A randomised, blinded, placebo-controlled clinical trial with allopurinol in canine leishmaniosis

Treatment of Leishmania infantum Infections in Dogs

Dogs are reservoir hosts of the zoonotic parasite Leishmania infantum, the causative agent of canine leishmaniosis. Antiparasitic drugs that are commonly used in dogs include allopurinol, miltefosine, and meglumine antimoniate. Treatment success is characterized by an improvement of disease signs, reduction in parasite load, as well as prevention of relapse. However, despite treatment, infections in dogs can usually not be cleared and often lead to (recurrent) signs of disease. Since most of the drugs used in dogs are also applied in human medicine, the prevention of treatment-induced drug-resistant Leishmania strains is a major one-health concern. This review article provides an overview of current treatment options for Leishmania-infected dogs with allopurinol, meglumine antimoniate, and miltefosine, related adverse effects, and drug resistance potential.

Antibody dynamics in dogs submitted to different canine visceral leishmaniasis treatment protocols

This study evaluated dynamics of antibodies in dogs treated for canine visceral leishmaniasis (CVL). Twenty-one dogs naturally infected by Leishmania spp. were grouped based on the treatment protocol: G1 (n=4) received allopurinol; G2 (n=10) allopurinol with miltefosine; and G3 (n=7) allopurinol, miltefosine and Leish-Tec® vaccine. The dogs were monitored monthly for a period of one year. To verify serum antibody titers, an indirect immunofluorescence reaction was performed. We found that dogs from G1 and G2 had lower clinical scores and antibody titers, when compared to the parameters evaluated in pre-treatment; however, clinical relapses were observed in three animals. In G3, clinical scores were lower than pre-treatment; however, they presented relatively stable antibody titers and no clinical relapse was observed. All animals submitted to the evaluated treatment protocols showed relative improvement in clinical signs. Furthermore, the immune response of animals must be considered, given the challenges of parasitic loads in infections. Therefore, it is necessary to complement the methods of clinical and therapeutic monitoring of dogs with CVL in order to establish the risk of transmissibility of the agent in infected and treated dogs.

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.

High Performance Liquid Chromatography Analysis and Description of Purine Content of Diets Suitable for Dogs with Leishmania Infection during Allopurinol Treatment-A Pilot Trial

Reducing the alimentary purine intake contributes to the prevention of purine (especially xanthine) urolith formation, a common adverse effect of allopurinol treatment in dogs with Leishmania infections. Analyses of the purine content are not required in order to advertise a diet as low in purine. Due to different analytical methods, data provided on purine content are barely comparable. The aim of this study was to investigate the total purine content of 12 different dog diets. For this, the purine bases adenine, guanine, xanthine, and hypoxanthine were determined by standardised high performance liquid chromatography in commercially available urinary diets (n = 4), kidney diets (n = 2), low protein diets (n = 3), 1 vegan diet, 1 regular diet for healthy adult dogs, and 1 homemade low purine diet. Total purine amounts ranged between 10.2 and 90.9 mg/100 g of dry matter. The daily purine intake calculated for a 20 kg standard dog with the analysed diets ranged between 21.9 and 174.7 mg. The lowest daily purine intakes were achieved by 2 urinary urate diets, followed by the homemade diet. Differences in the purine content of commercially available diets need to be considered. Awareness has to be raised when selecting diets for dogs with Leishmania infections during allopurinol treatment in order to minimise the risk of urolith formation.

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.

An Overview on Leishmaniasis in Romania: Diagnosis and Therapeutics

Leishmaniasis, a vector-borne disease considered to be one of the twenty neglected diseases by the World Health Organization, represents one of the public health concerns in endemic countries. In humans, as well as in animal counterparts, the infection can evolve with different clinical localizations, such as those that are cutaneous, mucocutaneous and visceral. Romania has been traditionally considered a nonendemic country for Leishmania species infection and has had sporadic positive human cases; however, the climate change recorded in recent decades has created potentially optimal conditions for the preponderant vectors of Phlebotomus spp., which has lately been identified in various parts of country. Moreover, with people and dogs (the prevailing hosts) traveling in endemic countries, the disease was imported and diagnosed in both species, and became a medical concern. In this review, we focused on the: (1) epidemiological data of leishmaniasis cases, both in humans and animals, reported by Romania; (2) diagnostic tools available for confirmation since there is a lack of gold-standard laboratory methods for human and dog patients; and (3) conventional antileishmanial therapy.

Clinical and parasitological impact of short-term treatment using miltefosine and allopurinol monotherapy or combination therapy in canine visceral leishmaniasis

Canine visceral leishmaniasis is an endemic zoonosis in Brazil. Dogs are the main hosts in urban environments. The treatment has gained popularity since the Brazilian government authorized miltefosine for canine treatment. The aim of this study was to investigate the clinical and parasitological impact of short-term treatment with miltefosine and allopurinol, alone and in combination. We evaluated the ability of pharmacotherapy to reduce clinical signs of disease, antibody levels using the indirect fluorescence antibody test (IFAT) and skin parasite load via qPCR after 28 days of treatment. The therapeutic protocols promoted a significant decline in clinical signs and in the skin parasite load in dogs (p < 0.01). We observed a moderate correlation between the skin parasite load and the clinical score in all three treatment groups (r > 0.5) Antibody levels did not decrease in this short period. It was concluded that the treatment with allopurinol reduced the number of parasites in the skin of dogs with visceral leishmaniasis in the short term. However, its efficiency is potentiated when associated with miltefosine.

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

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.

