedeutend.

Pre-test probability and likelihood ratios for clinical findings in canine leishmaniasis

Canine leishmaniasis is a parasitic zoonosis mainly caused by L. infantum; an obligate intracellular protozoan transmitted by haematophagous insects of the genus Phlebotomus, which affects dogs and wild canids. The clinical implications of this disease are highly variable, since infected animals may remain asymptomatic (absence of observable clinical signs) or present a wide spectrum of clinical alterations and degrees of severity, including the death of the animal. Symptoms such as lymphadenomegaly, alopecia, weight loss, keratoconjunctivitis and onychogryphosis are usually the first diagnostic reference available. The objectives of this study are to evaluate the validity (sensitivity, specificity and likelihood ratios) and diagnostic utility (pre-test probability) of the clinical signs commonly associated with canine leishmaniasis based on the prevalence in the area and to explore the combination of symptoms that best predicts the diagnosis of canine leishmaniasis. It is a matched case-control study in the canine population of southern Spain based on the comparison of the findings collected in the clinical history and the results of the LeisSCAN quantitative ELISA. A total of 39 cases and 78 controls were analysed. Approximately 80% of the infected animals showed signs compatible with the disease. The most frequent alterations were cutaneous (64.1%), systemic (51.3%) and oculo-nasal (30.7%). The most useful signs to support this diagnosis were alopecia and epistaxis (LR+ 6.69 and 6.0, respectively) (pre-test leishmaniasis probability is ≥70% for prevalence ≥28% when alopecia or epistaxis is present), followed by lameness (LR+ 5.0). The combinations of signs that showed greater validity were alopecia with hyperkeratosis of the snout and alopecia with onychogryphosis (LR+ > 10). None of the observed signs or their combinations resulted useful to rule out the diagnosis (LR- 0.55 to 1.15). The results found show notable differences in the diagnostic value of the clinical signs, individually and in combination, so we believe that medical decisions should be based on their diagnostic validity (LR+) and the estimation of the pre-test and post-test probability.

Canine Leishmaniasis: Update on Epidemiology, Diagnosis, Treatment, and Prevention

Dog are the main reservoir of Leishmania infantum, causing canine leishmaniasis, an incurable multisystemic disease that leads to death in symptomatic dogs, when not treated. This parasite causes visceral, cutaneous, and mucosal leishmaniasis in people in the Mediterranean Basin, North Africa, South America, and West Asia. This disease is mostly unknown by veterinarians outside the endemic areas, but the disease is expanding in the Northern Hemisphere due to travel and climate change. New methodologies to study the epidemiology of the disease have found new hosts of leishmaniasis and drawn a completely new picture of the parasite biological cycle. Canine leishmaniasis diagnosis has evolved over the years through the analysis of new samples using novel molecular techniques. Given the neglected nature of leishmaniasis, progress in drug discovery is slow, and the few drugs that reach clinical stages in humans are unlikely to be commercialised for dogs, but several approaches have been developed to support chemotherapy. New-generation vaccines developed during the last decade are now widely used, along with novel prevention strategies. The implications of the epidemiology, diagnosis, treatment, and prevention of canine leishmaniasis are fundamental to public health.

Urinary proteome of dogs with renal disease secondary to leishmaniosis

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

A Questionnaire-Based Survey on the Long-Term Management of Canine Leishmaniosis by Veterinary Practitioners

Simple Summary

Canine Leishmaniosis is a chronic and potentially fatal disease, caused by Leishmania infantum, a zoonotic microorganism. In economically disadvantaged regions, costs associated with long-term patient monitoring may determine that some owners decline veterinary follow-up of their dogs, with potentially severe implications for animal welfare and public health. This online, questionnaire-based survey aimed to assess how Portuguese veterinary practitioners perform long-term patient management and recognize relapses. More than half of the respondents stated that most dog owners declare having financial restraints, which condition the use of diagnostic tests during long-term follow-up. Allopurinol ad aeternum or until disease remission and domperidone were the most prescribed treatment, and relapses were detected by the reappearance or worsening of clinical signs by most veterinary practitioners. The rate of relapse detection was higher in the most economically favored regions, probably because of a lesser constraint on the use of the appropriate diagnostic tests. This study confirms that owner financial restraints negatively influence veterinary follow-up and relapse recognition, potentially compromising clinical decision making and favoring the maintenance of Leishmania infantum infection endemic status in Portugal.

Abstract

Canine Leishmaniosis (CanL) is a chronic and potentially fatal disease. In economically disadvantaged regions, costs associated with long-term patient monitoring may determine that some owners decline veterinary follow-up of their dogs. This online, questionnaire-based survey aimed to assess how Portuguese veterinary practitioners perform long-term patient monitoring and recognize relapses. More than 50% of respondents reported that 50–100% of dog owners declared financial restraints. Hence, in these circumstances, most veterinary practitioners only performed clinical examination and serology. However, when owners did not declare financial restriction, other tests were additionally performed, such as renal and hepatic profiles, hemogram, serum protein electrophoresis and urine protein creatinine ratio. The mean number of exams performed when owners presented financial restraints was significantly lower than the number of exams performed without economic limitations. Most veterinary practitioners prescribed allopurinol ad aeternum or until disease remission and domperidone. CanL relapses were recognized by more than half of respondents “Always”, through the reappearance or worsening of clinical signs, whereas about a quarter detected an increase in anti-Leishmania antibody levels and identified abnormalities in the serum protein electrophoresis profile. The relapse rate was higher in the Lisbon Metropolitan Area and north, the most economically favored regions of Portugal. This study confirms that owner financial restraints negatively influence veterinary follow-up and relapse recognition, ultimately compromising clinical decision making and favoring the maintenance of Leishmania infantum infection endemicity.