Clinical Significance of ROMs, OXY, SHp and HMGB-1 in Canine Leishmaniosis

This study aimed to investigate the role of oxidative stress parameters (ROMs, OXY, SHp), the Oxidative Stress index (OSi), and High Mobility Group Box-1 protein (HMGB-1) in canine leishmaniosis (CanL). For this study, thirty dogs, naturally infected with Leishmania spp. (Leishmania Group, LEISH) and ten healthy adult dogs (control group, CTR) were included. The diagnosis of CanL was performed by a cytological examination of lymph nodes, real time polymerase chain reaction on biological tissues (lymph nodes and whole blood), and an immunofluorescence antibody test (IFAT) for the detection of anti-Leishmania antibodies associated with clinical signs such as dermatitis, lymphadenopathy, onychogryphosis, weight loss, cachexia, lameness, conjunctivitis, epistaxis, and hepatosplenomegaly. The HMGB-1 and oxidative stress parameters of the LEISH Group were compared with the values recorded in the CTR group (Mann Whitney Test, p < 0.05). Spearman rank correlation was applied to evaluate the correlation between the HMGB-1, oxidative stress biomarkers, hematological and biochemical parameters in the LEISH Group. Results showed statistically significant higher values of SHp in the LEISH Group. Specific correlation between the ROMs and the number of red blood cells, and between HGMB-1 and SHp were recorded. These preliminary data may suggest the potential role of oxidative stress in the pathogenesis of CanL. Further studies are undoubtedly required to evaluate the direct correlation between inflammation parameters with the different stages of CanL. Similarly, further research should investigate the role of ROMs in the onset of anemia.

The Effects of Polyhexamethylene Biguanide (PHMB) and TLR Agonists Alone or as Polyplex Nanoparticles against Leishmania infantum Promastigotes and Amastigotes

Dogs are the main reservoir for Leishmania infantum, manifesting from a subclinical to a fatal disease. Limited treatments are available, although new antiparasitics and immunomodulators are pursued. Polyhexamethylene biguanide (PHMB) has a broad antimicrobial spectrum, including antiparasitic activity. Here, we evaluated the potential for Toll-like receptor agonists (TLRa) and PHMB alone, and as polyplex nanoparticles containing PHMB and TLR4 or TLR9 agonists, to selectively kill L. infantum. Susceptibility of L. infantum promastigotes to PHMB, miltefosine, and allopurinol was performed, and the half-maximum inhibitory concentrations (IC₅₀) were determined. Then, DH-82 cells were infected and treated with PHMB alone or combined with TLR4a (MPLA-SM) or TLR9a (CpG ODNs) and allopurinol alone. The IC₅₀ values of L. infantum promastigotes were PHMB (1.495 µM), miltefosine (9.455 µM), and allopurinol (0.124 µM). After infection, treated DH-82 cells displayed a lower percentage (p = 0.0316), intensity (p = 0.0002), and index of infection (p = 0.0022) when compared to non-treated cells. PHMB induced lower percentage of infection alone (p = 0.043), in combination with TLR9a (p = 0.043), and with TLR4a (p = 0.0213). Supernatants were collected and used to measure TNF-α and IL-6 levels. Increased TNF-α was observed after PHMB plus TLR4a, relative to uninfected and infected untreated macrophages (p = 0.043). PHMB combined with TLR4a shows promise as a potential anti-L. infantum drug combination, as well as inducer of proinflammatory response, as demonstrated by decreased infection and increased TNF-α production.

Feline leishmaniosis: diagnosis, treatment and outcome in 16 cats

OBJECTIVES

Leishmaniosis is a vector-borne disease and in European countries is caused by Leishmania infantum. Cats are considered secondary reservoirs of the infection in endemic areas. The objective of this retrospective study is to describe the clinical findings, diagnosis, treatment and outcome of feline leishmaniosis (FeL) in 16 cats in Spain.

METHODS

Medical records of cats diagnosed with leishmaniosis were retrospectively reviewed for cases that met the following inclusion criteria: identification of Leishmania organisms and/or DNA on cytological and/or histological specimens and/or a high anti-Leishmania antibody titre, compatible clinical findings and pathological abnormalities.

RESULTS

Sixteen cats met the inclusion criteria, all of which were living in areas endemic for canine leishmaniosis. Systemic signs were present in 11 cases (68.8%). The most common clinical signs on presentation included cutaneous lesions in 12 cats (75%), ocular disease in six cats (37.5%) and anorexia in six cats (37.5%). A polyclonal gammopathy was noted in 12 cats (85.7%). Non-regenerative anaemia and renal abnormalities were present in six (37.5%) and five patients (31.3%), respectively. In nine cats (56.3%), immunosuppressive conditions/comorbidities were identified. The diagnosis was made in eight of the cats (50%) by cytology, but a combination of diagnostic tests was needed for definitive diagnosis in the remaining patients. Twelve cats (75%) were treated specifically for leishmaniosis. Five of the 12 cats (41.7%) did not improve with treatment. The median survival time in the group of patients treated specifically for leishmaniosis was 17 months. Median survival of patients treated with concomitant diseases was 13 months vs 41 months in those without, although this was not statistically significant (P = 0.557).

CONCLUSIONS AND RELEVANCE

Presentation of FeL appears to be similar to canine leishmaniosis but with some specific features: ulcerative and nodular skin lesions are the predominant cutaneous signs; cats with immunosuppressive conditions or coexisting diseases were more commonly present than typically seen in dogs (mainly feline immunodeficiency virus). A combination of diagnostic tests may be needed for definitive diagnosis.

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.