Nutritional Modulation of the Immune Response Mediated by Nucleotides in Canine Leishmaniosis

Leishmaniasis is an emerging, uncontrolled, and neglected zoonotic disease. Climate change is contributing to its ongoing global expansion. The dog is the main reservoir; hence the importance of implementing effective treatment, prevention, and control measures in this animal species to protect public health. However, although the standard treatment for canine leishmaniosis (CanL) is effective, it does not provide full parasitological clearance, and side effects and drug resistance have been described. The host's immune system plays a key role in the establishment and evolution of leishmaniasis. Dietary nucleotides modulate the immune response and, given their reported efficacy and safety in sick and clinically healthy Leishmania-infected dogs and because they represent a sustainable option with no associated side effects or resistance, they could be included within the prevention, treatment, and control strategies for leishmaniasis. This article briefly summarizes the scientific literature on CanL management, including unresolved issues, and reviews the scientific evidence on immunomodulatory effects of dietary nucleotides in different animal species. It also proposes a CanL management algorithm, including nucleotides. It is concluded that nutritional modulation of the immune response with nucleotides can contribute to better management of leishmaniasis following a One Health approach, especially in the COVID-19 era.

Canine Leishmaniasis in Morocco: A Descriptive Prospective Clinical Study

Canine leishmaniasis (CanL) is a zoonotic vector-borne disease that is endemic in the Mediterranean Basin including Morocco. Dogs play a major epidemiological role in this zoonosis as reservoir hosts. This study investigated the clinical manifestations of CanL in dogs naturally infected with Leishmania infantum. A total of 96 dogs presented to the Small Animal Clinic of the Hassan II Agronomy and Veterinary Institute (IAV Hassan II) of Rabat, Morocco, and were tested by RT-PCR and/or serology. Among them, 32 (33.3%) were positive to Leishmania infantum infection. The majority of the positive dogs (93.7%) came from urban areas. Most of them were male (62.5%) and purebreds (65.6%), were aged between 3 and 7 years (71.8%), and had outside activities (guarding, hunting, livestock guarding, and service activities) (71.8%) and all of them were living exclusively outdoor or had free access to the outdoor environment. Lymphadenomegaly (81.2%), dermatological disorders (65.6%) (mostly exfoliative dermatitis), weight loss (59.3%), exercise intolerance (56.2%), anorexia (28.1%), hyporexia (15.6%), and ocular lesions (28.1%) were the most frequent clinical signs and complaints recorded. Anemia and hyperproteinemia due to hyperglobulinemia were observed in 68.7% and 72.7% of the cases, respectively. These results suggest that CanL leads to various nonspecific clinical signs as described previously, making the diagnosis challenging. Since CanL is endemic in Morocco, it should be recommended to systematically test dogs displaying clinical signs compatible with this disease and to regularly screen asymptomatic at-risk dogs. It is also crucial to educate dog owners about the zoonotic aspect of the disease and to encourage intersectorial collaboration following the “One Health” concept, in order to contribute to a more effective control/prevention of human and canine leishmaniasis.

Role of Circulating Immune Complexes in the Pathogenesis of Canine Leishmaniasis: New Players in Vaccine Development

During canine visceral leishmaniasis (CanL), due to Leishmania infantum (L. infantum), uncontrolled infection leads to a strong humoral immune response. As a consequence of the production of high antibody levels and the prolonged presence of parasite antigens, circulating immune complexes (CIC) are formed, which can be deposited in certain organs and tissues, inducing vasculitis, uveitis, dermatitis and especially glomerulonephritis and renal failure. A method to detect CIC and quantify their levels in serum samples from dogs infected with L. infantum has been recently described. It allowed demonstration of a correlation between CIC levels and disease severity. Thus, CIC measurement may be useful for diagnosis, assessment of disease progression and monitoring response to treatment. This is an interesting finding, considering that there remains an urgent need for identification of novel biomarkers to achieve a correct diagnosis and for optimal disease staging of dogs suffering from Leishmania infection. The objective of the present review is to shed light on the role of CIC in CanL, as well as to highlight their potential use not only as diagnostic and prognostic biomarkers but also as a valuable tool in vaccine development and new immunotherapy strategies to prevent or control disease outcome.

Comparison of Two Dosing Regimens of Miltefosine, Both in Combination With Allopurinol, on Clinical and Parasitological Findings of Dogs With Leishmaniosis: A Pilot Study

Miltefosine (MIL)–allopurinol combination therapy administered at standard dosage is effective to treat canine leishmaniosis, nevertheless for some dogs the digestive tolerance of MIL is not acceptable. This study evaluates an alternative therapeutic protocol by using a modified dosage of MIL to increase its effectiveness and improve the digestive tolerance. Thirty-four Leishmania infantum owned naturally infected dogs were included and monitored for 180 days. The dogs were allocated in two randomized groups: Group X−18 dogs treated with MIL registered dose of 2 mg/kg, oral administration, once daily, for 28 days; Group Y−16 dogs treated with 1.2 mg/kg for 5 days followed by 2.5 mg/kg for 25 days. Both groups were also treated with allopurinol. Digestive tolerance was monitored by adverse events observation. Treatments effectiveness was evaluated by monitoring the reduction of clinical score, the improvement of clinicopathological abnormalities, the reduction of parasitological load by PCR and the number of relapses. 16.6% dogs of group X and 12.5% dogs of group Y showed treatment associated adverse events. The reduction of clinical score was 61.7% for group X and 71.6% for group Y. All dogs showed an improvement of laboratory parameters after treatment. Quantitative PCR showed better results in group Y compared to group X; relapses were only registered in four dogs of group X. The modified protocol demonstrates a better trend of results in term of tolerance, clinical effectiveness, parasitological load reduction and relapses control, suggesting it could be considered for new large-scale studies.

Influence of domperidone supplementation on short-term changes in C-reactive protein and paraoxonase-1 in dogs with leishmaniasis undergoing meglumine antimoniate and allopurinol therapy

BACKGROUND

C-reactive protein (CRP) and paraoxonase 1 (PON1) might increase and decrease in canine leishmaniasis (CanL), , and both can rapidly normalize after therapy. Recently, supplementation of domperidone with conventional therapy , increasing the activity of cells involved in acute phase responses in vitro. This combined therapy has been recommended to treat mild forms of CanL; however, no studies have investigated the effects of domperidone supplementation on early CRP or PON1 changes in dogs with CanL.

OBJECTIVES

The aim of this study was to evaluate whether domperidone, added to conventional treatments, modifies CRP concentration and PON1 activity kinetics in CanL dogs responsive to conventional therapy.