An Overview of Immunotherapeutic Approaches Against Canine Visceral Leishmaniasis: What Has Been Tested on Dogs and a New Perspective on Improving Treatment Efficacy

Visceral leishmaniasis (VL), caused by digenetic protozoa of the genus Leishmania, is the most severe form of leishmaniasis. Leishmania infantum is one of the species responsible for VL and the disease caused is considered a zoonosis whose main reservoir is the dog. Canine visceral leishmaniasis (CVL) can lead to the death of the animal if left untreated. Furthermore, the available pharmocologial treatment for CVL presents numerous disadvantages, such as relapses, toxicity, drug resistance, and the fact treated animals continue to be reservoirs when treatment fails to achieve parasitological cure. Moreover, the available VL control methods have not been adequate when it comes to controlling parasite transmission. Advances in immune response knowledge in recent years have led to a better understanding of VL pathogenesis, allowing new treatments to be developed based on immune system activation, often referred to as immunotherapy. In fact, well-defined protocols have been described, ranging from the use of immunomodulators to the use of vaccines. This treatment, which can also be associated with chemotherapy, has been shown to be effective in restoring or inducing an adequate immune response to reduce parasitic burden, leading to clinical improvement. This review focuses on immunotherapy directed at dogs infected by L. infantum, including a literature review of what has already been done in dogs. We also introduce a promising strategy to improve the efficacy of immunotherapy.

Evaluation of nephrotoxicity and ototoxicity of aminosidine (paromomycin)-allopurinol combination in dogs with leishmaniosis due to Leishmania infantum: A randomized, blinded, controlled study

Canine leishmaniosis due to Leishmania infantum is a widespread zoonotic disease. Although aminosidine can be an effective treatment, current therapeutic recommendations do not advocate its use, mainly due to concerns regarding the potential nephrotoxicity and ototoxicity of this drug. The aim of this randomized, blinded, controlled study was to evaluate the nephrotoxicity and ototoxicity of aminosidine-allopurinol combination and compare it with that of meglumine antimonate-allopurinol combination in non-azotemic dogs with leishmaniosis. Forty dogs with leishmaniosis were randomly assigned to be treated with either aminosidine at 15 mg/kg, subcutaneously, once daily for 28 days (group A) or with meglumine antimonate at 100 mg/kg, subcutaneously, once daily for 28 days (group B). In addition to either drug, dogs in both groups were administered allopurinol at 10 mg/kg per os twice daily for 2 months. Kidney function was evaluated through measurement of serum creatinine, urea nitrogen, inorganic phosphorus, and cystatin-c concentrations and complete urinalysis, including protein-to-creatinine ratio, at baseline and after 14, 28, and 60 days from the beginning of the treatment. At the same time points, vestibular and auditory functions were evaluated through neurological examination and brainstem auditory evoked response (BAER) recordings of wave I, wave V, inter-wave I-V latencies, and minimum hearing thresholds. None of the dogs developed clinicopathological evidence of kidney disease during the study. Serum creatinine concentration increased >0.3 mg/dl over baseline in 2 dogs in group A and in 5 dogs in group B. Parameters of kidney function were not significantly different or were improved compared to baseline and the only difference between the two groups was the lower concentration of serum creatinine in group A. None of the dogs developed peripheral vestibular syndrome or hearing impairment. At the end of the study, parameters of auditory function were not significantly different or were improved compared to baseline and there were no differences between the two groups. The results of this study show that the nephrotoxicity and ototoxicity of aminosidine, when administered to non-azotemic dogs with leishmaniosis at 15 mg/kg subcutaneously once daily for 28 days along with allopurinol, is minimal and does not differ from that of meglumine antimonate.

Immunotherapy in clinical canine leishmaniosis: a comparative update

Leishmaniosis due to Leishmania infantum is a complex infection that can affect both humans and dogs, and present a wide range of clinical signs and clinicopathological abnormalities. The conventional treatment of this disease is challenging due to the fact that complete parasitological cure commonly does not occur. Furthermore, treatment of the disease with the conventionally used drugs has several shortcomings. These include the need for long-term treatment, side effects and the formation of drug resistance. Moreover, it is important to highlight that the host immune responses play a crucial role in the outcome of this infection. For this reason, the use of immunotherapy in clinical leishmaniosis to improve the result of treatment with the conventional anti-leishmanial drugs by enhancing the immune response is imperative. The aim of this review is to provide a comparative overview of the wide range of immunotherapeutical approaches and strategies for the treatment of L. infantum infection in animals focusing on dogs.

Exploiting knowledge on pharmacodynamics-pharmacokinetics for accelerated anti-leishmanial drug discovery/development

Introduction: Being on the top list of neglected tropical diseases, leishmaniasis has been marked for elimination by 2020. In the light of small armamentarium of drugs and their associated drawbacks, the understanding of pharmacodynamics and/or pharmacokinetics becomes a priority to achieve and sustain disease elimination. Areas covered: The authors have looked into pharmacological aspects of existing and emerging drugs for treatment of leishmaniasis. An in-depth understanding of pharmacodynamics and pharmacokinetics (PKPD) provides a rationale for drug designing and optimizing the treatment strategies. It forms a key to prevent drug resistance and avoid drug-associated adverse effects. The authors have compiled the researches on the PKPD of different anti-leishmanial formulations that have the potential for improved and/or effective disease intervention. Expert opinion: Understanding the pharmacological aspects of drugs forms the basis for the clinical application of novel drugs. Tailoring drug dosage and individualized treatment can avoid the adverse events and bridge gap between the in vitro models and their clinical application. An integrated approach, with pragmatic use of technological advances can improve phenotypic screening and physiochemical properties of novel drugs. Concomitantly, this can serve to improve clinical efficacies, reduce the incidence of relapse and accelerate the drug discovery/development process for leishmaniasis elimination.