METHODS

Serum CRP concentrations and PON1 activities were measured in dogs with mild CanL before (t-0) and 3 (t-1), 7 (t-2), 14 (t-3), and 21 (t-4) days after treatment with N-methylglucamine antimoniate and allopurinol alone (n = 18) or combined with domperidone (n = 18).

RESULTS

C-reactive protein concentrations increased at t-1 in the domperidone group, especially when the CRP concentration at t-0 was normal. However, the concentrations normalized at t-4 in 18/18 dogs compared with 14/18 dogs not receiving domperidone. The median PON1 activity decreased at t-1 in the domperidone group, and this decrease was more significant in dogs with normal PON1 activity at t-0.

CONCLUSIONS

Based on these results, transient increases in CRP concentrations or decreases in PON1 activities after domperidone administration should not be erroneously interpreted as signs of a worsening disease process.

Potential of Artesunate in the treatment of visceral leishmaniasis in dogs naturally infected by Leishmania infantum: Efficacy evidence from a randomized field trial

Leishmaniasis is among the world’s most neglected diseases. Dogs are the main reservoirs/hosts of Leishmania infantum, causative agent of both canine and human visceral leishmaniosis. Canine leishmaniasis (CanL) represents a public health problem as one of the most prevalent zoonotic diseases worldwide. Current therapeutics present drawbacks; thus, there is a need for more effective, safer, and cheaper drugs. The aim of this study was to evaluate and to compare the efficacy of oral administration of artesunate or meglumine antimoniate/allopurinol in dogs with clinical leishmaniasis. Forty-two dogs with naturally occurring clinical leishmaniasis were included in this open-label, simple randomized positive-control clinical field trial with 6 months of follow-up. Dogs received meglumine antimoniate 100 mg/kg/day and allopurinol 30 mg/kg/day for 28 days (control group, n = 26) or artesunate 25 mg/kg/day for 6 days (test group, n = 16). The animals were evaluated for their clinical evolution, parasite load (by qPCR) and humoral response at different time points: 0, 30, 90, and 180 days after treatment. Data analyses showed a significant improvement in both groups in clinical scores, parasitemia and antibody titers after treatment. Compared to the control group, the artesunate group showed significantly lower clinical score (P = 0.0001), lower parasitemia (P = 0.0001) and antibody titers after 6 months of follow-up. Compared to baseline values, a rapid, significant reduction (P < 0.012) in antibody levels, 2.28- versus 3.04-fold for the control versus artesunate groups, respectively, was observed 30 days after treatment. Antibody levels continued to decrease further in the artesunate group, where 58% of cases became seronegative at the 6-month follow-up. All qPCR-positive dogs were negative after treatment with artesunate, while 14.3% remained positive with the appearance of two new cases in the control group. Artesunate was well tolerated, and no side effects were recorded. Treatment failures were similar in both groups with 27.27% (6/22), including 18.18% (4/22) mortality in the control group, versus 26.66% (4/15), including 13.33% (2/15) mortality in the artesunate group. This is the first report showing the potential of artesunate in the treatment of dogs with clinical leishmaniasis. Artesunate showed higher efficacy than the current first-line treatment for CanL without any adverse effects. It could be a good alternative chemotherapy for CanL, and may be considered for further studies in human leishmaniases. Further clinical trials are needed to confirm these findings, to determine if there are relapses after treatment and if dogs remain infective to sandflies, to define the ideal therapeutic dosage and duration of treatment with artesunate.

Canine leishmaniasis (CanL) is a fatal, zoonotic vector-borne disease caused by Leishmania infantum, a common pathogen for both humans and dogs. Most CanL therapeutics are toxic, expensive, or ineffective. Artemisinin and derivatives have recently demonstrated potent antileishmanial activity in vitro and in experimental models. In this study, dogs with clinical leishmaniasis were randomly included in one of the treatment groups: meglumine antimoniate/allopurinol (control) or artesunate (alternative). Dogs were followed up for 6 months for their clinical score, parasitemia and Leishmania antibody levels. Both groups showed improved clinical scores, parasitemia and antibody titers after treatment. After six months of follow-up, treatment success was very similar in both groups, and 72.73% (16/22) of the controls versus 73.34% (11/15) in the artesunate group had clinical improvement. All dogs initially seropositive by PCR became negative after artesunate treatment, while 14.3% remained positive with the appearance of new cases in the control group. Antibody titers decreased rapidly (from day 30) from baseline especially in the artesunate group, where 58% of the dogs converted to seronegative after 6 months. Artesunate could be a good alternative for treatment of leishmaniasis. Additional clinical trials are needed to obtain more data on this drug.

Prognostic Factors and Life Expectancy in Canine Leishmaniosis

Canine leishmaniosis (CanL) is a chronic and potentially fatal disease. The prognosis of CanL depends on the severity of the clinical signs and clinicopathological abnormalities presented by the dog at the time of diagnosis. This study aims to estimate the survival time of dogs with CanL, determining the prognostic value of different clinical and clinicopathological parameters. Medical records of 99 dogs diagnosed with CanL in five veterinary centers of the Alentejo region (Portugal) were examined retrospectively. The majority of dogs presented hyperproteinemia, moderate normocytic normochromic anemia, normal blood urea and creatinine levels and were classified as stage 1 according to the International Interest Society (IRIS) guidelines at the time of diagnosis. The severity of anemia, presence of concomitant infectious diseases at the time of diagnosis and the anti-Leishmania therapy were correlated with the survival time. The influence of renal dysfunction was evaluated by Receiver Operating Characteristic (ROC) curve and survival analysis. Survival analysis demonstrated that patients classified as IRIS 1 at the time of diagnosis survived more than four years, in contrast with dogs classified as IRIS 2 that survived around two and half years and dogs classified as IRIS 3-4 that survived around one month. IRIS stage deteriorated during the course of CanL in one third of the dogs and was the principal cause of death or euthanasia in a high proportion of animals. In some cases, dogs did not receive anti-Leishmania treatment or abandoned the veterinary follow-ups, which may have considerable repercussions for animal wellbeing and public health. This study reinforces the value of blood urea and creatinine levels as prognostic factors in CanL.