Canine visceral leishmaniasis: Diagnosis and management of the reservoir living among us

This article reviews essential topics of canine visceral leishmaniasis (CVL) due to Leishmania infantum infection. It focuses on the current serological and molecular diagnostic methods used in epidemiological research and veterinary clinics to diagnose CVL and includes new point-of-care (POC) tests under development. The efficacy of different treatment regimens on the clinical improvement and infectiousness of dogs is also addressed. In the last section, the review provides a critical appraisal of the effectiveness of different control measures that have been implemented to curb disease transmission.

Dogs are the principal reservoir hosts of L. infantum and consequently play a critical role in the transmission cycle of urban VL, which also affects humans. This review provides updated information on important topics such as diagnostic tests and dog treatments that improve dog health and decrease their transmission efficacy to insect vectors. A critical review of control measures is also provided.

Treatment of canine leishmaniasis with marbofloxacin in dogs with renal disease

Treatment of canine leishmaniasis (CanL) represents a challenge. Due to the high prevalence of renal disease associated to CanL, it is important to find an effective drug that does not damage the kidneys. Marbofloxacin has been shown to be effective and well tolerated in non-azotemic dogs with leishmaniasis. To evaluate the safety and efficacy of marbofloxacin in dogs with leishmaniasis and decreased renal function, 28 dogs suffering from leishmaniasis and chronic kidney disease (CKD) were treated with oral marbofloxacin at 2 mg/Kg/day for 28 days. During treatment dogs were assessed by performing weekly physical exams, measuring blood pressure and evaluating blood and urine parameters. Lymph node aspirations were also obtained at days 0 and 28. The global clinical score decreased significantly, from 6.2±3.4 to 4.7±3.1 (p = 0.0001), after treatment. Marbofloxacin also decreased parasitic load in 72% of the dogs. No significant differences in plasma creatinine, urine specific gravity, urinary concentrations of cystatin C, ferritin and urinary protein loss were detected during treatment. A transient but significant decrease in blood pressure was detected up to day 14 (from 180.1±36.6 to 166.0±32.7 mmHg; p = 0.016). Moreover, dogs showed a significant increase in plasma albumin concentration (from 15.0±5.2 to 16.6±3.9 g/L; p = 0.014) and a significant decrease in globulin concentration (from 59.0±18.1 to 54.1±18.0 g/L; p = 0.005). The results demonstrate that, in addition to being effective for treatment of CanL, marbofloxacin is a very safe drug in dogs with CKD and leishmaniasis.

Randomized, allopurinol-controlled trial of the effects of dietary nucleotides and active hexose correlated compound in the treatment of canine leishmaniosis

First-line treatment for canine leishmaniosis (CanL) is N-methylglucamine antimoniate (MGA) combined with allopurinol. However, in some dogs allopurinol may induce hyperxanthinuria leading to urolithiasis. Moreover, allopurinol resistance has recently been described in Leishmania infantum isolates from treated dogs with a relapse of the disease. Alternative treatments are thus needed. Since the type of host immune response strongly influences CanL progression and prognosis, dogs could benefit from treatments targeted at modulating such response, such as nucleotides and active hexose correlated compound (AHCC). The aim of this study was to evaluate the effects of an oral combination of nucleotides and AHCC in dogs with clinical leishmaniosis. Sixty-nine dogs with naturally-occurring clinical leishmaniosis were included in this multicenter, open-label, positively-controlled clinical trial and randomized to receive 10mg/kg allopurinol PO BID (allopurinol group) or 17mg/kg AHCC plus 32mg/kg nucleotides PO SID (supplement group) for 180 days. All dogs were also given 50mg/kg MGA SC BID during the first 28 days. At the time points 0, 30, and 180 days of the trial, dogs underwent a clinical examination, and blood, urine, and bone marrow samples were submitted for analytical tests. Final data analyses (allopurinol group: n=29; supplement group: n=24) revealed a significant improvement in both groups in clinical scores and ELISA-determined antibody titers after treatment. However, the supplement group showed a significantly lower clinical score (P=0.005) and significantly higher antibody titers (P=0.032) after 180 days, compared to the allopurinol group. RT-PCR parasite loads were reduced in groups (mean±SD supplement: 0.38±0.56 vs 5.23±18.9; allopurinol: 0.45±1.47 vs 3.09±8.36 parasites/ng of DNA), but there were no significant differences over time or between groups. During the study, 12 dogs in the allopurinol group developed xanthinuria (41%) compared to no dogs (0%) in the supplement group (P=0.000). Both treatments led to significantly increased CD4+/CD8+ ratio, and improvements in protein electrophoretic pattern and acute phase response. In conclusion, 6-month oral treatment with nucleotides and AHCC in addition to MGA showed similar efficacy to the current first-line treatment for CanL, without producing xanthinuria. This combination could be a good alternative to MGA-allopurinol combination treatment for CanL, especially for dogs suffering allopurinol-related adverse events.