A Nutritional Supplement (DìLshTM) Improves the Inflammatory Cytokines Response, Oxidative Stress Markers and Clinical Signs in Dogs Naturally Infected by Leishmania infantum

The possibility to associate nutraceuticals, as immune-modulating tools, to the treatment of visceral leishmaniosis is a matter of great interest. In this study, we investigated whether the administration of a nutritional supplement (DìLshTM, Dynamopet SRL, Verona, Italy) was able to exert beneficial effects on the inflammatory state and oxidative stress of the dogs naturally infected by Leishmania infantum. To this purpose, specific parameters, namely Tumor Necrosis Factor -alpha (TNF), Interleukin-6 (IL-6), Inteleukin-10 (IL-10), leptin, derivates of Reactive Oxigen Metabolites (d-Roms) and Biological Antioxidant Potential (BAP), as well as the haematological and biochemical profiles of the infected dogs, were investigated upon the treatment with the nutritional supplement and compared with the conventional pharmacological anti-Leishmania therapy. The animals underwent complete clinical examination and blood sample collection before (T0) and 3 months after (T90) the onset of the two treatments. The two treatments showed similar results: significant clinical improvement, ELISA positivity and IgG decrease, an increase in IL-10, and a decrease in IL-6 were observed in animals treated with the nutritional supplement. A decrease in d-Roms and an increase in BAP were also detected in both groups. On the whole, the nutritional supplement possesses anti-inflammatory and antioxidant properties, suggesting that it may support animals' health and be useful to extend the time a drug therapy is needed.

Mathematical Modelling Using Predictive Biomarkers for the Outcome of Canine Leishmaniasis upon Chemotherapy

Prediction parameters of possible outcomes of canine leishmaniasis (CanL) therapy might help with therapeutic decisions and animal health care. Here, we aimed to develop a diagnostic method with predictive value by analyzing two groups of dogs with CanL, those that exhibited a decrease in parasite load upon antiparasitic treatment (group: responders) and those that maintained high parasite load despite the treatment (group: non-responders). The parameters analyzed were parasitic load determined by q-PCR, hemogram, serum biochemistry and immune system-related gene expression signature. A mathematical model was applied to the analysis of these parameters to predict how efficient their response to therapy would be. Responder dogs restored hematological and biochemical parameters to the reference values and exhibited a Th1 cell activation profile with a linear tendency to reach mild clinical alteration stages. Differently, non-responders developed a mixed Th1/Th2 response and exhibited markers of liver and kidney injury. Erythrocyte counts and serum phosphorus were identified as predictive markers of therapeutic response at an early period of assessment of CanL. The results presented in this study are highly encouraging and may represent a new paradigm for future assistance to clinicians to interfere precociously in the therapeutic approach, with a more precise definition in the patient's prognosis.

A randomized, blinded, controlled clinical trial comparing the efficacy of aminosidine (paromomycin)-allopurinol combination with the efficacy of meglumine antimoniate-allopurinol combination for the treatment of canine leishmaniosis due to Leishmania infantum

The aim of this 6-month, randomized, blinded, controlled clinical trial was to compare the efficacy and safety of aminosidine-allopurinol combination with that of meglumine antimoniate-allopurinol combination for the treatment of leishmaniosis in dogs without stage III or IV chronic kidney disease. Forty client-owned dogs were randomly assigned to group A [n = 20; aminosidine (15 mg/kg, subcutaneously, once daily, for 28 days) and allopurinol (10 mg/kg, per os, twice daily, for 6 months)] or group B [(n = 20; meglumine antimoniate (100 mg/kg SC, once daily, for 28 days) and allopurinol (10 mg/kg, per os, twice daily, for 6 months)]. Clinical and clinicopathological evaluations, parasitic load measurement (lymph node and bone marrow microscopy, bone marrow real-time PCR), specific serology and leishmanin skin test (LST) were performed at baseline (time 1) and after 14 (time 2), 28 (time 3), 60 (time 4) and 180 (time 5) days. Both treatments were safe and resulted in significant clinical and clinicopathological improvement, reduction of parasitic load and of indirect immunofluorescence antibody test (IFAT) titer and induction of positive LST. There was no significant difference between groups with regards to the primary outcome measures of the trial that included the proportion of dogs that presented severe treatment-related side effects, were cured and were parasitologically negative at time 5. However, some (proportion of dogs that presented no clinical signs, no hyperglobulinemia and negative serology at time 5) secondary outcome measures showed significant differences in favor of the meglumine antimoniate-allopurinol treatment arm. Treatment-related death occurred in one dog in each group, while injection site reactions appeared at a similar frequency in both groups. Due to the differences in some secondary outcome measures in association with the low power of this trial, it cannot be definitively concluded that the two treatments are equally effective. Therefore, the aminisodine-allopurinol combination cannot be proposed as a first-line treatment of CanL but rather as a second-line treatment that may be particularly useful to avoid repeated administration of meglumine antimoniate and in countries where the latter is not available or registered.

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

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

Early antibody response and clinical outcome in experimental canine leishmaniasis

Infected dogs are the main reservoir of zoonotic visceral leishmaniasis, a widespread parasitic disease caused by Leishmania infantum. Therefore, the control of canine infections is required to reduce the incidence of human cases. Disease outcome in dogs depends on the fine balance between parasite virulence and efficacy of the immune system. Thus, knowledge of early response could yield relevant information for diagnosis and follow-up. In our study, 20 Beagle dogs were intravenously infected with 10⁸ amastigotes of a fresh isolate of L. infantum and monitored along 16 weeks post inoculation. Specific antibody response and clinical evolution of infected animals were highly variable. Immunofluorescence antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) were useful to assess infection status, although only ELISA with promastigote-coated plates and, particularly, western blotting (WB) allowed an early diagnosis. Prominent antigens were identified by mass peptide fingerprinting. Chaperonin HSP60, 32 and 30 KDa antigens were recognized by all dogs on week 10 post infection. This suggests that these antigens may be valuable for early diagnosis. Advanced infection showed, in addition, reactivity to HSP83 and HSP70. Disease outcome did not show a clear relationship with ELISA or IFAT titers. Correlation between the clinical status and the combined reactivity to some antigens sustains their use for diagnosis and follow-up.

Evaluation of Cytopathological Techniques for the Diagnosis of Canine Visceral Leishmaniosis with Lymph Node Samples

The identification of the parasite in cytological smears of lymph node aspirates is a widely applied technique for the direct diagnosis of Leishmania spp. infection, especially in endemic areas. Although very specific, this method has limited sensitivity, and improving the technique would be highly desirable. This study aimed to evaluate the efficacy of conventional smear cytology (SC), liquid-based cytology (LBC), cell block (CB) stained with haematoxylin and eosin (HE) and immunocytochemistry (ICC), and formalin-fixed paraffin wax-embedded tissue immunohistochemistry (FFPE-IHC) compared with serology and polymerase chain reaction for the diagnosis of canine visceral leishmaniosis (CVL) in lymphoid tissue. The use of a preservative medium and centrifugation for cytological samples reduced the number of unsatisfactory artefacts/background. Moreover, LBC allowed excellent cellular preservation and the application of ancillary techniques, such as CB and ICC. SC was the most accurate morphological diagnostic method (45.0%). CB-ICC alone or associated with SC demonstrated significantly higher sensitivity (70.0% and 72.0%, respectively) when compared with SC alone (34.00%). CB-ICC was found to be more effective in the detection of infected animals with mild clinical signs, similar to FFPE-IHC. The specificity and positive predictive value were similar between all methods. Finally, the detection limit for CB-ICC and SC + CB-ICC was identical (18.46 amastigotes/mm²). Our study suggests that CB-ICC is a promising tool for improvement of the cytopathological diagnosis of CVL and may be applied in routine epidemiological screening.

Circulating immune complexes levels correlate with the progression of canine leishmaniosis in naturally infected dogs

Dogs are the main domestic reservoir of Leishmania infantum, and in cases of uncontrolled infection, a strong humoral immune response is elicited, which is inefficient against the parasites. Previous studies have suggested that an adequate antigen/antibody ratio, with a moderate prevalence of antigens with respect to the antibodies, could result in the formation of circulating immune complexes (CIC) in canine leishmaniosis (CanL). Deposition of these complexes in tissues has been associated with vasculitis, uveitis, arthritis, dermatitis and especially glomerulonephritis and renal failure. However, little is known about the relationship between the presence of CIC and disease progression. The aim of this study was to evaluate serum CIC level and its correlation with disease severity in infected dogs with different stages of disease and non-infected animals as a control. A total of 60 dogs were included in the study, classified according to the proposed LeishVet classification criteria: healthy non-infected (n = 13); healthy infected (n = 12); sick stage I (n = 9); sick stage II (n = 17); sick stage III (n = 8); and sick stage IV (n = 1). CIC were isolated from serum samples using a modified polyethylene glycol precipitation method, and their levels measured by ELISA and bicinchoninic acid protein assay. A nanoparticle tracking analysis was performed to investigate the relationship between the molecular size distribution of the CIC and disease progression. In conclusion, the results confirmed a positive association between CIC levels, their molecular size and disease progression that suggests a potential use of CIC as biomarkers of CanL.

Serum indirect immunofluorescence assay and real-time PCR results in dogs affected by Leishmania infantum: evaluation before and after treatment at different clinical stages

We compared results of a serum immunofluorescence assay (IFA) and lymph node quantitative PCR (qPCR) in dogs classified as exposed, infected, or sick because of leishmaniasis. We also determined how IFA or qPCR results changed in response to treatment and reflected different clinical and clinicopathologic improvement of dogs. We included 108 dogs in our retrospective study: 12 exposed, 25 infected, and 71 sick, as classified according to Canine Leishmaniasis Working Group standards. Between-group comparison showed higher IFA values ( p < 0.01) for sick dogs; qPCR values were higher for sick than infected dogs ( p < 0.01). A novel clinical and clinicopathologic score was created and applied to 50 sick dogs. Using this score, 41 were reclassified as partially recovered (PR) within 3 mo, and 37 as totally recovered (TR) 3-6 mo after presentation. Statistically significant differences in IFA values were found between the sick and TR dogs ( p < 0.01), but not between sick and PR dogs ( p = 0.98). During follow-up, qPCR revealed a progressive decrease in parasite load, with a statistically significant difference in sick versus PR ( p < 0.01), sick versus TR ( p < 0.01), and PR versus TR ( p < 0.01) dogs. A decrease of 1 point in the clinical score corresponded to 1.3 Leishmania/μL qPCR decrease ( p < 0.01) and decrease of 1:42 in IFA ( p < 0.01). Our findings confirm that the clinical status of dogs affected by leishmaniasis is closely related to parasite load and antibody level, both before and after treatment.

Biomarkers Associated With Leishmania infantum Exposure, Infection, and Disease in Dogs

Canine leishmaniosis (CanL) is a vector-borne disease caused by the protozoan Leishmania (Leishmania) infantum species [syn. L. (L.) infantum chagasi species in the Americas] which is transmitted by the bite of a female phlebotomine sand fly. This parasitosis is endemic and affect millions of dogs in Asia, the Americas and the Mediterranean basin. Domestic dogs are the main hosts and the main reservoir hosts for human zoonotic leishmaniosis. The outcome of infection is a consequence of intricate interactions between the protozoan and the immunological and genetic background of the host. Clinical manifestations can range from subclinical infection to very severe disease. Early detection of infected dogs, their close surveillance and treatment are essential to control the dissemination of the parasite among other dogs, being also a pivotal element for the control of human zoonotic leishmaniosis. Hence, the identification of biomarkers for the confirmation of Leishmania infection, disease and determination of an appropriate treatment would represent an important tool to assist clinicians in diagnosis, monitoring and in giving a realistic prognosis to subclinical infected and sick dogs. Here, we review the recent advances in the identification of Leishmania infantum biomarkers, focusing on those related to parasite exposure, susceptibility to infection and disease development. Markers related to the pathogenesis of the disease and to monitoring the evolution of leishmaniosis and treatment outcome are also summarized. Data emphasizes the complexity of parasite-host interactions and that a single biomarker cannot be used alone for CanL diagnosis or prognosis. Nevertheless, results are encouraging and future research to explore the potential clinical application of biomarkers is warranted.