Current status on prevention and treatment of canine leishmaniasis

Canine leishmaniasis (CanL) is a parasite-borne disease mainly induced by Leishmania infantum in the Old World and Leishmania chagasi (infantum) in the New World. CanL is a zoonosis transmitted by the bite of infected Phlebotominae flies that act as vectors. CanL is a very serious disease that usually produces death when remains untreated and can be a focus of transmission to other dogs or humans. Infected dogs and other domestic and wild animals act as reservoirs and are a real threat to uninfected/healthy dogs and humans in endemic areas where the sand flies are present. Prevention of new infections in dogs can help to stop the current increase of the disease in humans, reinforcing the concept of "One Health" approach. The management of CanL is being performed using prophylactic measures in healthy dogs - insecticides impregnated in collars or immunostimulants applied by spot-on devices - and chemotherapy in animals that suffer from the disease. Antimonials as first-line monotherapy have proven efficacy in reducing most of the clinical signs of CanL, but they need to be administered during several days, and no complete parasite clearance is achieved, favouring the presence of relapses among treated dogs. Therefore, new drugs, such as miltefosine, or combinations of this drug or antimonials with allopurinol are in the pipeline of clinical treatment of CanL. Recently, there has been an emergence of protective - prophylactic - and curative - autogenous vaccines - immunotherapy tools to face CanL, whose results are still under study. This review highlights the current use of preventive and eradicative weapons to fight against this disease, which is a scourge for dogs and a continuous threat to human beings.

Early reduction of Leishmania infantum-specific antibodies and blood parasitemia during treatment in dogs with moderate or severe disease

BACKGROUND

Leishmania infantum-specific antibodies are used extensively for the diagnosis and monitoring of treatment in canine leishmaniosis. Different views have been described for the measurement of L. infantum antibody levels for the monitoring of anti-leishmanial treatment. In addition, molecular techniques using blood are frequently employed in the clinical setting. However, there are not enough studies to prove the usefulness of PCR in diagnosis, treatment monitoring and in assessing the prognosis of the disease. The objectives of this study were to evaluate L. infantum-specific antibodies and blood parasitemia at the time of diagnosis and during treatment and to correlate these with the dog's clinical status.

METHODS

Thirty-seven dogs were diagnosed and followed-up during treatment (days 30, 180 and 365). The treatment protocol consisted of a combination of meglumine antimoniate for one month and allopurinol for at least one year. Leishmania infantum-specific antibodies and blood parasitemia were assessed by an end point sera dilution ELISA and by real-time PCR, respectively.

RESULTS

The majority of dogs were classified as LeishVet stage II (moderate disease) at the time of diagnosis (86 %) and the rest as stage III. Results showed variable levels of specific antibodies at the time of diagnosis [median ± interquartile range (IQR): 1372 ± 8803 ELISA units (EU)]. Twenty-three seropositive dogs (64 %) were detected as PCR-positive at the time of diagnosis. Interestingly, a rapid significant antibody level reduction was observed by day 30 of treatment (median ± IQR: 604 ± 2168 EU). A continuing significant decrease of specific antibodies was also found at days 180 (median ± IQR: 201 ± 676 EU) and 365 (median ± IQR: 133 ± 329 EU) in association with clinical improvement. A significant blood parasitemia reduction was also observed at all time points studied. Mean parasites/ml ± SD were 19.4 ± 79.1 on day 0, 2.2 ± 11.7 on day 30, 0.9 ± 2.9 on day 180, and 0.3 ± 0.7 on day 365.

CONCLUSIONS

This study reports a significant reduction of L. infantum antibodies measured by an end point sera dilution ELISA method after 30 days of treatment associated with clinical improvement. A low proportion of sick dogs with moderate disease were negative by blood real-time PCR at the time of diagnosis.

Allopurinol Resistance in Leishmania infantum from Dogs with Disease Relapse

BACKGROUND

Visceral leishmaniasis caused by the protozoan Leishmania infantum is a zoonotic, life threatening parasitic disease. Domestic dogs are the main peridomestic reservoir, and allopurinol is the most frequently used drug for the control of infection, alone or in combination with other drugs. Resistance of Leishmania strains from dogs to allopurinol has not been described before in clinical studies.

METHODOLOGY/PRINCIPAL FINDINGS

Following our observation of clinical disease relapse in dogs under allopurinol treatment, we tested susceptibility to allopurinol of L. infantum isolated from groups of dogs pre-treatment, treated in remission, and with disease relapse during treatment. Promastigote isolates obtained from four treated relapsed dogs (TR group) showed an average half maximal inhibitory concentration (IC50) of 996 μg/mL. A significantly lower IC50 (P = 0.01) was found for isolates from ten dogs before treatment (NT group, 200 μg/mL), as well as for five isolates obtained from treated dogs in remission (TA group, 268 μg/mL). Axenic amastigotes produced from isolates of the TR group also showed significantly higher (P = 0.002) IC50 compared to the NT group (1678 and 671 μg/mL, respectively). The lower sensitivity of intracellular amastigotes from the TR group relative to those from the NT group (P = 0.002) was confirmed using an infected macrophage model (6.3% and 20% growth inhibition, respectively at 300 μg/mL allopurinol).

CONCLUSIONS

This is the first study to demonstrate allopurinol resistance in L. infantum and to associate it with disease relapse in the canine host. These findings are of concern as allopurinol is the main drug used for long term control of the disease in dogs, and resistant L. infantum strains may enhance uncontrolled transmission to humans and to other dogs.

Long-term follow-up of dogs with leishmaniosis treated with meglumine antimoniate plus allopurinol versus miltefosine plus allopurinol

BACKGROUND

Visceral leishmaniosis is a potentially life-threatening illness caused by a protozoan parasite of the genus Leishmania. It is found mainly in areas where both the parasite and its vector are endemic and is one of the most challenging infectious diseases in the world to control. HIV infected patients are vulnerable to Leishmania infections, and the main reservoir hosts of Leishmania infantum parasites are domestic dogs. Here, we evaluated the long-term efficacy of treatment with meglumine antimoniate plus allopurinol (G1) compared to miltefosine plus allopurinol (G2) in dogs naturally infected L. infantum.