Measurement of urea and creatinine in saliva of dogs: a pilot study

BACKGROUND

Urea and creatinine in saliva have been reported to be possible markers of chronic kidney disease (CKD) in humans. The aim of this study was to assess if urea and creatinine could be measured in canine saliva, and to evaluate their possible changes in situations of CKD.

RESULTS

The spectrophotometric assays for urea and creatinine measurements in saliva of dogs showed intra- and inter-assay imprecision lower than 12% and coefficients of correlation close to 1 in linearity under dilution tests. Healthy dogs showed median salivary concentrations of urea of 39.6 mg/dL and creatinine of 0.30 mg/dL, whereas dogs with CKD showed median salivary urea of 270.1 mg/dL and creatinine of 1.86 mg/dL. Positive high correlations were found between saliva and serum activities of the two analytes (urea, r = 0.909; P < 0.001; creatinine, r = 0.819; P < 0.001).

CONCLUSIONS

Urea and creatinine concentrations can be measured in canine saliva with commercially available spectrophotometric assays. Both analytes showed higher values in saliva of dogs with CKD compared with healthy dogs and their values were highly correlated with those in serum in our study conditions.

Use of urinary γ-glutamyl transferase (GGT) to monitor the pattern of proteinuria in dogs with leishmaniasis treated with N-methylglucamine antimoniate

The aim of this study was to assess if the coupled analysis of the urinary protein to creatinine (UPC) ratio and of the GGT/UC ratio (the ratio between urinary γ-glutamyl transferase activity and urinary creatinine) may be used in treated leishmaniotic dogs to differentiate dogs with transient impairment of tubular function from dogs with persistent tubular damage. To this aim, 40 urine from 10 proteinuric and leishmaniotic dogs that at the first visit had high GGT/UC ratio, consistent with tubular damage, were collected and analyzed before treatments and 2, 4 and 6 weeks after treatment with N-methylglucamine antimoniate and allopurinol. Compared with pre-treatment values, at the end of the study period the UPC ratio decreased only in 5/10 dogs, which, however, were still proteinuric or borderline proteinuric. Conversely, the GGT/CU ratio decreased in 8/10 dogs and in 3 of them the values at the end of the study period were below the threshold consistent with tubular proteinuria. The GGT/UC values at 6 weeks was significantly lower than before treatment. However, transient increases were frequent for both the analytes. These results indicate that in most of the dogs that remain proteinuric after treatment, likely due to the persistent glomerular damage, the GGT/UC ratio tends to normalize. This suggests that in these dogs tubular proteinuria at admission depends on functional impairment of tubular cells likely due to the overflow of proteins from damaged glomeruli. However, tubular proteinuria occasionally persists, suggesting that tubulointerstitial damages persist even in dogs responsive to treatments.

Serum Symmetric Dimethylarginine as an Early Marker of Excretory Dysfunction in Canine Leishmaniosis (L. infantum) Induced Nephropathy

The aims of the study were to determine whether symmetric dimethylarginine (SDMA) was increased in dogs with leishmaniosis and to assess its relationship with creatinine concentration and urinary protein : creatinine ratio (UPC) to determine its utility as a marker of early excretory dysfunction. Fifty-three dogs with leishmaniosis classified according to the LeishVet clinical staging (stage I, n = 5, stage II, n = 30; stage III, n = 12; stage IV, n = 6) were selected and compared with 41 clinically healthy dogs. Thirty-nine dogs with leishmaniosis were also followed up for six months. SDMA concentrations on the day of diagnosis were significantly higher in dogs with leishmaniosis with respect to control dogs and in dogs from LeishVet stage IV when compared with the other stages. Increased UPC (>0.5), SDMA (>19 μg/dL), and creatinine concentrations (≥1.4 mg/dL) were found in 47.1%, 15.1%, and 9.4% of dogs with leishmaniosis, respectively. SDMA concentration was increased in 24% of proteinuric dogs, in 7% of nonproteinuric dogs, and in four of five dogs with increased creatinine. SDMA concentration ≥ 25 μg/dL was associated with clinical chronic kidney disease (CKD) after six months. Our results did not demonstrate advantages in using SDMA concentration as an early marker of CKD when compared to creatinine and UPC in canine leishmaniosis.

Inconsistent MHC class II association in Beagles experimentally infected with Leishmania infantum

The clinical outcome of Leishmania infantum infection in dogs varies from subclinical infection to severe disease. Researchers attribute this variability in clinical manifestations to the ability of the immune response to limit pathogen multiplication and dissemination, which is, in part, likely determined by the immune response genes. The aim of this study was to test the hypothesis that MHC class II genes are associated with disease outcome of experimental L. infantum infection in Beagles. Dog leukocyte antigen (DLA) class II haplotypes were characterised by sequence-based typing of Beagle dogs experimentally infected with L. infantum during vaccine challenge studies. Variability of response to infection was determined by clinical score, serology and quantification of L. infantum DNA in the bone marrow over the study period. Dogs showed limited DLA diversity and the DLA profiles of dogs recruited for the different vaccine challenge studies differed. There were variable responses to infection, despite the apparent restriction in genetic diversity. One haplotype DLA-DRB1*001:02-DQA1*001:01-DQB1*002:01 was associated with increased anti-Leishmania antibodies in one infection model, but no DLA associations were found in other groups or with parasite load or clinical score. Examination of this particular DLA haplotype in a larger number of dogs is required to confirm whether an association exists with the immune or clinical responses to L. infantum infection.

Canine Leishmaniasis: An Overview of the Current Status and Strategies for Control

Canine leishmaniasis (CanL) is a vector-borne disease caused by Leishmania infantum and is transmitted by female phlebotomine sand flies primarily between animals and secondarily to humans. The course of infection may be different from one individual dog to another, ranging from spontaneous cure to acute evolution that leads to death, if proper management and therapy are not adopted. A parasitological cure is rarely achieved and clinical recurrences in CanL are frequent. Vaccination associated with the use of topical insecticides is undoubtedly the most effective form of prevention and control of the disease. In order to integrate the most important scientific knowledge of the literature in one objective publication, this review proposes a short overview of the main points of CanL.

A ready-to-use duplex qPCR to detect Leishmania infantum DNA in naturally infected dogs

Canine visceral leishmaniasis (CVL) is a systemic disease caused by Leishmania infantum. A precise CVL diagnosis would allow for a faster and more specific treatment. Quantitative PCR (qPCR) is a sensitive and specific technique that can diagnose CVL and also monitor parasite load in the animal during the course of the infection or treatment. The aim of this study was to develop a ready-to-use (gelified and freezer-free) duplex qPCR for the identification of infected animals. We combined a new qPCR protocol that detects the canine 18S rRNA gene with an existing protocol for L. infantum kDNA detection, creating a duplex qPCR. This duplex method was then developed into a ready-to-use format. The performance of the duplex and singleplex reactions were compared in the traditional format (liquid and freezer-stored). Furthermore, the duplex qPCR performance was compared between the ready-to-use and traditional formats. The singleplex and new duplex qPCR exhibited the same detection limit in the traditional format (0.1 parasites/reaction). The ready-to-use format showed a detection limit of 1 parasite/reaction without affecting the reaction efficiency. The performance of the new qPCR protocol in the two formats was assessed using canine tissue samples from 82 dogs in an endemic CVL area that were previously characterized by standard serological and parasitological protocols. Splenic aspirates provided a higher rate of positivity (92.9%) followed by skin (50%) and blood (35.7%). The reported detection limits were observed for all tissues studied. Our results show that the amplification of L. infantum kDNA and canine DNA in a single tube, using either the traditional or ready-to-use format, exhibited the same diagnostic performance as amplification of the parasite kDNA alone. The detection of the host gene strengthens the qPCR results by confirming the presence and quality of DNA in the samples and the absence of polymerase inhibitors. The ready-to-use duplex qPCR format has many advantages. By joining two qPCR protocols into one, more results can be obtained in the same amount of time with reduced costs and embedded quality control. Reagents are preloaded and stored on the plate, reducing the operator's hands-on time to set up a reaction, as well as decreasing manipulation steps, which reduces the risk of mistakes or contamination. Thus, the ready-to-use duplex format turns qPCR into a robust, easy-to-use tool, which could help increase the availability of qPCR for CVL diagnosis.

An ELISA immunoassay employing a conserved Leishmania hypothetical protein for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans

In the present study, a conserved Leishmania hypothetical protein, namely LiHypA, was evaluated for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans. This protein showed a high amino acid sequence homology between viscerotropic and cutaneotropic Leishmania species. An enzyme-linked immunosorbent assay (ELISA) was developed using the recombinant antigen (rLiHypA), in addition to the A2 protein and two parasite antigenic preparations, which were used as controls. Regarding human diagnosis, results showed that rLiHypA was more sensitive and specific than ELISA-L. braziliensis SLA in detecting both cutaneous or mucosal leishmaniasis patients, but not those from Chagas disease patients or healthy subjects. Regarding canine diagnosis, this recombinant antigen showed higher sensitivity and specificity values, as well as a perfect accuracy to identify asymptomatic and symptomatic visceral leishmaniasis (VL) in dogs, but not those from vaccinated animals or those developing babesiosis, ehrlichiosis, or Chagas disease. However, using the rA2 protein or L. braziliensis SLA as controls, significant cross-reactivity was found when these samples were used, hampering their sensitivity and specificity values for the diagnosis. In this context, LiHypA could be considered a candidate to be evaluated for the serodiagnosis of visceral and tegumentary leishmaniasis in dogs and humans.

Hypertension and its correlation with renal lesions in dogs with leishmaniosis

To evaluate the prevalence of hypertension and its correlation with the severity of renal injury and proteinuria in dogs with leishmaniosis, sixty-six dogs were divided into two groups. Group 1 (G1) was composed of 54 dogs included in stage 1 of chronic kidney disease (CKD), and group 2 (G2) of twelve dogs in stages 2 and 3 of CKD. Prevalence of hypertension was 28.8%, comprising 22.2% of the dogs from G1 and 58.3% from G2 (P=0.011). The mean arterial blood pressure (BP) of dogs from G1 (135.7 ± 20.5) was lower than from G2 (170.0 ± 26.3) (P <0.001). Urine protein-creatinine ratio (UP/C) revealed values above 0.5 in 75.7% of the dogs, with 34% presenting hypertension. All dogs with hypertension had histopathological and laboratory evidence of glomerular disease. Although there was no statistically significant correlation between elevated BP and the severity of glomerular lesions (P=0.408), there was a statistically significant correlation between elevated BP and increased UP/C in the studied population (P=0.002). Thus, dogs with leishmaniosis and renal disease must be screened for the presence of hypertension so that treatment may be instituted as early as possible, in countries where treatment is allowed, to prevent the progression of renal damage.

Laboratory tests for diagnosing and monitoring canine leishmaniasis

Although several reviews on canine leishmaniasis have been published, none thoroughly described clinicopathologic abnormalities and their clinical usefulness. The aim of this review was to provide information concerning current diagnostic tests relevant for clinical pathologists and from a practical perspective. Specifically, in canine leishmaniasis, nonregenerative normocytic normochromic anemia, thrombocytopenia, or leukogram changes may be present. Clinical chemistry and urinalysis may indicate renal dysfunction (azotemia, decreased urine specific gravity, proteinuria) and an inflammatory/immune response (increased acute phase proteins [APP] or α₂ - and/or γ-globulins). Although a potential gammopathy is usually polyclonal, it may also appear oligo- or monoclonal, especially in dogs coinfected by other vector-borne pathogens. When lesions are accessible to fine-needle aspiration (lymphoadenomegaly, nodular lesions, joint swelling), cytology is strongly advised, as the presence of Leishmania amastigotes in a pattern of pyogranulomatous inflammation or lymphoplasmacytic hyperplasia is diagnostic. If the cytologic pattern is inconclusive, the parasite should be identified by histology/immunohistochemistry or PCR on surgical biopsies. Alternatively, cytology and PCR may be performed on bone marrow samples where amastigotes, along with erythroid hypoplasia, myeloid hyperplasia, plasmacytosis, or secondary dysmyelopoiesis can be observed. Dogs with overt leishmaniasis generally have high antibody titers, while low titers predominate in immunologically resistant infected dogs or in exposed dogs with no parasite confirmation. Quantitative serology is recommended in clinically suspect dogs as high-titer antibodies titers may confirm the clinical diagnosis. In confirmed and treated dogs, renal function and inflammatory/immune response variables should be periodically monitored.