METHODS

Eighteen dogs with leishmaniosis were divided into the following two groups: G1 (n = 9) was treated subcutaneously with meglumine antimoniate (100 mg/kg/day/30 days) plus allopurinol (10 mg/kg/per day/30 days), while G2 (n = 9) was treated orally with miltefosine (2 mg/Kg/day/30 days) plus allopurinol (10 mg/kg/day/30 days). Thereafter, the same dose of allopurinol was administered to both groups for 6 years. Leishmania DNA in lymph node aspirates from the G1 and G2 dogs was quantified by real-time quantitative PCR at baseline and every 3 months for 24 months, and then at 28, 36, 48, 60 and 72 months. At each assessment, the dogs were examined for signs of disease, and their clinical scores were recorded.

RESULTS

Both combination therapies produced significant clinical improvements in the dogs, with a significant reduction in the parasitic load in the lymph nodes of the dogs from both groups after 3 months of treatment. Clinical relapses were observed in four dogs from G2 (miltefosine/allopurinol), and just one dog from G1 (meglumine antimoniate/allopurinol). All dogs that relapsed had increased clinical scores, and increased anti-Leishmania antibody titers and parasitic loads in their lymph nodes.

CONCLUSIONS

Long-term, the clinical and laboratory findings of the G1 dogs were more stable than those of the G2 dogs, thus indicating that meglumine antimoniate had better clinical efficacy than miltefosine. The results suggest that treatment with allopurinol as a maintenance therapy is crucial for stabilizing the care of canine leishmaniosis.

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.

Polymeric colloidal particulate systems: intelligent tools for intracellular targeting of antileishmanial cargos

INTRODUCTION

Targeted cargo delivery systems can overcome drawbacks associated with antileishmanials delivery, by defeating challenges of physiological barriers. Various colloidal particulate systems have been developed in the past; few of them even achieved success in the market, but still are limited in some ways.

AREAS COVERED

This review is focused on the pathobiology of leishmaniasis, interactions of particulate systems with biological environment, targeting strategies along with current conventional and vaccine therapies with special emphasis on polymeric nanotechnology for effective antileishmanial cargo delivery.

EXPERT OPINION

The problems concerned with limited accessibility of chemotherapeutic cargos in conventional modes to Leishmania-harboring macrophages, their toxicity, and resistant parasitic strain development can be sorted out through target-specific delivery of cargos. Vaccination is another therapeutic approach employing antigen alone or adjuvant combinations delivered by means of a carrier, and can provide preventive measures against human leishmaniasis (HL). Therefore, there is an urgent need of designing site-specific antileishmanial cargo carriers for safe and effective management of HL. Among various colloidal carriers, polymeric particulate systems hold tremendous potential as an effective delivery tool by providing control over spatial and temporal distribution of cargos after systemic or localized administration along with enhancing their stability profile at a comparatively cost-effective price leading to improved chances of commercial applicability.

Strategies for the design of orally bioavailable antileishmanial treatments

Leishmaniasis is one of the six major tropical diseases targeted by the World Health Organization. The most serious, life-threatening form is visceral leishmaniasis (VL). No vaccine is yet available for human use and chemotherapy is the main mean of dealing with this disease. This review focuses on the development of drug delivery systems (DDS) for treatment of leishmaniasis. After an overview of the significance of leishmaniasis in 2013, current chemotherapy and its limitations are considered, leading to possible strategies to improve the treatment of VL: new drugs, combinations of existing drugs and DDS, particularly for oral administration. Nanostructured biomaterials such as lipid-based or polymeric nanoparticles have unique physicochemical properties, ultra-small and controllable size, large surface area to mass ratio and the possibility of surface modification which can be used to advantage for the oral administration of antileishmanial drugs. They can improve the rate of dissolution of poorly water-soluble drugs, increase intestinal residence time by bioadhesion and, especially when lipid additives are used, influence the route and efficiency of absorption. These recent advances in this very active field should lead to better management of this serious disease.

Canine visceral leishmaniasis: relationships between oxidative stress, liver and kidney variables, trace elements, and clinical status

The aim of this study was to investigate the role of oxidative stress in the pathology of canine visceral leishmaniasis (CVL). We therefore studied the relationships between oxidative stress markers, liver and kidney variables, trace elements, and clinical status in dogs naturally infected with Leishmania infantum. Two groups of Leishmania-infected dogs [asymptomatic (AD, n = 14) and symptomatic (SD, n = 16)] were assessed and compared with a group of non-infected control dogs (CD, n = 30). A significant decrease (p < 0.001) in serum total antioxidant status (TAS) and albumin concentration (p < 0.05) and a significant increase in serum malondialdehyde (MDA) and blood urea nitrogen (BUN) concentrations (p < 0.001), in the SD group, were observed when compared to CD and AD groups. Dogs of the AD group presented a significant decrease in copper (p < 0.01) and zinc (p < 0.001) concentrations, when compared to CD group, while the SD group presented a significant decrease (p < 0.001) in copper and zinc concentrations, when compared to CD and AD groups. Oxidative stress markers (MDA and TAS) showed significant correlations (p < 0.001) with trace elements (copper and zinc) and liver (alanine aminotransferase) and kidney (BUN and creatinine) variables. The results of the present study revealed that symptomatic dogs showed more severe oxidative stress than asymptomatic and non-infected dogs and enhanced lipid peroxidation may be linked to liver and kidney damage in canine visceral leishmaniasis.

Efficacy of combined therapy with liposome-encapsulated meglumine antimoniate and allopurinol in treatment of canine visceral leishmaniasis

An innovative liposomal formulation of meglumine antimoniate (LMA) was recently reported to promote both long-term parasite suppression and reduction of infectivity to sand flies in dogs with visceral leishmaniasis. However, 5 months after treatment, parasites were still found in the bone marrow of all treated dogs. In order to improve treatment with LMA, the present study aimed to evaluate its efficacy in combination with allopurinol. Mongrel dogs naturally infected with Leishmania infantum were treated with six doses of LMA (6.5 mg Sb/kg of body weight/dose) given at 4-day intervals, plus allopurinol (20 mg/kg/24 h per os) for 140 days. Comparison was made with groups treated with LMA, allopurinol, empty liposomes plus allopurinol, empty liposomes, and saline. Dogs remained without treatment from day 140 to 200 after the start of treatment. The drug combination promoted both clinical improvement of dogs and significant reduction in the parasitic load in bone marrow and spleen on days 140 and 200 compared to these parameters in the pretreatment period. This is in contrast with the other protocols, which did not result in significant reduction of the bone marrow parasite load on day 200. Strikingly, the combined treatment, in contrast to the other regimens, induced negative quantitative PCR (qPCR) results in the liver of 100% of the dogs. Both xenodiagnosis and skin parasite determination by qPCR indicated that the drug combination was effective in blocking the transmission of skin parasites to sand flies. Based on all of the parasitological tests performed on day 200, 50% of the animals that received the combined treatment were considered cured.

One-year clinical and parasitological follow-up of dogs treated with marbofloxacin for canine leishmaniosis

The purpose of this international, multicentric, and non-comparative field trial was to obtain complementary data on long-term clinical and parasitological follow-up of dogs treated with marbofloxacin for canine leishmaniosis (CanL). Seventy-four dogs with clinical signs of CanL and without severe renal failure were recruited in France, Spain and Italy, and 61 of them were part of the analysis. Each dog was treated with palatable tablets of marbofloxacin at 2 mg/kg once a day for 28 days. A clinical and parasitological follow-up was performed regularly up to 12 months. Efficacy was demonstrated in 42 dogs (68.9%), within 51 days (mean value), 10 of them (23.8%) being clinically cured after 3 months. A decrease of 61% in the sum of clinical scores was observed after 3 months. Haemato-biochemical parameters improved in general, supporting the observed clinical efficacy. Relapse was observed in 20/38 dogs (52.6%) approximately 5.5 months after treatment completion. The blood parasite load generally developed in conformity with the clinical outcome, even if exceptions were not rare. Lymph nodes remained positive by culture or PCR for a long time, even in dogs for which a good clinical response was observed. Despite the incomplete parasite clearance, as is also the case with other anti-leishmanial drugs, these results nevertheless confirm the relevance of marbofloxacin as a CanL treatment.

Vector-borne diseases in client-owned and stray cats from Madrid, Spain

The role of various vector-borne pathogens as a cause of disease in cats has not been clearly determined. The current study evaluated risk factors, clinical and laboratory abnormalities associated with Ehrlichia spp., Anaplasma spp., Neorickettsia spp., Leishmania spp., and Bartonella spp. infection or exposure in 680 client-owned and stray cats from Madrid, Spain. Our results indicate that a large portion (35.1%) of the cat population of Madrid, Spain, is exposed to at least one of the five vector-borne pathogens tested. We found seroreactivity to Bartonella henselae in 23.8%, to Ehrlichia canis in 9.9%, to Anaplasma phagocytophilum in 8.4%, to Leishmania infantum in 3.7%, and to Neorickettsia risticii in 1% of the feline study population. About 9.9% of cats had antibody reactivity to more than one agent. L. infantum DNA was amplified from four cats (0.6%), B. henselae DNA from one cat (0.15%), and B. clarridgeiae DNA from another cat (0.15%).

Occurrence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies in dogs with visceral leishmaniasis

Uninfected dogs and those naturally infected with Leishmania chagasi exhibiting different clinical forms of disease were evaluated for the presence of anti-Neospora caninum and anti-Toxoplasma gondii antibodies. Blood samples were collected from 110 mongrel dogs. Sera were tested using the indirect fluorescent antibody test (IFAT), and the animals with visceral leishmaniasis (VL) (n=60) were classified clinically. Out of the 110 sera investigated, 5 (4.5%) were positive for N. caninum (IFAT>50) and 36 (32.7%) for T. gondii (IFAT>16). Anti-L. chagasi antibody titers in asymptomatic dogs (n=10) were found to be significantly lower (P<0.05) than those in oligosymptomatic ones (n=22), which were in turn significantly lower (P<0.05) than those in symptomatic ones (n=28). No association between Leishmania and N. caninum infections was observed. Among dogs infected with L. chagasi, a tendency (P=0.053) towards an association between the infection with T. gondii and the appearance of VL symptoms was observed, suggesting that the clinical manifestation of VL in dogs may enhance their susceptibility to T. gondii. The possible influence of the immunosuppressive status of canine leishmaniasis in the different clinical forms of the disease is discussed.

LeishVet guidelines for the practical management of canine leishmaniosis

The LeishVet group has formed recommendations designed primarily to help the veterinary clinician in the management of canine leishmaniosis. The complexity of this zoonotic infection and the wide range of its clinical manifestations, from inapparent infection to severe disease, make the management of canine leishmaniosis challenging. The recommendations were constructed by combining a comprehensive review of evidence-based studies, extensive clinical experience and critical consensus opinion discussions. The guidelines presented here in a short version with graphical topic displays suggest standardized and rational approaches to the diagnosis, treatment, follow-up, control and prevention of canine leishmaniosis. A staging system that divides the disease into four stages is aimed at assisting the clinician in determining the appropriate therapy, forecasting prognosis, and implementing follow-up steps required for the management of the leishmaniosis patient.