Proteinuria reduction after treatment with miltefosine and allopurinol in dogs naturally infected with leishmaniasis

Aim:

The aim of this study was to evaluate changes in proteinuria in dogs naturally infected with visceral leishmaniasis, following treatment with miltefosine (MLF) and allopurinol.

Materials and Methods:

Medical records of 40 dogs with leishmaniasis, treated with 2 mg/kg MLF every 24 h PO and 10 mg/kg allopurinol every 12 h for 28 days were reviewed. 20 dogs were included in the study, and clinical staging was performed following guidelines of the Canine leishmaniasis (CanL) Working Group, and dogs were categorized for proteinuria according to the International Renal Interest Society (IRIS) staging system. Clinical score, indirect fluorescent antibody test titer, serum total protein, gamma globulin (IgG), serum creatinine and urea concentration, and urine protein creatinine ratio (UP/C) were recorded at the time of diagnosis before the start of therapy (D0) and at the end of 28 days of therapy (D28).

Results:

Following the CanL Working Group staging, all 20 dogs were classified as the clinical Stage C (Clinical disease) before and after the cycle of treatment. Before the cycle of therapy, dogs were categorized according to the IRIS staging system, as: 9/20 non-proteinuric (NP), 7/20 borderline proteinuric (BP), and 4/20 proteinuric (P). After treatment, 12/20 dogs were NP, 7/20 were BP, and 1/20 was P. There was a significant change in UP/C values before and after one cycle of treatment with MLF. In detail, after 28 days of therapy, 2 of 9 NP dogs became BP, 3 of the 7 BP dogs became NP, and 2 of the 4 P dogs became NP.

Conclusion:

This study showed a significant decrease in UP/C values occurred after one cycle of treatment with MLF and allopurinol in dogs naturally affected with CanL. This suggests that MLF does not increase proteinuria, and the use of MLF could be considered for the management of dogs with leishmaniasis, particularly in those with impaired renal function at the time of diagnosis.

Clinical leishmaniasis in dogs living in the UK

OBJECTIVES

To investigate the prevalence of leishmaniasis in dogs in the UK and to describe clinical presentation, clinicopathological abnormalities, therapeutic protocols and outcome in this non-endemic country.

MATERIALS AND METHODS

Medical records of dogs diagnosed with leishmaniasis at seven referral centres in the UK were retrospectively reviewed.

RESULTS

The prevalence was between 0·007 and 0·04% with a higher number of cases in southern England. All dogs had a history of travel to or from an endemic country. Lethargy, dermatological disease, decreased appetite and lameness were the most common reasons for presentation. Allopurinol was used alone for treatment in the majority of cases.

CLINICAL SIGNIFICANCE

Although rare, leishmaniasis should be considered in dogs in the UK if they have compatible clinical signs and history of travel to or from endemic areas.

The first report of autochthonous non-vector-borne transmission of canine leishmaniosis in the Nordic countries

Background

Leishmania spp. are zoonotic protozoans that infect humans and other mammals such as dogs. The most significant causative species in dogs is L. infantum. In dogs, leishmaniosis is a potentially progressive, chronic disease with varying clinical outcomes. Autochthonous cases of canine leishmaniosis have not previously been reported in the Nordic countries.

Results

In this report we describe the first diagnosed autochthonous cases of canine leishmaniosis in Finland, in which transmission via a suitable arthropod vector was absent. Two Finnish boxers that had never been in endemic areas of Leishmania spp., had never received blood transfusions, nor were infested by ectoparasites were diagnosed with leishmaniosis. Another dog was found with elevated Leishmania antibodies. A fourth boxer dog that had been in Spain was considered to be the source of these infections. Transmission occurred through biting wounds and semen, however, transplacental infection in one of the dogs could not be ruled out.

Two of the infected dogs developed a serious disease and were euthanized and sent for necropsy. The first one suffered from membranoproliferative glomerulonephritis and the second one had a chronic systemic disease. Leishmania sp. was detected from tissues by PCR and/or IHC in both dogs. The third infected dog was serologically positive for Leishmania sp. but remained free of clinical signs.

Conclusions

This case report shows that imported Leishmania-infected dogs may pose a risk for domestic dogs, even without suitable local arthropod vectors.

An update on the diagnosis and treatment of canine leishmaniosis caused by Leishmania infantum (syn. L. chagasi)

Canine leishmaniosis caused by Leishmania infantum is still a common disease in endemic areas, such as the Mediterranean countries, and has progressively expanded into non-endemic areas like Central and Northern Europe. The aim of this article is to critically review current knowledge on the diagnosis and treatment of this disease. In dogs with typical clinical signs and clinicopathological abnormalities, diagnosis is relatively easy based on the exclusion of major differentials, the demonstration of the parasite (e.g., with lymph node and/or skin cytology) and the presence of Leishmania-specific immunoglobulin G antibodies (quantitative serology). In less typical cases, these criteria together with the exclusion of possible differentials and the demonstration of compatible histological lesions in affected organs and tissues form the basis for a sound diagnosis. In clinically healthy dogs, molecular techniques are the most sensitive means for detecting L. infantum infection. Treatment of canine leishmaniosis should follow clinical staging and is usually based on meglumine antimonate or miltefosine administration for a few weeks in combination with allopurinol for several months. However, allopurinol monotherapy may be used in very mild cases as well as in dogs with end stage kidney disease. Aminosidine administered once daily at a revised dosage shows some promise but additional controlled studies are needed. Close attention to published guidelines regarding treatment and follow-up is necessary to achieve the best possible therapeutic outcome.