Multicentric, controlled clinical study to evaluate effectiveness and safety of miltefosine and allopurinol for canine leishmaniosis

The aim of this trial was to evaluate the effectiveness and safety of miltefosine-allopurinol combination therapy vs. the current reference combination therapy, meglumine antimoniate-allopurinol, for canine leishmaniosis. Dogs included in the study exhibited clinical signs of the disease, were positive by PCR and serologically positive by immunofluorescent antibody test for leishmaniosis, and negative for ehrlichiosis. Dogs were divided into two groups: Group 1 was treated with 2 mg/kg of miltefosine orally once daily for 28 days and 10 mg/kg of allopurinol orally twice daily for 7 months; Group 2 was treated with 50 mg/kg of meglumine antimoniate sub-cutaneously twice daily for 28 days and allopurinol (same dose as Group 1) for 7 months. Dogs were examined according to the following schedule: pre-inclusion, Day 0 (D0), D14, D28, D84, D140 and D196. At each visit, blood, urine and bone marrow samples were collected. Parameters monitored included haematology, biochemistry, protein electrophoresis, serology, urinary protein/creatinine ratio and RTQ-PCR performed on bone marrow aspirates. A significant reduction in total clinical score and parasite load was observed in both groups over the 7-month study period (P < 0.0001), with no significant difference between groups (P = 0.3). The safety of miltefosine-allopurinol combination therapy was confirmed by lack of effect on renal and hepatic parameters and adverse reactions. Miltefosine, in combination with allopurinol, offers a safe, convenient and effective alternative treatment option for canine leishmaniosis compared to the reference therapy.

Dynamics and predictive potential of antibodies against insect-derived recombinant Leishmania infantum proteins during chemotherapy of naturally infected dogs

A predictive marker for the success treatment of canine leishmaniasis is required for the application of a more rational therapy protocol, which must improve the probability of cure and reduce Leishmania resistance to drugs. We investigated the dynamics and predictive value of antibodies against insect-derived recombinant L. infantum proteins rKMPII and rTRYP by using an enzyme-linked immunosorbent assay with retrospective serum samples from 36 dogs during treatment of canine leishmaniasis. In the entire group of dogs, concentrations of antibodies against rKMPII and rTRYP significantly decreased earlier than concentrations of antibodies against crude total Leishmania antigen (one versus six months), which suggested that the dynamics of antibodies against recombinant proteins may be useful for assessing clinical improvement after treatment. Interestingly, decreases in antibody concentrations against rKMPII occurred earlier in disease-free dogs than in dogs that remain clinically ill one year after beginning of treatment, which suggested that these antibodies may be useful for predicting disease-free survival one year after the beginning of therapy against canine leishmaniasis.

Comparative study on the short term efficacy and adverse effects of miltefosine and meglumine antimoniate in dogs with natural leishmaniosis

The aim of this study was to compare the efficacy and safety of oral administration of miltefosine (Milteforan) at 2 mg/kg/day for 28 days (Group M; n = 60) with a subcutaneous administration of meglumine antimoniate (Glucantime) at 50 mg/kg/12 h or at 100 mg/kg/day for 28 days (Group G; n = 59) in the treatment of canine leishmaniosis in dogs. Out of 119 dogs included in the study, 90 could be used for efficacy assessment and 112 for safety assessment. Treated dogs were followed up for 6 weeks, with re-checks every 14 days. The mean total clinical scores significantly decreased throughout the study in both treatment groups. The evolution of parasitological results after treatment (D42) shows a high percentage of dogs with negative bone marrow smears, 90% and 91.3% in groups M and G respectively, and did not significantly differ between groups (p = 0.8066). Out of the 112 dogs used for the safety assessment, only 26 dogs (23.2%) presented product-related adverse events concerning the gastrointestinal tract. These results showed that miltefosine at 2 mg/kg once daily can be safely used over a 28-day period in the treatment of canine leishmaniosis and provides both a steadily increasing improvement of the clinical signs and a good leishmanicidal efficacy.

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

Canine leishmaniosis (CanL) due to Leishmania infantum is a life threatening zoonotic disease with a wide distribution in four continents and importance also in non-endemic regions. The purpose of this report is to present a consensus of opinions on the diagnosis, treatment, prognosis and prevention of CanL in order to standardize the management of this infection. CanL is a disease in which infection does not equal clinical illness due to the high prevalence of subclinical infection among endemic canine populations. The most useful diagnostic approaches include serology by quantitative techniques and PCR. High antibody levels are associated with severe parasitism and disease and are diagnostic of clinical leishmaniosis. However, the presence of lower antibody levels is not necessarily indicative of disease and further work-up is necessary to confirm CanL by other diagnostic methods such as cytology, histopathology and PCR. We propose a system of four clinical stages, based on clinical signs, clinicopathological abnormalities and serological status. Suitable therapy and expected prognosis are presented for each of the stages. The combination of meglumine antimoniate and allopurinol constitutes the first line pharmaceutical protocol. However, although most dogs recover clinically after therapy, complete elimination of the parasite is usually not achieved and infected dogs may eventually relapse. Follow-up of treated dogs with blood counts, serum biochemistry, urinalysis, serology and PCR is essential for prevention of relapses. Protection against sand fly bites by topical insecticides is effective in reducing infection, and recent development of vaccines has indicated that prevention by vaccination is feasible.